sandygautam

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Sandeep Gautam is a psychology and cognitive neuroscience enthusiast, whose basic grounding is in computer science.

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Posts by sandygautam

Dopamine mediated ‘sign’ based learning

There is an interesting must watch Video of Paul Phillips discussing dopamine based learning and I have embedded the video below. Please do have a look. Original video with some other relevant information can be found here.

Paul discusses the dopamine surge at the Unconditioned Stimulus/reward (US) before the training being replaced by a dopamine surge at Conditioned stimulus(CS) after the learning and how this has led to the reward prediction theory (Schultz) of dopamine function. He also discusses the Cambridge(UK) or Ken Berridge group of objections to this and their discovery that different regions of the brain react differently (ventral and dorsal striatum have different dopamine surges associated with the same stimulus/reward pair in the same animal). He uses electrochemical methods (suing electrodes implanted in the rats brains) to measure tonic dopamine release and there are interesting and informative graphics as well as videso of rats indulging in approach behavior as soon as CS is presented (after conditioning).

He also discusses model-free and model-based reinforcement learning paradigms and discusses how dopamine is only necessary for model-free (simple value association) learning and is not necessarily involved in model-based learning. this he demonstrates beautifully with videos and graphs of selectively bred mice (bred for locomotion), in which high locomotors follow a different (sign-based or model-free) while the low locomotors display goal based or model-based learning. By dopamine manipulations (giving a dopamine antagonist) he is able to show that dopamine is not really necessary for model-based learning.

All in all a very engaging and informative video. A must, must watch that is very highly recommended for anybody who has given a minor thought also to dopamine and what it does in the brain.

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A brief history of autism

ResearchBlogging.org

{{en|Subject: Quinn, an ~18 month old boy with...
Image via Wikipedia

A mouse trap reader, using skribit, asked me to write a blog post about the history of madness; that is a dauting task, as she herself mentioned that Foucault wrote an entire book on the subject; so though I promise to write that post, in the meantime here is a post about the history of Autism.  After this , the next in series  would be a brief history of Schizophrenia.

Two Furies, from an ancient vase.
Image via Wikipedia

References to schizophrenia can be found since time immemorial, though the actual term and diagnosis is recent. It is believed that the people haunted by Furies of ancient Greek were actually schizophrenics suffering from delusions and hallucinations. As I contrast Autism and Schizophrenia it is apt that I start here; for similar to the rich historic al tradition, Autism can be equated with the ,blessed Fools’ of old Russia, “who were revered for their unworldiness. The apparent insensitivity to pain, bizarre behaviour, innocence, and lack of social awareness that these “Blessed Fools” showed, suggest that they may have had autism. ” (Happe). Similarly in almost all cultures one can find anecdotes and folktales about foolish boys (note that it is a boy and not a girl as autism has always been more prevalent in boys) who take what their mother said too literally- word for word , rather than figuratively and metaphorically or idiomatically.

The modern diagnosis of autism starts with Leo Kanner. Kanner published his first paper about  autistic children in 1943, the full text of which can be found here.  Some excerpts from the paper, which has many case studies , should help:

Since 1938, there have come to our attention a number of children whose condition differs so markedly and uniquely from anything reported so far, that each case merits – and, I hope, will eventually receive – a detailed consideration of its fascinating peculiarities.

The outstanding, “pathognomonic,” fundamental disorder is the children’s inability to relate themselves in the ordinary way to people and situations from the begining of life. Their parents referred to them as having always been “self-sufficient”; “like in a shell”; “happiest when left alone”;“acting as if people weren’t there”; “perfectly oblivious to everything about him”; “giving the impression of silent wisdom”; “failing to develop the usual amount of social awareness”;“acting almost as hypnotized.”T his is not, as in schizophrenic children or adults, a departure from an initially present relationship; it is not a “withdrawal”from formerly existing participation. There is from the start an extreme autistic aloneness that, whenever possible, disregards, ignores, shuts out anything that comes to the child from the outside. Direct physical contact or such motion or noise as threatens to disrupt the aloneness is either treated “as if it weren’t there”or, if this is no longer sufficient, resented painfully as distressing interference.


