Localizing g in the brain!

Deric Bownds from MindBlog reports on a fascinating study by Adolphs, Damasio, et al., that found an association between general intelligence (g) and:

"... damage to a remarkably circumscribed, although distributed, network in frontal and parietal cortex, critically including white matter association tracts and frontopolar cortex. They suggest hat general intelligence draws on connections between regions that integrate verbal, visuospatial, working memory, and executive processes."

Bownds quotes from their discussion:

"The largest overlap between WAIS subtests and g was found for Arithmetic, Similarities, Information, and Digit Span; the former two tests also exhibited the greatest conjunction with g. These subtests assess verbal knowledge about the world, verbal reasoning, and abstraction, as well as working memory capacity, and are associated with the left inferior frontal gyrus, the superior longitudinal/arcuate fascicule, and to some degree with parietal cortex. This suggests that g draws on the combination of conceptual knowledge and working memory, and that the communication between areas associated with these capacities is of crucial importance."

The actual article is available here.

Ritalin increases brain plasticity

From ScienceDaily: Ritalin Boosts Learning by Increasing Brain Plasticity. The report states that Ritalin not only improves concentration, but also increases the speed of learning (at least in animal models). It does this by increasing brain plasticity, especially in the amygdala. Antonello Bonci, the lead scientist, stated:

"We found that a dopamine receptor, known as the D2 receptor, controls the ability to stay focused on a task -- the well-known benefit of Ritalin," said Patricia Janak, PhD, co-senior author on the paper. "But we also discovered that another dopamine receptor, D1, underlies learning efficiency."

Fascinating stuff that bears looking into.

See the research abstract here.

Children not overmedicated?

There is a general concern that children are overmedicated, especially with psychotropic medication such as Ritalin. While in South Africa, the dosages used are typically lower than in the U.S.A., the same concern exists here. Judith Warner, columnist for the New York Times, started investigating this issue six years ago. Whereas she started out biased against the use of medication for childhood developmental disorders, against expectations she had to change her mind.

Here are some excerpts from a review of her book, We've got Issues:
Children and Parents in the Age of Medication:

"A couple of simple truths have become clear,” she writes with the passion of a new convert. “That the suffering of children with mental health issues (and their parents) is very real. That almost no parent takes the issue of psychiatric diagnosis lightly or rushes to ‘drug’ his or her child; and that responsible child psychiatrists don’t, either. And that many children’s lives are essentially saved by medication, particularly when it’s combined with evidence-based forms of therapy."

and

"But the big picture is far brighter than its components. Ms. Warner argues that child psychiatry is actually one of the major public health success stories of our time. As one expert tells her, when it comes to mental health, “the horse is out of the barn by adulthood.” Treating troubled children is more than symptom management for a calmer classroom: the medications seem actually to change the structure of the brain, helping it develop in what all evidence indicates is the right direction. More children in treatment should spell the beginnings of a healthier adult world."

Warner's conclusions are interesting and one has to recognize her intellectual honesty in coming to change her mind. One has to, however, recognize that her "research" method was not much more than the collection of anecdotes. For a more critical review of her book, read Alison Gopnick in The Slate.

Sarcasm and the right hemisphere

Jonah Lehrer from Frontal Cortex posted on the cognitive challenge posed by sarcasm:

"Sarcasm is a cognitive challenge. In order to get the sarcastic sentiment, we can't simply decode the utterance, or decipher the literal meaning of the sentence. Instead, we have to understand the meaning of the words in their larger social context. For example, if it's a beautiful day outside - the sun is shining, etc - and somebody states "What a nice day!," there is no sarcasm; the sentence makes perfect sense. However, if the same statement is uttered on a rainy day, then there is a clear contradiction, which leads to an interpretation of sarcasm. (We typically exaggerate the expression of sarcastic statements, thus making it easier to pick up the verbal/social contradiction.) Psychologists refer to such utterances as an incongruent word-emotion situation."

He continues to point out the involvement of the right hemisphere in processing sarcasm. I've previously posted on this in the context of contextual processing (unintended pun) and Cook's model of topographic callosal inhibition. Read more about it in my post on the left brain right brain myth.