Well, the grant has finally been submitted, so itís time to start up journal club again! Weíll meet this Friday, July 25th at 1pm, when Leighton Hinkley will present a paper on cortical activity during free choice reaching behavior.

 

When we consider what cortical areas are active when we decide to make a reach movement, we think of a top-down process where prefrontal areas decide where to reach, and then premotor and parietal areas control the actual reach made. But in fact, the division of labor may not be so clear-cut: The paper Leighton will present finds evidence that premotor and parietal areas may also be involved in the process of deciding where to reach:

 

Pesaran, B., Nelson, M. J., & Andersen, R. A. (2008). Free choice activates a decision circuit between frontal and parietal cortex. Nature, 453(7193), 406-409. (link to pdf of article)

 

We often face alternatives that we are free to choose between. Planning movements to select an alternative involves several areas in frontal and parietal cortex that are anatomically connected into long-range circuits. These areas must coordinate their activity to select a common movement goal, but how neural circuits make decisions remains poorly understood. Here we simultaneously record from the dorsal premotor area (PMd) in frontal cortex and the parietal reach region (PRR) in parietal cortex to investigate neural circuit mechanisms for decision making. We find that correlations in spike and local field potential (LFP) activity between these areas are greater when monkeys are freely making choices than when they are following instructions. We propose that a decision circuit featuring a sub-population of cells in frontal and parietal cortex may exchange information to coordinate activity between these areas. Cells participating in this decision circuit may influence movement choices by providing a common bias to the selection of movement goals.