Movement and perception disorders : a case for dissolution?

I have touched upon the work of Hughlings-Jackson earlier, albeit very obliquely, and readers familiar with with his work will know the immense contributions he has made to the understanding of epilepsy and other neurological disorders. I was recently reading the Croonian Lectures on the Evolution and dissolution of human nervous system and I encourage my readers to read the 3 lectures in their entirety. Let me briefly try to summarize his approach to brain first:

Hughligs Jackson believed that the brain had evolved. Also that the human brain is heterogeneous with three distinct evolutionary distinct components that were perfected in evolutionary dissimilar times: in this sense he sort of laid the groundwork for the Triune Brain theory of Paul MacLean.

He also believed that these three evolutionary distinct (logical) components of the human brain were hierarchical in nature and that all that these centers really did was representation of impressions and movements or re-representation of that initial representation (in successively higher centers). He also proposed that lower centers were more simple, more organized, more automatic and more reflexive in nature; while the highest centers were the least automatic, least organized , but the most complex and the least reflex-like in nature.

As these centers evolved one after the other, each such center has a positive function that only it can provide and it also inhibits some of the functions that were earlier provided by the lower layers; or in other words keeps the lower layers in check.

He also believed in the concept of dissolution: whereby when a higher center is not working properly then this would result in the lower centers asserting their autonomy. The loss of the higher layer/ center would not only result in the loss of function associated with that center (negative symptoms) ; but by freeing the autonomic activity of lower center from higher inhibition, it would also lead to some new functions to be experienced (positive symptoms). Thus a dissolution that affects the third or highest layer , would free the intermediate layer to produce some positive effects, and because of unavailability of the higher layer function would also lead to loss of some functionality.

He most fully developed these ideas in association with epilepsy patients, in which he believed, that the epileptiform seizure or discharge leads to inactivity of higher layers (1, 2 or all 3) and inappropriate activity in lower layers, thereby produce different degrees of negative and positive symptoms/ behaviors. My earlier post did contain references to this.

We find evidence for the truth of most of his ideas in today's neuroscience developments.

This time I will like to touch upon how he himself had, sort of extended the triune brain, to an eight stage brain and how he delineated eight different levels of dissolution, each progressively of a more severe level than the earlier one , while he related the concept of dissolution in the Croonian lectures (lecture 1) with the help of movement disorders.

Before we proceed, it is instructive to note that Jackson believed in two levels of consciousness: subject and object- the former related to awareness of impressions; while the latter to movements. In simpler terms , he believed that we could discuss, movement (and volitional) related stuff separate from perceptual stuff and I'll stick to that distinction in this post.

I'll first quote at length from him (I have reformatted the stuff, so please read the original lecture for a balanced view):

I now come to give examples of dissolution. I confess that I have selected cases which illustrate most definitely, not pretending to be able to show that all the diseases of which we have a large clinical knowledge exemplify the law of dissolution. However, I instance very common cases, or cases in which the pathology has been well worked out; they are cases dependent on disease at various levels from the bottom to the top of the central nervous system. Most of them are examples of local dissolution.

