Amygdala-Orbitofrontal interplay in cognitive flexibility November 29, 2007Posted by Johan in Learning, Neural Networks, Neuroscience.
1 comment so far
This rat doesn’t get sucrose, but is probably happier than Stalnaker et al’s rats
Today’s title may be the least accessible yet, but bear with me; this is an interesting paper. Stalnaker et al (2007) investigated the neural basis of what they call cognitive flexibility – this is a very fancy term for a rat’s ability to handle a conditioning paradigm known as reversal learning. The method that Stalnaker et al used serves as a good example of the paradigm.
Rats were first trained on an odour discrimination task. Poking at one little door that is laced with odour A produces delivery of a tasty sucrose solution. Poking at another little door that is laced with odour B produces delivery of an unpleasant quinine solution (incidentally, quinine is a component in Vermouth, but we’ll assume that these particular rats like their martinis very dry). The actual door that is associated with each odour is varied, so that the rats have to rely on the odour cues alone to learn how to get their treat. Once the rats have achieved a criterion level of accuracy at this task, the contingency reverses, so that odour B now produces a treat while odour A produces quinine. The model finding is that the rats will be slower to learn the reversal than they were to learn the original task.
Stalnaker et al were interested in investigating the role of orbitofrontal cortex (OFC) and the basolateral amygdala (ABL) in bringing about this reversal. There are two basic ideas on how this might work: the OFC might directly encode the preferred stimulus, or the OFC might play an indirect role where it facilitates changes in downstream areas, such as the ABL. So in other words, downstream areas bring about the actual behaviour, while the OFC plays more of a modulatory role in telling the downstream areas when contingencies change.
To test these notions, Stalnaker et al lesioned the OFC in one group of rats, the ABL in another group, and both the OFC and the ABL in a third group. After this, the rats learned the odour discrimination task. The three groups did not differ significantly at this point. In other words, neither area or the combination of them was necessary to learn the task. Next, the rats went through two serial reversals – odour A switched places with odour B, and then back again. The effect of the brain lesions was measured by the number of trials taken to learn the reversals to the same accuracy level as the initial odour task.
Rats with OFC damage were slower to learn the reversals than the other groups. However, rats with ABL lesions and rats with combined OFC and ABL lesions did not significantly. So in other words, although OFC lesions in isolation cause impairments, this effect is abolished when the ABL is sectioned as well.
Stalnaker et al interpret these findings as support for an indirect role for the OFC in reversal learning. The ABL is stubborn, simply put. Without the modulatory influence of the OFC, the ABL persists in responding as though the contingency had not reversed, which produces slower reversal learning. By removing the ABL as well, this persistent influence is gone and reversal learning can occur normally. It is somewhat counter-intuitive that lesioning more of the brain helps, but there you go.
This is a nice study because it answers one question, but asks a number of new questions. If the rats can carry out reversal learning normally without either the OFC or the ABL, why is this circuit even involved in the paradigm, that is, why should OFC lesions have an effect, if the pathway as a whole is not needed? Also, if the ABL produces such deficient behaviour when the OFC is lesioned, why don’t lesions to the ABL affect behaviour? And most importantly, if behaviour is normal after ABL and OFC lesions, which other area must be lesioned to impair behaviour yet again. And what happens if this area is lesioned in isolation?
Enough questions to make your head spin, but the take-home message for those studying humans is that there is an entire range of complex interactions in the brain that fMRI, with its blurry temporal resolution and lack of experimental manipulation, can only hint at. We know much about functional localisation in the human brain, but the issue of how these areas connect and interact is largely uncharted territory.
Stalnaker, T.A., Franz, T.M., Singh, T., and Schoenbaum, G. (2007). Basolateral Amygdala Lesions Abolish Orbitofrontal-Dependent Reversal Impairments. Neuron, 54, 51-58.
Classical Conditioning in a Nutshell April 21, 2007Posted by Johan in Learning.
add a comment
I began snorting/smoking heroin. when i finally decided to shoot it was because i was spending way too much to get high and i just didnt care anymore. before the first time i stuck myself i had a huge phobea of needles. At doctors offices i would bitch and whine and sometimes pass out from needles. right after i got the courage to stick myself it was all out the window. I became addicted to the needles as well. I would often stick myself with water when i had no dope to shoot just to get the feeling of putting a needle in my flesh.
