Sunday, May 24, 2009

Brain processes and their energy efficiencies.

Life cannot exist without energy. In a previous post, I hypothesized that “Evolution itself acts in accordance with the energy consideration...” such that energy is used efficiently. Although it is obvious that energetic processes are at the very core of life, relatively little attention has been paid to them in the neurosciences. However, some researchers have started down the energy path as will be discussed more fully in future posts. Some examples of such studies of energy are, with respect to brain structure and function, Laughlin (2004) and Warrant (2009), and with respect to evolution Niven & Laughlin (2008).

One very broad approach to studying energy in the nervous system would be to compare energetic processes in various discrete and specialized functions, for example, photoreception as Laughlin and his group have done so well. What I wish to introduce here is the idea of comparing energetic processes in more general functions of the brain especially those of the human brain. In my last post, “A promising overarching viewpoint: Reflexive versus reflective processes as two fundamental specialized brain-behaviour systems.” I briefly described Lieberman’s (2007) argument that the brain functions in two fundamentally different ways: reflexive and reflective. Lieberman points out that one of the features that differentiates the reflexive from the reflective system is that the former acts in a relatively effortless manner while the latter requires significant effort (energy). Additional evidence information about energy and brain function comes from the work of Baumeister (e.g. Baumeister et al (1998)) and Gailliot (2008). They have presented evidence that the mental processes usually subsumed under the phrase “executive function” are relatively energy demanding and cause mental fatigue. Since these executive functions would fall into the classification of being reflective they support Lieberman’s hypothesis about the reflective system being relatively more energy demanding.

It can be argued that the brain functions are not just divisible into two systems: reactive (automatic) and reflective (controlled). Aunger and Curtis (2008) have argued for three not two basic kinds of neural processing or what they refer to as levels of control over behaviour:
1. Reactive
2. Motivation (But see Berridge (2004) for evidence that there are probably different kinds (levels of complexity) of motivation. This suggests that this division into just three levels might be an over simplification.
3. Executive control

Aunger and Curtis state that “Behaviour can also be classified by the type of evolutionary benefit it bestows: it can deliver either immediate benefits (food, gametes), improvements in the individual’s position with respect to the world (resource access, social status), or improvements in the ability to secure future benefits (knowledge, skill).” They refer to these as respectively “Physiological, situational, and aptitudinal”. Aunger and Curtis conclude “Combining history and function implies the existence of seven types of behaviour production systems in human brains responsible for reflexive, instinctual, exploratory, driven, emotional, playful and planned behaviour.” I would like to propose that this list may also reflect increasing levels of required energy and that a comparison of energetic processes among them would be revealing and useful.

The above remarks are speculative but I will now introduce some even more speculative comments, suggestions and proposals. It would be interesting to compare energy consumption in the nervous system across the complete life cycle of the organism from early embrogenisis to senescence. I remember some classical evidence that there is a gradient in energy consumption from anterior to posterior end of the embryonic neural tube. Also during embryogenesis the nervous system can engage in overproduction of nerve fibres followed by a pruning back to the minimum required for function. Perhaps here some kind of energy homeostatic regulation is at work. As well, the current view is that during postnatal development the brain can develop using neuroplastic changes. It would seem likely that neuroplasticity is relatively highly demanding in terms of energy consumption since both neurons and glia must engage in the anabolic processes involved in neuroplastic changes.

A final “wild and crazy” bit of speculation is that energetic processes play an essential role in the well recognized complexity of the nervous system. It has been said that the number of connections in the adult human brain is in the quadrillion range putting it in the same order of magnitude as the number of stars in our galaxy. And what I am wondering is how much metabolic energy is required just to maintain this enormous complexity. I also wonder if, in senescence, less energy is available for this maintenance function and hence this complexity begins to degrade. I remember a colleague of mine, Dr. Ted Petit, years ago, speculating that with age, it is the most terminal dendritic synaptic structures which deteriorate first leaving intact the larger and more proximal synapses. The latter have been present for a longer period of time perhaps and perhaps because they have been used more over their longer existence, they have been strengthened structurally in some way perhaps by extracellular matrix elaborated by the glia so that less energy is required for their maintenance.

