Behaviour neurologist explains how our brains feel emotion

Interview with behaviour neurologist, Antonio Damasio on how our brains feel emotion.

"An emotion consists of a very well orchestrated set of alterations in the body. Its purpose is to make life more survivable by taking care of a danger or taking advantage of an opportunity."

Question: What is happening in our brain when we feel an emotion?

Antonio Damasio: Feeling of an emotion is a process that is distinct from having the emotion in the first place. So it helps to understand what is an emotion, what is a feeling, we need to understand what is an emotion. And the emotion is the execution of a very complex program of actions. Some actions that are actually movements, like movement that you can do, change your face for example, in fear, or movements that are internal, that happen in your heart or in your gut, and movements that are actually not muscular movements, but rather, releases of molecules. Say, for example, in the endocrine system into the blood stream, but it’s movement and action in the broad sense of the term.

And an emotion consists of a very well orchestrated set of alterations in the body that has, as a general purpose, making life more survivable by taking care of a danger, of taking care of an opportunity, either/or, or something in between. And it’s something that is set in our genome and that we all have with a certain programmed nature that is modified by our experience so individually we have variations on the pattern. But in essence, your emotion of joy and mine are going to be extremely similar. We may express them physically slightly differently, and it’s of course graded depending on the circumstance, but the essence of the process is going to be the same, unless one of us is not quite well put together and is missing something, otherwise it’s going to be the same.

And it’s going to be the same across even other species. You know, there’s a, you know, we may smile and the dog may wag the tail, but in essence, we have a set program and those programs are similar across individuals in the species.

Then the feeling is actually a portrayal of what is going on in the organs when you are having an emotion. So it’s really the next thing that happens. If you have just an emotion, you would not necessarily feel it. To feel an emotion, you need to represent in the brain in structures that are actually different from the structures that lead to the emotion, what is going on in the organs when you’re having the emotion. So, you can define it very simply as the process of perceiving what is going on in the organs when you are in the throws of an emotion, and that is achieved by a collection of structures, some of which are in the brain stem, and some of which are in the cerebral cortex, namely the insular cortex, which I like to mention not because I think it’s the most important, it’s not. I actually don’t think it’s the number one structure controlling our feelings, but I like to mention because it’s something that people didn’t really know about and many years ago, which probably now are going close to 20 years ago, I thought that the insular would be an important platform for feelings, that’s where I started. And it was a hypothesis and it turns out that the hypothesis is perfectly correct. And 10 years ago, we had the first experiments that showed that it was indeed so, and since then, countless studies have shown that when you’re having feelings of an emotion or feelings of a variety of other things, the insular is active, but it doesn’t mean that it’s the only thing that is active and there are other structures that are very important as well.

Recorded July 2, 2010
Interviewed by David Hirschman

Somatic markers - how the body affects the mind

Your somatic markers know when to hold ‘em

By Lorimer Moseley in Body In Mind:Research into the role of the brain and mind in chronic pain, 21 March 2011

There is a very large body of data that show that the body affects the mind. That is, bodily processes and responses to stimuli affect our thoughts about those stimuli and our behavioural responses to them. Some of the most intriguing research in this area has been done by Antonio Damasio – most famously the Iowa gambling project [1]. They have primarily investigated people who have damage to their emotional system – ventromedial prefrontal cortex - yet seem to function very well on language and intelligence tests. They do, however, act in a socially inappropriate manner and make stunning judgement errors. One of the earliest studies showed that while healthy volunteers began to choose advantageously before they worked out which strategy was in fact advantageous, patients with damage to their prefrontal lobe chose disadvantageously the whole time – even if they had worked out which strategy was in fact advantageous. The study also showed that normals would have a galvanic skin response, a sign of sympathetic activation, before they realised they were about to make a risky choice. Damasio’s group has done a bunch of studies that underpin their Somatic Marker Hypothesis – “Somatic markers are events or chemicals in your body, detection of which evokes particular feelings or emotions. A note here that, according to Damasio – check out his very readable book ‘The feeling of what happens’, emotions are brain representations of body states. That is, you see a scary looking man approaching you, your sympathetic nervous system is activated, this sends feedback to your brain and your brain registers this feedback and you feel frightened). So, the essence of the somatic marker hypothesis is that when a “negative somatic marker is linked to a particular future outcome it becomes an alarm bell and when a positive somatic marker is linked to a particular future outcome it becomes an incentive” [2].

So, people who have damage to the part of the brain that registers feedback from the somatic markers, don’t ‘read the signals’ from their internal environment. The somatic marker hypothesis argues that this is why they make errors of judgement and do socially inappropriate things – they can’t process the shift in the somatic markers. So, next time you join the poker game, remember what the somatic marker hypothesis says: it is your body that tells you when to hold ‘em, when to fold ‘em, when to walk away and when to run, not Kenny Rogers. So, clearly there is bottom-up influence on cognition – the embodied cognition people talk about this a great deal. We have shown (see here for BiM discussion on ‘Rubber Hand makes your real hand go colder‘ and visual distortion) a top-down effect of cognitive representations on the body [3, 4]. The next blog will raise the stakes even further, albeit rather speculatively…..