Came across this forum post by a former drug addict. While this isn’t the typical classical conditioning, where a neutral stimulus becomes pleasant or aversive, it’s quite a striking example of how powerful conditioning can be. Even something as unpleasant as a needle sting can become satisfying if it has been paired with a reinforcer as powerful as opiates…
Operant Conditioning in a Nutshell April 2, 2007Posted by Johan in Learning.
add a comment
The video below is a good example of operant conditioning – in a cat, no less!
Clicker training is a popular way to teach pets tricks. The technique is based on first “loading” the clicker by giving the animal a treat and clicking. Eventually, then, the clicker becomes a pleasant stimulus in itself through classical conditioning, and can be used as a quick, easily administered reinforcer in operant conditioning. This guy seems to be using the clicker in a somewhat unorthodox way – he gives the cat a treat each time, so this way, the clicker only serves to let the animal know that a treat is coming. This may be a handy way to let the animal know exactly which behaviour is being rewarded (if you just give a treat, you might not have time to give the reward before the animal has started another, unrelated behaviour).
Before you conclude that if you can teach cats to operate levers, you can teach anyone anything, you may wish to look at this classic paper…
Confirmation Bias – Not Just for Pseudoscientists March 10, 2007Posted by Johan in Evolutionary Psychology, Learning, Neuroscience, Psychology Freakshow.
add a comment
This is an excerpt from a lecture that James Randi gave at Princeton a few years back. For fans, the full lecture is available here. There is nothing new here if you are already familiar with the basic premises of homeopathy, but Randi does tell the story quite well. See also this amusing series of clips from a website advocating homeopathy.
See, at the Phineas Gage Fan Club we cover both sides of every story. Fair and balanced, just like Fox News. Ahem.
James Randi is perhaps most famous among academics for Project Alpha, an elaborate hoax which exposed the gullibility of researchers into the paranormal. Essentially, Randi had two of his magician friends present themselves as psychics at the high-profile Phillips group. The magicians used simple sleight-of-hand tricks to convince the scientists that they had paranormal abilities. Randi did eventually end this game, but not until the two magicians had become quite famous in psychic circles. Embarrassing enough for the researchers, Randi could show that he had in fact contacted them before the experiments began with a list of crucial factors that needed to be controlled during the experiments to prevent cheating. It turned out that the magicians had been able to exploit those very same gaps, since the researchers had neglected to take Randi’s points into consideration.
Most disturbingly, the field of “parapsychology” is enjoying some recognition, even today. Recently The Psychologist, the official magazine of the British Psychological Society, ran a cover story on parapsychology, written from a completely uncritical standpoint.
The real finding to come out of all these experiments into psi and telepathy is the sheer strength of confirmation bias. Whether it concerns belief in homeopathy, psychoanalysis, or the paranormal, it’s striking how successfully people manage to select and interpret information to make it consistent with their own views.
It’s easy to look down on this, as a supposedly objective scientist. But the reality is probably that we all fall victim to this confirmation bias to some extent. It’s just less noticeable when you believe in something that also happens to be consistent with existing evidence. When the evidence changes, surprisingly many stick to their beliefs, rather than to the evidence. For me, the strongest example of this is perhaps the last paper by Skinner (1990). Finished the evening before his death, but long after the cognitive revolution, he still argues against the usefulness of positing mental constructs between stimulus and response. He goes as far as suggesting that as we learn more about the workings of the brain, it only becomes less useful as a way of understanding behaviour – something that may sound a little outlandish now, in the age of fMRI, MEG, EEG and other acronyms. The strict behaviourism that Skinner advocated had run into trouble more than 20 years ago, yet Skinner, and many with him, clung to their paradigm.
This shouldn’t be interpreted as a criticism of Skinner. When the next shift comes around in psychology, say, if Buss somehow succeeds in making evolutionary psychology the next big thing (cf Buss, 1995), I’m sure lots of cognitive psychologists will cling to their beliefs – start their own journals, host their own conferences. It’s easy to assume that supposedly intelligent people, especially psychologists who know all about cognitive biases, should thus be immune to them.
