Selective visual experience fails to modify receptive field properties of rabbit striate cortex neurons

Development of visually guided behaviour requires oriented contours

Kittens do not learn to use visual information to guide their behaviour if they are deprived of the optic flow that accompanies their own movements. We show that the optic flow that is required for developing visually guided behaviour is derived from changes in contour orientations, rather than from velocity patterns. We used several tests to assess visually guided behaviour. The performance of kittens that had only been allowed to see isolated dots of light was indistinguishable from that of kittens that had received no visual exposure at all. Kittens that had seen streaks of light performed better on several tasks. We discuss this finding with relation to the visual pathways that are presumably involved.

Frequency specific effects of stroboscopic rearing in the visual cortex of the rabbit

Rearing animals in stroboscopic illumination deprives those animals of the experience of visual motion. In the rabbit, stroboscopic rearing produces a significant alteration in the response properties of cells in the visual cortex, demonstrating that the rabbit visual system is susceptible to environmental manipulation during early postnatal life. Response properties were determined for single units recorded in the primary visual cortex of 3 groups of rabbits. One group had been reared from birth to 2 months of age at a stroboscopic flash frequency of 8 Hz, a second group was raised at a flash frequency of 4 Hz and a third was reared normally. Compared to normal rabbits, rabbits reared at 8 Hz showed a reduction in the proportion of orientation selective cells which were also direction-selective, and there was an increase in the proportion of cells responsive to stroboscopic flashes. There was no reduction, however, in the overall proportion of orientation-selective cells. This contrasts with the finding for the rabbits raised at a flash frequency of 4 Hz. In addition, cortical cells in the rabbits raised at 8 Hz responded to frequencies of stroboscopic flashes which were significantly higher than the frequencies found for cells in the rabbits raised at 4 Hz. The effects of stroboscopic rearing on the rabbit visual cortex are dependent, therefore, on the flash frequency experienced by the rabbits during development.

Stroboscopic rearing reduces direction selectivity in rabbit visual cortex

Rabbits reared from birth in stroboscopic illumination have no experience of visual motion. In primary visual cortex of these animals there is a large reduction in the number of cells which are direction selective. This result, contrary to previous reports, shows that the rabbit visual system can be modified by early visual experience.

The rabbit and the cat: a comparison of some features of response properties of single cells in the primary visual cortex

Receptive field characteristics of single cells in primary visual cortex of rabbit were studied. Seventy-two percent of cells were found to be orientation selective, and the remainder had concentric, uniform, movement selective or pure direction selective receptive fields. Single cells were also recorded from primary visual cortex of cat to permit a comparison of visual cortical organization in cats and rabbits. Laminar organization of receptive field types was observed in rabbits which was similar in most respects to that described in the cat. Although the major categories of orientation selective cells (simple, complex, hypercomplex) were similar for both cat and rabbit, many differences emerged: (I) tuning of orientation selectivity was narrower in cats than in rabbits; (II) units which preferred oblique orientations were less frequently represented in rabbits than in cats; (III) orientation preferences appeared to be arranged in clusters in rabbit cortex; in rabbits we found no evidence of the columnar organization of orientation selectivity which characterizes cat visual cortex. A comparison of our data with those previously reported for mouse, rat, hamster and opossum visual cortex suggest that mammals in which a significant proportion of visual cortical cells are not orientation selective have in common certain patterns of cortical organization involving a less precise and less specilized representation of stimulus orientation.

Early selective visual experience and pattern discrimination in hooded rats

The early visual experience of hooded rats was restricted to either vertical or horizontal stripes. In a discrimination task pairing a gray surface and stripes of either the same orientation or an orientation orthogonal to that experienced during rearing, the rats made significantly fewer correct choices with the orthogonal orientation. However, the relatively lower overall performance of the vertically reared-horizontally tested animals was a major factor in the main effect of testing condition. We conclude that functional of the rat visual system through early selective visual experience is possible.

Directional selectivity in hamster superior colliculus is modified by strobe-rearing but not by dark-rearing

Visual response properties of superior collicular neurons of normal hamsters were compared with those of animals reared from birth to adulthood in either total darkness or with stroboscopic illumination. Directional selectivity was markedly reduced only in the strobe-reared animals, thus demonstrating visual plasticity in a system that develops apparently normally without visual experience.

