Category Archives: Defining Life-Knowledge in Action

Tibet Consciousness – Quantum Physics – The Concept of Emptiness

Quantum Physics plays no role in understanding the reality of ‘Consciousness’ which has both Subjective and Objective basis to verify its existence. Quantum Physics encounters a problem in accounting for true nature of Light rays due to Wave vs Particle Dualism. To the same extent, Quantum Physics encounters a problem to account for the Subjective and the Objective Reality of Man’s existence in physical universe.

The condition called Existence can only be experienced by things which have structural and functional complexity. Particles can exist but cannot experience condition of their own existence unless and until they get incorporated into higher levels of structural and functional organization which is displayed by large molecules called polymers.

To explain this, I shall use the analogy of experiencing taste sensation imparted by Salt or Sodium Chloride. This sensation can never, ever be experienced from verifying the reality of its constituent Chemical Elements, Sodium, and Chlorine. Only a Chemical Compound called Salt is associated with Saltiness. Atoms of Sodium or Chlorine and their subatomic particles cannot account for such experience; and it serves no purpose by bringing Quantum Physics into discussion of the concept of Emptiness or Sunyata.

For there is a fundamental division or separation of animate and inanimate matter, the study of Quantum Physics belongs to the realm of Inanimate or Non-Living Matter. The Concept of Emptiness or “SUNYATA” shared by Acharya Nagarjuna has to be interpreted by Biology and not by using principles of Physical Science like Quantum Physics. It should not be of any surprise if Physics and Chemistry fail to account for Buddha’s ‘Enlightenment’ whether it is real or not. As such I have to state that Quantum Physics cannot verify or account for ‘Tibet Consciousness’, the reality of my Subjective and Objective Existence in Physical World.

MOTHERBOARD

Dalai Lama: Religion Without Quantum Physics Is an Incomplete Picture of Reality

Written by

DANIEL OBERHAUS
Contributor

 
November 17, 2015 // 08:45 AM EST

The Dalai Lama in New Delhi. Photo: Daniel Oberhaus

Ever since Copernicus published On the Revolutions of the Heavenly Spheres in 1543 to outline his heliocentric cosmology and thereby kick-start modern scientific inquiry, an uneasy truce has existed between science and religion. Although Copernicus wasn’t persecuted for his views by the dominant religious authorities (in fact,Pope Clement VII expressed great interest in Copernicus’s work, and the latter would end up dedicating his Revolutions to Pope Paul III), his intellectual heir Galileo was not so lucky when he faced down the Roman Inquisition in 1633, a testament to the fragility of this philosophical truce.

This either/or approach to the world, where one considers phenomena through either a scientific or religious lens, has colored scientific inquiry ever since Galileo was placed under house arrest for his heretical (but scientifically accurate) views. Its legacy can still be seen today in the vehement spats between religiously motivated climate deniers and the militaristic guardians of science known as the New Atheists.

Yet what if there was a different approach to the world, which didn’t require planting oneself firmly in either the science or religion camp? This was the question posed by Tenzin Gyatso, the 14th Dalai Lama, as he presided over a two day conference on quantum physics and Madhyamaka philosophy in New Delhi last week. And according to His Holiness, figuring out a way to reconcile scientific and religious philosophies may prove to be essential to the future of our species.

“I hope conferences like this can address two purposes: extending our knowledge and improving our view of reality so we can better tackle our disturbing emotions,” the Dalai Lama said, opening the conference on Thursday. “Early in my lifetime, science was employed to further material and economic development. Later in the 20th century, scientists began to see that peace of mind is important for physical health and well-being… As a result of combining warm-heartedness with intelligence, I hope we’ll be better equipped to contribute to humanity’s well-being.”

The Dalai Lama has never been a stranger to science, and throughout his tenure as Tibet’s leader in exile he has advocated for the collusion of science and Eastern philosophy (even Chairman Mao commended the Dalai Lama for his “scientific mind” directly after reminding His Holiness that “religion is poison”). This intersection of interests was manifest in the diversity of His audience, which was comprised of roughly 150 Tibetan bhikkhus, academics, and students who had piled into the conference center at Jawaharlal Nehru University to listen to the Dalai Lama and a panel of physicists and monastic scholars discuss the intersection of quantum physics and Madhyamaka Buddhist philosophy.

Selections from day 1 of the conference at JNU in New Delhi

As the Dalai Lama noted in his opening remarks at the Delhi conference, he was only alerted to the intersection of quantum science and Madhyamaka, one of the main schools of Buddhist thought, about 20 years ago after having a discussion with the late Indian nuclear physicist Raja Ramanna.

According to His Holiness, Ramanna had been reading the texts of Nagarjuna, and he was struck by just how much the ideas of this 2,000 year old Madhyamaka philosopher matched his own understanding of contemporary quantum physics.

The Dalai Lama weighs in on a discussion with Geshe Ngawang Sangye and Geshe Ngawang Samten about Cittramatrin’s view of emptiness. Photo: Daniel Oberhaus

There are generally considered to be two main philosophical schools in Buddhism, known as Mahayana and Theravada. Madhyamaka (“one who holds to the middle” or “the middle way”) belongs to the Mahayana school of thought and was developed by Nagarjuna in the second century. Although a staggering number of subtly different interpretations of Nagarjuna’s philosophies have emerged in commentaries on his work over the years, a core idea uniting them all is that of emptiness.

In Madhyamaka thought, all things are empty insofar as they lack any inherent essence or existence. This emptiness applies not just to people and things, but also to the analytic categories which are used to describe them. According to Nagarjuna, this emptiness is the product of the dependent origination of all things. In other words, all phenomena lack their own inherent existence because their very existence is dependent on the conditions that gave rise to them.

Yet for Nagarjuna, to say that nothing has any inherent existence is not the same as saying nothing exists; it is merely to posit that nothing has a “fixed and permanent nature. In order to clarify this, Nagarjuna posited two truths: a conventional truth and an ultimate truth. In so doing, he recognized that it is possible to simultaneously perceive things as actually existing out there in the world (the conventional truth) as well as recognizing that they lack any inherent existence (the ultimate truth). Holding these two seemingly contradictory positions is only possible by recognizing that ‘reality’ is an experiential phenomenon, not one that has an objective existence independent of our experience of it.

If you’re confused as to just what these ancient musings on the nature of reality have to do with contemporary quantum physics, you’re not alone.