Research on energy and the brain would seem to offer an exciting new way to understand brain structure and function, how the brain evolved, and how it develops ontologically. In a future post I will propose some ideas about why during development, tasks initially processed by one system e.g. the reflective system may become incorporated into another system e.g. the reactive in order to save the organism’s vital energy supply.

References:
Aunger, R. & Curtis, V. (2008).
Kinds of behaviour. Biology and Philosophy, 23, 317-345.

Baumeister, R. F., Bratslavsky, E., Muraven, M., & Tice, D. M. (1998). Ego depletion: Is the active self a limited resource? Journal of Personality and Social Psychology, 74, 12521265.

Gailliot M. T. (2008). Unlocking the energy dynamics of executive functioning. Perspective on Psychological Science, 3, 245-263.

Berridge K. C. (2004). Motivation concepts in behavioral neuroscience. Physiology and Behavior, 81, 179-209.

Laughlin, S.B. (2004). The implication of metabolic energy requirements for the representation of information in neurons. In: The Cognitive Neurosciences III, ed MS Gazzaniga, Cambridge, Mass., MIT Press.

Lieberman, M. D. (2007). Social cognitive neuroscience: a review of core processes. Annual Review Psychology, 58, 259-289.

Copyright © 2008 Brian S. Scott

Wednesday, May 20, 2009

A promising overarching viewpoint: Reflexive versus reflective processes as two fundamental specialized brain-behaviour systems.

As I wrote in a previous post (Some strategic problems with the scientific endeavour) “A particular problem with respect to psychology, and perhaps to some other sciences, is that there is no general theory, to connect the latest advances in the many sub-disciplines of psychology...” However one such general approach was discussed briefly by Mathew Lieberman in 2007. He reviewed the long held view (e.g. Schneider and Shiffrin, 1977) that there are two “broad organizing principles of social cognition within the human brain...” each with a distinct underlying neural basis and evolutionary history:
Reflexive (the X system, x for the x in reflexive)
Reflective (the C system for the c in reflective)
Although Lieberman focussed on human cognition I feel these principles can be useful to understanding how information is processed and turned into adaptive behaviour in all sentient life forms.

Reflexive responding. We are responding reflexively when we quickly pull our hand from a hot stove. We don’t have to think about doing so, it just happens automatically, effortlessly, and with great speed. Such reflex actions can be highly adaptive and protect us from injury or even death. They are so adaptive in fact, that the neural circuits required for reflexes have evolved as innate genetic mechanisms in even the most primitive invertebrates and vertebrates .

Reflective behaviour. If the environment changes a lot or is relatively complex, a more flexible kind of responding became more adaptive than rigid reflexive action. It is in humans that a new type of responding called reflective responding evolved most highly although it is also present in non-human primates and arguably in other species. In the case of humans, we evolved in a complex society of cooperative hunting and gathering with lots of novel challenges. More flexible responding was required. Today, if we act automatically, without reflecting on the consequences of our actions, social or otherwise, we are likely to be ostracized by our social group or rejected by our mate. For our highly interdependent species, rejection is extremely dangerous not only to our happiness but to our physical health and even survival. Therefore we have evolved brain mechanisms to inhibit automatic responding if appropriate and instead respond more adaptively. The brain mechanism underlying reflective responding permitted the individual to tolerate some pain or to delay immediate gratification in order to obtain longer term goals.

An example of reflective responding is the situation in which we grasp a plate that is so hot it hurts us but we don’t drop it because it is loaded with our favourite food. We force ourselves to hold on to the plate long enough to put it down safely. This is a much more complicated process than reflexively just letting go of the hot plate; it requires us to inhibit the reflexive response and take time to think of a more suitable response and then with deliberation and effort to put the plate down safely.

Reflective responding also allows one to adapt in a much more flexible way when presented with a challenge of some kind. Hence reflective responding increases our problem solving ability in general. This aspect of reflective responding is at the heart of the higher more sophisticated kinds of responses humans can make. In future posts I will argue that such flexibility is intimately related to the evolution of the cerebral cortex.

