Topographic organization, number, and laminar distribution of callosal cells connecting visual cortical areas 17 and 18 of normally pigmented and Siamese cats

1992 ◽  
Vol 9 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Nancy E. J. Berman ◽  
Simon Grant
Keyword(s):  
Pyramidal Neurons ◽  
Area 17 ◽  
Vertical Meridian ◽  
Cortical Areas ◽  
Area Centralis ◽  
Areas 17 And 18 ◽  
Contralateral Eye ◽  
Visual Cortical ◽  
Callosal Pathway ◽  
Cell Zone

AbstractThe callosal connections between visual cortical areas 17 and 18 in adult normally pigmented and “Boston” Siamese cats were studied using degeneration methods, and by transport of WGA-HRP combined with electrophysiological mapping. In normal cats, over 90% of callosal neurons were located in the supragranular layers. The supragranular callosal cell zone spanned the area 17/18 border and extended, on average, some 2–3 mm into both areas to occupy a territory which was roughly co-extensive with the distribution of callosal terminations in these areas. The region of the visual field adjoining the vertical meridian that was represented by neurons in the supragranular callosal cell zone was shown to increase systematically with decreasing visual elevation. Thus, close to the area centralis, receptive-field centers recorded from within this zone extended only up to 5 deg into the contralateral hemifield but at elevations of -10 deg and -40 deg they extended as far as 8 deg and 14 deg, respectively, into this hemifield. This suggests an element of visual non-correspondence in the callosal pathway between these cortical areas, which may be an essential substrate for “coarse” stereopsis at the visual midline.In the Siamese cats, the callosal cell and termination zones in areas 17 and 18 were expanded in width compared to the normal animals, but the major components were less robust. The area 17/18 border was often devoid of callosal axons and, in particular, the number of supragranular layer neurons participating in the pathway were drastically reduced, to only about 25% of those found in the normally pigmented adults. The callosal zones contained representations of the contralateral and ipsilateral hemifields that were roughly mirror-symmetric about the vertical meridian, and both hemifield representations increased with decreasing visual elevation. The extent and severity of the anomalies observed were similar across individual cats, regardless of whether a strabismus was also present. The callosal pathway between these visual cortical areas in the Siamese cat has been considered “silent,” since nearly all neurons within its territory are activated only by the contralateral eye. The paucity of supragranular pyramidal neurons involved in the pathway may explain this silence.

Response properties of visual cortical neurons in cats reared in stroboscopic illumination

1983 ◽  
Vol 49 (3) ◽  
pp. 686-704 ◽  
Author(s):  
H. Kennedy ◽  
G. A. Orban
Keyword(s):  
Visual Field ◽  
Receptive Fields ◽  
Normal Animal ◽  
Area 17 ◽  
Central Vision ◽  
Area 18 ◽  
Areas 17 And 18 ◽  
Contralateral Eye ◽  
Visual Cortical ◽  
High Pass

1. The response properties of 182 units were studied in the primary visual cortices (155 in area 18 and 27 in area 17) in eight cats reared from birth in a stroboscopically illuminated environment (frequency, 2/s; duration, 200 microseconds). Multihistogram quantitative testing was carried out in 82 units (64 in area 18 and 18 in area 17). Two hundred three neurons recorded and quantitatively tested in areas 17 and 18 of the normal adult cat were used for comparison. 2. Spatial characteristics of receptive fields investigated using hand-held stimuli were found to be abnormal. The correlation between receptive-field width and eccentricity was lost in area 18 and consequently, receptive fields were significantly wider in area 18 subserving central vision. Cells could be classified according to the spatial characteristics of their receptive fields. There was a much smaller proportion of end-stopped cells in strobe-reared animals. Orientation tuning in the deprived animals was normal except for a small number of cells that showed no selectivity for stimulus orientation. 3. Compilation of velocity-response curves made it possible to classify areas 17 and 18 neurons into four categories: velocity low-pass, velocity broad-band, velocity tuned, and velocity high-pass cells. The proportion of velocity high-pass cells was reduced in area 18 subserving peripheral vision, as was the proportion of velocity-tuned cells in area 18 subserving central vision. 4. In the strobe-reared animal velocity sensitivity was somewhat different from that of the normal animal. Neurons in area 18 subserving the peripheral visual field failed to respond to fast velocities. Neurons in area 17 subserving the central visual field in strobe-reared animals responded to slightly higher velocities than in the normal animal. 5. In the deprived animals the number of neurons that were selective to the direction of motion was strongly reduced. The majority of neurons failed to show a selectivity for direction at all velocities. A number of neurons could be directional at some velocities but were unreliable, since they inverted their preferred direction with velocity changes. 6. Binocular convergence onto visual cortical cells was perturbed. In area 18 the majority of neurons were driven by the contralateral eye. In area 17 most neurons could be driven only by either the ipsilateral or contralateral eye. 7. Quantitative testing (of direction selectivity, sensitivity to high velocities, response latency, and strength) and qualitative testing (receptive-field width, end stopping, and ocular dominance) showed that the normal influence of eccentricity on functional properties was strongly reduced by strobe rearing.