One of the most glaring examples of the intersection of Madhyamaka and quantum physics is to be found in the principle of wave-particle duality, which holds that elementary particles (fermions and bosons) can exhibit the characteristics of both particles and waves, yet can be wholly reduced to neither.

“There seems no likelihood for forming a consistent description of the phenomena of light by a choice of only one of the two languages [particle or
wave],” Einstein once said while discussing the nature of light. “It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do.”

Like the quantum wave function, a probability matrix used by physicists to describe the state of a system at a given time, wave-particle duality points us to one of the central problems at the heart of quantum science: is there an objective, independent reality that is capable of being quantified, or are all such measurements subjective by virtue of the fact that they are always dependent on an observer to take them, thus merely reflecting the observer’s knowledge?

As Einstein and the physicists at the conference pointed out, these seemingly contradictory pictures of reality really only make sense if you take them both together: a middle way, much like the Madhyamaka philosophy.

On the one hand, the act of observation collapses the indeterminacy of the wave function into a definite reality: the cat in the box is either dead or alive, the beam of light is composed of either particles or waves, which is determined through the act of observation. Yet in each case, the underlying reality is that the cat and light don’t inherently have the characteristic of being alive or dead, or a wave or particles; rather, the underlying reality, the wave function, is indeterminate and can only be quantified as a set of probabilities.

Another aspect of quantum mechanics worth mentioning is the principle of entanglement. This principle, tackled by both Einstein and Schrödinger in 1935, occurs when pairs or groups of particles are generated in such a way that the state of any given particular particle cannot be determined. Rather, the observer must measure the state of the quantum system as a whole. With an entangled system, the state of each particle is correlated with the others; therefore, measuring single particle will influence its entangled partners (what Einstein called “spooky action at a distance”), collapsing the superimposed states of the entire quantum system.

His Holiness insisted on the need for both physics and philosophy in the quest to overcome ignorance and end suffering, which are arguably the main aims of Buddhism.

To borrow from the language of Nagarjuna’s philosophy, we might say that quantum physics possesses two truths: a conventional truth (the determinate reality brought about through observation) and the ultimate truth (an indeterminate reality expressed as probabilities). These truths of quantum mechanics mirror Madhyamaka philosophy insofar as the latter professes that things do actually exist out there in the world yet have no intrinsic, objective essence and only derive their essence from our subjective interpretations.

What is more, in both cases, the explanation for the two truths is remarkably similar in both quantum mechanics and Madhyamaka philosophy. In the case of quantum mechanics, entanglement is a quantifiable expression of Nagarjuna’s notion of dependent origination—the state of a particular quantum particle cannot be expressed because it is dependent on the quantum system as a whole, much like Nagarjuna’s phenomena which cannot have their own inherent essences because their existence is dependent on the conditions which brought them forth.

Such were the ideas expressed over the course of the two-day conference at JNU in New Delhi. For the most part, the explicit connections between Madhyamaka and quantum physics were left up to the interpretation of the audience. The physicists stuck to physics and the monastic scholars stuck to Buddhism.

Yet much like each concept itself, composed of seemingly contradictory ideas that nevertheless prove to be complimentary, His Holiness insisted on the need for both physics and philosophy in the quest to overcome ignorance and end suffering, which are arguably the main aims of Buddhism. Both science and religion have their own specific uses, but one without the other can lead to less than desirable results, to say nothing of painting an incomplete picture of reality.

“Right now when we see the sad things going on in the world, crying and prayer won’t achieve very much,” His Holiness said. “Although we may be inclined to pray to God or Buddha to help us solve such problems, they might reply that since we created these problems it is up to us to solve them. Most of these problems were created by human beings, so naturally they require human solutions. We need to take a secular approach to promulgating universal human values. The sense that our basic human nature is positive is a source of hope [that]… If we really make an attempt, we can change the world for the better.”

© 2015 Vice Media LLC.

The Rudi-Grant Connection nullifies the mental concept of the Buddhist Doctrine of Emptiness or Sunyavada

In 1965, while I was a student of Human Anatomy at Kurnool Medical College, I had the opportunity to know about Dr. J. C. B. Grant (1886-1973), the author of Grant’s Atlas of Anatomy. The 5th Edition of his Atlas was published in 1962 and was available in India in our Medical College Library.

Born in Loanhead (south of Edinburgh) in 1886, Grant studied medicine at the University of Edinburgh Medical School and graduated with an M.B., Ch.B. degree in 1908. While at Edinburgh, he worked under the renowned anatomist Daniel John Cunningham.

Grant became a decorated serviceman of the Royal Army Medical Corps during the First World War before moving to Canada. He established himself as an ‘anatomist extraordinary’ at the University of Toronto, publishing three textbooks that form the basis of Grant’s Anatomy. The textbooks are still used in anatomy classes today, and made unforgettable memories for those who found themselves in his classes nearly a century ago. One of Grant’s many accomplishments was establishing a division of histology within the department.

As a medical student, I used Grant’s Atlas of Anatomy, the seminal work of Scottish-born Dr. John Charles Boileau Grant, who would become the chair of Anatomy at the University of Toronto in 1930 and retired in 1965.

John Charles Boileau Grant (1886–1973)

The author of Grant’s Atlas of Anatomy (1943), Grant used to train thousands of medical students around the world. He came to University of Toronto’s Faculty of Medicine from University of Manitoba (and previously Edinburgh), and was Chair of the Department of Anatomy there from 1930 to 1965. Although he is best known for this famous atlas, his research and teaching also included biological anthropology, as evidenced by such work as Anthropometry of the Cree and Saulteaux Indians in Northeastern Manitoba (Archaeological Survey of Canada 1929). The human skeletal collection he formed, the “J.C.B. Grant Collection,” is still a core collection for human osteology in the Department of Anthropology at University of Toronto. He is also remembered in the Grant’s Museum at the Medical Sciences Building at the University of Toronto. This museum, with its displays of anatomical specimens, many of which were dissected by Grant himself, continues to be used in an active learning environment by more than 1000 students each year.

Students continue to use Grant’s textbooks today, and for the more artistic anatomist there’s even a Grant’s Anatomy Coloring Book, published in 2018.

