Coding of the Reach Vector in Parietal Area 5d
Competing models of sensorimotor computation predict different topological constraints in the brain. Some models propose population coding of particular reference frames in anatomically distinct nodes, whereas others require no such dedicated subpopulations and instead predict that regions will simultaneously code in multiple, intermediate, reference frames. Current empirical evidence is conflicting, partly due to difficulties involved in identifying underlying reference frames. Here, we independently varied the locations of hand, gaze, and target over many positions while recording from the dorsal aspect of parietal area 5. We find that the target is represented in a predominantly hand-centered reference frame here, contrasting with the relative code seen in dorsal premotor cortex and the mostly gaze-centered reference frame in the parietal reach region. This supports the hypothesis that different nodes of the sensorimotor circuit contain distinct and systematic representations, and this constrains the types of computational model that are neurobiologically relevant.
Additional Information© 2012 Elsevier Inc. Accepted: May 21, 2012. Published: July 25, 2012. This work was supported by National Institutes of Health Grant EY005522. We thank Tessa Yao for editorial assistance, Kelsie Pejsa and Nicole Sammons for animal care, Igor Kagan for magnetic resonance imaging, Viktor Shcherbatyuk for technical assistance, and Bijan Pesaran and Matthew Nelson for helpful discussions.
Accepted Version - nihms386447.pdf
Supplemental Material - mmc1.pdf