Eight of the eleven children acquired the ability to speak either at the usual age or after some delay. Three (Richard, Herbert, Virginia) have so far remained “mute.”In none of the eight “speaking” children has language over a period of years served to convey meaning to others. They were, with the exception of John F., capable of clear articulation and phonation. Naming of objects presented no difficulty; even long and unusual words were learned and retained with remarkable facility. Almost all the parents reported, usually with much pride, that the children had learned at an early age to repeat an inordinate number of nursery rhymes, prayers, lists of animals, the roster of presidents, the alphabet forward and backward, even foreign-language (French) lullabies. Aside from the recital of sentences contained in the ready-made poems or other remembered pieces, it took a long time before they began to put words together. Other than that, “language”consisted mainly of “naming,”of nouns identifying objects, adjectives indicating colors, and numbers indicating nothing specific.
Their excellent rote memory, coupled with the inability to use language in any other way, often led the parents to stuff them more and more verses, zoologic and botanic names, titles and composers of Victrola record pieces, and the like. Thus, from the start, language-which the children did not use for the purpose of communication-was deflected in a considerable measure to a self-sufficient, semantically and conversationally valueless or grossly distorted memory exercise.

When sentences are finally formed, they are for a long time mostly parrot-like repetitions of heard word combinations. They are sometimes echoed immediately, but they are just as often “stored”by the child and uttered at a later date. One may, if one wishes, speak of delayed echolalia. Affirmation is indicated by literal repetition of a question. “Yes”is a concept that it takes the children many years to acquire. They are incapable of using it as a general symbol of assent. Donald learned to say “Yes”when his father told him that he would put him on his shoulders if he said “Yes.”This word then came to “mean”only the desire to be put on his father’s shoulders. It took many months before he could detach the word “Yes”from this specific situation, and it took much longer before he was able to use it as a general term of affirmation.

The same type of literalness exists also with regard to prepositions. Alfred, when asked, “What is this picture about?”replied:”People are moving about.”

John F. corrected his father’s statement about pictures on the wall; the pictures were “near the wall.” Donald T., requested to put something down, promptly put it on the floor. Apparently the meaning of a word becomes inflexible and cannot be used with any but the originally acquired connotation.

But the child’s noises and motions and all of his performances are as monotonously repetitious as are his verbal utterances. There is a marked limitation int he variety of his spontaneous activies. The child’s behavior is governed by an anxiously obsessive desire for the maintenance of sameness that nobody but the child himself may disrupt on rare occasions. Changes of routine, of furniture arrangement, of a pattern, of the [form] in which every-day acts are carried out, can drive him to despair. When John’s parents got ready to move to a new home, the child was frantic when he saw the moving men roll up the rug in his room. He was acutely upset until the moment when, in the new home, he saw his furniture arranged in the manner as before. He looked pleased, all anxiety was suddenly gone, and he went around affectionately patting each piece. Once blocks, beads, sticks have been put together in a certain way, they are always regrouped in exactly the same way, even though there was no definite design. The children’s memory ws phenomenal in this respect. after the lapse of several days, a multitude of blocks could be rearranged in precisely the same unoganized pattern, with the same color of each block turned up, with each picture or letter on the upper surface of each block facing in the same direction as before. The absence of a block or the presence of a supernumerary block was noticed immediately, and there was an imperative demand for the restoration of the missing piece. If someone removed a block, the child struggled to get it back, going into a panic tantrum until he regained it, and then promptly and with sudden calm after the storm returned to the design and replaced the block.

The children’s relation to people is altogether different. Every one of the children, upon entering the office, immediately went after blocks, toys, or other objects, without paying the least attention to the persons present. It would be wrong to say that they were not aware of the presence of persons. But the people, so long as they left the child alone, figured in about the same manner as did the desk, the bookshelf, or the filing cabinet. When the child was addressed, he was not bothered. He had the choice between not responding at all or, if a question was repeated too insistently, “getting it over with”and continuing with whatever he had been doing. Comings and goings, even of the mother, did not seem to register. Conversation going on in the room elicited no interest. If the adults did not try to enter the child’s domain, he would at times, while moving between them, gently touch a hand or a knee as on other occasions he patted the couch. But he never looked into anyone’s face. If an adult forcibly intruded himself by taking a block away or stepping on an object that child needed, the child struggled and became angry with the hand or the foot, and became angry with the hand or the foot, which was dealt with perse [?] and not as a part of a person. He never addressed a word or a look to the owner of the hand or foot. When the object was retrieved, the child’s mood changed abruptly to one of placitidy. When pricked, he showed fear of the pin but not of the person who pricked him.

