Inhibitory effect of remote visual stimuli on visual responses of cat superior colliculus: spatial and temporal factors.

Saccades are useful for directing the high-acuity fovea to visual targets that are of behavioral relevance. The selection of visual targets for eye movements involves the superior colliculus (SC), where many neurons respond to visual stimuli. Many of these neurons are also activated before and during saccades of specific directions and amplitudes. Although the role of the SC in controlling eye movements has been thoroughly examined, far less is known about the nature of the visual responses in this area. We have, therefore, recorded from neurons in the intermediate layers of the macaque SC, while using a sparse-noise mapping procedure to obtain a detailed characterization of the spatiotemporal structure of visual receptive fields. We find that SC responses to flashed visual stimuli start roughly 50 ms after the onset of the stimulus and last for on average ∼70 ms. About 50% of these neurons are strongly suppressed by visual stimuli flashed at certain locations flanking the excitatory center, and the spatiotemporal pattern of suppression exerts a predictable influence on the timing of saccades. This suppression may, therefore, contribute to the filtering of distractor stimuli during target selection. We also find that saccades affect the processing of visual stimuli by SC neurons in a manner that is quite similar to the saccadic suppression and postsaccadic enhancement that has been observed in the cortex and in perception. However, in contrast to what has been observed in the cortex, decreased visual sensitivity was generally associated with increased firing rates, while increased sensitivity was associated with decreased firing rates. Overall, these results suggest that the processing of visual stimuli by SC receptive fields can influence oculomotor behavior and that oculomotor signals originating in the SC can shape perisaccadic visual perception.

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Cross-correlated and oscillatory visual responses of superficial-layer and tecto-reticular neurones in cat superior colliculus

Experimental Brain Research ◽

10.1007/s002219900263 ◽

2000 ◽

Vol 131 (1) ◽

pp. 44-56 ◽

Cited By ~ 4

Author(s):

A. Chabli ◽

D. Guitton ◽

S. Fortin ◽

S. Molotchnikoff

Keyword(s):

Superior Colliculus ◽

Superficial Layer ◽

Visual Responses ◽

Cat Superior Colliculus

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Both striate cortex and superior colliculus contribute to visual properties of neurons in superior temporal polysensory area of macaque monkey

Journal of Neurophysiology ◽

10.1152/jn.1986.55.5.1057 ◽

1986 ◽

Vol 55 (5) ◽

pp. 1057-1075 ◽

Cited By ~ 88

Author(s):

C. J. Bruce ◽

R. Desimone ◽

C. G. Gross

Keyword(s):

Visual Field ◽

Receptive Field ◽

Superior Colliculus ◽

Striate Cortex ◽

Visual Stimuli ◽

Receptive Fields ◽

Visual Responses ◽

Stimulus Motion ◽

Visual Hemifields ◽

Visual Properties

Although the tectofugal system projects to the primate cerebral cortex by way of the pulvinar, previous studies have failed to find any physiological evidence that the superior colliculus influences visual activity in the cortex. We studied the relative contributions of the tectofugal and geniculostriate systems to the visual properties of neurons in the superior temporal polysensory area (STP) by comparing the effects of unilateral removal of striate cortex, the superior colliculus, or of both structures. In the intact monkey, STP neurons have large, bilateral receptive fields. Complete unilateral removal of striate cortex did not eliminate visual responses of STP neurons in the contralateral visual hemifield; rather, nearly half the cells still responded to visual stimuli in the hemifield contralateral to the lesion. Thus the visual properties of STP neurons are not completely dependent on the geniculostriate system. Unilateral striate lesions did affect the response properties of STP neurons in three ways. Whereas most STP neurons in the intact monkey respond similarly to stimuli in the two visual hemifields, responses to stimuli in the hemifield contralateral to the striate lesion were usually weaker than responses in the ipsilateral hemifield. Whereas the responses of many STP neurons in the intact monkey were selective for the direction of stimulus motion or for stimulus form, responses in the hemifield contralateral to the striate lesion were not selective for either motion or form. Whereas the median receptive field in the intact monkey extended 80 degrees into the contralateral visual field, the receptive fields of cells with responses in the contralateral field that survived the striate lesions had a median border that extended only 50 degrees into the contralateral visual field. Removal of both striate cortex and the superior colliculus in the same hemisphere abolished the responses of STP neurons to visual stimuli in the hemifield contralateral to the combined lesion. Nearly 80% of the cells still responded to visual stimuli in the hemifield ipsilateral to the lesion. Unilateral removal of the superior colliculus alone had only small effects on visual responses in STP. Receptive-field size and visual response strength were slightly reduced in the hemifield contralateral to the collicular lesion. As in the intact monkey, selectivity for stimulus motion or form were similar in the two visual hemifields. We conclude that both striate cortex and the superior colliculus contribute to the visual responses of STP neurons. Striate cortex is crucial for the movement and stimulus specificity of neurons in STP.(ABSTRACT TRUNCATED AT 400 WORDS)