1. Starting at the bottom of the central nervous system, the first example is the commonest variety of progressive muscular atrophy. We see here that atrophy begins in the most voluntary limb, the arm; it affects first the most voluntary part of that limb, the hand, and first of all the most voluntary part of the hand; it then spreads to the trunk, in general to the more antomatic parts. To speak of a lower level of evolution in this case is almost to state a barren truism. At a stage when the muscles of the hand only are wasted, there is atrophy of the first or second dorsal anterior horn; the lower level of evolution is made up of the higher anterior horns for muscles of the arm. This statement, however, is worth making, for it shows clearly that by higher and lower is meant anatomico-physiologically higher or lower.
2. Going a stage higher we come to hemiplegia, owing to destruction of part of a plexus in the mid-region of the brain. Choosing the commonest variety of hemiplegia, we say that there is loss of more or fewer of the most voluntary movements of one side of the body; we find that the arm, the more voluntary limb, suffers the more and longer; we find, too, that the most voluntary part of the face suffers more than the rest of the face. Here we must speak particularly of the lower level of evolution remaining; strictly we should say collateral and lower. We note that although unilateral movements (the more voluntary) are lost, the more automatic (the bilateral) are retained. Long ago this was explained by Broadbent. Subsequent clinical researches are in accord with his hypothesis. The point of it is that the bilateral movements escape in cases of hemiplegia in spite of destruction of some of the nervous arrangements representing them; the movements are doubly represented—that is, in each half of the brain. Hemiplegia is a clear case of dissolution, loss of the most voluntary movements of one side of the body with persistence of the more automatic movements.
3. The next illustration is paralysis agitans. Apart from all speculation as to the seat of this disease, the motorial disorder illustrates dissolution well. In most cases the tremor affects the arm first, begins in the hand, and in the thumb and index-finger. The motorial disorder in this disease becomes bilateral; in an advanced stage paralysis agitans is double hemiplegia with rigidity—is a two-sided dissolution.
4. Next we speak of epileptiform seizures which are unquestionably owing to disease in the midregion of the brain (middle motor centers). Taking the commonest variety, we see that the spasm mostly begins in the arm, nearly always in the hand, and most frequently in the thumb or index-finger, or both; these two digits are the most voluntary parts of the whole body.
5. . [The next illustration was by cases of temporary paralysis after epileptiform seizures.]
6. Cborea is a disease in which the limbs (the most voluntary parts) are affected more than the trunk (the more automatic parts), and the arms (the more voluntary limbs) suffer more than the legs. The localization of this disease has not been made out;symptomatically, however, it illustrates dissolution. Chorea has a special interest for me. The great elaborateness of the movements points to disease “high up" —to disease on a high level of evolution. Twenty years ago, from thinking on its peculiarities, it occurred to me that some convolutions represent movements. A view I have taken ever since.
7. Aphasia. This well illustrates the doctrine of dissolution, and in several ways. We will consider a case of complete speechlessness. (a) There is loss of intellectual (the more voluntary) language, with persistence of emotional (the more automatic) language. In detail the patient cannot speak, and his pantomime is of a very simple kind; yet, on the other hand, he smiles, frowns, varies the tones of his voice (be may be able to sing), and gesticulates as well as ever. Gesticulation, which is an emotional manifestation, must be distinguished from pantomime, which is part of intellectual language. (b) The frequent persistence of “Yes“ and “No“ in the case of patients who are otherwise entirely speechless is a fact of extreme significance. We see that the patient has lost all speech, with the exception of the two most automatic of all verbal utterances. “Yes“and “No“ are evidently most general, for they assent to or dissent from any statement. In consequence of being frequently used, the correlative nervous arrangements are of necessity highly organized, and, as a further consequence, they are deeply automatic. (c) A more important, though not more significant, illustration is that the patient who cannot get out a word in speech nevertheless understands all that we say to him. Plainly this shows loss of a most voluntary service of words, with persistence of a more automatic service of words. We find illustrations in small corners. (d) There are three degrees of the utterance “No“ by aphasics. A patient may use it emotionally only—a most automatic service; another patient may also be able to reply correctly with it—a less automatic, but still very automatic service. (Here there is some real speech.) There is a still higher use of it, which some aphasics have not got. A patient who can reply “No“ to a question may be unable to say ‘No“ when told to do so. You ask the aphasic, “is your name Jones?“ he replies “No.“ You tell him to say “No,“ he tries and fails. You ask, “Are you a hundred years old ?“ He replies “No.“ You tell him to say “No.“ He cannot. Whilst not asserting that the inability to say “No“ when told is a failure in language, it is asserted that such inability with retention of power to use the word in reply illustrates dissolution. (e) A patient who is speechless may be unable to put out his tongue when told to do so; that he knows what is wanted is sometimes shown by his putting his finger in his mouth to help out the organ. That the tongue is not paralyzed in the ordinary sense is easily proved. The patient swallows well, which he could not do if bis tongue were as much paralysed as "it pretends to be.“ Besides, on other occasions he puts out his tongue, for example, to catch a stray crumb. Here is a reduction to a more automatic condition; there is no movement of the tongue more voluntary than that of putting it out when told. [The lecturer then remarked on swearing and on the utterance of other and innocent ejaculations by aphasics, remarking that some of these utterances had elaborate propositional structure but no propositional value. The patients could not repeat, say, what under excitement they uttered glibly and well. He spoke next of the frequent retention of some recurring utterance by aphasics, such as “Come on to me.“ These were not, from the mouth of the aphasic, of any propositional value, were not speech. He had no explanation to offer of these, but stated the hypothesis that they were the words the patient was uttering, or was about to utter, at the time he was taken ill.]
8. . So far I have spoken of local dissolution occurring on but one half of the nervous system on different levels. Coming to the highest centers I speak of uniform dissolution—of cases in which all divisions of these centers are subjected to the same evil influence. I choose some cases of insanity. In doing this I am taking up the most difficult of all nervous diseases. I grant that it is not possible to show in detail that they exemplify the principle of dissolution, but choosing the simplest of these most complex cases we rnay show clearly that they illustrate it in general. I take a very common-place example—delirium in acute non-cerebral disease. This, scientifically regarded, is a case of insanity. In this, as in all other cases of insanity, it is imperative to take equally into account not only the dissolution but the lower level of evolution that remains. The patient‘s condition is partIy negative and partly positive. Negatively, he ceases to know that be is in hospital, and ceases to recognise persons about him. In other words, he is lost to his surroundings, or, in equivalent terms, he is defectively conscious. We must not say that he does not know where he is because he is defectively conscious; his not knowing where he is is itself defect of consciousness. The negative mental state signifies, on the physical side, exhaustion, or loss of function, somehow caused, of some highest nervous arrangements of his highest centers. We may conveniently say that it shows loss of function of the topmost layer of his highest centers. No one, of course, believes that the highest centers, or any other centers, are in layers; but the supposition will simplify exposition. The other half of his condition is positive. Besides his not knowings, there are his wrong knowings. He imagines himself to be at home or at work, and acts as far as practicable as if he were; ceasing to recognize the nurse as a nurse, he takes her to be his wife. This, the positive part of his condition, shows activity of the second layer of his highest centers; but which, now that the normal topmost layer is out of function, is the then highest layer; his delirium is the “survival of the fittest states,“ on his then highest evolutionary level. Plainly, he je reduced to a more automatic condition. Being (negatively) lost, from loss of function of the highest, latest developed, and least organized, to his present “real,“ surroundings, he (positively) talks and acts as if adjusted to some former “ideal“ surroundings, necessarily the more organized.