At the University of Toronto, Dr.McMurrich, Chair of Anatomy was succeeded as chairman in 1930 by Dr. John Charles Boileau Grant. Dr. Grant wrote three text books, of which “An Atlas of Anatomy” (published in 1943) rapidly gained international prominence and is still, one of the most widely used anatomical atlases in the world. It is now known as “Grant’s Atlas of Anatomy” and is in its tenth edition. The atlas was based on a series of elegant dissections done either by Grant or by others under his supervision. Many of these dissections are currently housed in Grant’s Museum at the University of Toronto. 

The Rudi-Grant Connection is about knowing the man, the building blocks and the structural units and organization of the human body. To defend human existence, the Rudi-Grant Connection lays the emphasis on knowing the person who is at risk apart from knowing the agent posing the risk.

The Identity of Multicellular Human Organism:

Daniel John Cunningham was born on 15 April 1850 in Scotland. After his initial schooling at his home town, Crieff, he took up the study of medicine at the University of Edinburgh and passed with honours. He is best known for the excellent series of dissection manuals, namely Cunningham’s Dissection Manuals. Cunningham’s Manual of Practical Anatomy has provided me the learning tools to know and understand Man’s External and Internal Reality and its Identity described by Cells, Tissues, Organs,and Organ Systems.

I learned about the human body while dissecting the body in a systematic manner. The Manual of Practical Anatomy which guides us through this entire process was published in England. The author Dr. Daniel John Cunningham prepared the Manual while dissecting cadavers of British or Irish citizens. He had never encountered cadavers of Indian citizens. At Kurnool Medical College, Kurnool, Andhra Pradesh, India, where I was a student, the Department of Anatomy obtains dead bodies from  Government General Hospital Kurnool and most of the deceased are the poor, illiterate, and uneducated people of that region. None of the deceased had the chance to know this man called Cunningham and Cunningham had no knowledge about the existence of these people who arrive on our dissection tables. But, as the dissection of the human body proceeds, inch, by inch, we recognize the anatomical parts as described by Cunningham. The manual also lists some anatomical variations and we very often exchange information between various dissection tables and recognize the variations mentioned. The dissections also involve slicing the organs and studying them, both macroscopically, and microscopically. We did not miss any part of the human body. So what is the Identity of this Human person or Human subject? How does the living Human organism maintain its Identity and Individuality? Apart from the Cultural Traditions of India, several Schools of Religious Thought claim that the Human Individual and its Identity is represented by Human Soul. Where does this soul exist in the human body? What is the location if the soul is present in the living person? Does man have a soul? How does the human organism acquires Knowledge about its own structures and the functions they perform?

There is Joy in Emptiness

The Dalai Lama is believed to be a manifestation of Avalokiteshvara or Chenrezig, the Bodhisattva of Compassion and the patron saint of Tibet. Bodhisattvas are enlightened beings who have postponed their own nirvana and chosen to take rebirth in order to serve humanity.

Tenzin Gyatso, the 14th Dalai Lama, was born in 1935 in a small hamlet in northeastern Tibet. At the age of 2, the child who was named Lhamo Dhondup, was recognized as the reincarnation of the 13th Dalai Lama, Thubten Gyatso.

The 14th Dalai Lama visited Ann Arbor for a series of talks in Crisler Arena at the University of Michigan on Saturday and Sunday April 19 and 20, 2008. His presentation of the University of Michigan’s annual Peter M. Wege Lecture on Sustainability is in celebration of Earth Day. The Wege Lecture is sponsored by the Center for Sustainable Systems at the School of Natural Resources and Environment. He also presented a two-day program with two sessions on April 19 and 20. The focus of the session was on “Engaging Wisdom and Compassion.” The teaching is based on Acharya Nagarjuna’s Commentary on Ultimate Compassion and Je Tsong Khapa’s “In Praise of Dependent Origination.”

The Nature of Existence – The concept of Sunyata (Emptiness or Nothingness):

Acharya Nagarjuna (A.D. 150- A.D. 250) born into a Brahmin family had lived in the present State of Andhra Pradesh, India. The emptying of the mind and the attainment of an undifferentiated unity is the theme of the ‘SUNYATA’ doctrine developed by Acharya Nagarjuna. ‘Sunyata’ is described as a state of “Pure Consciousness” in which the mind has been emptied of all particular objects and images. The emptied mind reflects or manifests the undifferentiated reality in which the world appears without distinctions and multiplicity. Nagarjuna was critical of both Buddhist and Hindu views on existence. According to Nagarjuna, the individual person is empty and lacks an eternal self. He extended the concept of ‘Sunyata’ to cover all concepts and all entities. Nagarjuna’s philosophy is also called ‘Madhyamika’ because it claims to tread the middle path. As per Nagarjuna, the nature of existence is relational. There is no eternal reality behind changing forms of existence. There is no soul, no thing, no concept independent of its context, all things are empty of an absolute reality and exist only in relation to conditions. The knowledge, perceiving the emptiness of all things and hence becoming detached from them, would help us to practice “nonattachment” in our engagement with people. If “Emptiness” is the highest Wisdom, it would help us to develop a sense of detachment and enable us to act with Compassion.

Engaging Wisdom and Compassion

“At the root of all our suffering lies a form of ignorance, a form of unknowing”. The origin of suffering is attachment. “Self-grasping (or self-focus) gives rise to suffering. It is the root of all afflictions.” “Self-grasping” leads to attachment to impermanent things or thoughts which gives rise to suffering. Emptiness is created by casting aside the attachment to everyday things and worries. “The ultimate awakening mind is the Wisdom that directly realizes emptiness.”

H.H. Dalai Lama advised practicing loving kindness to eliminate the afflictions caused by attachment. The ultimate goal, he said is “cultivating the Wisdom of no self”, a sense of grand emptiness that leaves behind everyday pollutants that can take both physical or emotional form.

The Rudi-Grant Connection examines the Buddhist Doctrine of Causality or Dependent Origination

Dependent Origination (pratītyasamutpadā/ paṭiccasmuppāda) is the Buddhist doctrine of causality. This system of thought maintains that everything has been caused into existence. Nothing has been created ex nihilo.

In my analysis, the Law of Dependent Origination or the Doctrine of Causality must deal with the dependent or conditioned nature of all existence. At a fundamental level, living things exist on the surface of fast spinning Earth on account of ignorance or the lack of sensory awareness of the realities of Earth’s motions. The Fundamental Force called Gravitation imposes this state of ignorance giving the man an opportunity to formulate mental concepts or perspectives such as the Law of Dependent Origination and the Law of Emptiness or Sunyavada shared by Buddhist thinker Acharya Nagarjuna.

