Visual responses in the postarcuate cortex (area 6) of the monkey that are independent of eye position

1983 ◽  
Vol 50-50 (2-3) ◽  
Author(s):  
M. Gentilucci ◽  
C. Scandolara ◽  
I.N. Pigarev ◽  
G. Rizzolatti
Keyword(s):  
Eye Position ◽  
Visual Responses ◽  
Cortex Area ◽  
Area 6

Response properties and behavioral modulation of ‘mouth’ neurons of the postarcuate cortex (area 6) in macaque monkeys

1981 ◽  
Vol 225 (2) ◽  
pp. 421-424 ◽  
Author(s):  
G. Rizzolatti ◽  
C. Scandolara ◽  
M. Gentilucci ◽  
R. Camarda
Keyword(s):  
Macaque Monkeys ◽  
Response Properties ◽  
Cortex Area ◽  
Area 6

Interconnections within the postarcuate cortex (area 6) of the macaque monkey

1984 ◽  
Vol 310 (2) ◽  
pp. 388-392 ◽  
Author(s):  
M. Matelli ◽  
R. Camarda ◽  
M. Glickstein ◽  
G. Rizzolatti
Keyword(s):  
Macaque Monkey ◽  
Cortex Area ◽  
Area 6

scholarly journals Dissociation of visual and saccade-related responses in superior colliculus neurons

1980 ◽  
Vol 43 (1) ◽  
pp. 207-232 ◽  
Author(s):  
L. E. Mays ◽  
D. L. Sparks
Keyword(s):  
Superior Colliculus ◽  
Visual Stimulation ◽  
Usual Sense ◽  
Eye Position ◽  
Visual Responses ◽  
Retinal Position ◽  
Position Information ◽  
Visual Cells ◽  
Retinal Stimulation ◽  
Saccade Onset

1. Single-unit activity was recorded from the superior colliculus (SC) of monkeys trained to look to visual targets presented on an oscilloscope screen. On one task, target localization required that information concerning the retinal position of the target be combined with information concerning current or future eye position. This task also permitted a dissociation between the site of retinal stimulation and the metrics of the saccade triggered by the stimulation. 2. Vigorous visual responses of superficial SC neurons may occur that do not result in the activation of underlying saccade-related cells. The activity of these neurons signals the occurrence of a visual stimulus, whether or not the stimulus is selected for foveal viewing. 3. Saccade-related (SR) discharges of most intermediate and deep-layer SC neurons precede saccades with particular vectors, regardless of the region of retinal activation initiating the saccade. The discharge of these neurons is tightly coupled to saccade onset, even if changes in eye position have occurred since target appearance. Thus, the discharge of these SR neurons must occur after retinal error and eye-position signals have been combined to compute the necessary saccade vector. For most SR neurons, direct retinal activation of overlying visual neurons had no effect on either the vigor or probability of a SR discharge. The discharge of overlying visual cells is neither necessary nor sufficient to activate most SR cells. 4. The discharge of some SR cells is dependent on prior activation of overlying visual cells. Of 53 SR cells, only 3 were completely dependent on visual stimulation, while another 8 discharged less vigorously if corresponding visual activation failed to occur. 5. About one-quarter of the SR cells showed long-lead preburst activity. This activation was characterized by a low level of firing, which began after the saccade signal and continued until a saccade-linked burst occurred. 6. Cells were isolated that were visually responsive yet discharged prior to saccades in the absence of appropriate retinal stimulation. No component of the discharge of these quasi-visual (QV) cells appeared to be motor in the usual sense. The activity of these neurons appears to reflect eye-position error (the difference between actual and desired eye position) and to hold this information in spatial register until a saccade occurs or is cancelled. 7. It is concluded that the presumed linkage, implied in earlier versions of the foveation hypothesis, between the superficial layers (receiving direct retinal inputs) and the deeper layers of the SC is not necessary for the activation of SR neurons. Results suggest that the SC must generate or receive a signal that combines retinal error and eye-position information. These findings are discussed in terms of current models of the saccadic-control system.

Imagery of Voluntary Movement of Fingers, Toes, and Tongue Activates Corresponding Body-Part-Specific Motor Representations

2003 ◽  
Vol 90 (5) ◽  
pp. 3304-3316 ◽  
Author(s):  
H. Henrik Ehrsson ◽  
Stefan Geyer ◽  
Eiichi Naito
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Supplementary Motor Area ◽  
Premotor Cortex ◽  
Body Part ◽  
Cortical Activation ◽  
Motor Area ◽  
Cortex Area ◽  
Area 6 ◽  
Motor Areas

We investigate whether imagery of voluntary movements of different body parts activates somatotopical sections of the human motor cortices. We used functional magnetic resonance imaging to detect the cortical activity when 7 healthy subjects imagine performing repetitive (0.5-Hz) flexion/extension movements of the right fingers or right toes, or horizontal movements of the tongue. We also collected functional images when the subjects actually executed these movements and used these data to define somatotopical representations in the motor areas. In this study, we relate the functional activation maps to cytoarchitectural population maps of areas 4a, 4p, and 6 in the same standard anatomical space. The important novel findings are 1) that imagery of hand movements specifically activates the hand sections of the contralateral primary motor cortex (area 4a) and the contralateral dorsal premotor cortex (area 6) and a hand representation located in the caudal cingulate motor area and the most ventral part of the supplementary motor area; 2) that when imagining making foot movements, the foot zones of the posterior part of the contralateral supplementary motor area (area 6) and the contralateral primary motor cortex (area 4a) are active; and 3) that imagery of tongue movements activates the tongue region of the primary motor cortex and the premotor cortex bilaterally (areas 4a, 4p, and 6). These results demonstrate that imagery of action engages the somatotopically organized sections of the primary motor cortex in a systematic manner as well as activating some body-part-specific representations in the nonprimary motor areas. Thus the content of the mental motor image, in this case the body part, is reflected in the pattern of motor cortical activation.

Residual eye-movements in macaque and their effects on visual responses of neurons

2002 ◽  
Vol 19 (1) ◽  
pp. 31-38 ◽  
Author(s):  
JASON FORTE ◽  
JONATHAN W. PEIRCE ◽  
JAMES M. KRAFT ◽  
JOHN KRAUSKOPF ◽  
PETER LENNIE
Keyword(s):  
Random Walk ◽  
Eye Movements ◽  
Muscle Relaxant ◽  
Average Distance ◽  
Sampling Period ◽  
Eye Position ◽  
Square Root ◽  
Visual Responses ◽  
Rhythmic Movements ◽  
Macaque Monkeys

We recorded continuously, with high precision, the positions of the eyes in anesthetized macaque monkeys prepared for physiological recording. Most recordings were made after the infusion of muscle relaxant to immobilize the eyes; in some cases we also were able to record eye position for periods before the eyes were immobilized. In all monkeys, the eyes moved continuously by as much as 0.5 deg over a 10-min sampling period. The average distance moved was proportional to the square root of the sampling period, as would be expected from a random walk. The movements had three distinct components: slow drifts, and two rhythms driven by the pulse and respiration. The rhythmic movements occurred only under paralysis: they were not discernible in measurements made before the infusion of muscle relaxant. The movements of the eye in the paralyzed animal can have substantial effects on the measured physiological characteristics of neurons. For excursions in the midrange of those we observed, a neuron's sensitivity to a spatial frequency of 10 cycle/deg might be underestimated by as much as a factor of three, depending on the method by which responses were averaged. We show how the effects of eye-movements can be mitigated by appropriate data analysis.

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