1. Bechara, A. (1997). Deciding Advantageously Before Knowing the Advantageous Strategy Science, 275 (5304), 1293-1295 DOI:10.1126/science.275.5304.1293

2. Damasio AR (1996). The somatic marker hypothesis and the possible functions of the prefrontal cortex. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 351 (1346), 1413-20 PMID: 8941953

3. Moseley, G., Olthof, N., Venema, A., Don, S., Wijers, M., Gallace, A., & Spence, C. (2008). Psychologically induced cooling of a specific body part caused by the illusory ownership of an artificial counterpart Proceedings of the National Academy of Sciences, 105 (35), 13169-13173 DOI: 10.1073/pnas.0803768105

4. Moseley, G., Parsons, T., & Spence, C. (2008). Visual distortion of a limb modulates the pain and swelling evoked by movement Current Biology, 18 (22) DOI:10.1016/j.cub.2008.09.031

On chronic pain and body schema

Pain: The Science and Culture of Why We Hurt

by Marni Jackson

"Why do we still distinguish between mental pain and physical pain," she asks, "when pain is always an emotional experience? Why is pain so poorly understood, especially in a century of self-scrutiny? Hasn't anyone noticed the embarrassing fact that science is about to clone a human being but still can't cure the pain of a bad back?"

A new take on the Gate Control Theory, or, The benefits of rubbing your boo-boos

from the blog of Dave Walton, physiotherapist and Assistant Professor with the School of Physical Therapy at University of Western Ontario.

" ... (I)t is conceivable that the brain's sentry body-self neuromatrix maintains that heightened state of arousal and sensitivity in it's efforts to obtain knowledge about the state of the painful part. This might also be the mechanism behind Peter O'Sullivan's observations that some people with chronic low back pain exhibit behaviours that result in further pain (ie. it's painful to extend the lumbar spine, but some people habitually adopt this posture despite the pain). In that case, this theory would suggest that any stimuli coming from the area, even if unpleasant, can offer at least some form of relief to a neuromatrix seeking information, especially in those conditions that you can't see. Not saying this is good, just saying it makes sense in light of my pseudo-theory. Note that this theory would also support the notion that manual therapies probably have much of their effect through drawing attention to, and providing neurophysiological stimulus from, painful parts of the body. The focus on identifying very specific movement impairments (ie. restricted superior glides of the facet) becomes less of a priority than does identifying the amount of stimulus that can be applied to a body in pain that provides adequate stimuli without being perceived as threatening to the sensitized 'pain' system."

I can't find it! Distorted body image and tactile dysfunction in patients with chronic back pain

By G. Lorimer Moseley

ABSTRACT: The conscious sense of our body, or body image, is often taken for granted, but it is disrupted in many clinical states including complex regional pain syndrome and phantom limb pain. Is the same true for chronic back pain? Body image was assessed, via participant drawings, in six patients with chronic back pain and ten healthy controls. Tactile threshold and two-point discrimination threshold (TPD) were assessed in detail. All the patients, and none of the controls, showed disrupted body image of the back. Five patients were unable to clearly delineate the outline of their trunk and stated that they could not “find it”. TPD was greatly increased in the same zone as the absence or disruption of body image, but was otherwise similar to controls. The disturbance of body image and decrease in tactile acuity coincided with the normal distribution of pain, although there was no allodynia and there was no relationship between resting pain level and TPD. Tactile threshold was unremarkable for patients and controls. These preliminary data indicate that body image is disrupted, and tactile acuity is decreased, in the area of usual pain, in patients with chronic back pain. This finding raises the possibility that training body image or tactile acuity may help patients in chronic spinal pain, as it has been shown to do in patients with complex regional pain syndrome or phantom limb pain.

You Are What You Touch: How Tool Use Changes the Brain's Representations of the Body

"While we think of our body as a fixed feature of our lives, the brain displays a surprising ability to accept as part of ‘me’ whatever I happen to be touching and using at any given time."

How tools become a part of your body

By Patrick Haggard and Matthew R. Longo

All our experience of the world, and ability to act on it, are channelled through our body. The pioneering computer scientist, Alan Turing, correctly realised the human mind is special not particularly because of its computing power, but because the body provides it with a unique interface to the world. Current research in psychology and neuroscience is probing how the brain represents the body. Recent advances have revealed that body representation is fundamentally multisensory, arising from the combination of many different sensory signals. These include classical “senses,” such as touch and vision, and also much more specific signals, such as the flexion or extension of each muscle, which define the body’s posture in space. This information is integrated to construct a multisensory representation of the current state of the body. Intriguingly, multisensory signals also affect what we perceive our body to be like, for example by making us feel like a rubber hand really is our hand! Our thoughts about what our body is are highly flexible, and track the multisensory inputs that the brain receives.