An examination of linking hypotheses drawn from the perceptual consequences of experimentally induced changes in neural circuitry

2013 ◽  
Vol 30 (5-6) ◽  
pp. 271-276 ◽  
Author(s):  
DONALD E. MITCHELL ◽  
STEPHEN G. LOMBER
Keyword(s):  
Striate Cortex ◽  
Extended Period ◽  
Monocular Deprivation ◽  
Specific Cell ◽  
Cortical Areas ◽  
Good Spatial Resolution ◽  
Areas 17 And 18 ◽  
Visual Cortical ◽  
Areas Of Interest ◽  
Induced Changes

AbstractBecause targeted early experiential manipulations alter both perception and the response properties of particular cells in the striate cortex, they have been used as evidence for linking hypotheses between the two. However, such hypotheses assume that the effects of the early biased visual input are restricted to just the specific cell population and/or visual areas of interest and that the neural populations that contribute to the visual perception itself do not change. To examine this assumption, we measured the consequences for vision of an extended period of early monocular deprivation (MD) on a kitten (from 19 to 219 days of age) that began well before, and extended beyond, bilateral ablation of visual cortical areas 17 and 18 at 132 days of age. In agreement with previous work, the lesion reduced visual acuity by only a factor of two indicating that the neural sites, other than cortical areas 17 and 18, that support vision in their absence have good spatial resolution. However, these sites appear to be affected profoundly by MD as the effects on vision were just as severe as those observed following MD imposed on normal animals. The pervasive effects of selected early visual deprivation across many cortical areas reported here and elsewhere, together with the potential for perception to be mediated at a different neural site following deprivation than after typical rearing, points to a need for caution in the use of data from early experiential manipulations for formulation of linking hypotheses.

Receptive fields of neurons at the confluence of cerebral cortical areas 17, 18, 20 a, and 20 b in the cat

1990 ◽  
Vol 4 (05) ◽  
pp. 475-479 ◽  
Author(s):  
B. R. Payne ◽  
D.F. Siwek
Keyword(s):  
Visual Angle ◽  
Receptive Fields ◽  
Cortical Areas ◽  
Contralateral Eye ◽  
The Individual ◽  
Visual Cortical

AbstractThe activity of neurons was recorded extracellurayly at the junction of visual cortical areas 17, 18, 20a, and 20b in the cat. The receptive fields of these neurons were striking for their size, which ranged from a diameter of more than 40 deg of visual angle to the complete visual of the contralateral eye. It is speculated that these large receptive fields may be generated by perturbations in the individual maps as the four areas merge together.

scholarly journals An unconventional GABAergic circuit differently controls pyramidal neuron activity in two visual cortical areas via endocannabinoids

2021 ◽  
Author(s):  
Martin Montmerle ◽  
Fani Koukouli ◽  
Andrea Aguirre ◽  
Jeremy Peixoto ◽  
Vikash Choudhary ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Cannabinoid Receptor ◽  
Gaba Release ◽  
Network Activity ◽  
Connectivity Pattern ◽  
Neuron Activity ◽  
Cortical Areas ◽  
Visual Cortical ◽  
And Function

Perisomatic inhibition of neocortical pyramidal neurons (PNs) coordinates cortical network activity during sensory processing, and it has been mainly attributed to parvalbumin-expressing basket cells (BCs). However, cannabinoid receptor type 1 (CB1)-expressing interneurons also inhibit the perisomatic region of PNs but the connectivity and function of these elusive, yet prominent, neocortical GABAergic cells is unknown. We found that the connectivity pattern of CB1-positive BCs strongly differs between primary and high-order cortical visual areas. Moreover, persistently active CB1 signaling suppresses GABA release from CB1 BCs in the medial secondary visual cortex (V2M), but not in the primary (V1) visual area. Accordingly, in vivo, tonic CB1 signaling is responsible for higher but less coordinated PN activity in V2M than in V1. Our results indicate a differential CB1-mediated mechanism controlling PN activity, and suggest an alternative connectivity schemes of a specific GABAergic circuit in different cortical areas

Interocular transfer of adaptation after effect in neurons of area 17 and 18 of split chiasm cats

1986 ◽  
Vol 55 (5) ◽  
pp. 966-976 ◽  
Author(s):  
L. Maffei ◽  
N. Berardi ◽  
S. Bisti
Keyword(s):  
Corpus Callosum ◽  
Interocular Transfer ◽  
Optic Chiasm ◽  
Area 17 ◽  
Simple Cells ◽  
Complex Cells ◽  
Sinusoidal Gratings ◽  
After Effect ◽  
Contralateral Eye ◽  
Callosal Pathway