This to me seems very promising: I am a die-hard fan of the eight stage evolutionary/ developmental model whereby the first five stages are more similar, the next two on a qualitatively different level; while the last or eighth one takes one a notch higher up the octave to a different qualitative level altogether, although resembling or analogous to the first stage to an extent.

I keep mapping analogies between the different stages evident in different developmental / evolutionary processes and this piece of puzzle fits in nicely.

I'll now like to speculate a bit. I'll first restrict myself to movement/action planning, execution and control. I believe that the regions of the brain involved in this activity are (in a heirarchichal order) :

1. Frontal Cortex (supplementary motor area) : decides which action to initiate/ plans and co-ordinates with respect to complex actions involving say both hands. More involvement in 'voluntary' actions
   
2. Primary Motor cortex : Actual execution of the intended/ chosen action.
3. Pre-motor cortex:responsible for motor guidance of movements especially with respect to external cues
   
4. Parietal cortex:responsible for transforming visual information into motor commands
5. Somatosensory cortex: this too is involved in motor circuits ; see this too.(synapses to and from this go to cerebellum/ basal ganglia): probably involved in triggering visual information related to the action. I am tempted to replace this with Thalamus and I just might do that after some more research!!
   
6. Basal Ganglia: a set of structures that are involved in gross motor control
7. Cerebellum: a structure involved in fine motor control
8. Brain Stem: a structure involve in controlling vital involuntary movements like breathing, heart beat etc. these movements are neither voluntary nor automatic; they are involuntary and thus a notch different.

Now coming back to the disorders of the movement delineated by hughlings-Jackson, we can readily see some correspondences. The Basal Ganglia abnormality leading to Huntington's Chorea is clearly at level 6. The primary motor cortex lesion leading to stage 2 hemiplegia is also well established. The epileptofm seizure related spasms and temporary paralysis just after that may be plausibly related to lesions of parietal and somatosnesory cortices. The lesion of pre-motor area may give rise to alien hand syndrome (to be distinguished from Anarchic hand syndrome), whereby you grab any object in sight compulsively. The hughlinghs-jackson description of Parkinsonisms at level 3 does not really gel here as Parkinsonism is more of a basal ganglia problem. Similarly PMA (progressive muscular atrophy) is no longer a valid diagnosis, so it may not map to SMA lesion or dysfunction. SMA dysfunction or lesion may instead produce syndromes like the mirror hand syndrome , in which both hands are used for the same action, though only one hand would have sufficed. It is interesting to note that this mirror hand syndrome is conceptualized today as freeing of SMA inhibition of PMA, thus allowing parallel planning of the same action. Similarly level 7 lesions of cerebellum may be more related to Ataxia rather than aphaisas.

Despite the above problems with the above conceptualization, I find the efforts of Jackson is the right direction and ahead of hist time.

I'll now end with a teaser of things to come. It is related to disorders of phenomenal consciousness classified by Thomas Metzinger in Being No One, and they are as follows :

Deviant phenomenal models of reality

1. Agnosia
   
2. Neglect
   
3. Blindsight
   
4. Hallucinations
   
5. Dreams

To me they follow the same 5 stage process, with each stage analogous to the movement related disorder.More about that later.

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Intentionality: order, order!

I have been reading, of late, some articles that have invoked the concept of intentionality and its orders. More specifically, this has been with respect to Social Brian hypothesis of Robin Dunbar, whereby he claims that humans evolved intelligence to be able to cope with your in-laws (and other social members of one's groups). Leaving asides the main premise of the social brain hypothesis, which I find convincing to an extent, he also claims that monkeys have only first order intentionality, while apes have second order and humans are able to function at about fifth order of intentionality, with some like Shakespeare being able to work on the sixth order. To quote at length form the 'beginner's guide to intentionality':

Computers can be said to know things because their memories contain information; however, it seems unlikely that they know that they know these things, in that we have no evidence that they can reflect on their states of ‘‘mind.’’ In the jargon of the philosophy of mind, computers are zero-order intentional machines. Intentionality is the term that philosophers of mind use to refer to the state of having a state of mind (knowing, believing, thinking, wanting, understanding, intending, etc).

Most vertebrates are probably capable of reflecting on their states of mind, at least in some crude sense: they know that they know. Organisms of this kind are first-order intentional. By extension, second-order intentional organisms know that someone else knows something, and third-order intentional organisms know that someone else knows that someone else knows something. In principle, the sequence can be extended reflexively indefinitely, although, in practice, humans rarely engage in more than fourth-order intentionality in everyday life and probably face an upper limit at sixth-order (‘‘Peter knows that Jane believes that Mark thinks that Paula wants Jake to suppose that Amelia intends to do something’’).

A minimum of fourth-order intentionality is required for literature that goes beyond the merely narrative (‘‘the writer wants the reader to believe that character A thinks that character B intends to do something’’). Similar abilities may be required for science, since doing science requires us to ask whether the world can be other than it is (a second-order problem at the very least) and then ask someone else to do the same (an additional order of intentionality).

