Neuroscience 2005 Abstract
| Presentation Number: | 980.21 |
|---|---|
| Abstract Title: | Comparison of single neuron activity and 2DG uptake in M1 of trained monkeys. |
| Authors: |
Picard, N.*
; Matsuzaka, Y.
; Strick, P. L.1
1VAMC , Pitt., PA |
| Primary Theme and Topics |
Sensory and Motor Systems - Visuomotor Processing -- Visually guided reaching |
| Session: |
980. Visuomotor Processing: Visually Guided Reaching I Poster |
| Presentation Time: | Wednesday, November 16, 2005 1:00 PM-2:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # BB15 |
| Keywords: | DEOXYGLUCOSE, MOTOR CORTEX, REACHING, MOTOR LEARNING |
We previously showed that abundant neuron activity can be found in regions of M1 that have relatively low levels of metabolic activation (2-deoxyglucose, 2DG) during the same behavior (Picard & al SFN Abstr, 2001). This observation suggested that functional activation can be uncoupled from neuron activity. Here, we extend the comparison of neuron activity and 2DG uptake in M1 in two monkeys overtrained on a sequential movement task. We recorded from 504 neurons at 96 sites in one animal and from 217 neurons at 60 sites in the other, while the monkeys performed learned and random sequences of movements. At the end of the recording period, we measured 2DG uptake in M1 in these animals while one performed a learned sequence and the other performed random sequences. As in previous 2DG experiments, we observed a large reduction of 2DG uptake in the arm area of M1 during performance of a learned sequence compared to random sequences (Picard & al SFN Abstr, 1998, 2001). Average neuron activity during the 2DG experiments was estimated from the single neuron data obtained previously in the same animals and mapped by location in M1 for comparison with local 2DG uptake. In contrast to the 2DG differences, both animals showed only slight differences in total spiking activity (<2 spikes/sec) at the population level for performance of overtrained vs random sequences. Task-related differences in spiking activity could be demonstrated for <20% of recording sites. However, these differences were not consistent with the patterns of 2DG uptake. In fact, correlations between measures of spiking activity and 2DG uptake were negligible (R2<0.1). These results confirm that metabolic measures of activity in M1 can be strongly decoupled from traditional measures of neuronal activity (i.e., spikes/sec) under certain behavioral conditions. Our observations raise the possibility that overtraining and learning of movement sequences result in altered processing efficacy in the motor system.
Supported by VA Med. Res. Serv., NS24328 & NS044393-01 (PLS)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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