Neurophysiology of prehension. II. Response diversity in primary somatosensory (S-I) and motor (M-I) cortices.

Full Abstract

Prehension responses of 76 neurons in primary somatosensory (S-I) and motor (M-I) cortices were analyzed in three macaques during performance of a grasp and lift task. Digital video recordings of hand kinematics synchronized to neuronal spike trains were compared with responses in posterior parietal areas 5 and AIP/7b (PPC) of the same monkeys during seven task stages: 1) approach, 2) contact, 3) grasp, 4) lift, 5) hold, 6) lower, and 7) relax. S-I and M-I firing patterns signaled particular hand actions, rather than overall task goals. S-I responses were more diverse than those in PPC, occurred later in time, and focused primarily on grasping. Sixty-three percent of S-I neurons fired at peak rates during contact and/or grasping. Lift, hold, and lowering excited fewer S-I cells. Only 8% of S-I cells fired at peak rates before contact, compared with 27% in PPC. M-I responses were also diverse, forming functional groups for hand preshaping, object acquisition, and grip force application. M-I activity began < or =500 ms before contact, coinciding with the earliest activity in PPC. Activation of specific muscle groups in the hand was paralleled by matching patterns of somatosensory feedback from S-I needed for efficient performance. These findings support hypotheses that predictive and planning components of prehension are represented in PPC and premotor cortex, whereas performance and feedback circuits dominate activity in M-I and S-I. Somatosensory feedback from the hand to S-I enables real-time adjustments of grasping by connections to M-I and updates future prehension plans through projections to PPC.

Author information

Author/s: Gardner, Esther P (EP); Ro, Jin Y (JY); Babu, K Srinivasa (KS); Ghosh, Soumya (S);

Affiliation: Department of Physiology and Neuroscience, New York University School of Medicine, 550 First Avenue, MSB 442, New York, NY 10016, USA. gardne01(-atsign-)endeavor.med.nyu.edu

Grants: R01 NS 11862 (Agency:NINDS NIH HHS) ; R01 NS 44820 (Agency:NINDS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural

Journal: Journal of neurophysiology (J Neurophysiol), published in United States. (Language: eng)

Reference: 2007-Feb; vol 97 (issue 2) : pp 1656-70

Dates: Created 2007/02/09; Completed 2007/04/02; Revised 2007/12/03;

PMID: 17093113, status: MEDLINE (last retrieved date: 2/18/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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