I find the above definitions (and other I have found on the web), slightly problematic, so I'll attempt my own synthesis on the matter:

1. Zeroth order or No intentionality: Having knowledge but no 'awareness ' of knowledge. Mere representation of information, but no meta awareness of that representation. Computers and machines , and even simple life forms like bacteria etc, may have this (no) intentionality, wherein they have 'facts' about the world, but no beliefs, desires etc.
   
2. First Order Intentionality: Awareness of knowledge that is distinct from mere knowledge. A belief system. Knowing that something you know may be incorrect from the actual world scenario. You know what you know and you know what you don't know. Meta cognition. Beliefs, desires etc. Important thing to note is that only 'I know' is covered in this definition. A limited 'You know as I know' may be covered at this order as one may be aware of other people as being intentional agents , but whose beliefs are congruent with one's own! 'You know something that may be different from what I know' is not possible yet. Most mammals including rats and monkeys are at this level. Awareness ta this level may be that others too have facts of world at their disposal.
   
3. Second order intentionality: Awareness of a belief-system that is distinct from the belief system itself. A Theory of Mind. You know that someone else may know things differently from both as they are and as you think they are. Awareness that others have a mind or a belief-system. Ability to keep two different belief systems in the mind- one of your own and the other of another third person. Apes and children age 4 demonstrate this level and order of intentionality. They have a theory of mind as to the fact that others have beliefs and that these are after all beliefs and can be false too. Awareness that others have beliefs, but still no awareness that they have a ToM too!
4. Third order intentionality: Awareness of a ToM that is distinct from the ToM itself. A communicative intent. Joint attention. Language. symbol grounding. Knowing that someone else may have different views regarding what you yourself believe and thus it is important to communicate your internal intentions, beliefs , desires etc to others so that there is common ground on which communication and speech acts can proceed. this also enables grounds for lies and deceptions in the sense that one can deliberately lead someone to believe what one oneself does not believe. As per this source , communication requires third order of intentionality. To quote:
   



Suppose my little brother intends for me to jump. He might (and sometimes does) achieve this by sneaking up behind me and yelling "Boo!". But that's not communication, in the fullest sense of the word. It would be quite a different sort of action were he to instead request of me, "please jump." (I don't think he'd find that nearly so fun, for one thing.) Such a speech-act would show not only that he intends me to jump, but also that he intends for me to recognize that he wants me to jump.

Purposive communication requires an intentional state of at least third-order complexity. The speaker wants his audience to recognize what the speaker intends by his utterance. Put another way, you don't just communicate 'X', you rather communicate, "I am trying to convey 'X'". (This is the difference between discreetly insulting someone, or making it clear to him that you want him to know you're insulting him.) Anything less would fail to qualify as 'communication', in the fullest sense of the word.



5. Fourth-order Intentionality: Awareness of a communicative act that is distinct from the communicative act itself: A narrative or story telling/ story understanding capability. An ability to weave experiences into a running narrative such that it incorporates different communicative acts or 'scenes'. An understanding of 'roles' that one is playing that give shape to all the communicative acts one participate sin and the narrative one weaves for oneself. A limited awareness that others are also communicative agents , but not a full awareness , that like oneself, they are also acting a script/ playing a role/ having a running narrative using which they interpret events. It is important to emphasize that story telling requires one to visit a new world in which the protagonist is separate, but also one is in a state of willful suspension of disbelief and thus one feels along-with the protagonist, but still retains one's own narrative: separate, and quite distinct, form the story-teller's narrative. Story-telling, and story understanding and the interpreter module of humans that gives rise to stream of consciousness to me are the hallmarks of fourth order of intentionality and most of us juts stop there. One may mistakenly believe that there is only one role / narrative and that everybody shares the same narrative.
   
6. Fifth order intentionality: Awareness of roles and narratives that are distinct from the role or narrative. An organizing system of religion/ myths using which one interprets stories. Awareness that others too have their own narratives and are playing a script/ performing their roles. Awareness that one's role/ stance / understanding of world can be radically different from someone having the same experiences but using a different interpretation. A culture . A worldview. It is instructive to note that Dunbar considers that religion and story telling are higher level intentional activities.

I'll leave things as they are for now as this fits nicely with my obsession with 5 + 3 stage developmental process. Higher orders of intentionality may exist, but probably we humans are not yet evolved to appreciate their subtleties/ find practical examples.

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Love and bond

The blogosphere and the news tabloids are abuzz with the latest discovery that Vasoprassin may serve a similar role in humans as it does in prairie voles, when it comes to pair bonding. While , it might be true that 'if you love someone , set him free' a more strategic and evolutionary sound strategy is to keep him bound in a pair-bond. The females do this, by somehow , releasing Vasporossin in their partners brain and when this vasporossin binds to its receptors in the Brain, it leads to more bonding and pro-social behavior by the male.  

A recent PNAS paper has implicated the vasoprassin receptor gene alleles for some variation in the marital bond. Read the excellent Not Exactly Rocket Science post for more details. Interestingly the gene variant , while conferring lower marital bond probability, also ups the risk for Autism. The mechanism underlying this must therefore be social - as social difficulties in Autistics may be related to this. This leads to the interesting hypothesis that people with Psychosis may have a stronger version o this pair-bonding receptor gene and thus may be less prone to depart ways, once a pis bond has been formed, and this may explain why despite low chances for procreation, the genes for schizophrenia may be carried out as the limited number of offspring's are more heavily invested in by parents due to a stable pair bond.

