Neuronal Activity in the Supplementary Motor Area of Monkeys Adapting to a New Dynamic Environment

2004 ◽  
Vol 91 (1) ◽  
pp. 449-473 ◽  
Author(s):  
Camillo Padoa-Schioppa ◽  
Chiang-Shan Ray Li ◽  
Emilio Bizzi

To execute visually guided reaching movements, the central nervous system (CNS) must transform a desired hand trajectory (kinematics) into appropriate muscle-related commands (dynamics). It has been suggested that the CNS might face this challenging computation by using internal forward models for the dynamics. Previous work in humans found that new internal models can be acquired through experience. In a series of studies in monkeys, we investigated how neurons in the motor areas of the frontal lobe reflect the movement dynamics and how their activity changes when monkeys learn a new internal model. Here we describe the results for the supplementary motor area (SMA-proper, or SMA). In the experiments, monkeys executed visually guided reaching movements and adapted to an external perturbing force field. The experimental design allowed dissociating the neuronal activity related to movement dynamics from that related to movement kinematics. It also allowed dissociating the changes related to motor learning from the activity related to motor performance (kinematics and dynamics). We show that neurons in SMA reflect the movement dynamics individually and as a population, and that their activity undergoes a variety of plastic changes when monkeys adapt to a new dynamic environment.

2015 ◽  
Vol 113 (7) ◽  
pp. 2845-2858 ◽  
Author(s):  
Yoshihisa Nakayama ◽  
Osamu Yokoyama ◽  
Eiji Hoshi

The caudal cingulate motor area (CMAc) and the supplementary motor area (SMA) play important roles in movement execution. The present study aimed to characterize the functional organization of these regions during movement by investigating laterality representations in the CMAc and SMA of monkeys via an examination of neuronal activity during a button press movement with either the right or left hand. Three types of movement-related neuronal activity were observed: 1) with only the contralateral hand, 2) with only the ipsilateral hand, and 3) with either hand. Neurons in the CMAc represented contralateral and ipsilateral hand movements to the same degree, whereas neuronal representations in the SMA were biased toward contralateral hand movement. Furthermore, recording neuronal activities using a linear-array multicontact electrode with 24 contacts spaced 150 μm apart allowed us to analyze the spatial distribution of neurons exhibiting particular hand preferences at the submillimeter scale. The CMAc and SMA displayed distinct microarchitectural organizations. The contralateral, ipsilateral, and bilateral CMAc neurons were distributed homogeneously, whereas SMA neurons exhibiting identical hand preferences tended to cluster. These findings indicate that the CMAc, which is functionally organized in a less structured manner than the SMA is, controls contralateral and ipsilateral hand movements in a counterbalanced fashion, whereas the SMA, which is more structured, preferentially controls contralateral hand movements.


1997 ◽  
Vol 77 (4) ◽  
pp. 2197-2201 ◽  
Author(s):  
Nathalie Picard ◽  
Peter L. Strick

Picard, Nathalie and Peter L. Strick. Activation on the medial wall during remembered sequences of reaching movements in monkeys. J. Neurophysiol. 77: 2197–2201, 1997. We used the 2-deoxyglucose (2DG) method to map activation in the motor areas on the medial wall of the hemisphere. One group of monkeys licked juice delivered at variable time intervals (LICK task). For these animals, the motor areas on the medial wall displayed restricted activation. 2DG uptake was limited largely to the face representation of the supplementary motor area (SMA). Additional labeling was present more rostrally in the banks of the cingulate sulcus. A second group of animals performed remembered sequences of reaching movements (REM task) for juice rewards. Activation related to licking also was present in this group. In addition, separate, discrete activations were found on the superior frontal gyrus and in the cingulate sulcus during the REM task. The most intense and extensive 2DG labeling was located in the dorsal bank of the cingulate sulcus, coincident with the dorsal cingulate motor area (CMAd). Weaker activations were present in the arm area of the SMA and in the pre-SMA. There was no significant 2DG incorporation in the ventral bank of the cingulate sulcus where the ventral cingulate motor area is located. Our findings suggest that the CMAd is involved more than any other medial area in the preparation for and/or execution of highly practiced, remembered sequences of movements. Overall, our results indicate that the attributes of motor control are not represented equally across the motor areas on the medial wall.


1985 ◽  
Vol 53 (1) ◽  
pp. 129-141 ◽  
Author(s):  
J. Tanji ◽  
K. Kurata

The present report contrasts neuronal activity in two motor cortical fields after instructions that determine which of two sensory signals will trigger a movement and which will not. The goal of the study was to determine possible differential roles of the two cortical fields in the process of preparing to move in response to one external cue and to ignore another. Single-cell recordings were made from the supplementary motor area (SMA) and the precentral motor area (PCM) of monkeys trained to perform key-press movements in two different modes. In the auditory mode, an instruction signal warned the animal to prepare to start the movement promptly in response to a forthcoming 1,000-Hz tone burst (trigger signal), but to remain motionless if the signal was vibrotactile (nontrigger signal). In the tactile mode, the trigger and nontrigger signals were reversed: a different instruction signal warned the animal to prepare to perform the key-press movement in response to the vibrotactile cue, but to withhold it in response to the 1,000-Hz tone. The instruction signals were auditory tones of 300 Hz for the auditory mode and 100 Hz for the tactile mode. Out of 259 task-related SMA neurons, 128 (49%) responded to instructions. Three types of instruction responses were observed: 1) 95 neurons showed continuous instruction-induced activity changes lasting until the occurrence of the movement-triggering signal, regardless of whether an intervening nontrigger signal occurred. 2) 24 neurons showed increased activity until the occurrence of the nontriggering signal, after which the activity subsided. When there was no nontrigger signal, the activity increased during a period when the nontrigger signal might have been given. 3) Nine neurons responded with a transient, short-latency discharge after the instruction. The responses of SMA neurons to two instructions were often different. Forty-four SMA neurons exhibited a selective response to only one of the two instructions. In 43 neurons the response was differential, with the magnitude of activity increase or decrease being at least three times greater after one instruction than the other. In the remaining 41 neurons the response was nondifferential. Out of 112 task-related PCM neurons, 25 (22%) responded to the instructions. In the majority of them (21 neurons), the instruction response was nondifferential.(ABSTRACT TRUNCATED AT 400 WORDS)


2010 ◽  
Vol 21 (7) ◽  
pp. 1602-1612 ◽  
Author(s):  
Alexandra Reichenbach ◽  
Jean-Pierre Bresciani ◽  
Angelika Peer ◽  
Heinrich H. Bülthoff ◽  
Axel Thielscher

2012 ◽  
Vol 12 (9) ◽  
pp. 609-609
Author(s):  
P. Fattori ◽  
K. Hadjidimitrakis ◽  
R. Breveglieri ◽  
F. Bertozzi ◽  
G. Dal Bo' ◽  
...  

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