Responses to sinusoidal gratings for neurons in area 17 and 18 of split chiasm cats were recorded extracellularly, and the interocular transfer of the effect of adaptation to high-contrast gratings was studied. In area 17 all but one of the simple cells showed the phenomenon of adaptation and its interocular transfer; 60% of the complex cells showed the effect of adaptation, and of these cells 35% showed an interocular transfer of adaptation. The adaptation aftereffect was comparable both in strength and duration for the direct and the callosal pathway. The strength of the adaptation aftereffect through the callosal pathway was not related to the strength of the input from the contralateral eye. An interocular transfer of the adaptation aftereffect was found in several neurons with a very weak input from the contralateral eye and in five simple cells apparently responding only to the ipsilateral eye. Fifty-eight percent of the neurons in area 18 showed the effect of adaptation, and 55% of them showed interocular transfer. No interocular transfer of the adaptation aftereffect was found in those neurons where an input from the contralateral eye was undetectable. Interocular transfer of the adaptation was found in all the neurons recorded in area 17 of animals with section of the corpus callosum but intact chiasm. No interocular transfer was found in neurons recorded in area 17 of cats with both the optic chiasm and the corpus callosum sectioned. We conclude that callosal connections are sufficient for the transfer of the adaptation aftereffect, although they are not necessary.

Visuomotor properties of corticotectal cells in area 17 and posteromedial lateral suprasylvian (PMLS) cortex of the cat

2001 ◽  
Vol 18 (1) ◽  
pp. 77-91 ◽  
Author(s):  
THEODORE G. WEYAND ◽  
ADELE C. GAFKA
Keyword(s):  
Eye Movements ◽  
Oculomotor System ◽  
Oscillatory Activity ◽  
Visual Response ◽  
Area 17 ◽  
Stimulus Motion ◽  
Velocity Amplitude ◽  
Cortical Areas ◽  
Saccade Velocity ◽  
Visual Cortical

We studied the visuomotor activity of corticotectal (CT) cells in two visual cortical areas [area 17 and the posteromedial lateral suprasylvian cortex (PMLS)] of the cat. The cats were trained in simple oculomotor tasks, and head position was fixed. Most CT cells in both cortical areas gave a vigorous discharge to a small stimulus used to control gaze when it fell within the retinotopically defined visual field. However, the vigor of the visual response did not predict latency to initiate a saccade, saccade velocity, amplitude, or even if a saccade would be made, minimizing any potential role these cells might have in premotor or attentional processes. Most CT cells in both areas were selective for direction of stimulus motion, and cells in PMLS showed a direction preference favoring motion away from points of central gaze. CT cells did not discharge with eye movements in the dark. During eye movements in the light, many CT cells in area 17 increased their activity. In contrast, cells in PMLS, including CT cells, were generally unresponsive during saccades. Paradoxically, cells in PMLS responded vigorously to stimuli moving at saccadic velocities, indicating that the oculomotor system suppresses visual activity elicited by moving the retina across an illuminated scene. Nearly all CT cells showed oscillatory activity in the frequency range of 20–90 Hz, especially in response to visual stimuli. However, this activity was capricious; strong oscillations in one trial could disappear in the next despite identical stimulus conditions. Although the CT cells in both of these regions share many characteristics, the direction anisotropy and the suppression of activity during eye movements which characterize the neurons in PMLS suggests that these two areas have different roles in facilitating perceptual/motor processes at the level of the superior colliculus.

Corticotectal circuit in the cat: a functional analysis of the lateral geniculate nucleus layers of origin

1988 ◽  
Vol 59 (6) ◽  
pp. 1783-1797 ◽  
Author(s):  
C. L. Colby
Keyword(s):  
Superior Colliculus ◽  
Lateral Geniculate Nucleus ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Visual Responses ◽  
Cortical Input ◽  
Cortical Areas ◽  
Lateral Geniculate ◽  
Contralateral Eye ◽  
Visual Cortical ◽  
Y Cells

1. The dorsal lateral geniculate nucleus (LGN) of the cat is a major thalamic relay between the retina and several visual cortical areas. These cortical areas in turn project to the superior colliculus (SC). The aim of the present experiment was to determine which LGN layers provide a necessary input to the corticotectal circuit. 2. Individual layers of the LGN were reversibly inactivated by microinjection of cobalt chloride during recording of visual responses in the retinotopically corresponding part of the superior colliculus. 3. For cells driven through the contralateral eye, inactivation of layer A or the medial interlaminar nucleus (MIN) had little effect on visual responsiveness in the superior colliculus. In contrast, inactivation of layer C abolished visual responses at one-quarter of the SC recording sites, reduced responses at another quarter, and left half of the recording sites unaffected. 4. For cells driven through the ipsilateral eye, inactivation of layer C1 or the MIN had no effect. Inactivation of layer A1 uniformly reduced visual responses in the superior colliculus and usually abolished them entirely. 5. These results are compatible with previous work showing that cortical input to the SC originates from Y-cells. They indicate that two of the five Y-cell containing layers (A1 and C) provide major inputs to the corticotectal circuit. The results suggest that layer A1 is functionally allied to layer C as well as to layer A.

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