But I digress, let this Post be about Love and what better way to celebrate that with a 'Prairie voles in Love' poem by Scicurious!

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Oligodendrocytes, Homunculus and surgery for Epilepsy

Guess what each of them have in common? While the discovery of oligodendrocytes was a result of painstaking cyto-architectural efforts of Dr. Penfield, the Montreal procedure he developed, which involved probing the brain areas around the tumor to be removed, also paved the way for the 'scientific phrenology' whereby the sensory and motor (and other areas too eventually) areas were mapped and gifted us with the Homunculus. If you, like me, were unaware of the oligodendrocytes link with Penfield, you may find Neurophiliosophy post on Penfield fascinating. Even if you knew this fact, do checkout the excellent profile of Dr. Penfield, and discover how he is connected to the who's who of Neuroscience- from Hughlinghs Jackson to Donald Hebb. An excellent article indeed and one that will definitely find place in the Open Lab 2008.

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Overcoming the Monster- Indian style!

Thanks to Vaughan, I spent a greater time of my day researching the 'basic plots' that are behind all good stories. Regular readers of this blog, would know that I am a sucker for 'five basic' or 'eight basic' anything (with a variation that 'seven basic' is also accommodated as, as per my theory the eighth basic may be on a different qualitative level and thus likely to be missed!

The original Mind Hacks post was regarding Levitin's new book that claims that there are only six basic types of songs: Friendship, Joy, Comfort, Knowledge, Ceremony/religion/ritual and Love, but I strayed from the main course and started savoring the eight basic dramatic plots served by Dennis Johnson: Cinderella, Achilles, Faust, Tristan , Circe, Romeo&Juliet, Orpheus and the Irrepressible Hero (The FOOL anyone?) (all but the last named after famous characters). It wasn't long before I was reading 'The Seven Basic Plots' by Christopher Booker.

The seven basic plots Booker outlines are : Overcoming the Monster, Rags to Riches, The Quest, Voyage & return, Comedy, Tragedy and Rebirth. while I'll most probably write more on the topic after reading the whole book , I would like to comment now on the first plot: 'Overcoming the Monster' .

In this, typically a Hero is pitted against a monster, whom he slays to win a princess/ treasure / kingdom etc. While reading this plot, two famous Lord Krishna myths immediately flashed before me:

The first is the myth of how Satrjit's Mani (pearl) came in possession of Jambvant and how Krishna fought and defeated Jambvant to defend himself from the false theft accusation of the pearl. Now this is no 'traditional' overcoming the monster myth as Jambvant is no monster- rather he is a revered chiranjivi being. Also, Jambvant is not killed, but gracefully withdraws from the fight after realizing the 'god' nature of Krishna. Howvere, like traditional 'overcome the monster' plot, there is treasure guarded and a princess (Jambvati , the daughter of Jambvant) married after the defeat. This time another princess (two marriages!) Satyabhama, who is the daughter of the King Satarjit, is also married to Krishna. Krishna, of course doesnt take the pearl (treasure) buts ends up with two wives! So some form of the plot is there, but not in its entirety. Also, the whole narrative is pre-ordained as Krishna saw moon during inauspicious time, so the take home is that there is no real evil or fight involved - it is all Maya or illusion!!

The second 'overcoming the monster' myth is again from Krishna myth. This time the monster is indeed really monstrous-a big, venomous serpent called Kaliya, and like traditional story the kingdom and the common people are troubled by this serpent; but in this case also no death of Kaliya is involved: he is just tamed and sent to a different place; also it seems Kaliya was there because of fear of Garuda, so again Kaliya per se is not 'really ' evil and all is Maya.

I like this circularity and 'fictional maya-like' view of things of Indian culture very much and I am sure the other plots would also have been similarly adapted by Indians: circular and without any 'real' 'evil' lurking around.

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Exploration/ Exploitation == Maximisers/ Satisficers?

There is an interesting research coverage at We are Only Human blog regarding whether people may have two different cognitive styles- one based on exploration of novel ideas and the other based on exploitation or focus on a particular familiar idea. The study employs evolutionary concepts and theorizes that these different cognitive styles may be a reflection of the different foraging styles that might have been selected for and relevant in EEA.

Specifically, while foraging for food in a habitat where the food supply and resources are unpredictable , one is faced with a choice when one has discovered a food source: whether to exploit this food source (a jungle area having sparse edible leaves) or to move ahead in search of a potentially better food source (a jungle area having abundant edible and nutritious fruits) . Both strategies , that of exploring or exploiting can be advantageous and may have been selected for. It is also possible that humans can use either of the strategies based on the environment- (food source distribution) , but may be inclined towards one strategy or the other. The authors of the study surmised that both the strategies have been selected for and we have the potential to use either of the strategy. Moreover, the same foraging strategy we use or are primed of, would also be visible in the cognitive strategy we use.