This, if anything, is a dangerous belief, because in reality it actually makes you more vulnerable to biases. The most biased people are those who believe they are “fair and balanced.”
Buss, D.M. (1995). Evolutionary Psychology: A New Paradigm for Psychological Science. Psychological Inquiry, 6, 1-30.
Skinner, B.F. (1990). Can Psychology be a Science of Mind? American Psychologist, 45, 1206-1210.
Self-Management November 24, 2006Posted by Johan in Learning, Raves, Self-Management.
add a comment
Mindhacks has an interesting post up on how Skinner was not a fascist, which deserves to be said in itself… But the really interesting bit is the article that is linked: Skinner as a Self-Manager, by Robert Epstein.
Self-management, for those unfamiliar with the Psychobabble, is basically how you get yourself to achieve your goals. If your goal is to write an essay, self-management would involve setting aside time to write, ensuring that your topic is appropriate, and so forth. By extension, self-management is the stuff that productivity websites like Lifehacker are concerned with. And it turns out that decades before GTD reared its ugly head, Skinner was already on it:
“a few examples and a brief analysis can’t begin to capture how pervasive self-management was in his life. It was much more than a few gizmos and timers. It was what many would call an attitude. He managed his own behavior almost continuously. When I was in graduate school, a fellow student mentioned that Fred seemed to dispose of envelopes and junk mail in an especially efficient way. I had never noticed this before, but it was true. When he opened his mail in the morning, he usually positioned his chair and trash can so that the very slightest flick of his wrist did the job. This was no accident, and it was part of the reason he was able to reply to virtually every letter he ever received, even until the end (Vargas, 1990).” (Epstein, 1997, p. 547)
“Fred kept lists of things to do, because people who keep lists of things to do do more things. He made schedules for himself to keep himself on track. We all use daily and weekly schedules, but Fred made longterm schedules as well —even 10- and 20-year schedules (Skinner, 1979, 1983b). “ (Epstein, 1997, p. 554)
“He knew that the best ideas are often fleeting, so he developed special ways to capture them. He kept a notebook or a tape recorder by his bed and by his pool, for example. He knew that writing was a delicate and easily disrupted activity, so he took pains to shelter it from disruptions. He built special shelves so that his dictionaries and other reference books were always at arm’s reach. He used his writing desk for serious writing only; he answered letters and paid bills elsewhere.” (Epstein 1997, 554)
Skinner was proud of his self-management skills, as he considered them a direct application of Behaviourism. And of course, this could be related to other scientific paradigms:
“Freud was unable to stop smoking cigars, up to 25 a day, though smoking must have been obviously related to the heavy ‘‘catarrh’’ he suffered from most of his life, as well as to the protracted cancer of the jaw in his last years . . . an astonishing lack of self-understanding or self-control. Was he not bothered by it, or did much of his theory spring from the need to acknowledge that the habit was ‘‘bigger than he was’’? (Epstein, 1980, p. 341)
Of course, poking fun a psychoanalysis is a bit like shooting fish in a barrel. A final quote sums up the core of Skinner’s self-management:
“Fred’s most important self-management practice is implied in his writings but is nowhere clearly stated. He always spent a few minutes each day, often scattered throughout the day, searching for and analyzing variables of which his behavior seemed to be a function. It is not enough to live your life, he told me; you also need to analyze it and make changes in it frequently and regularly.” (Epstein, 1997, p. 559)
On reading Epstein’s article, you do not get the impression that this was an ascethic, disciplinarian lifestyle that Skinner imposed on himself. Self-management was a source of joy, a constant pet project that was carried out because it was a positive reinforcer, not a negative one.
I believe that this kind of constant, critical re-evaluation of your lifestyle is crucial, if you aim to achieve anything beyond the norm. Epstein goes as far as suggesting that this self-management skill was the crucial factor that enabled Skinner to achieve as much as he did. I’m not sure about that, but it’s nevertheless inspiring to see that at the base of it, it may not be just an abstract “genius” quality that separates those who achieve something from those who don’t. There is a method here, and it can be applied to just about anyone.
I will outline my own self-management attempts in a future post.