A common illustration of just how flexible the sense of our body is comes from changes in the brain’s representation of the body due to tool use. Humans, and some other animals, are able to use tools as additions to the body. When we use a long pole to retrieve an object we couldn’t otherwise reach, the pole becomes, in some sense, an extension of our body. Is this merely a poetic way of speaking, or does the brain actually incorporate the tool into its representation of the body? Studies of monkeys learning to use a rake to obtain distant objects show that this may be more than a mere metaphor. Multisensory brain cells respond both to touch on the hand or visual objects appearing near the hand. When the monkeys used the rake, these cells began to respond to objects appearing anywhere along the length of the tool, suggesting the brain represented the rake as actually being part of the hand.

A recent paper in Psychological Science elegantly illustrates the plasticity of body representation, and provides further evidence that representations of the body really do expand to include ‘external’ objects we hold. Thomas Carlson of the University of Maryland and colleagues at Harvard University and Utrecht University in the Netherlands used an unusual subjective experience of the body first reported by Franklin Taylor of Princeton University in 1941. If you look towards your hand in a darkened room and see it illuminated by a bright flash, an afterimage of your hand remains after the flash. If you then move your hand, the afterimage changes, though no actual visual signal is present. The precise effect, like so much of the richness of human sensation, is difficult to catch in words, but is like a fading, or loss of clarity of the hand. This fading is normally explained by the multisensory nature of body representation: when the hand moves, but the afterimage does not, visual information and ‘proprioceptive’ information from muscles no longer agree about where the hand is. The visual impression of the hand fading may be a by-product of this inability to integrate different sensations due to conflict about where they are in space.

Carlson et al used this fading to investigate the limits of the brain’s representation of the body. When participants held an object and then moved their hand after the flash, the object’s afterimage faded as well. Further, if participants reached for the object after the flash, the object still faded. The brain may detect a conflict between the location of the object in the afterimage (on the table) and the location where the object is actually felt (in their hand). Alternatively, the object may be rapidly assimilated into the representation of the body and therefore subject to the same perceptual conflict.

The authors also ran additional tests in which volunteers dropped the object, providing new evidence for a spatial bound on plasticity of body representation. Objects released from a mechanical gripper held in the hand did not fade, while those released directly from the hand’s grasp did fade. These conditions suggest that direct contact with the skin may be an important cue to plastic bodily extension. A critical, though elaborate, test might involve forming an initial afterimage of the hand, gripper and object placed separately on the table, then picking up the gripper, and using this to pick up the object. The authors would predict a fading of the afterimage of the gripper, due to its incorporation in the body representation. However, the object should not be incorporated because it would not be touched directly.

These results elegantly confirm that the human brain maintains a highly flexible representation of the body, despite the tendency in everyday life to think of ourselves as having a fixed personal identity, linked to our body. Two distinctive features of mental body representation emerge. First, from the brain’s perspective, the body is by far the most familiar object in the world: the body, as William James elegantly put it, is “always there.” In these experiments, the mechanical gripper could be treated as part of one’s own body. However, this did not extend to an object held in the gripper, perhaps because this situation wasn’t familiar enough. We speculate that skilled prosthesis users might experience objects grasped in the prosthetic hand as fading, even though first-time users in the present experiment did not. Given the ability to move an object through voluntary action, and sufficient sensory experience of doing so, the capacity to extend the self may be virtually unlimited.

Second, these studies suggest a view of the body as an interface between the brain and the external world. This view has important implications for human psychology generally. The sensorimotor mechanisms of the body are effectively a tool for our voluntary actions to respond to the environment and to change it. While we think of our body as a fixed feature of our lives, the brain displays a surprising ability to accept as part of ‘me’ whatever I happen to be touching and using at any given time.

About the authors:

Patrick Haggard leads a research group at the Institute of Cognitive Neuroscience, University College London. His research interests include the brain's representation of one's own body, and the control of voluntary action. Matthew Longo is a postdoctoral fellow at the Institute of Cognitive Neuroscience, University College London, and soon to be a lecturer at Birkbeck College, University of London. He is interested in how we represent our bodies and how this shapes how we perceive the external world.

Source: Scientific American via Body in Mind

Making Sense of Sense - The roads less travelled – four paths to get from touch to the body

By Nadia Barnsley, a third year medical students from the University of New South Wales.

Nadia's research interests include bodily awareness, body ownership and immune responses. She is doing an independent learning project on Body in Mind research. Here she reviews Serino and Haggard’s paper “Touch and the Body” which was published in Neuroscience and Biobehavioural Reviews.