The man’s wisdom is strictly dependent upon the ignorance imposed by the Fundamental Force Gravitation. To that extent, it can be asserted that there is no Nirvana without the blessings of ignorance imposed by the Fundamental Force to facilitate the existence of the entity seeking Nirvana or Wisdom or Liberation from Ignorance.

According the Madhyamika, or Middle Way Buddhist philosophy, ordinary beings misperceive all objects of perception in a fundamental way. The misperception is caused by the psychological tendency to grasp at all objects of perception as if they really existed as independent entities. This is to say that ordinary beings believe that such objects exist ‘out there’ as they appear to perception. Another way to frame this is to say that objects of perception are thought to have svabhava or ‘inherent existence’—’own being’ or ‘own power’—which is to say that they are perceived and thought to exist ‘from their own side’ exactly as they appear. In this light, sunyata is the concept that all objects are Empty of svabhava, they are Empty of ‘inherent existence’. Therefore, emptiness refers to Emptiness of inherent existence. The Buddhist concept of Emptiness is a very subtle concept. In the Mūlamadhamaka kārikas, Śūnyatā is qualified as “…void, unreal, and non-existent.” Rawson states that: “one potent metaphor for the Void, often used in Tibetan art, is the sky. As the sky is the emptiness that offers clouds to our perception, so the Void is the ‘space’ in which objects appear to us in response to our attachments and longings.”

However, ‘Emptiness’ is not the same as ‘Nothingness’, a mistake which is often made. Emptiness does not negate the play of appearances which manifest to a multitude of sentient beings, it asserts that they are insubstantial.

The theme of śūnyatā emerged from the Buddhist doctrines of Anatta (nonexistence of the self) and Pratitya-samutpada (Interdependent Arising or the Law of Dependent Origination). The Suñña Sutta, part of the Pali Canon, relates that monk Ananda, the attendant to Gautama Buddha asked, “It is said that the world is empty, the world is empty, lord. In what respect is it said that the world is empty?” The Buddha replied, “Insofar as it is empty of a self or of anything pertaining to a self: Thus it is said, Ananda, that the world is empty.”

The Madhyamika School of Thought on Human Essence and Human Identity

The Doctrine of Emptiness or Sunyavada represents that all things are, in very broad strokes, empty of inherent existence and Nature or Svabhava because of the Law of Dependent Origination. Madhyamika is based on the text called Mulamadhyamaka Karika which describe the Middle Way, the path between self-indulgence and self-denial. The Law of Dependent Origination considers all phenomenal existence is characterized by 1.Impermanence or Transient, 2. Unsatisfactory (not self-sufficient), and 3. Lack inherent existence.

Svabhava (Sanskrit: स्वभाव, svabhāva; Pali: सभाव, sabhāva; Chinese: 自性; pinyin: zìxìng; Tibetan: རང་བཞིན, Wylie: rang-bzhin) literally means “own-being” or “own-becoming”. It is the intrinsic nature, essential nature or essence of beings. The three dimensions of Svabhava are, 1. Essence, the essential property of that object. It denotes a property of that thing by which we can identify that object. This property is fundamental to the being of the object; it is the property without which that object ceases to be that very thing. 2. Absolute Svabhava, a property which is regarded as the true ultimate nature of things, and 3. Substance, which is not dependent on anything else. An object which has Substance or Svabhava is fundamental, irreducible and does not depend for its existence on being constructed mentally or linguistically.

In my analysis, the Essence of Life is the biological characteristic called Consciousness, the essential property of a Living Thing is the Cognitive ability called awareness of the fact or reality of its own condition called Existence. The true, ultimate nature of all Living Things or Absolute Svabhava is the Spiritual Nature of the Living, Corporeal Matter that essentially constitutes the Life of the Living Thing. This Living Matter is constituted by Substance described as the Chemical Elements, the fundamental building blocks of all that lives. The Chemical Elements are Irreducible, Immutable, Imperishable, Immortal, Eternal and even Unborn. Because of this fundamental attributes of the Chemical Elements, Life is existing on planet Earth which experienced numerous events called Extinction which wiped out the existence of some Life Forms while others continue to reproduce as if Life is Imperishable.

The Emotional Experience of Atman as Ananda, Pure Joy, or Pure Bliss:

Atman is a Sanskrit term which describes the spiritual life principle found in all living things, especially regarded as inherent in the real or true Self of the human individual. For all purposes of conversation, Indians use the term Atman to speak about a person’s Soul which is distinct from the Body, and Mind of the person.

Indian thinkers speak extensively describing in great detail the concept of the Atman. Apart from characteristics such as imperishable, indestructible, and immutable, the Atman is viewed as ‘Light’ that dispels the darkness called Ignorance. Indian thinkers adamantly refuse to describe the structural and the functional attributes of the Atman making it difficult to define the term Atman using the information provided by Human Anatomy and Human Physiology. However, there is general agreement among the Indian thinkers about the nature of the Atman. There are four recurrent themes in the discourse about the Atman. These are, 1. The association of the Atman as the ultimate source of Great Knowledge to overcome the veiling effects of Maya or the Grand Illusion, 2. The experience of the Atman is the prerequisite to find Peace, Harmony, and Tranquility in the conditioned nature of the human existence characterized by pain, and suffering, 3. The Atman is manifested as the emotional experience of Ananda, Pure Joy, Perfect Happiness, and Pure Bliss Consciousness, and 4. The Atman is the Fourth Condition, the Fourth State, or the Fourth Quarter of Consciousness which is Pure for it is devoid of all contents, has no functional attributes, and most importantly, cannot be described.

In my analysis, the concept of the Atman, or the Soul is useful and when validated, the concept will provide the tools for practical application to promote human well-being. To that extent, I invite my readers to study the Functional Anatomy of the Reticular Formation of the Brainstem to interpret it as the structural and functional organization called the Soul. Please review the concept of ‘Emotional Brainstem’ to understand the anatomical and physiological basis of the human emotional experience called Ananda, Pure Joy, Perfect Happiness, and Pure Bliss.

