Participation of the Primate Presupplementary Motor Area in Sequencing Multiple Saccades

2004 ◽  
Vol 92 (1) ◽  
pp. 653-659 ◽  
Author(s):  
Masaki Isoda ◽  
Jun Tanji

The aim of this study was to investigate whether, and how, the presupplementary motor area (pre-SMA) is involved in the organization of oculomotor sequence. We trained two monkeys to perform three center-out saccades in six different orders. Each sequence consisted of a block of eight trials, initially with visual instruction (4 trials) and then from memory (4 trials). During memory-guided performance of sequential saccades, ∼75% of task-related neuronal activity was selective for, or influenced by, the numerical position of saccades within each sequence (rank order). Neurons tuned for the direction of saccades were in the minority. We also found that 22% of sampled neurons increased their activity preferentially at a transitional period when monkeys were in the process of renewal of required saccade sequences. These data indicate that the pre-SMA is involved in the organization of oculomotor sequence, particularly in representing rank-order information and in updating sequence information. Together with previous reports on the participation of the pre-SMA in sequencing of multiple arm movements, we propose here that this area may contribute to cognitive aspects of sequential behavioral control, in an effector-independent manner.

Brain ◽  
2019 ◽  
Vol 142 (11) ◽  
pp. 3530-3549 ◽  
Author(s):  
Shuo Wang ◽  
Adam N Mamelak ◽  
Ralph Adolphs ◽  
Ueli Rutishauser

Abstract The medial frontal cortex is important for goal-directed behaviours such as visual search. The pre-supplementary motor area (pre-SMA) plays a critical role in linking higher-level goals to actions, but little is known about the responses of individual cells in this area in humans. Pre-SMA dysfunction is thought to be a critical factor in the cognitive deficits that are observed in diseases such as Parkinson’s disease and schizophrenia, making it important to develop a better mechanistic understanding of the pre-SMA’s role in cognition. We simultaneously recorded single neurons in the human pre-SMA and eye movements while subjects performed goal-directed visual search tasks. We characterized two groups of neurons in the pre-SMA. First, 40% of neurons changed their firing rate whenever a fixation landed on the search target. These neurons responded to targets in an abstract manner across several conditions and tasks. Responses were invariant to motor output (i.e. button press or not), and to different ways of defining the search target (by instruction or pop-out). Second, ∼50% of neurons changed their response as a function of fixation order. Together, our results show that human pre-SMA neurons carry abstract signals during visual search that indicate whether a goal was reached in an action- and cue-independent manner. This suggests that the pre-SMA contributes to goal-directed behaviour by flexibly signalling goal detection and time elapsed since start of the search, and this process occurs regardless of task. These observations provide insights into how pre-SMA dysfunction might impact cognitive function.


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.


2010 ◽  
Vol 30 (44) ◽  
pp. 14657-14675 ◽  
Author(s):  
X. Chen ◽  
K. W. Scangos ◽  
V. Stuphorn

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)


2003 ◽  
Vol 89 (3) ◽  
pp. 1223-1237 ◽  
Author(s):  
Xuguang Liu ◽  
Edwin Robertson ◽  
R. Christopher Miall

Testing the hypothesis that the lateral cerebellum forms a sensory representation of arm movements, we investigated cortical neuronal activity in two monkeys performing visually guided step-tracking movements with a manipulandum. A virtual target and cursor image were viewed co-planar with the manipulandum. In the normal task, manipulandum and cursor moved in the same direction; in the mirror task, the cursor was left-right reversed. In one monkey, 70- and 200-ms time delays were introduced on cursor movement. Significant task-related activity was recorded in 31 cells in one animal and 142 cells in the second: 10.2% increased activity before arm movements onset, 77.1% during arm movement, and 12.7% after the new position was reached. To test for neural representation of the visual outcome of movement, firing rate modulation was compared in normal and mirror step-tracking. Most task-related neurons (68%) showed no significant directional modulation. Of 70 directionally sensitive cells, almost one-half ( n = 34, 48%) modulated firing with a consistent cursor movement direction, many fewer responding to the manipulandum direction ( n = 9, 13%). For those “cursor-related” cells tested with delayed cursor movement, increased activity onset was time-locked to arm movement and not cursor movement, but activation duration was extended by an amount similar to the applied delay. Hence, activity returned to baseline about when the delayed cursor reached the target. We conclude that many cells in the lateral cerebellar cortex signaled the direction of cursor movement during active step-tracking. Such a predictive representation of the arm movement could be used in the guidance of visuo-motor actions.


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