Serino and Haggard’s paper gives a four-part model that explains the notion that our sense of touch carries information about both the external object touching our skin and also our own body. Tactile information can influence (or be influenced by) our mental representation of the physical body. Mental body representations (MBR) are simply descriptions in our mind of the parts of the body, their position in space and their organization into a structural whole (us!)

Serino and Haggard firstly examined the idea that the physical body structures tactile sensation – that when we touch or get touched, tactile afferents will map this into a homunculus, “little man”, in the parietal lobe of the brain. This information is conveyed to what’s known as S1 (the primary somatosensory cortex) of the opposite hemisphere.

Serino and Haggard’s second pathway explains that tactile information provides an important afferent input to mental body representations. Importantly they clarified the difference between body schema and body image; where body schema is short-lived and represents the positions of body parts in space, whereas body image remains fixed over time, representing a basic appearance of the body as an object in third person perspective.

Interestingly they reviewed how visual information relates to tactile sensation; the third pathway. They found that tactile acuity improved when subjects viewed the body. Moreover, this is independent from visuo-spatial orienting to the location of the body. The paper explained those with poor tactile ability will have vast improvements in tactile sensation when visual information is added. This has clinical implications for those with reduced sensation following brain lesions.

The last pathway explained how MBRs not only contribute to our body perception, but the perception of external objects. Basically, our touch of external objects is ‘body referenced’. This implies that MBRs are not just a stored body image; they are updated to integrate current sensory information.

So the first pathway tells the brain where we are being touched, the second pathway gives our brain a representation of what we are (our body image), the third is that this representation influences how we understand our sense of touch and the last being that our body image alters how external objects are perceived.

Reference: Serino A, & Haggard P (2010). Touch and the body. Neuroscience and biobehavioral reviews, 34 (2), 224-36 PMID: 19376156 Epub 2009 Apr 17.

Touch and the body
Serino A, Haggard P. Dipartimento di Psicologia and Centro studi e ricerche in Neuroscienze Cognitive, Università degli Studi di Bologna, Italy.

Abstract
The dual nature of touch has long been understood. The sense of touch seems to carry information at the same time about the external object touching our skin, and also about our body itself. However, how these two interact has remained obscure. We present an analytic model of how tactile information interacts with mental body representations in the brain. Four such interactions are described: the link between the body surface and the maps in primary somatosensory cortex, the contribution of somatosensory cortical information to mental body representations, the feedback pathway from such higher representations back to primary tactile processing in somatosensory cortex, and the modulation of tactile object perception by mental body representations.

Source: Body in Mind Research into the role of the brain and mind in chronic pain disorders

The embodied nature of meaning and metaphor

BODY AWARENESS by Penny Tompkins and James Lawley

Extract from notes first presented at The Developing Group, 25 September 2004

6. The embodied nature of meaning and metaphor

Mark Johnson in The Body in the Mind makes the case that:

"The centrality of human embodiment directly influences what and how things can be meaningful for us, the ways in which these meanings can be developed and articulated, the ways we are able to comprehend and reason about our experience, and the actions we take. Our reality is shaped by the patterns of our bodily movements, the contours of our spatial and temporal orientation, and the forms of our interactions with objects. It is never merely a matter of abstract conceptualizations and propositional judgements.

Human bodily movement, manipulation of objects, and perceptual interactions involve recurring patterns without which our experience would be chaotic and incomprehensible. They are gestalt structures, consisting of parts standing in relations and organized into unified wholes, by means of which our experience manifests discernible order. When we seek to comprehend this order and to reason about it, such bodily based schema play a central role." (p. xix)

Thus,
"Through metaphor, we make use of patterns that obtain in our physical experience to organise our more abstract understanding. Understanding via metaphorical projection from the concrete to the abstract makes use of physical experience in two ways. First, our bodily movements and interactions are structured, and that structure can be projected by metaphor onto abstract domains. Second, metaphorical understanding is not merely a matter of arbitrary fanciful projection from anything to anything with no constraints. Concrete bodily experience not only contrails the "inputs" to the metaphorical projections but also the nature of the projections themselves, that is, the kinds of mappings that can occur across domains." (p. xv)

For example,
"Balancing is an activity we learn with our bodies and not by grasping a set of rules or concepts. First and foremost, balancing is something we do. The baby stands, wobbles, and drops to the floor. It tries again, and again, and again, until a new world opens up — the world of balanced erect posture.

We also come to know the meaning of balance through the closely related experience of bodily equilibrium, or loss of equilibrium. We understand the notion of systemic balance in the most immediate, preconceptual fashion through our bodily experience. There is too much acid in the stomach, the hands are too cold ... Things are felt as 'out of balance.' There is 'too much' or 'not enough' so that the healthy organization of forces, processes, and elements is upset " (pp. 74-75)