The Functional Anatomy of the Reticular Formation

Frontiers in Neuroanatomy., 29 May 2019 | https://doi.org/10.3389/fnana.2019.00055

Ugo Faraguna¹, Michela Ferrucci¹, Filippo S. Giorgi^1,2 and Francesco Fornai^1,3*

• ¹Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
• ²Section of Neurology, Department of Clinical and Experimental Medicine, Pisa University Hospital, University of Pisa, Pisa, Italy
• ³I.R.C.C.S. I.N.M. Neuromed, Pozzilli, Italy

https://www.frontiersin.org/articles/10.3389/fnana.2019.00055/full

In 1949 Moruzzi and Magoun first described the activating role of a wide area within the brainstem. They defined some physiological features of what they called the ascending reticular activating system, setting the scene for the discovery of the multifaceted roles of the reticular formation. In particular, beyond the original effects on behavioral arousal, a variety of effects is generated in the brain by the activation of these discrete nuclei population of the brainstem. In this way, physiological conditions such as the sleep-waking cycle, the level of arousal and attention, the drive for novelty seeking behaviors, the mood states and other brain activities were shown to depend on the ascending reticular formation. Meanwhile, it became more and more evident that an equal amount of processes is controlled by its descending pathways. More specifically, the reticular formation plays a key role in the modulation of posture, extrapyramidal movements, cardiovascular activity, breathing and a variety of harmonic variations in the sympathetic and parasympathetic systems which accompanies motor activity. The descending fibers of the reticular formation, as well as the ascending system, are critical in gating the sensory inputs and play a critical role in pain modulation, mainly by acting on the posterior horn of the spinal cord.

All these activities are impaired when a damage affects critical nuclei of the reticular formation. This may occur either suddenly, due to vascular disorders, or progressively, as it happens in neurodegenerative conditions. Interestingly, in this latter case the spreading of neurodegeneration has been attributed to the rich collaterals connecting various reticular nuclei, which are more and more involved in later stages of many neurodegenerative disorders.

During the last decades the anatomical counterparts of the reticular formation have been further investigated, even though a comprehensive description is still missing. Thus, the present research topic is designed to welcome contributions both defining the updated anatomy of the reticular formation and its physiological functions (sleep-wake cycle, EEG synchronization, postural control, etc.) as well as its involvement in a wide array of neuropsychiatric disorders (Parkinson and extrapyramidal disorders, epilepsy, sleep disorders, ADHD, degenerative dementia, neurovascular disorders, etc.).

The brainstem reticular formation (RF) represents the archaic core of those pathways connecting the spinal cord and the encephalon. It subserves autonomic, motor, sensory, behavioral, cognitive, and mood-related functions. Its activity extensively modulates cortical excitability, both in physiological conditions (i.e., sleep-wake cycle and arousal) and in disease (i.e., epilepsies). Such a wide variety of effects arises from the long course and profuse axonal branching of isodendritic reticular neurons, which allows the neuronal message to travel toward the entire cerebral cortex and downstream to the spinal cord. On the other hand, the isodendritic architecture featuring a monoplanar branching allows most RF neurons to cover roughly half of the brainstem and to be impinged by ascending and descending pathways. In parallel, such a generalized influence on CNS activity occurs in combination with highly focused tasks, such as those involved in the coordination of gaze.

The Journal Frontiers in Neuroanatomy offers an updated view to define the anatomical correlates of the multiple and interconnected roles played by the brainstem reticular formation in health and disease.

In fact, the integration of multiple activities within the brainstem reticular circuitries may explain why alterations of each of these domains may affect the emotional sphere, paving the way to the concept of emotional brainstem (Venkatraman et al.). 

The Brainstem in Emotion: A Review

Anand Venkatraman¹, Brian L. Edlow² and Mary Helen Immordino-Yang^3,4,5*

• 1*. Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
• 2*.Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
• 3*.Brain and Creativity Institute, University of Southern California, Los Angeles, CA, USA
• 4*.Rossier School of Education, University of Southern California, Los Angeles, CA, USA
• 5*.Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA

Emotions depend upon the integrated activity of neural networks that modulate arousal, autonomic function, motor control, and somatosensation. Brainstem nodes play critical roles in each of these networks, but prior studies of the neuroanatomic basis of emotion, particularly in the human neuropsychological literature, have mostly focused on the contributions of cortical rather than subcortical structures. Given the size and complexity of brainstem circuits, elucidating their structural and functional properties involves technical challenges. However, recent advances in neuroimaging have begun to accelerate research into the brainstem’s role in emotion. In this review, we provide a conceptual framework for neuroscience, psychology and behavioral science researchers to study brainstem involvement in human emotions. The “emotional brainstem” is comprised of three major networks – Ascending, Descending and Modulatory. The Ascending network is composed chiefly of the spinothalamic tracts and their projections to brainstem nuclei, which transmit sensory information from the body to rostral structures. The Descending motor network is subdivided into medial projections from the reticular formation that modulate the gain of inputs impacting emotional salience, and lateral projections from the periaqueductal gray, hypothalamus and amygdala that activate characteristic emotional behaviors. Finally, the brainstem is home to a group of modulatory neurotransmitter pathways, such as those arising from the raphe nuclei (serotonergic), ventral tegmental area (dopaminergic) and locus coeruleus (noradrenergic), which form a Modulatory network that coordinates interactions between the Ascending and Descending networks. Integration of signaling within these three networks occurs at all levels of the brainstem, with progressively more complex forms of integration occurring in the hypothalamus and thalamus. These intermediary structures, in turn, provide input for the most complex integrations, which occur in the frontal, insular, cingulate and other regions of the cerebral cortex. Phylogenetically older brainstem networks inform the functioning of evolutionarily newer rostral regions, which in turn regulate and modulate the older structures. Via these bidirectional interactions, the human brainstem contributes to the evaluation of sensory information and triggers fixed-action pattern responses that together constitute the finely differentiated spectrum of possible emotions.

Introduction

Emotions are mental and bodily responses that are deployed automatically when an organism recognizes that a situation warrants such a reaction (Damasio, 1994). Due to humans’ intellectual capacities, human emotional reactions are not necessarily triggered by immediate (real) physical or social circumstances, but can also be precipitated by inferences, memories, beliefs or imaginings (Immordino-Yang, 2010). Although human emotions can involve complex cognitive deliberations (Immordino-Yang, 2010, 2015) their activating power fundamentally depends upon the modulation of arousal, motor control and somatosensation. Emotions are therefore regulated by a broad range of subcortical and cortical structures, with a critical role being played by subcortical nuclei in the pontine and midbrain tegmentum (Nauta, 1958; Parvizi and Damasio, 2001), as well as by autonomic and cardiorespiratory nuclei in the medulla (Edlow et al., 2016). Currently, most investigations of human emotion, especially in the neuropsychology literature, have focused on contribution of cortical rather than subcortical structures to human emotion, with a few notable exceptions (Buhle et al., 2013). Given that the brainstem plays a critical role in regulating and organizing emotion-related processing, the aim of this review is to provide a conceptual framework for affective researchers to study the brainstem’s role in human emotion.

Organization of Brain Regions Involved in Emotion

For the purpose of studying its role in emotion, the brainstem can be conceptualized as being composed of Ascending, Descending, and Modulatory networks. The gray matter nodes and white matter connections within each of these networks are summarized in Table 1, while Figure 1 provides a schematic overview of the networks’ brainstem nodes. 

Integration of signaling within these three networks occurs at all levels of the brainstem, while progressively more complex levels of integration occur in the thalamus, hypothalamus and cerebral cortex. This encephalization and hierarchical organization allows phylogenetically older pathways in the brainstem, which evaluate sensory information and give rise to fixed-action pattern responses, to be regulated by evolutionarily newer rostral regions (Tucker et al., 2000). It is important to emphasize here that this conceptual model is based upon limited information about the functioning of the human brainstem, and will likely require revision and further differentiation as new evidence arises (Seeley et al., 2007; Coenen et al., 2011; Hermans et al., 2014).

Ascending Network

Damasio’s (1996) Somatic Markers Hypothesis suggests that emotion processing incorporates somatosensory and visceral feedback from the periphery, either directly or through intervening sensory representations in caudal structures. Multiple representations of the body state in the brainstem and in the insular cortices are believed to enable simulation of future actions and sensations to guide decision making, as well as to contribute to empathy and theory of mind in humans. Self-awareness may arise from successive temporal representations of the body with increasing levels of detail (Craig, 2003a). Even the simple sensory representations of the body in the brainstem nuclei can alter affective experience, as demonstrated by studies showing that subtle modulation of a subject’s facial expressions can change self-reported affect (Harrison et al., 2010).

Interoception, which is the sense of the internal condition of the body, and emotional feeling, may share a common route through the brainstem to the anterior insular cortex (Craig, 2003a; Drake et al., 2010). The interoceptive system, represented in the cortex by the insula and adjacent regions of the frontal operculum, is particularly important for the internal simulation of observed emotion in humans (Preston et al., 2007; Pineda and Hecht, 2009) and for the experience of complex social emotions (Immordino-Yang et al., 2009, 2014, 2016). The other body map in the somatosensory cortex, which is built from dorsal column inputs and segments of the anterolateral pathway, contributes to affective understanding by simulation of facial expressions (Pineda and Hecht, 2009), analogous to the proposed function of primate mirror neurons in perception/action coupling (Rizzolatti and Craighero, 2004).

The neuroanatomic basis for the Ascending sensory network and the mechanisms by which it modulates human emotion remain poorly understood. Although the structural and functional properties of these ascending pathways have been studied extensively in rodents and non-human primates using premortem tract-tracing and invasive electrophysiological studies, these techniques cannot be applied in humans. Recent studies using diffusion tractography and resting-state functional connectivity techniques in humans have found that forebrain regions involved in regulation of mood and affect are interconnected not only with mesencephalic and pontine arousal nuclei, but also with medullary cardiorespiratory and autonomic nuclei through the medial and lateral forebrain bundles (Vertes, 2004; Edlow et al., 2016). Figure 2 provides an overview of the main structures in the Ascending network.

It is well established that sensations from the human body are carried in two major ascending pathways in the brainstem – the dorsal columns of the spinal cord, which continue as the medial lemnisci, carry discriminatory sensation, deep touch and proprioception; the anterolateral pathway, composed of the spinothalamic tracts, carries nociceptive and temperature-related signals (Nogradi et al., 2000-2013).

The Anterolateral Pathway

The nociceptive fibers in the anterolateral pathway give off collaterals at every level that converge with projections from visceral sensory neurons in the brainstem, thereby ensuring close coordination of pain and autonomic processing (Craig, 2003b). The pathway begins with small-diameter fibers that transmit signals of fast and slow pain, chemical changes, temperature, metabolic state of muscles, itch, and sensual or light touch to lamina I of the spinal cord, from where ascending projections arise. In the caudal brainstem, these projections target the nucleus of the tractus solitarius in the medulla (Figure 2), which is also innervated by visceral and taste sensations through the vagus, glossopharyngeal and facial nerves.

The Parabrachial Complex

Tract-tracing studies in rodent models have revealed that ascending projections from the nucleus of the tractus solitarius travel to the parabrachial complex (Figures 1, 2) in the upper pons (Herbert et al., 1990), which also receives direct projections from lamina I neurons (Craig, 2003b), in addition to other inputs such as balance (Balaban, 2002). Rat studies suggest that the parabrachial complex integrates multiple types of converging sensory inputs and in turn projects to rostral regions such as the thalamus, hypothalamus, basal forebrain and amygdala, and may play an important role in arousal (Fuller et al., 2011; Edlow et al., 2012). The upper brainstem, where the parabrachial complex lies, is therefore the most caudal structure where a topographically complete map of the body can be assembled that includes all manner of interoceptive information (Damasio and Carvalho, 2013). There is also ongoing investigation of the role played by the superior colliculus, a structure in the dorsal aspect of the upper brainstem, in sensory and emotional processing in humans, but the available evidence is sparse (Celeghin et al., 2015).

The Thalamus

Immediately rostral to the upper brainstem is the thalamus, and the spinothalamic tracts, as their name indicates, end in the thalamus. A subset of thalamic nuclei function as relay structures between the emotional brainstem and rostral brain structures. The ventral posteromedial nuclei of the thalamus, which receive projections from the parabrachial complex and other parts of the anterolateral pathway, project to the insular cortex, particularly the mid/posterior dorsal part. Craig and colleagues suggested that the posterior part of the ventral medial nucleus of the thalamus, or VMPo, was uniquely involved in pain processing, particularly in primates (Craig, 2003a), but other authors had questioned the separate existence of this nucleus (Willis et al., 2002).

