Orienting behavior in hamsters with lesions of superior colliculus, pretectum, and visual cortex

1992 ◽  
Vol 90 (1) ◽  
Author(s):  
LaurieS. Carman ◽  
GeraldE. Schneider
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Orienting Behavior

Glutamate-like immunoreactivity in the cat superior colliculus and visual cortex: Further evidence that glutamate is the neurotransmitter of the corticocollicular pathway

1997 ◽  
Vol 14 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Chang-Jin Jeon ◽  
Michael K. Hartman ◽  
R. Ranney Mize
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Optical Density ◽  
Retrograde Tracing ◽  
Biochemical Studies ◽  
Deep Layers ◽  
Dense Band ◽  
Cat Superior Colliculus ◽  
Made In ◽  
In Cells

AbstractBiochemical studies provide evidence that the pathway from visual cortex to the superior colliculus (SC) utilizes glutamate as a neurotransmitter. In the present study, we have used immunocytochemistry, visual cortex lesions, and retrograde tracing to show directly by anatomical methods that glutamate or a closely related analog is contained in corticocollicular neurons and terminals. A monoclonal antibody directed against gamma-L-glutamyl-L-glutamate (gamma glu glu) was used to localize glutamate-like immunoreactivity in both the superior colliculus (SC) and visual cortex (VC). Unilateral lesions of areas 17–18 were made in four cats to determine if gamma glu glu labeling was reduced in SC by this lesion. WGA-HRP was injected into the SC of 10 additional cats in order to determine if corticocollicular neurons were also labeled by the gamma glu glu antibody. A distinctive dense band of gamma glu glu immunoreactivity was found within the deep superficial gray and upper optic layers of SC where many corticotectal axons are known to terminate. Both fibers and cells were labeled within the band. Immunoreactivity was also found in cells and fibers throughout the deep layers of SC. Measures of total immunoreactivity (i.e. optical density) in the dense band were made in sections from the SC both ipsilateral to and contralateral to the lesions of areas 17–18. A consistent reduction in optical density was found in both the neuropil and in cells within the dense band of the SC ipsilateral to the lesion. A large percentage of all corticocollicular neurons that were retrogradely labeled by WGA-HRP also contained gamma glu glu. These results provide further evidence that the corticocollicular pathway in mammals is glutamatergic. The results also suggest that visual cortex ablation alters synthesis or storage of glutamate within postsynaptic SC neurons, presumably as a result of partial deafferentation.

Acute effects of alcohol on evoked potentials in visual cortex and superior colliculus of the rat

1981 ◽  
Vol 51 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Bruce E Hetzler ◽  
Robert L Heilbronner ◽  
Judith Griffin ◽  
Gregory Griffin
Keyword(s):  
Visual Cortex ◽  
Evoked Potentials ◽  
Superior Colliculus ◽  
Acute Effects

Direct and indirect visual inputs to superficial layers of cat superior colliculus: a current source-density analysis of electrically evoked potentials

1983 ◽  
Vol 49 (5) ◽  
pp. 1075-1091 ◽  
Author(s):  
B. Freeman ◽  
W. Singer
Keyword(s):  
Visual Cortex ◽  
Optic Nerve ◽  
Superior Colliculus ◽  
Current Source ◽  
Afferent Fiber ◽  
Synaptic Activity ◽  
Spatiotemporal Pattern ◽  
Visual Inputs ◽  
Electrolytic Lesions ◽  
Cat Superior Colliculus

1. The spatiotemporal pattern of visual inputs to the stratum griseum superficiale (SGS) and stratum opticum (SO) of the cat superior colliculus (SC) has been determined by an analysis of the current sinks occurring during postsynaptic activity following stimulation of each optic nerve (ON) and the optic chiasm (OX). Electrolytic lesions were used to determine the locations of the five major current sinks. 2. Direct SC afferents from the contralateral ON induced three current sinks whose maxima were located a) in the upper part of the SGS, b) in the middle part of the SGS, and c) in the lower part of the SGS and upper part of the SO. These three sinks were generated by three afferent fiber groups conducting in the optic nerve with modal and maximum velocities, respectively, of a) 4 and 5 m/s (slow W-group), b) 7 and 10 m/s (fast W-group), and c) 32 and 43 m/s (Y-group). 3. Indirect SC inputs from the contralateral ON via the ipsilateral visual cortex were identified by comparing the pattern of current sinks generated by OX stimulation before and after cortical ablation. The most prominent and fastest indirect sink (Y-group) was found in ;the lower half of the SGS and uppermost part of the SO. Low-amplitude, long-latency indirect current sinks were also found in the upper and lower thirds of the SGS. 4. The principal conclusions of this report are first, that the SGS is divisible into three physiologic regions according to the spatiotemporal pattern of excitatory synaptic activity generated by the afferent inputs and second, that there is a spatiotemporal matching of the direct collicular afferents from the contralateral retina and the indirect retinal afferents relaying through the ipsilateral visual cortex.

Bilateral impact of unilateral visual cortex lesions on the superior colliculus

2003 ◽  
Vol 151 (4) ◽  
pp. 542-547 ◽  
Author(s):  
R. Jarrett Rushmore ◽  
Bertram R. Payne
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus

scholarly journals Response Recovery Cycles in the Visual Cortex and Superior Colliculus Following Conditioning ‘ON” and ‘OFF” Stimulation in the Rabbit

1977 ◽  
Vol 4 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Stéphane Molotchnikoff ◽  
Michel Dubuc
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Conditioning Stimulus ◽  
Superficial Layer ◽  
Evoked Responses ◽  
Ventral Part ◽  
Response Recovery ◽  
Optic Nerve Stimulation ◽  
Recovery Cycles ◽  
Conditioning Stimuli

SummaryThe responsiveness of the visual cortex (VC) and superior colliculus (SC) was simultaneously compared following conditioning “ON” or “OFF” stimulation, in the rabbit.Average evoked responses were recorded simultaneously from the visual cortex and superior colliculus. “ON” or “OFF” steps constituted the conditioning stimuli whereas the test stimulus consisted of optic nerve stimulation. All evoked responses exhibited a reversal of their polarity when the electrode was moved in the dorsoventral direction (Negative-Positive in the SC, Positive-Negative in the VC). This assured the somato-dentritic origin of the potentials. The results showed that responsiveness in both structures was significantly higher following an “OFF” stimulus than after an “ON” step. Collicular responsiveness was higher than in the VC when the same conditioning stimulus was applied. The spatial distribution of the source of “OFF” responses was circumscribed to the ventral part of the superficial layer of the superior colliculus. These results suggest specific properties associated with the brightening and dimming systems.

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