Sunday, September 09, 2007

Human knowledge is based upon directed connectivity between brain areas

Which brain processes enable humans to rapidly access their personal knowledge?

What happens if humans perceive either familiar or unfamiliar objects?

The answer to these questions may lie in the direction of information flow transmitted between specialized brain areas that together establish a dynamic cortical network. This finding is reported in the latest issue of the scientific journal PLoS ONE published on August 1st, 2007.

Fruit or vegetable, insect or bird, familiar or unfamiliar – humans are used to classify objects in the world around them and group them into categories that have been formed and shaped constantly through every day's experience. Categorization during visual perception is exceptionally fast. Within just a fraction of a second we effortlessly access object-based knowledge, in particular if sufficient sensory information is available and the respective category is distinctly characterized by object features...

...”Human knowledge is definitely not stored in one single brain area. Access to knowledge results from the cooperation of several brain areas that jointly build a dynamic brain network. In this study we were not only able to confirm that recognition of familiar and unfamiliar objects activates a set of distributed brain areas. Rather, importantly, for the first time we have measured in humans how brain areas communicate with each other by directed information transfer, depending whether object-specific knowledge was available or not,' tells co-author and initiator of the study, Thomas Gruber of the Department of Psychology of the University of Leipzig...

...The contribution of our study is that by using a new method of signal analysis we succeeded in measuring the directionality of neuronal interactions. Cooperating brain areas forming a dynamic network are not just connected, but rather each area can be engaged either in receiving or sending signals or both. Until now this has been difficult to investigate, but our analysis suggests that most areas are involved in both during access to object-related knowledge,” ...

This from Physorg.

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