An additional characteristic of reflective responding is that, in situations of high stress and arousal, it can be superseded by reflexive behaviour. An example of this is when humans in a theatre fire situation panic and stampede for the exit thereby perhaps injuring others as well as themselves. However awareness of this inhibiting effect of high stress on reflection can be used positively. For example, one way to increase reflective responding is to decrease stress and to increase positive affects such as feeling serene or grateful. This is likely the neuroscientific mechanism underlying some of the processes focussed on in positive psychology.

For information about how to utilize knowledge about the two systems to improve your interpersonal or social life I suggest two posts on my other blog called Psych-matters
entitled “How to move yourself and others from reflexive to reflective responding. Part One.” and “Ten ways to improve your relationship by learning to respond reflectivelyAs Lieberman (2007) points out, one of the features that differentiates the reflexive from the reflective system is that the former acts in a relatively effortless manner while the latter requires significant effort (energy). In a previous post, "Some wild and crazy hypotheses", I proposed the hypothesis that “Evolution itself acts in accordance with the energy consideration...” such that energy is used efficiently. I believe that energy utilization is an important consideration in understanding the differences between the reflexive versus the reflective system and this will be the subject of a future post.


Lieberman, M. D. (2007). Social cognitive neuroscience: a review of core processes. Annual Review Psychology, 58, 259-289.

Schneider, W. & Shiffrin, R. M. (1977). Controlled and automatic human information processing: I. Detection, search, and attention. Psychological Review, 84, 1-66.


Copyright © 2008 Brian S. Scott

Sunday, May 17, 2009

Would you want computer chip replacements for age related cognitive deficits?

I have just finished Arthur C. Clarke’s "Rama Revealed" in which the heroine, Nicole, in her old age, rejects the aliens’ offer to update her brain function with advanced computer circuits. She does so because she worries about what will be left of her true self after a long series of such transplants. I imagine she was reflecting Clarke’s own opinion about the usefulness of such procedures as one grew into old age. He was a very imaginative and bold futurist, predicting satellites in geosynchronous orbits around the earth 18 years before it actually occurred (Clarke). So I take his views on the future quite seriously and initially Nicole’s decision seemed quite logical and emotionally valid to me also.

However, yesterday after a telephone conversation with a very old friend of mine in Toronto I have changed my mind. Jack is now 80 and his memory for proper names is becoming problematical. For example, during our conversation, he could not remember the name of the prime minister of the UK during WWII. But despite the memory deficit, and this is the most important fact here, there was absolutely no doubt in my mind that I was engaging in a conversation with Jack as I have come to know him over the years. He was the same sensitive but assertive person of strong opinions topped by an engaging and sophisticated sense of humour.

What I concluded from this enjoyable conversation with Jack was that, although some cognitive abilities decline with age, the basic personality endures. It is hard wired into the brain. Now, in my 74th year of life, as I anticipate the mental declines of old age, I would definitely be accepting of new computer devices to compensate for future cognitive deficits. I feel comfortable that my basic personality would remain unchanged; that my basic self which has been formed over earlier years would persist for good or bad. I would not be worried about losing my personal identity, who I really am. So now I am quite open to having a computer assisted brain. But it seems that such a possibility will not become a reality in my lifetime.

Tuesday, May 12, 2009

Some wild and crazy hypotheses

“I cannot give any scientist of any age better advice than this: the intensity of the conviction that a hypothesis is true has no bearing on
whether it is true or not.” (Medawar, 1979, p. 39). Medawar, P.B., 1979. Advice to a Young Scientist. Harper & Row, New York).

I remember that, during my years of doing research, unexpected research results proved most of my hypotheses were wrong. However this wrongness was a stepping stone to a deeper and more valid understanding of the problem or phenomenon. It is with this in mind that I pose the following “wild and crazy” hypotheses.

I propose that there are some very basic principles or laws underlying life forms on this planet:

Life forms maximize energy availability for reproduction and associated processes and minimize the amount of energy expended in carrying out reproduction and related functions such as food digestion. I call this the energy consideration principle.

