| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Neurobiology, Harvard Medical School, Boston, MA, USA; Program in Biophysics, Harvard University, Cambridge, MA, USA
2 Neurobiology, Harvard Medical School, Boston, MA, USA
* To whom correspondence should be addressed. E-mail: irwin_lee{at}student.hms.harvard.edu.
To examine the role of basal-ganglia-cortical circuits in movement initiation we trained monkeys to make the same arm movements in two ways - in immediate reaction to a randomly timed external cue (cued movements) and also following a variable delay without an explicit initiation signal (self-timed movements). The two movement types were interleaved and balanced in overall timing to allow a direct comparison of activity before and during the movement. Posterior putaminal neurons generally had phasic, movement-related discharges that were comparable for both cued and self-timed movements. On cued movements neuronal activity increased sharply following cue onset. However, for self-timed movements, there was a slow build-up in activity that preceded the phasic discharge. This slow build-up was time-locked to movement and restricted to a narrow time window hundreds of milliseconds before movement. The difference in premovement activity between cued and self-timed trials was present before the earliest cue-onset times and was not related to any differences in the overall time-to-move between the two types of trials. These features suggest that activity evolving in the basal-ganglia-cortical circuitry may drive the initiation of movements by increasing until an activity threshold is exceeded. The activity may increase abruptly in response to an external cue or gradually when the timing of movements is determined by the animals themselves rather than an external cue. In this view, small changes in activity that occur in advance of the much larger perimovement neuronal activity may be an important determinant of when movement occurs. In support of this hypothesis, we found that even for cued movements, faster reaction times were associated with slightly higher levels of activity hundreds of milliseconds before movement.
This article has been cited by other articles:
|
|
 |
|
  M. A. Lebedev, J. E. O'Doherty, and M. A. L. Nicolelis Decoding of Temporal Intervals From Cortical Ensemble Activity J Neurophysiol, January 1, 2008; 99(1): 166 - 186. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Tanaka Cognitive Signals in the Primate Motor Thalamus Predict Saccade Timing J. Neurosci., October 31, 2007; 27(44): 12109 - 12118. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. H. Snyder, A. R. Dickinson, and J. L. Calton Preparatory Delay Activity in the Monkey Parietal Reach Region Predicts Reach Reaction Times J. Neurosci., October 4, 2006; 26(40): 10091 - 10099. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. H. Lee, A. R. Seitz, and J. A. Assad Activity of Tonically Active Neurons in the Monkey Putamen During Initiation and Withholding of Movement J Neurophysiol, April 1, 2006; 95(4): 2391 - 2403. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Leblois, T. Boraud, W. Meissner, H. Bergman, and D. Hansel Competition between feedback loops underlies normal and pathological dynamics in the basal ganglia. J. Neurosci., March 29, 2006; 26(13): 3567 - 3583. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Maimon and J. A. Assad Parietal Area 5 and the Initiation of Self-Timed Movements versus Simple Reactions J. Neurosci., March 1, 2006; 26(9): 2487 - 2498. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. R. Bailey and R. G. Mair The Role of Striatum in Initiation and Execution of Learned Action Sequences in Rats J. Neurosci., January 18, 2006; 26(3): 1016 - 1025. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Amirnovin, Z. M. Williams, G. R. Cosgrove, and E. N. Eskandar Visually Guided Movements Suppress Subthalamic Oscillations in Parkinson's Disease Patients J. Neurosci., December 15, 2004; 24(50): 11302 - 11306. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
