The role of the eyes in the amygdala experience and perception of fear

on 31 August 2018
Clearly we are nuts

Have you heard of the "Amygdala?" Of course, you have but do you know what it does? Do you know what it doesn't do? Turns out you're not alone but you are in good company . . . . . . . . . . . . .

For many years the amygdala, 2 almond-shaped structures, one in each hemisphere, were thought to be the fear centre of the brain. But with the advancements of better and more sophisticated machinery, better methods and more interest, the amygdala is slowly giving up its secrets, or more to the point, the secrets of other brain regions and networks!

Joseph Le Doux, refers to the amygdala and its buddies, as the threat detection system and sees the emotion that we call fear, as in the physical feeling of fear, as being derived from other areas and quite unique to us humans. The amygdala, BNST (bed nucleus of the stria terminalis, part of the extended amygdala), hypothalamus and PAG (periaqueductal grey) detect and create the responses to a threat, feelings of fear arise when we become consciously aware of a threat. The hypothalamus plays a part in the arousal and secretion of stress hormones, involving the autonomic nervous system (ANS), sympathetic and parasympathetic branches to initiate bodily and hormonal responses in preparation for defensive action (fight or flight). This detection of a threat occurs outside of conscious awareness, although the timeframe between detection and awareness can be very quick; possibly alluding to the fear itself being a consequence of conscious awareness of the feeling? In essence a perception of a reversal of the reality! This could also create an illusion because very often we give meaning to the feelings, "it was because of . . . . . . . . . . . ." When in fact it may be a response to unknown and, maybe, unrelated sensory stimulus. Once we believe we know the reason, that allows us to subconsciously programme the brain/mind to a conditioned stimulus that now gives rise and strength to an unconditioned stimulus.

As I said above, all this can, and mostly does, occur outside of conscious awareness. It is only once we become consciously aware, that the "feeling" we call fear, becomes apparent. Sometimes we have no real understanding of the cause and will often make up a reason or excuse (subconsciously most probably). It is not uncommon for the real reason to escape our attention and this can both compound the problem and make it more complex. Sometimes an emotional experience or lesson can lay dormant for many years, only to surface when an event or circumstance takes place at some future point in our life. For example, the inculcation of deep-seated religious beliefs about morality when you were a young child, now surface due to a subconscious violation, by you, of those beliefs. For instance, you are divorced and are now in a romantic, sexual, relationship, but, according to your religious beliefs, divorce is not allowed; thus making you an adulterer! The psychology being, you are legally divorced but not morally or spiritually so! The obvious feelings of fear and the feeder of subsequent fear experience, consequentially, lay in the afterlife; judgment day!

Whatever we think the cause or reason may be; we have to consider the exact opposite also. We are so often taught that we have to think "out of the box." However, sometimes we have to go deeper into the box; maybe all the way through it because the world of our subconscious is also the world of the sub-logical and, sub-reasonable?

If you are experiencing unfathomable fear, anxiety or maybe feeling depressed, hypnotherapy has an excellent record of helping people, with all manner of emotional, psychological and mental issues. It also helps us to find peace and inner calm. It is the unique way in which hypnosis allows the inner workings of the subconscious, to rewrite the neural code that elicits such unwanted and illogical responses and help restore more correct and functional ways of living a good and productive life! Hypnotherapy; C'est la Vie!

The objective here is to help people understand how and why we become illogically trapped into irrational emotional experiences that may actually be happening for reasons different to that which we would imagine! If you want to know more about how Hypnotherapy can help you; why not make an appointment for a Free Consultation?

For more information on the Free Consultation - Go Here Or, to book your Free Consultation today, you can do so here


The Research: 

Researchers have long believed that the amygdala, an almond-shaped structure in the brain, is central to the experience and perception of fear. Studies initiated in the 1990s of a patient with a rare condition affecting the amygdala initially seemed to support this conclusion. However, as Lisa Feldman Barrett, PhD, of the Massachusetts General Hospital (MGH) Department of Psychiatry, writes in a new paper, the role of the amygdala has turned out to be more complex than originally thought. Barrett, a research scientist at the Athinoula A. Martinos Center for Biomedical Imaging at MGH and a University Distinguished Professor of Psychology at Northeastern University, was invited to write the paper for the 40th-anniversary issue of the journal Trends in Neurosciences.

"Scientists originally hypothesised that the amygdala contained the circuitry necessary for fear and its related behaviours," says Barrett. "They continually broadened their hypotheses for the amygdala's role with accumulating research in both humans and non-human animals. The amygdala was then thought to contain the circuitry for negative emotions, for emotions in general, and eventually, for anything that is broadly affective, such as a threat. Through the natural process of systematic scientific investigation, it's become clearer that the amygdala plays a role in signaling the rest of the brain to information that is important to learn because it is relevant to allostasis -- the brain's process of anticipating the needs of the body and attempting to meet those needs before they arise. Whether threatening, rewarding or novel, this to-be-learned information will help the brain better predict future occasions."

The amygdala has been linked to fear since the publication of a 1930s paper by University of Chicago researchers Heinrich Klüver and Paul C. Bucy, who described profound behavioural changes -- including a newfound willingness to approach snakes and other dangerous animals -- in rhesus monkeys whose temporal lobes, including the amygdala, had been removed. This work spurred decades of continuing research in non-human animal models into the role of the amygdala in creating states of fear. By the early 1990s, Barrett writes in the current paper, investigators had concluded the structure was integral to a central fear system in the brain.

However, understanding of the amygdala's role started to change around that time when a team at the University of Iowa College of Medicine began to publish a series of studies of a woman known in the literature as S.M. with rare bilateral lesions of the amygdala resulting from a condition known as Urbach-Wiethe disease. A 1994 study published in Nature, showed that S.M. was unable to recognize facial expressions of fear, underscoring the earlier conclusions about the role of the amygdala; but a more complex picture began to emerge in the following years. Further studies with the patient revealed that she had difficulty perceiving facial expressions of other emotions when those expressions involve a widening of eyes, and even then, only in particular contexts.

As described in Barrett's paper, these findings spurred the development of new hypotheses about the role of the amygdala in the experience and perception of fear. Instead of directly mediating fear, it now appears that the amygdala is involved in a person's ability to attend to the whites of another person's widened eyes, something that is more generally important to social functioning. "The amygdala is not necessary to experience or perceive fear," Barrett says. "Amygdala neurons very likely contribute to fear in some instances, but the neurons can't be said to actually compute fear. More likely, amygdala neurons act as a context-sensitive sentinel for learning threat and reward."

She adds that the work with S.M. over the years offers an excellent example of "science's self-correcting process," in which new findings are used to challenge and, if necessary, revise current hypotheses. "The original hypotheses about the amygdala's role in fear turned out not to be supported after careful study across decades," Barrett says. "This is a good example of how the scientific method, at its best, works."

Barrett's paper was supported by U.S. Army Research Institute for the Behavioural and Social Sciences grant W911NF-16-1-019, National Cancer Institute grant U01 CA193632, National Institute of Mental Health grants R01 MH113234 and R01 MH109464 and National Science Foundation grant CMMI 1638234.


Story Source:

Materials provided by Massachusetts General HospitalNote: Content may be edited for style and length.

Journal Reference:

  1. Lisa Feldman Barrett. Seeing Fear: It’s All in the Eyes?Trends in Neurosciences, 2018; 41 (9): 559 DOI10.1016/j.tins.2018.06.009