They used an ingenious technique to prime the subjects with either of the foraging strategies (go read the excellent We are only human blog post) and found that humans were flexible in the use of the appropriate strategy, given the appropriate context, and that the foraging strategy primed the corresponding cognitive strategy. To boot, those primed with an exploratory foraging strategy would be more prone to using exploratory cognitive strategies when confronted with a cognitive task and vice versa. They also found systematic differences between individuals cognitive and foraging styles- some were more exploratory than the others.

This reminds me of the Maximizers/ Satisficers distinction in decision-making style that Barry Scwatrz has introduced and brought to public attention. Basically a Maximizer , when faced with a decision and choice, would go on computing the utility of different choices and try to choose the option that maximizes his utility and is the 'best'. A Satisficer, on the other hand would also explore options, but stop his exploration, when he finds an option that is 'good enough'. I wonder, if just like the exploratory/ Exploitative cognitive and foraging styles, this is just another dimension of the same underlying phenomenon- whether to explore more - or to exploit what is available. To take an example, for marriage, a satisficing strategy may work best - as told in "The Little Prince" one should stop searching for more flowers if one has already had the fortune of possessing a flower.

"People where you live," the little prince said, "grow five thousand roses in one garden... yet they don't find what they're looking for..."

"They don't find it," I answered.

"And yet what they're looking for could be found in a single rose, or a little water..."

An interesting experiment would be to see, if the foraging style, the cognitive style, and the decisions style are all correlated within individuals and if priming one can influence the outcome of the other style.

If so, could there be an underlying neural phenomenon , common to all?

Wray, the author of We are only human blog makes a bold conjecture and relates this to the finding that dopamine levels.

Exploratory and inattentive foraging—actual or abstract—appears linked to decreases in the brain chemical dopamine.

He even relates this to cognitive disorders like Autism and ADHD.

By analogy, in conditions where baseline dopamine is more, like in bipolar and psychosis, one may be more inclined to a more staisficing/ 'I'm feeling Lucky' strategy in which the very first option is acceptable. This may explain the 'jumping-to-conclusions' bias in schizophrenia/ psychosis.

To make things more explicit, though the leading dopamine theory in vogue now is of 'error-prediction' , a competing, and to me more reasonable, view of dopamine function is incentive salience i.e. what 'value'/ importance does the stimuli have for the person in question. The importance can be both positive and negative and thus we have found that dopamine is involved in both dread and desire. The dominant reward prediction theory faces many challenges, the least of which is response of dopamine neurons to novel events. A dopamine burst is also associated with 'novel' events and thus dopamine is somehow involved in/ triggered by Novelty. Baseline dopamine may constrain the dopamine surge felt on a novel event. Thus, in schizophrenia/ psychosis , with baseline dopamine high, a dopamine burst on novelty detection may be high enough so that it is meaningful and may not lead to more exploratory behavior. While in the disorders where baseline dopamine is low, one may require a more profound dopamine burst before the stimuli becoming meaningful and thus may go on seeking novel stimulus till one finds one 'big enough to trigger salience'.

We may extend the salience argument to other domains than incentive. If the chief function of dopamine is to mark salience, then it may also be instrumental in memory and attention. Only what is Salient gets attention, and only what is salient gets into Working Memory. Thus,a high dopamine level may predispose to treating almost everything as salient, leading to delusions of reference (everything is meaningfully related to self etc) etc. Working Memory may be taxed due to everything trying to get in- and thus poor WM in people with schizophrenia. Also, every trivial thing may grab attention- leading to poor sensory gating and conditions like lack of pre-pulse inhibition. On the flip side, while making sense of ones experience, one may accept the first possible explanation and do not search further - thus leading to persistence of delusions.

An opposite scenario would be when one keeps exploring the environment and nothing seems novel due to low dopamine levels. This would be the classical Autistic repetitive and stereotype behaviors. There would be sensory over stimulation, as nothing is salient and one needs to explore more and more. On the other hand, WM capabilities may be good/ savant like, as not every piece of information grabs attention. Everything should seem insignificant and the only way to arrive at decision / choose action would be via exhaustive enumeration and logical evaluations of all options. even after obvious explanations for phenomenon, one may keep looking for a better explanation. No wonder , as per my theory, more scientists would be autistic.

Perhaps, I am stretching things too far, but to me the dopamine connection to Salience/ Meaning/ Importance is sort of worth exploring and I will write more about that in future. For now, let us be willing to associate Salience not just with stimuli related to motivation, but also with stimuli relevant in sensation, perception,learning and memory. If so the common underlying mechanism responsible for differentiating us as a exploratory and expolitatory forager (food) may also be related to our different cognitive styles, our different decision-making styles and our different baseline dopamine levels.

Dopamine though is most strongly related to food and sex. I could even stretch this argument and say this may be related to r and K reproductive styles (note these styles are species specific, but I believe individuals in a specie may also vary on the reproductive strategy along this dimension). Thus, while explorers may have r type of reproductive style, the exploiters may have a K reproductive style.

At one extreme are r-strategies, emphasizing gamete production, mating behavior, and high reproductive rates, and at the other extreme are K-strategies, emphasizing high levels of parental care, resource acquisition, kin provisioning, and social complexity.