The intralaminar nuclei of the thalamus receive non-topographical sensory input from the spinal cord, which are in turn projected to the orbitofrontal and anterior cingulate cortices. The intralaminar nuclei are involved in orienting and attention, while arousal and visceral sensation are subserved by the midline nuclei (Morgane et al., 2005). In primates a direct pathway from lamina I to the anterior cingulate through the medial dorsal nucleus is also present (Craig, 2003a), and it has been suggested that these pathways may mediate the affective aspect of pain (Tucker et al., 2005). Indeed, the mediodorsal nucleus progressively increases in cytoarchitectonic complexity in higher animals, and is also known to project to the frontal and prefrontal cortices (Morgane et al., 2005). Thus, the thalamus contains multiple structures that appear to play a role in transmitting the signals essential for emotion processing from the brainstem to the forebrain.

Summary statement: Representations of the body of varying degrees of complexity that exist at multiple levels in the Ascending network, including the nucleus of the tractus solitarius and the parabrachial nucleus, are believed to be give rise to the “feeling” of an emotion.

Descending Network

The chief descending pathway in the human brainstem is composed of large, myelinated axons of the corticospinal tracts, transmitting motor impulses to the anterior horn cells of the spinal cord and thereafter to skeletal musculature (Nogradi and Gerta, 2000–2013). In addition, the midbrain and pontine tegmentum, as well as the medulla, contain several structures that serve as the output centers for motor and autonomic regulatory systems, which in turn regulate the bodily manifestations of the “emotion proper” (Damasio, 1994). Holstege (2009) considered the interconnected network of descending fibers and effector regions in the brainstem an “emotional motor system,” distinct from the corticospinal somatic motor pathway, each of which they divided into lateral and medial parts [Figure 3, adapted from (Holstege, 2016)].

The brainstem, as noted previously, contains a hierarchy of circuits linking ascending sensory neurons and descending effector neurons. Evidence from rat and cat studies indicates that the lower-level circuits enable quick stereotypical responses to stimuli, while the higher-level involvement of rostral centers allows for complex motor and autonomic activity and action specificity (Bandler et al., 2000; Gauriau and Bernard, 2002). This close relationship between sensory and effector networks in emotion processing is best illustrated by the close overlap seen between sites involved in emotional vocalization and pain processing in animals. Both physical and psychological pain (caused by separation from caregivers, for example) can produce distress vocalizations in animals, with the caudal brainstem containing multiple regions that control the respiratory and phonetic changes of vocalization (Tucker et al., 2005) and cardiorespiratory function during emotion (Lovick, 1993; Rainville et al., 2006; Edlow et al., 2016). The rostral nuclei are able to modulate the activity of caudal nuclei that control cardiorespiratory control and vocalization in a coordinated manner that makes the resultant action more complex and nuanced.

Lateral Part of the Emotional Motor System

The emotional motor system’s lateral part consists of projections primarily from the periaqueductal gray, as well as more rostral structures such as the amygdala and hypothalamus, to the lateral tegmentum in the caudal pons and medulla (Figures 3, 4). This lateral part of the emotional motor system is involved in specific motor actions invoked in emotions, as well as in the control of heart rate, respiration, vocalization, and mating behavior (Holstege, 2009). Studies in multiple animal models as well as in humans have revealed that the periaqueductal gray (Figures 1, 4) is a major site of integration of affective behavior and autonomic output, with strong connections to other brainstem structures (Behbehani, 1995).

Several fixed patterns of behavior, particularly those related to responding to external threats, with accompanying autonomic changes, are organized in the different columns of the periaqueductal gray in rats (Brandao et al., 2008). The lateral/dorsolateral column receives well-localized nociceptive input (superficial ‘fast’ pain, as might be expected from bites or scratches) and is believed to organize fight-or-flight reactions. When stimulated this column produces emotional vocalization, confrontation, aggression and sympathetic activation, shown by increased blood pressure, heart rate, and respiration. Many of these responses are mediated by descending projections to the paragigantocellularis lateralis nucleus in the rostral ventrolateral medulla (respiratory rhythm), the dorsal motor nucleus of the vagus (heart rate and rhythm), and caudal raphe (cardiorespiratory integration; Lovick, 1993; Edlow et al., 2016). Within this dorsolateral/lateral column itself, there are two parts. The rostral part is responsible for power/dominance (producing a “fight” response), while the caudal part invokes fear (producing a “flight” response) with blood flow to the limbs (Sewards and Sewards, 2002).

The ventrolateral column of the periaqueductal gray receives poorly localized “slow, burning” somatic and visceral pain signals, and on stimulation produces passive coping, long-term sick behavior, freezing with hyporeactivity and an inhibition of sympathetic outflow (Parvizi and Damasio, 2001; Craig, 2003b; Brandao et al., 2005; Benarroch, 2006). In this way, it is likely involved in background emotions such as those that contribute to mood. Rat studies have further revealed that lesions of the dorsolateral periaqueductal gray reduce innate defensive behaviors, while lesions of the caudal ventrolateral part reduce conditioned freezing and increase locomotor activity (Brandao et al., 2005). When the predator is far away, the ventromedial prefrontal cortex and the hippocampus, through the amygdala, activate midbrain structures centered around the ventrolateral periaqueductal gray, which results in freezing (Tucker et al., 2000). In the “circa-strike” stage when the predator is imminent, forebrain pathways are silenced, and the dorsolateral periaqueductal gray is activated, resulting in fight-or-flight reactions.

The Periaqueductal Gray in Human Emotion

Though the reactions detailed above are almost certainly incorporated into human emotion, the precise mechanisms have not been elucidated. One study involving high-resolution MRI of the human periaqueductal gray indicated that this structure has discrete functional subregions that parallel the divisions seen in animals – aversive stimuli caused activation in the ventrolateral regions of the caudal periaqueductal gray and in the lateral/dorsomedial regions of the rostral periaqueductal gray (Satpute et al., 2013). The periaqueductal gray threat response system is likely co-opted in the pathophysiology of conditions such as panic disorder and generalized anxiety disorder. Blood flow analysis suggests that the inhibitory influence of the cortex over the fight-or-flight mechanisms in the periaqueductal gray is reduced in panic disorder (Del-Ben and Graeff, 2009). Functional MRI has also revealed activation of the human periaqueductal gray in complex emotions such as frustration (Yu et al., 2014), admiration and compassion (Immordino-Yang et al., 2009), in addition to more immediate threat responses (Lindner et al., 2015).

