|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Electrical Engineering, Stanford University, Stanford, California, United States; Neurosciences Program, Stanford University, Stanford, California, United States
2 Electrical Engineering, Stanford University, Stanford, California, United States
3 Electrical Engineering, Stanford University, Stanford, California, United States; Neurosurgery, Stanford University, Stanford, California, United States
4 Electrical Engineering, Stanford University, Stanford, California, United States; Medical Scientists Training Program, Stanford University, Stanford, California, United States
* To whom correspondence should be addressed. E-mail: shenoy{at}stanford.edu.
When a human or animal reaches out to grasp an object, the brain rapidly computes a pattern of muscular contractions that can acquire the target. This computation involves a reference frame transformation, since the target's position is initially available only in a visual reference frame, yet the required control signal is a set of commands to the musculature. One of the core brain areas involved in visually guided reaching is the dorsal aspect of the premotor cortex (PMd). Using chronically implanted electrode arrays in two Rhesus monkeys, we studied the contributions of PMd to the reference frame transformation for reaching. PMd neurons are influenced by the locations of reach targets relative to both the arm and the eyes. Some neurons encode reach goals using limb-centered reference frames, while others employ eye-centered reference fames. Some cells encode reach goals in a reference frame best described by the combined position of the eyes and hand. In addition to neurons like these where a reference frame could be identified, PMd also contains cells that are influenced by both the eye-centered and limb-centered locations of reach goals, but for which a distinct reference frame could not be determined. We propose two interpretations for these neurons. First, they may encode reach goals using a reference frame we did not investigate, such as intrinsic reference frames. Second, they may not be adequately characterized by any reference frame.
This article has been cited by other articles:
![]() |
G. U. Sorrento and D. Y. P. Henriques Reference Frame Conversions for Repeated Arm Movements J Neurophysiol, June 1, 2008; 99(6): 2968 - 2984. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. A. Chestek, A. P. Batista, G. Santhanam, B. M. Yu, A. Afshar, J. P. Cunningham, V. Gilja, S. I. Ryu, M. M. Churchland, and K. V. Shenoy Single-Neuron Stability during Repeated Reaching in Macaque Premotor Cortex J. Neurosci., October 3, 2007; 27(40): 10742 - 10750. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |