Comparative study on direction selectivity and functional organization of the primary visual cortical cells in monkeys and cats

The response properties of 217 cells recorded from the monocular segment of primary visual cortex in rabbits reared with lid suture of the contralateral eye (monocular deprivation, MD) were studied. These data were compared with 280 cells recorded from normal rabbits. There was no change in the percentage of orientation-selective cells, nonorientation-selective cells, or unmappable/unresponsive cells in MD animals compared with normals. Among orientation selective cells the orientation-tuning range of cells in MD animals was normal, and the predominance of cells with horizontal preferred orientation was maintained. However, some abnormalities were seen in orientation-selective cells of MD animals. These included an increased frequency of SI cells; a change in the distribution of preferred orientations; a disruption of the clustered organization of the cortex; a decrease in direction selectivity; an increase in the percentage of cells preferring slow stimulus movements and having low spontaneous activity; an increase in receptive-field size in all cell classes except SI. Among nonorientation-selective cells there was an increase in the percentage of movement sensitive cells and an increase in receptive-field size in MD animals. It is concluded that the effects of MD are much less severe in rabbit than in cat. In MD rabbits, many cells develop normally. In cells that do not develop normally, many of the changes observed can be interpreted as reflecting deficits in inhibitory functions.

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Adaptation in single units in visual cortex: The tuning of aftereffects in the temporal domain

Visual Neuroscience ◽

10.1017/s0952523800003539 ◽

1989 ◽

Vol 2 (6) ◽

pp. 609-620 ◽

Cited By ~ 46

Author(s):

A. B. Saul ◽

M. S. Cynader

Keyword(s):

Frequency Tuning ◽

Temporal Frequency ◽

Direction Selectivity ◽

Cortical Cells ◽

Specific Effects ◽

A Cell ◽

Visual Cortical ◽

Velocity Matching ◽

Induced Changes ◽

Direction Opposite

AbstractAdaptation-induced changes in the temporal-frequency tuning and direction selectivity of cat visual cortical cells were studied. Aftereffects were induced largely independent of direction. Adapting in either direction reduced responses in both directions. Aftereffects in the direction opposite that adapted were only slightly weaker than were aftereffects in the adapted direction. No cell showed any enhancement of responses to drifting test stimuli after adapting with moving gratings. Adapting in a cell's null direction usually had no effect. Dramatic differences between the adaptation characteristics of moving and stationary stimuli were observed, however.Furthermore, aftereffects were temporal frequency specific. Temporal frequency-specific aftereffects were found in both directions: adapting in one direction induced frequency-specific effects in both directions. This bidirectionality of frequency-specific aftereffects applied to the spatial domain as well. Often, aftereffects in the direction opposite that adapted were more narrowly tuned.In general, adaptation could shift a cell's preferred temporal frequency. Aftereffects were most prominent at high temporal frequencies when testing in the adapted direction. Aftereffects seemed to be more closely linked to temporal frequency than to velocity matching.These results constrain models of cortical connectivity. In particular, we argue against schemes by which direction selectivity is generated by inhibiting a cell specifically when stimulated in the nonpreferred direction. Instead, we argue that cells receive bidirectional spatially and temporally tuned inputs, which could combine in spatiotemporal quadrature to produce direction selectivity.

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Critical periods for functional and anatomical compensation in lateral suprasylvian visual area following removal of visual cortex in cats

Journal of Neurophysiology ◽

10.1152/jn.1984.52.5.941 ◽

1984 ◽

Vol 52 (5) ◽

pp. 941-960 ◽

Cited By ~ 39

Author(s):

L. Tong ◽

R. E. Kalil ◽

P. D. Spear

Keyword(s):

Visual Cortex ◽

Critical Period ◽

Ocular Dominance ◽

Direction Selectivity ◽

Visual Area ◽

Critical Periods ◽

Cortex Lesion ◽

Thalamic Projections ◽

Adult Cats ◽

Visual Cortical

Previous experiments have found that neurons in the cat's lateral suprasylvian (LS) visual area of cortex show functional compensation following removal of visual cortical areas 17, 18, and 19 on the day of birth. Correspondingly, an enhanced retino-thalamic pathway to LS cortex develops in these cats. The present experiments investigated the critical periods for these changes. Unilateral lesions of areas 17, 18, and 19 were made in cats ranging in age from 1 day postnatal to 26 wk. When the cats were adult, single-cell recordings were made from LS cortex ipsilateral to the lesion. In addition, transneuronal autoradiographic methods were used to trace the retino-thalamic projections to LS cortex in many of the same animals. Following lesions in 18- and 26-wk-old cats, there is a marked reduction in direction-selective LS cortex cells and an increase in cells that respond best to stationary flashing stimuli. These results are similar to those following visual cortex lesions in adult cats. In contrast, the percentages of cells with these properties are normal following lesions made from 1 day to 12 wk of age. Thus the critical period for development of direction selectivity and greater responses to moving than to stationary flashing stimuli in LS cortex following a visual cortex lesion ends between 12 and 18 wk of age. Following lesions in 26-wk-old cats, there is a decrease in the percentage of cells that respond to the ipsilateral eye, which is similar to results following visual cortex lesions in adult cats. However, ocular dominance is normal following lesions made from 1 day to 18 wk of age. Thus the critical period for development of responses to the ipsilateral eye following a lesion ends between 18 and 26 wk of age. Following visual cortex lesions in 2-, 4-, or 8-wk-old cats, about 30% of the LS cortex cells display orientation selectivity to elongated slits of light. In contrast, few or no cells display this property in normal adult cats, cats with lesions made on the day of birth, or cats with lesions made at 12 wk of age or later. Thus an anomalous property develops for many LS cells, and the critical period for this property begins later (between 1 day and 2 wk) and ends earlier (between 8 and 12 wk) than those for other properties.(ABSTRACT TRUNCATED AT 400 WORDS)

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