Evolution itself acts in accordance with the energy consideration with adaptation being a structural/functional change in a species which increases the ratio of energy available to energy consumed.

Adaptation is a function which depends on the interaction of genetic variables and environmental variables.

For many species this interactivity between genetic and environmental factors has resulted in social living to enhance resource (energy) availability and the efficiency of energy expending processes such as hunting.

The human brain represents the pinnacle of interactivity with postnatal development of the cerebral cortex through neuroplasticity facilitated by a relatively long period of nurturing and both informal and formal education/learning.


It is impossible for any one person to be cognizant of the latest advances in the varied sub disciplines of psychology ranging from neuropsychology to evolutionary psychology. Indeed I think that one reason psychology is in a kind of disarray right now, with so many disparate sub disciplines and competing explanatory theories, is that there are too few, if any, general principles or “laws” which could be used to integrate findings and theories. I think the development of such fundamental principles would help psychologists synthesize the vast amount of research data being reported today in scientific journals.

You are invited to make comments about these hypotheses or to suggest alternative ones. It is hoped that the speculations, reflections, and ongoing discussions in Sci-mat will contribute in some small ways to solutions for the many problems faced by modern human civilization.

Wednesday, May 6, 2009

Retired scientists: an untapped resource

Long past are my days of striving for great scientific achievements which sadly never came. With the passing decades, I have mellowed and become more accepting of my relatively limited contributions to scientific progress. I have become more tolerant, and less judgemental of the opinions of others including my fellow scientists. Also retirement has given me the leisure time to take the broader outlook on matters scientific and life in general. Although I still tend to approach science from the old fashioned reductionist approach popular in my youth, I simultaneously adhere to a humanist stance philosophically. I have never lost faith in the dream that science is a powerful means for advancing the quality of life of mankind. And I am sure I am not the only retired or semi retired scientist who holds these views. I think the retired status is useful because only then are scientists relatively free of external pressures and influences e.g. granting agencies, university promotions etc. As such I believe that retired scientists constitute a most valuable resource for when it comes to applying science to solve modern society’s problems and making this world a better place.

The problems which plague current civilization have two fundamental sources. Firstly, our biological and psychological nature and our social, political, and economic systems have roots extending back to our ancient evolutionary origins. These roots and their disadvantageous consequences go largely unrecognized by most of mankind. Secondly, modern civilization is not adequately attuned to, and in control of, the sometimes subtle, sometimes dramatic, effects on it of the technology made possible by scientific research. These are two very different sources of current world problems.

It is my belief that the solution to the problems created by these two root causes would be greatly facilitated by tapping the accumulated wisdom of the community of mature scientists. It cannot be left completely in the hands of politicians or worse still the blind hand of the market economy. Perhaps I am being influenced too much by my Jungian archetype of the wise old person or by my reading of Plato’s republic. And I know that science alone is not enough in this reshaping of modern civilization. But nevertheless, I believe that retired scientists can make a useful contribution along with others to making the world a better place.

I have listed below three serious societal problems which I think are ripe to be managed by the “wise” application of recent discoveries in neuroscience and psychology after consultation with and input from the community of retired scientists. I have also included what I feel are the important effects of these problems and a few of the most recent research articles on these topics. If you know of any other important research on these topics, please send them in to this blog. In future posts I will discuss these and other topics.

Some basic world problems, their effects, and recent research references


Inadequate parenting/nurturing of children (child abuse/neglect) leads to difficulties such as poor emotional self-regulation, deficient ability to respond to life’s challenges in a reflective (mindful) way, and limited interpersonal skills.

Recent research:
Teicher, M. H., Tomoda, A., & Andersen, S. L. (2006). Neurobiological consequences of early stress and childhood maltreatment: are results from human and animal studies comparable? Ann. N. Y. Acad. Sci 2006; 1071:313-323. This article is one of a series in a special issue of the New York Academy of Sciences called “PSYCHOBIOLOGY OF POSTTRAUMATIC STRESS DISORDER: A Decade of Progress”. Part V is called “Contributions of Developmental and Basic Neuroscience to Understanding PTSD”.