If K-strategy is what humans have chosen, maybe exploitation in all areas (cognitive, decision-making, foraging) is more relevant and in tune with our nature. Maybe that's why I'll always be on the side of Psychosis than Autism!! Though, to put things in perspective, maybe humans have evolved to use both strategies as the situations demands , and the best thing would be to use the strategy situation-specific and not lean towards either extremes.

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Top 100 cutting edge science blogs!

A top 100 cutting edge science blogs list has been compiled by X-Ray Technician Schools and includes a host of good science blogs. Some I already knew and some are new to me. It is a must-visit for every science buff who is interested in cutting edge science and would like to increase the number of good science blogs that one regularly monitors/ reads.

The list is broken up into categories and there are categories like Health and Biology; a category that is conspicuously missing is psychology/neuroscience, but you can find many good blogs related to psychology/neuroscience in that list, so do take a look.

I would also like to thank the hosts for featuring The Mouse Trap blog in that list and hope that this blog lives up to the expectations and does retain its cutting edge focus!

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Ode to the Brain: Encephalon 51st edition now out!

Welcome to the 51st edition of the brain carnival, Encephalon.

25 little gems,
on the mind and the brain-
aren't they one and the same!

SharpBrains sets the tone for this edition of the Encephalon with a collection of 25 haikus contributed by its readers- all with either the brain or the mind as their guiding theme. While each haiku present there is unique and worth a read, the allusion above to 'aren't they one and the same' has more to do with the 'mind and the brain' part --- is the age-old dichotomy still relevant; do we still need a mind when we are increasingly comfortable talking in terms of the brain?

Daniel from Neuranthropology examines this age-old dichotomy from a Critical Neurosciences perspective and argues that instead of trying to resolve this dichotomy, one should focus instead, on the new paradigms, methods and approaches that become available when one tries to explain mental phenomenon in neural terms. The other two aspects of Critical Neuroscience he highlights are how ideology may influence the (neuro) science and how the new neuroscience should be a science for change- actively taking responsibility for the impact that new findings bring about.

What's in a name? That which we call a rose
By any other name would smell as sweet
Shakespeare

Continuing with the mind-brain theme, is it plausible that the reason we focus so much on the dichotomy is just because we have a separate name for the mind from the brain? Dennett seems to think so for consciousness- he believes that just because we have invented a unitary name for that inner-subjective-feel phenomena that may be a result of diverse neural phenomena, we are tricked into believing that we have a unitary consciousness. This trickery or illusion is accomplished by a Magical sleight of hand- that of giving a name to an un-existing phenomenon. Vaughan, over at The Mind Hacks, illustrates this beautifully using a card trick called 'The Tuned Deck' in which just attributing a magical tuning property to 'the' deck leads to even seasoned magicians getting dumb-founded as they try to discover a single concept behind the many diverse tricks that are used to create that trickery. So it seems that naming something a rose endows it with an essence that was not earlier present!

Oh sweet memory,
my heart breaks deep inside.
Oh sweet memory,
it's you I'm trying to hide.
Mahfooz Ali

While a rose may or may not smell sweet, depending on whether it is given a name or not, we all know too well the association between sweet and memories. But I bet you didn't knew that there was another angle to this association between sweet and memories. Latest research indicates that moderate increases in blood sugar levels can lead to better short-term memory. Jeniifer Gibson, from The BrainBlogger, highlights this recent research and cautions that those who have better blood sugar regulation, do better cognitively and that high levels of baseline blood sugar are associated with reduced hippocampal volume and reduced cognitive functioning. So do control your intake of sugar-and don't use this as a pretext to indulge your sweet cravings- after all research such as this keeps indicating that Alzheimer's may just be a type-III diabetes!!.

"Where is our Safe Haven?"
"Where do we hide?"
"Up ahead is a church still standing!
I'd better hurry, and get inside."
WrittenBylucky90250

While it may be difficult to hide one's memories, it is very easy for us to spot a hiding place- a safe haven, a nest. Is the same true of mice- do they have 'concepts' and 'categories' - like the 'nest'- built-up / learned in their brains? Doctor Spurt at Effortless Incitement revisits a PNAS paper, that had been widely discussed at its time of publication, regarding whether mice encode concepts like nests using its hippocampal neurons. He finds evidence for three such type of neurons and comes out convinced ready to take on all Heideggereans!

No man is an island, entire of itself..
..any man's death diminishes me, because I am involved in mankind
John Donne

You may prefer to be confined to your safe haven or your own private island, but research shows that humans, in general, are extremely social and empathetic- determined to get inside each others' mind- and sometimes on each others nerves! but what about those, who have a diminished 'theory of mind'? Doc at the Mind, Soul and Body blog describes people with Asperger's syndrome and how they may lack some of the core prerequisites for discerning other peoples minds- deficits in recognizing faces, interpreting non-verbal cues and figurative languages and reduced empathy. He also takes stock of leading theories of why this difference may be - from inability to ignore sensory stimulus to the ever ubiquitous mirror neurons!

Mirror, mirror, on the wall,
Who in this land is fairest of all?

