Learning and Memory
jhalper | March 22, 2011
Is having a beer and sandwich at the local pub the best way to improve your brain awareness? At least in the city of Rehovot one evening last week, those eating and drinking in a few select establishments got to hear Weizmann Institute neurobiology graduate students give informal talks and demonstrations. The event was a part of Brain Awareness week, an annual, international affair. The aim is not really to make people more aware of their brains (or their brains more aware), but to promote brain research.
Some participated in an experiment in which they found that a smell can help imprint…
purepedantry | June 30, 2008A lot of people have read The Wisdom of Crowds by James Surowiecki. In the book, he gives an example of a group of people forced to estimate the weight of a cow. (This was actually an experiment that geneticist Franics Galton attempted.) When you do this, you find that the accuracy of the average response from the group is much greater than the accuracy of each individual estimate.
This is the so-called wisdom of crowds. The assumption with experiments like this is that each individual will make the best guess they can and this guess will be stable over time -- minus any new information…
purepedantry | May 16, 2008This is a cool story, but not for the reason the authors are attributing. Researchers at Princeton showed that bacteria can evolve to anticipate future environmental changes. Here is the coverage in Science:
Researchers already know that microbes can mount simple responses to changes in their environment, such as acidity fluctuations, by altering their internal workings. If the changes are regular enough, bacteria can respond ahead of time. But systems biologist Saeed Tavazoie of Princeton University wondered if microbes were capable of more sophisticated reasoning. Could they, for example…
purepedantry | February 21, 2008I remember when I was studying for Step I of the medical Boards. Step I is the first of three very large tests that you have to take to become a doctor. This first test comprises everything you learn in the first two years of medical school, and it can in theory include the pathology and physiology of anything that can go wrong with the human body. Most people take at least 6 weeks of continuous time to study for it.
Sufficeth to say it is a lot to learn.
Numerous techniques are employed by medical students studying for the Boards. There are the readers who attempt to reread every one…
purepedantry | February 11, 2008In behavioral neuroscience, we use a lot of animal models. We assume that these animal models have features that are the same or similar to features of humans. However, it is always reassuring when someone gets around to proving that this assumption is accurate.
Talmi et al., publishing in the Journal of Neuroscience, show that a well-documented type of learning called Pavlovian-Instrumental Transfer (PIT) occurs in humans under identical experimental conditions to those we use to test animals.
Background
In order to understand this paper, I need to define some terms that you come across in…
purepedantry | August 22, 2007NYTimes Science section, why do you make me so mad?
Gretchen Reynolds published an article in the Times on cognitive improvements associated with exercise, and I would like to use it to make a point about how science journalism often gets the facts right but the interpretation wrong.
It begins with the following incorrect statement:
The Morris water maze is the rodent equivalent of an I.Q. test: mice are placed in a tank filled with water dyed an opaque color. Beneath a small area of the surface is a platform, which the mice can't see. Despite what you've heard about rodents and sinking…
purepedantry | August 20, 2007We tend to think of memories in the brain once they are consolidated as relatively stable things. For example, you don't tend to think of any active biochemical process being necessary to maintain long-term memories. This is almost an intuitive conclusion: wouldn't any active process required for memory maintenance be eventually disrupted if expected to operate over a long period? Further, we know that it forgetting is an active rather than a passive process -- such as in fear extinction where activity in certain parts of the brain is necessary to successfully "forget" the fear.
However,…
purepedantry | August 8, 2007Vindication at last. I catch a lot of hell because I tend to talk with my hands.
However, Susan Wagner Cook for the University of Chicago has shown that when teaching math problems kids who repeat the hand gestures of the teacher are more likely to get the problem right. In other words, practicing gestures aids in retention:
Kids asked to physically gesture at math problems are nearly three times more likely than non-gesturers to remember what they've learned. In today's issue of the journal Cognition, a University of Rochester scientist suggests it's possible to help children learn…
purepedantry | March 29, 2007This is interesting. Researchers at Columbia have established that restricting neurogenesis in the hippocampus improves working memory:
New research from Columbia University Medical Center may explain why people who are able to easily and accurately recall historical dates or long-ago events, may have a harder time with word recall or remembering the day's current events. They may have too much memory -- making it harder to filter out information and increasing the time it takes for new short-term memories to be processed and stored.
Published in the Proceedings of the National Academy of…
purepedantry | February 8, 2007We have been talking about this paper in PNAS around the lab, so I thought I would share.
Hassabis et al, publishing in PNAS, have shown that patients with hippocampal damage lack the ability to imagine novel situations. This is a truly interesting finding, but it isn't why I want to talk about this paper. Actually, I want to talk about this paper because of how they explain this finding.
To tip my hand a little, Hassabis et al attribute this lack of novel mental imagery to a deficit in spatial context provided by the hippocampus. This would fit squarely in the body of thought that…
purepedantry | September 6, 2006I wrote earlier this week about evidence from electrode arrays that LTP occurs in vivo in behaving rats ("Rats, you behave!"). The paper showed that if you use an avoidance learning paradigm you can detect LTP in the hippocampus after one trial. The paper does not, however, necessarily prove that this LTP is actually necessary for learning (although there is a huge body of evidence in vitro that suggests that this is the case).
Another paper in Science rectifies that deficiency. Pastalkova et al. also show in Science that if we infuse an inhibitor to a particular enzyme into the rat…
purepedantry | September 5, 2006My suspicion is that the people who know about neuroscience read the title of this and said: "Wow, Jake, there's a shocker. Tell us something we didn't know." Everyone else probably said: "Guh?" Therefore, I should probably explain why I think this finding is cool.
LTP or Long Term Potentiation is an experimental paradigm that is believed to simulate learning in vivo. In the paradigm, an exciting electrode and a recording electrode are placed into the brain of the animal, usually into an area called the hippocampus. The electrodes are position such that the action of the excitation…
purepedantry | June 21, 2006I must admit that in general I like David Brooks. He seems to lack the stridency of many pundits, and I don't generally like people who shout. He also tends -- like Walter Bagehot -- not to think that people who disagree with him are evil, just that they disagree with him.
But on this piece I think he may have gone a little off. (Incidentally I would read this excellent review by Language Log, which is where I found out about it. They go into it in considerably more detail than I plan to.)
Here's Brooks:
Over the past two decades, there has been a steady accumulation of evidence that…
purepedantry | June 13, 2006This paper shows that leptin injections into the hippocampus improves memory in a T-maze footshock avoidance and step down inhibitory avoidance tasks. It caught my eye because I just finished a course in behavioral neuroscience, but I have never for the life of me thought the two were related.
Leptin is a hormone that is released by fat cells that tells your brain that you're good on food and that you should stop eating. Leptin insufficiency causes obesity. Before you get excited though you should know that leptin is not a diet drug because if you have too much of it your brain stops…