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Excitatory Amino Acid Receptors Participate in Synaptic Transmission of Visual Responses in the Superficial Layers of the Cat Superior Colliculus

European Journal of Neuroscience ◽

10.1111/j.1460-9568.1994.tb00257.x ◽

1994 ◽

Vol 6 (1) ◽

pp. 161-169 ◽

Cited By ~ 31

Author(s):

K. E. Binns ◽

T. E. Salt

Keyword(s):

Amino Acid ◽

Synaptic Transmission ◽

Superior Colliculus ◽

Excitatory Amino Acid ◽

Visual Responses ◽

Excitatory Amino Acid Receptors ◽

Amino Acid Receptors ◽

Cat Superior Colliculus

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Functional development of a central visual map in cat

Journal of Neurophysiology ◽

10.1152/jn.1994.72.1.266 ◽

1994 ◽

Vol 72 (1) ◽

pp. 266-272 ◽

Cited By ~ 14

Author(s):

C. Q. Kao ◽

J. G. McHaffie ◽

M. A. Meredith ◽

B. E. Stein

Keyword(s):

Visual Field ◽

Superior Colliculus ◽

Visual Stimuli ◽

Visual Activity ◽

Behavioral Observations ◽

Functional Development ◽

Deep Layers ◽

Entire Visual Field ◽

Eye Opening ◽

Cat Superior Colliculus

1. The onset of visual activity in the superficial layers of the cat superior colliculus begins abruptly at about 6 days postnatal (DPN), just before natural eye opening. Despite the presence of many inactive sites at this time, the systematic nature of the superior colliculus visuotopy is already evident. The number of inactive sites across the horizontal dimension of the superficial layers decreases rapidly so that by 9–10 DPN most sites are visually responsive. 2. Initially, visual activity is restricted to the topmost portion of the superficial gray layer, where W-cell terminals predominate, but rapidly extends down to include Y-cell territory at 10 DPN. 3. In contrast to what might have been expected based on earlier behavioral observations, there was no physiological evidence for a central-to-peripheral gradient in the development of the superior colliculus visuotopy. Rather, the entire visual field is well represented long before the expression of any visually initiated behaviors. 4. In contrast to the rapidity of the appearance and organization of the visual representation in superficial layers, deep layers remain refractory to visual stimuli for weeks.

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Nonequivalent visual, auditory, and somatic corticotectal influences in cat

Journal of Neurophysiology ◽

10.1152/jn.1978.41.1.55 ◽

1978 ◽

Vol 41 (1) ◽

pp. 55-64 ◽

Cited By ~ 36

Author(s):

B. E. Stein

Keyword(s):

Visual Cortex ◽

Auditory Cortex ◽

Superior Colliculus ◽

Functional Significance ◽

Critical Role ◽

Visual Responses ◽

Visual Cells ◽

Acoustic Stimuli ◽

Cortical Cooling ◽

Cat Superior Colliculus

1. The effects of cortical cooling on the responses of cells to visual, somatic, and acoustic stimuli were studied in the cat superior colliculus (SC). When the visual cortex was cooled, the responses of many visual cells of the SC were depressed or eliminated, but the activity of nonvisual cells remained unchanged. This response depression was found in visual cells located in both superficial and deep laminae and was most pronounced in neurons which were binocular and directionally selective. 2. Cooling somatic and/or auditory cortex had no effect on visual SC cells and, with few exceptions, did not alter the activity of somatic or acoustic cells either. 3. The specificity of visual cortex influences on visual responding in the SC was most apparent in multimodal cells. In trimodal cells, the simultaneous cooling of visual, somatic, and auditory cortex eliminated responses to visual stimuli, but did not affect responses to somatic or acoustic stimuli. Visual responses were returned to the precooling level in both unimodal and multimodal cells by cortical rewarming. 4. The present experiments indicate that despite the organizational parallels among visual, somatic, and acoustic cells of the cat SC, the influences they receive from cortex are non-equivalent. Cortical influences appear to play a more critical role in the responses of visual cells than in the responses of somatic and acoustic cells. These observations raise questions about the functional significance of nonvisual corticotectal systems.

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