Medial Part of the Emotional Motor System

The medial part of the emotional motor system (Figures 3, 4) consists of descending projections from the reticular formation that are involved in level-setting and modulatory functions (Holstege, 2009). Once again, the vast majority of the research on this subject has been in animals. The caudal third of the locus coeruleus (Sasaki et al., 2008) and the caudal raphe nuclei both send projections downward to the spinal cord, as depicted in Figure 4, and are responsible for descending pain modulation (Renn and Dorsey, 2005). The effect of norepinephrine from the locus coeruleus is mostly antinociceptive, while serotonin from the raphe nuclei can have varying effects depending upon the type of receptor activated (Benarroch, 2008). In rats, it has been shown that the midbrain tectum and the dorsal/lateral periaqueductal gray indirectly produce the analgesia that occurs in fear (Coimbra et al., 2006), through a primarily non-opioid mechanism involving GABAergic and serotonergic neurons (as opposed to the ventrolateral periaqueductal gray that produces a long-lasting opioid mediated analgesia; Gauriau and Bernard, 2002). It is likely that this system of fear suppressing the pain system is still present in humans, allowing us to act and move rapidly in situations of threat (Mobbs et al., 2007).

In addition to nociceptive modifications, the medial part of the emotional motor system is also involved in level-setting for arousal levels and muscle function – studies on rodents and monkeys indicate that this is accomplished through norepinephrine secretion from the locus coeruleus (Aston-Jones and Cohen, 2005; Lang and Davis, 2006) and cholinergic projections from the pedunculopontine tegmental nucleus in the upper pons (Bechara and van der Kooy, 1989; Homs-Ormo et al., 2003). Further detail regarding these important structures is provided in the section below on the Modulatory network.

Summary statement: The Descending network, otherwise referred to here as the emotional motor system, has a lateral part that triggers patterned emotional behaviors, while the medial part is responsible for level-setting in sensory and arousal systems that might be important in emotionally charged situations.

Modulatory Neurotransmitter Network – Valence, Arousal, and Reward

Since a major characteristic of an adaptive emotional behavioral response is flexibility, a network that modulates the autonomic, motor, affective and memory changes brought about by different stimuli is needed. The chief upper brainstem structures involved in this modulation are the neurotransmitter pathways arising from the upper raphe nuclei (serotonergic), the ventral tegmental area-substantia nigra pars compacta complex (dopaminergic), and the upper locus coeruleus (noradrenergic), which project widely throughout the hypothalamus, cortex and other parts of the forebrain. In addition, the laterodorsal and the pedunculopontine tegmental nuclei are sources of cholinergic fibers, which stimulate cortical activation through the thalamus. These structures are depicted in Figures 1, 5. Ascending projections from the brainstem to subcortical and cortical structures communicate the states of brainstem structures to more rostral regions of the nervous system, where these states contribute to affective experience. Since these pathways are involved in arousal and in the maintenance of consciousness (Jones, 2003), they are sometimes called the Ascending Reticular Activating System or Ascending Arousal Network (Moruzzi and Magoun, 1949; Edlow et al., 2012). The following sections on the various pathways that comprise the Modulatory network are in large part descriptions of the Ascending Reticular Activating System, albeit with a focus on how these relate to emotion.

The Valence-Arousal Model of Emotion and Its Critiques

The modulation of affective states by these upper brainstem-based pathways has been expressed through the two domains of valence and arousal. According to the circumplex model of emotions, each basic emotion is postulated to be a combination of these two domains, in differing degrees (Russell, 1980; Zald, 2003; Posner et al., 2009). In humans, valence correlates with pleasantness ratings, heart rate, and facial muscle activity, while arousal correlates with skin conductance, interest ratings and viewing time for stimuli (Lang and Davis, 2006). Both valence and arousal have significant impact on an organism’s relationship with the environment, influencing, for example, the allocation of attention and long term memory formation (Arbib and Fellous, 2004).

Recent work, especially in the neuroimaging literature, has raised questions about whether complex neurological processes like emotions can actually be represented by reducing to dimensions of valence and arousal. Kragel and LaBar (2016), in an interesting review of the nature of brain networks that subserve human emotion, argue that each emotion uniquely correlates with activation of a constellation of cortical and subcortical structures (Kragel and LaBar, 2016), and that the current neuroimaging data do not support the valence-arousal model of emotions. They focused on fMRI studies which have applied novel statistical methods collectively known as multivoxel pattern analysis to identify mappings between mental states and multiple measures of neural activity. The mainstay of earlier neuroimaging research on emotion was univariate pattern analysis, but multivariate analyses have the advantages of higher sensitivity, and the ability to detect counterintuitive relationships because of the lack of reliance on a priori hypotheses. These approaches also have the advantage of overcoming the assumption that dedicated modules or homogeneous neural units subserve each emotion, because they can investigate various neuronal populations at much larger spatial scales.

Kragel and LaBar (2016) suggest that while the use of machine learning approaches to large neuroimaging datasets is likely to expand in the near future, it might be premature to draw conclusions about neural substrates underlying each emotion, because the current studies using multivariate analyses have not all been consistent with one another. These differences may be coming from technical variations in the methods used to induce and assess the emotion and associated neural activations, but might also represent fundamental variations in the circuitry employed in different individuals, or even a lack of emotional “essences” that can be studied in a standardized manner across people and cultures. While this is a valid critique, we believe that the older valence-arousal classification still holds value in furthering our understanding of brainstem contributions to emotions and especially to basic emotions shared with intelligent animals. This debate may eventually be resolved with technical advances in functional neuroimaging and multidisciplinary approaches to studying emotional experiences (Immordino-Yang and Yang, 2017, in press).

Conclusion and Future Directions

The brainstem contains several structures that are likely of critical importance in the generation and experience of emotion. Most prior research on human emotion has focused on cortical mechanisms, largely because of the complexity of the brainstem coupled with the difficulty of analyzing brainstem functioning using current technologies. We have provided a conceptual overview of how tegmental structures of the brainstem are involved in emotion-related processes. Future research on the structural and functional connectivity of the human brainstem is needed to further understand its role in emotion. Such work will undoubtedly contribute to a more enriched and nuanced understanding of the neurobiology of human emotion in psychology and in affective neuroscience.