Note already that all the currently accepted DSM-IV characteristics of Autism like communicative difficulties, social difficulties and stereotyped or repetitive behavior are already well delineated by Kanner. Here one has to pause and note that autism and autistics were used from the social aloofness first observed and documented in schizophrenics by Kreplin and we seem to have come a full circle now by positing that Autism and schizophrenia are opposites on a continuum. It is also heartening to note that Kanner was also way ahead of his times by focusing on the deficit in ‘mentalizing’ in autistic kids.

Just a year after, Hans Asperger , published his paper on ASD kids, and it is remarkable that despite not knowing about each others papers they came with similar terminology (autistic ) to describe the children and agreed on more points than they disagreed on.

Asperger published the first definition of Asperger Syndrome, in 1944. In four boys, he identified a pattern of behavior and abilities that he called “autistic psychopathy”, meaning autism (self) and psychopathy (personality disease). The pattern included “a lack of empathy, little ability to form friendships, one-sided conversation, intense absorption in a special interest, and clumsy movements.” Asperger called children with AS “little professors” because of their ability to talk about their favorite subject in great detail. It is commonly said that the paper was based on only four boys.

Asperger and Kanner agreed as well as disagreed on many things:

Hans Asperger deserves credit for some very striking insights into autism: some insights which Kanner (1943) lacked and which it has taken us many years of research to rediscover. Before considering these particular observations of Asperger’s, it is worth noting the many features on which the two physicians agreed.
Kanner’s and Asperger’s descriptions are surprisingly similar in many ways, especially when one remembers that each was unaware of the other’s ground-breaking paper. Their choice of the term “autistic” to label their patients is itself a striking coincidence. This choice reflects their common belief that the child’s social problems were the most important and characteristic feature of the disorder. The term “autistic” comes from Bleuler (1908), who used the word (from the Greek “autos” meaning “self”) to describe the social withdrawal seen in adults with schizophrenia. Both Kanner and Asperger believed the social handicap in autism to be innate (in Kanner’s words) or constitutional (as Asperger put it), and to persist through life into adulthood. In addition, Kanner and Asperger both noted the children’s poor eye contact, their stereotypies of word and movement, and their marked resistance to change. The two authors report the common finding of isolated special interests, often in bizarre and idiosyncratic objects or topics. Both seem to have been struck by the attractive appearance of the children they saw. Kanner and Asperger make a point of distinguishing the disorder they describe from schizophrenia, on the basis of three features: the improvement rather than deterioration in their patients, the absence of hallucinations, and the fact that these children appeared to be abnormal from their earliest years, rather than showing a decline in ability after initially good functioning. Lastly, both Kanner and Asperger believed that they had observed similar traits—of social withdrawal or incompetence, obsessive delight in routine, and the pursuit of special interests to the exclusion of all else—in the parents of many of their patients.
There are three main areas in which Asperger’s and Kanner’s reports disagree, if we believe that they were describing the same sort of child. The first and most striking of these is the child’s language abilities. Kanner reported that three of his 11 patients never spoke at all, and that the other children did not use what language they had to communicate: “As far as the communicative functions of speech are concerned, there is no fundamental difference between the eight speaking and the three mute children” (Kanner 1943). While phonology (as demonstrated in accurate echolalia) and vocabulary were often excellent, Kanner concluded that of his 11 cases “In none …has language…served to convey meaning”. The picture in all is of a child with profound communicative difficulties and delay; in seven of the 11 cases so profound that deafness was initially suspected (but ruled out). Asperger, by contrast, reported that each of his four case study patients (and, by implication, most of the unspecified number of such children he treated) spoke fluently. Although two of his patients showed some delay, this was followed in both cases by a rapid mastery of language, and it is difficult to imagine any of his cases having been mistaken for deaf. All four cases, by the age of examination (between 6 and 9 years old), spoke “like little adults”. Asperger notes their “freedom” and “originality” in language use, and reports that two of his four cases had a tendency to tell “fantastic stories”.
Asperger’s description also conflicts with Kanner’s on the subject of motor abilities and co-ordination. Kanner (1943) reported clumsiness in only one case, and remarks on the dexterity of four of his patients. He concluded that “several of the children were somewhat clumsy in gait and gross motor performance, but all were very skilful in terms of finer muscle coordination”—in line with their success on the Seguin form board (in which dexterity plays a part) and their ability to spin objects. Asperger, by contrast, described all four of his patients as clumsy, and recounted their problems not only with school sports (gross co-ordination), but also with fine motor skills such as writing. This feature is part of a larger contrast in Asperger’s and Kanner’s beliefs. Kanner believed the autistic child to have a specific impairment in social understanding, with better relations to objects than to people: while his children showed “excellent, purposeful and ‘intelligent’ relations to objects” their “relations to people [were] altogether different”. Asperger, on the other hand, believed that his patients showed disturbances in both areas: “the essential abnormality in autism is a disturbance of the lively relationship with the whole environment” (Asperger 1944, translated in Frith 1991b).
The last area of disagreement in the clinical pictures painted by Asperger and Kanner is that of the child’s learning abilities. Kanner believed that his patients were best at learning rote fashion, but Asperger felt that his patients performed “best when the child can produce spontaneously”, and suggests that they are “abstract thinkers”. (Happe)