Fair or not, Mirror Neurons have been around for quite some time and have been credited with everything from Global Warming to US economic woes. Marc Dingman, at the Neuroscientifically Challenged, challenges this hegemony of Mirror Neurons, and though does not outright dismisses them, is sure that they would be replaced soon by neuronal groups called convergence-divergence zones (CDZs).Have we already come full circle? Would a mirror by any other name still keep us trapped? Before we jump to conclusions, we ought to read that well written piece about the latest Antonia Damasio paper in Nature, and appreciate that non-local CDZs with which the mirror neurons are to be replaced, are a neuronal circuit- and that too not specific to or linked to imitation. Rather, it is a higher-order association area are where many local CDZs inputs converge and which may subsequently reactivate those local CDZs when one aspect of the older experience is re experienced.

Mine eye and heart are at a mortal war,
How to divide the conquest of thy sight;
Mine eye my heart thy picture's sight would bar,
My heart mine eye the freedom of that right.
Shakespeare

Talking of debunking something-anything-one should not forget the Neurocritic. After all, it is his prerogative to criticize and thrash the Junk science. I'm sure Neurocritic would agree with Marc in debunking the Autism-is-due-to-mirror-neurons theory, but this time he is busy analyzing the gazes of people with Autism (hypo social), Williams syndrome (hyper social) and normal children especially how much time and which portions of a social scene do these different populations focus on. He finds that indeed the eye may have a will of its own and tracking it may reveal some of our inner dynamics. He reviews recent research that found that children with Williams syndrome spend more time looking at faces (and in that too on eyes); while the opposite pattern was observed for those with Autism. This Area of Interest had a statistically significant interaction with the group type (Autism, Williams, normal). However the most important takeaway from the study (which one of the commentators pointed and Neurocritc too concurred) was that 'normal' children spent a significant time staring at the breasts of the lady in the picture!!

"The brain is my second favorite organ"
Woody Allen

While many psychologist do not hesitate in advising on how to keep your first favorite organ in shape; other saner folks are more concerned about how to exercise your second favorite organ's muscles and what the emerging trends are. Alvaro at the SharpBrains blog lists the top 10 emerging trends in the brain fitness market and asks for other predictions - offering a free The State of the Brain Fitness Software Market 2008, for the best prediction/ comment. The trends he documents range from low tech computer software to involvement of doctors and pharmacists, insurance agencies and corporate wellness and leadership groups.

Man is the flying eagle, Woman, the singing nightingale.
To fly is to conquer space. To sing is to conquer the Soul.
Man is a temple, Woman a shrine.
Before the temple we discover ourselves, before the shrine we kneel.
In short, man is found where earth finishes, woman where heaven begins.
Victor Hugo

That brings us to the all important question of whether all those who would be spearheading this brain fitness revolution would have our best interests in mind. When big money like Insurance companies, pharmacists (drug companies) and corporates get involved, there is potential for dishing out the Neurotosh, Neurodosh and Nuerodash i.e. tosh or junk science, dosh or big money and dash or corruption all dressed up with a Neuro salad. While brain fitness movement may still be nascent and free of all such corrupting influences, Daniel at the Neuroanthropolgy blog found that this was the current state of affairs with respect to some practitioners of Neuroscience like Louann Brizendine the author of The Female Brain. Reporting from Montreal Critical Neurosciences conference he unearthed evidence of drug company linkages of Louann and how she twisted and over exaggerated the sexual differences in the brain to advocate her own interests.

I shall not sing a May song.
A May song should be gay.
I'll wait until November
And sing a song of gray.

I'll wait until November
That is the time for me.
I'll go out in the frosty dark
And sing most terribly.

And all the little people
Will stare at me and say,
"That is the Crazy Woman
Who would not sing in May."
Gwendolyn Brooks

Greg over at the Neuroanthropology blog takes this line of argument one step further and looks at how psychiatrists like Prof. Joseph Biederman, who may also have dubious drug company linkages, nevertheless end up being an institution in themselves, and end up having a profound influence on how we conceive and label normalcy or difference. Specifically, Prof Biederman, was responsible for pushing the diagnosis of bipolairty in children and as a result has resulted in for-better-or-for-worse an overwhelming number of children who are now diagnosed with the illness. Does labeling them as bipolar introduce new dynamics in their interaction with parents and peers? What about the lasting effects the anti-psychotics would have during the critical developmental periods? Would this grip of psychiatry in this case, or the just-so evolutionary psychology stories that one readily accepts to rationalize ones prejudices in other cases, over our discourse really good or is it leading to a harmful effect? He leaves us with many more questions than answers! While we normally tend to turn a deaf ear to such songs of gloom, it is important that we heed the warning and at least not label the doomsayer a 'crazy woman'!

Lastly if you are wondering how you got that headache - it has nothing to do with this ode to the brain. It is because you just ate freezing ice-cream - it has lead to a freezing sensation and to a condition called sphenopalatine ganglioneuralgia. Now, if reading the name of the condition itself leads to a headache don't blame me. Jokes apart, Waynekid Kam, from the BrainBlogger, describes this condition and explains how eating ice-cream could lead to headaches. Now, if you find the prospect of eating ice-cream a little too unpalatable, you are welcome to send all your ice-cream money to my way- I don't mind the headaches - or the ice-creams!

That's all for this edition folks! Do keep sending in your submissions to encephalon.host@gmail.com and it will be featured in the next edition due 19 August at Ouroboros.

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