Addictions (drug, gambling, etc); insatiable needs e.g. for sex, power, status, material things; and obsessions lead to personal and interpersonal distress e.g. unemployment, divorce and widespread social problems e.g. poverty.
Recent research:
Robbins, T.W., Everitt, B.J. & Nutt, D.J. (2008). Introduction. The neurobiology of drug addiction: new vistas. Phil. Trans. R. Soc. B, 363, 3109-3111.
Potenza, M. N. (2008). The neurobiology of pathological gambling and drug addiction: an overview and new findings. Phil. Trans. R. Soc. B , 363, 3181–3189.
Both of these articles appear in a special issue of The Philosophical Transactions of the Royal Society B in 2008 entitled “The Neurobiology of Addictions.”

Prejudices and lack of tolerance for differences of all kinds including disfigurements of any kind, mental or physical handicaps, differences in skin colour, race, religion, and sexual orientation. These types of prejudice lead to much of individual suffering as well as wars between nations.
Recent research:
Pettigrew, T. F. (2009). Probing the complexity fo intergroup prejudice.
International Journal of Psychology. 44(1), 40-42.
Muraven, M. (2008). Prejudice as self-control failure. Journal of Applied Social Psychology, 38(2), 314-333.
Ito, T. A., Willadsen-Jensen, E., Correll,J., Harmon-Jones, E. (Ed), Winkielman, P. (Ed). (2007). Social Neuroscience and Social Perception: New Perspectives on Categortization, Prejudice and Stereotyping.
In “Social neuroscience: Integrating biological and psychological explanations of social behavior.” (pp. 401-421). New York, NY, US: Guilford Press.

In concluding, I would like once again to state the purpose of this blog. Are you an older retired scientist who just loves science? Does your interest in science continue unabated in your heart and mind? Would you like to have some way of sharing with others your reflections on various topics in science in an informal and accepting platform? Do you believe that science has the potential to make the world a better place? If so I hope you will visit this blog often. I hope that Sci-mat will provide a convenient and useful means for retired scientists to communicate with each other and with society at large.

Friday, May 1, 2009

Some strategic problems with the scientific endeavour

I believe that progress in scientific knowledge is being hindered by several factors. First, knowledge is increasing faster than it can be reviewed, digested, and integrated. The rate of increase in scientific knowledge, for example knowledge about the brain and human psychology, is exponentially increasing and, in fact, in the last decade or so, has been explosive. New techniques such as brain scans and methods for exploring the “adaptive” unconscious are being applied to a constantly wider range of topics ranging from the classical areas such as learning, memory, attention, sexuality, and sports psychology to name but a few.

Secondly younger scientists in order to keep up to date can hardly take time to review the history of important historical events and trends in science. Consequently Sci-mat, which especially welcomes the speculations and reflections of retired scientists, provides a novel opportunity for mature scientists to reflect on previous research results and theories and integrate them with current research to create new theories of brain and mental function. When I think of the older biological research papers, for example in physiology, which were written before the Watson and Crick DNA revolution, I wonder how much important information has been lost.

A particular problem with respect to psychology, and perhaps to some other sciences, is that there is no general theory, to connect the latest advances in the many sub-disciplines of psychology ranging from neuropsychology to evolutionary psychology let alone related sciences such as anthropology. This makes it difficult to integrate material (assuming one person was able to understand research in these disparate specialities).

One final problem is that there are few places that scientists feel free to speculate freely about their scientific ideas and theories. I know from my own nearly half century of personal experience as a research neurobiologist and later clinical psychologist is that making “wild” speculative theories is frowned upon by working scientists in their everyday research. It is further hoped that other retired scientists who like myself, are not competing for research grants, will feel free to share their ideas. After all, we no longer have to guard against being scooped in the highly competitive arena of scientific research.

I hope that this blog acts as an antidote to these problems by providing a place to broadly reflect and imaginatively speculate on the implications of the most recent scientific discoveries for the advancement of mankind.