We now know that many of the insights of Asperger were correct especially for those suffering from high-functioning autism or Asperger’s syndrome.

A dark period of autism research was the ‘refrigerator mother‘ hypothesis , which posited based on a psychogenic theory that autism was due to bad parenting. The seeds of this theory can be traced back to Kanner, but Bruno Bettelheim gave it a prominence. this theory as now been widely debunked and discredited and caused undue suffering and guilt to a generation of parents.

Leading researchers in the field after these have been Uta Frith, Leslie, Happe and Simon-Baron-Cohen with his ‘mind-blindness’ theory.

Before concluding please visit the DSM criteria and reassess them as now autism, at least by me and many leading researchers, is conceptualized more as a continuum disorder. Hope the DSM-V has a continuum framework for autism.

Kanner L (1968). Autistic disturbances of affective contact. Acta paedopsychiatrica, 35 (4), 100-36 PMID: 4880460

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The downside of cognitive enhancement

The Morris water maze task has been used to de...

Jonah Lehrer, has an article in this week’s Nature News, (find a PDF here) , regarding 30 or so cognitively enhanced mice strains that have been bred and genetically engineered.  As Lehrer  very elaborately documents, all these have enhanced LTP as an intervening mechanism that leads to improvements in learning and memory. Most of the genes involved affcet the LTP mechanism in one way or the other to breed super mnemonist mice. However, from the time of Luria, t has been well known that those who have enhanced memory also suffer from some of its disadvantages and that the ability to forget is also very important.

Little is known about the side effects and tradeoffs
of both the current usage or the drugs in
development, but initial clues offered by smart
mice raise concerns. The Hras strain developed
in Silva’s lab might be good at learning, but its
fear response for a relatively benign stimulus
would be counterproductive for a wild mouse.
Its enhanced memory is both a blessing and a
burden. Silva cites other strains of smart mice
that excel at solving complex exercises, such as
the Morris water maze, but that struggle with
simpler mazes. “It’s as if they remember too
much,” he says — possibly taking in irrelevant
information such as the position of windows
or lights but missing the big clues.
Farah sees a parallel between these mice
and one of the few case studies of an individual
with profoundly enhanced memory.
In the early 1920s, the Russian neurologist
Alexander Luria began studying the learning
skills of a newspaper reporter called Solomon
Shereshevsky, who had been referred to the
doctor by his editor. Shereshevsky had such
a perfect memory that he often struggled to
forget irrelevant details. After a single read of
Dante’s Divine Comedy, he was able to recite
the complete poem by heart. Although this

Little is known about the side effects and tradeoffs of both the current usage or the drugs in development, but initial clues offered by smart mice raise concerns. The Hras strain developed in Silva’s lab might be good at learning, but its fear response for a relatively benign stimulus would be counterproductive for a wild mouse. Its enhanced memory is both a blessing and a burden. Silva cites other strains of smart mice that excel at solving complex exercises, such as the Morris water maze, but that struggle with simpler mazes. “It’s as if they remember too much,” he says — possibly taking in irrelevant information such as the position of windows or lights but missing the big clues.

