23 September 2009

The Connections Behind Concept Formation

The human brain never rests. It constantly compares patterns and attempts to determine the relevance of sense clusters. We like to think we understand "the difference that makes a difference." Since we think in terms of concepts, metaphors, models, and emotion-tinged intuitions, it is important that they be laid down as soundly as possible -- from top to bottom.
...while there is little doubt that humans form and use concepts all the time, very little is known about how conceptual knowledge is created in the brain or how it allows us to make efficient choices.

Now, Dr Kumaran and colleagues have used behavioural and neuroimaging techniques to reveal how this knowledge emerges in the human brain, and how it is used to guide decision making. The results of the study, which was funded by the Wellcome Trust, are published in the journal 'Neuron'.

In the study, 25 volunteers were asked to predict whether the weather would be sunny or raining based on the appearance of the night sky. The night sky was represented by patterns on a computer screen. If correct, the participants could win money.

Initially, participants tended to memorise the outcome associated with specific patterns. However, it soon became clear to the participants that groups of patterns were conceptually related - by applying this information, participants were able to solve the task in a different setting where the concepts were similar but the patterns themselves new.

By applying fMRI scanning techniques, which measure changes in blood flow in the brain to identify areas of activity, Dr Kumaran and colleagues were able to show that the emergence of conceptual knowledge was underpinned by a coupled circuit involving the hippocampus (an area of the brain responsible for learning and memory) and the ventromedial prefrontal cortex (used in decision-making).

Most significantly, however, the researchers found that activity in the hippocampus alone predicted which participants would be able to successfully apply the concepts they had learned in a new setting. This suggests that the hippocampus creates and stores these concepts, and passes this information to the prefrontal cortex where it can be put to use, for example in making choices where financial reward is at stake.

The results highlight the role of the hippocampus in acquiring new concepts, possibly through its unique networking capacities, which allow multiple memories to be related to one another. _WellcomeTrust
Of course, just because concepts are well formed and accessible, doesn't mean the brain will make use of them at the proper time and place, and in the proper way. A great deal depends upon whether the person is paying attention.
The findings of the Salk researchers, published in the September 24, 2009 issue of the journal Neuron, reveal that the uptick in the firing rate is only a small part of the story. "What we found is that attention also reduces background activity," says postdoctoral researcher and first author Jude Mitchell, Ph.D. "We estimate that this noise reduction increases the fidelity of the neural signal by a factor that is as much as four times as large as the improvement caused by attention-dependent increases in firing rate. This reduction in noise may account for as much as 80% of the attention story." _SD
A very interesting finding. As one of the authors (Reynolds) remarks: we need a much better understanding of the brain's attentional mechanisms.

Some brains are much better at all of this than others, of course. And very few brains are actually trained to reach their potential, in this age of dumbed down curricula and politically correct indoctrination. Yet, it is good for researchers to focus on these critically important areas, so that when society decides that it is serious about meeting the challenges of the future, a new generation of more enlightened educators and scientists can find ways to optimise the brain function of its young persons.

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