Farah sees a parallel between these mice and one of the few case studies of an individual with profoundly enhanced memory. In the early 1920s, the Russian neurologist Alexander Luria began studying the learning skills of a newspaper reporter called Solomon Shereshevsky, who had been referred to the doctor by his editor. Shereshevsky had such a perfect memory that he often struggled to forget irrelevant details. After a single read of Dante’s Divine Comedy, he was able to recite the complete poem by heart. Although this flawless memory occasionally helped Shereshevsky at work — he never needed to take notes — Luria also documented the profound disadvantages of such a capacious memory. Shereshevsky, for instance, was almost entirely unable to grasp metaphors, as his mind was so fixated on particulars. When he tried to read poetry, for example, “the obstacles to his understanding were overwhelming”, Luria wrote in his book The Mind of a Mnemonist. “Each expression gave rise to a remembered image; this, in turn, would conflict with another image that had been evoked.”

For Luria, Shereshevsky’s struggles were a powerful reminder that the ability to forget is as important as the ability to remember. Enhancing human memory in individuals without severe cognitive defects might prove counterproductive.

It is interesting to pause here and note that many savants who have excellent memory are also autistic and that schizophrenics on the opposite end of the spectrum are characterized by too much reliance of metaphors and too much generalizations and abstractions. Further Martha Farah notes the following:

Many scientists are concerned that the animal models of enhanced cognition might obscure subtle side effects, which can’t be studied in rodents or primates. Farah is currently looking at the trade-off between enhanced attention — she gives human subjects a mild amphetamine — and performance on creative tasks. Other researchers have used computer models to show that memory is actually optimized by slight imperfections, as they allow one to see connections between different but related events9. “The brain seems to have made a compromise in that having a more accurate memory interferes with the ability to generalize,” Farah says. “You need a little noise in order to be able to think abstractly, to get beyond the concrete and literal.”

Again, one can easily see the correlations with Autism and Schizophrenia- one end marked by too narrow a focus , while the other marked by too much noise and divergent creativity. I would have been happy to incorporate the more LTP as autistic and less LTP as schizophrenics, but it flies in face of my earlier findings regarding experience dependent plasticity in autism and schizophrenia where the conclusions were just the revers. Yet, it is clear that synaptic plasticity is a majo mechanism involved in the autism/psychosis differentiation. Do let me know if you can reconcile the new findings with the older ones to come up with the right LTP and psychosis/autism relationship.

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Rubber hand illusion and other videos from WatchKnow

Today I discovered a  new educational video portal,WatchKnow, that aggregates educational videos in categories. The psychology category has about 14 or so videos and one video that caught my fancy was a video by New Scientist that demonstrates the Rubber Hand illusion.

This becomes pertinent in light of a post today by Mind Hacks about new research that showed that rubber hand illusion can be induced in amputee, for a robotic arm, and the effcet is the same rubber hand illusion extended.

Another series of videos I liked were BBC‘ Horizon series on Memory, where I found for the first time that  Memory was correlated with self-recognition (mirror test) in children.

The part 2 and part 3 of the above clip are about a memento style John , who cannot form memories adequately and an eternal sunshine of the spotless mind type lady who needs to get her PTSD memories erased.

There are more available at the source, so go have a look!

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The new look of Mouse Trap

Daily Disney - Tick... Tock... Tick... Tock...
Image by Joe Penniston via Flickr

I am almost done with the new look of The Mouse Trap blog. I strongly encourage my RSS feed subscribers to come visit the new blog and give me feedback about the look and feel of the new site.  There are a host of ratings and review plugins added that would let you rate individual posts as well as individual comments. Do explore the site and I am sure you will have some constructive feedback.

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