Alterations in receptive field properties of superior colliculus cells produced by visual cortex ablation in infant and adult cats

To determine if functional alterations in the superior colliculus might account for recovery of visual behaviors following visual cortex removal in infant cats, the receptive field characteristics of single units in the superior colliculus of cats whose visual cortex was removed within the first week of life were compared with those of cats which sustained visual cortex lesions in adulthood and with those of normal cats. In the normal superior colliculus, 90% of all cells responded to moving stimuli irrespective of shape or orientation. Sixty-four percent of these units were directionally selective, responding well to movement in one direction but poorly or not at all to movement in the opposite direction. Ninety percent of units were binocular, the vast majority of these responding equally to stimulation of either eye or showing only slight preference for stimulation of the contralateral eye. Responses to stationary flashes of light were observed in only 33% of all visually activated cells in the normal superior colliculus. After visual cortex ablation in adult cats, only six percent of movement sensitive cells were directionally selective. Binocular preference was shifted following adult visual cortex lesions such that sixty percent of all cells responded exclusively or predominantly to stimulation of the contralateral eye. Seventy-one percent of all visually responsive units responded to stationary lights flashed on or off within their receptive field boundaries. Lesions limited primarily to area 17 had the same effect as larger lesions of visual cortex. Infant visual cortex lesions resulted in receptive field alterations similar to those observed after adult ablation. Only fifteen percent of motion sensitive units were directionally selective. Seventy-one percent responded exclusively or predominantly to stimulation of the contralateral eye. Seventy-six percent of visually responsive cells were activated by stationary light. Lesions largely confined to area 17 produced the same alterations as more extensive lesions of visual cortex. Thus, no evidence was found that the superior colliculus is involved in the functional reorganization presumed to occur following visual cortex ablation in infant cats. Recovery of visual behaviors following neonatal injury may therefore not involve alterations in the receptive fields of single cells.

Development of visually evoked responses and visually guided behavior in kittens: effects of superior colliculus and lateral geniculate lesions

The development of visually evoked responses (VER's) and visually guided behavior was studied in kittens for 3 months after unilateral lesions of the superior colliculus (SC) or lateral geniculate nucleus (LGN) made at an early age. Of 37 kittens studied, data are presented for 6 which met 3 criteria: survival to at least 90 days of age; adequate lesion size and location; and technically satisfactory VER's and behavioral observations at appropriate intervals. The SC and LGN lesions markedly reduced or eliminated different VER components in infancy, but only the effects of LGN lesions persisted to 3 months of age. Visual field behavior deficits occurred following both types of lesions, but only those following SC lesions persisted to 3 months of age. These results are interpreted in terms of the functional status of the structures mediating the VER's and behavior at the time the lesions were made.

Innate and environmental factors in the development of the kitten's visual cortex

1. This is a study of the receptive fields of 771 cells recorded in the visual cortex of twenty-five kittens reared normally or subjected to various kinds of visual deprivation or environmental manipulation. 2. Kittens deprived of patterned visual experience, by dark rearing or diffuse occlusion of the eyes, have a majority of cirtical neurones with little or no specificity for the orientation or axis of movement of visual stimuli. However, in such deprived animals, especially those younger than 3 weeks, there are a number of genuinely orientation selective cells. They are broadly "turned" (by adult standards), they are almost always of the simple type, are heavily dominated by one eye, and are found mainly in the deeper layers of the cortex, especially layer IV. 3...

Development of receptive fields in rabbit visual cortex: changes in time course due to delayed eye-opening

Rabbit pups had one eye sutured closed before the time at which the eyes normally open. At 20-27 days of age, single-unit recordings were made both from the striate cortex contralateral to the sutured eye (deprived cortex) and from that contralateral to the eye which had opened normally (control cortex). The percentages of units encountered which fell into various receptive field categories differed on the two sides. The deprived cortices had a lower percentage of visually responsive cells, a higher percentage of indefinite cells, and totally lacked cells sensitive to orientation of a stimulus bar. In these respects they closely resembled previous observations on rabbit pups just before normal eye-opening. By contrast, the control cortices of the same animals were comparable to normally reared rabbits of the same age. We conclude, therefore, that developmental events which normally follow eye-opening can be affected in their time course by delaying eye-opening.

Raising rabbits in a moving visual environment: an attempt to modify directional sensitivity in the retina

1. Rabbits were raised inside drums with vertical stripes painted on the inside. The rabbits were held stationary while the drum rotated continually around them: rotation was always in the same direction for any one animal. Rabbits in one litter were put in the drum for 15 min/day from 10-15 days after birth to about 60 days after birth, with the drum rotating to the right. Rabbits in another litter were put in for 15 min/day with the drum moving left. Rabbits in three other litters were put in for 2-3 hr/day with the drum moving right. All rabbits were kept in the dark when not in the drum.2. Optokinetic nystagmus was measured by photographing eye movements during drum rotation at various stages of development. The response to rotation in both directions was measured in a few adult animals. Only small differences were found in the adult animals between optokinetic nystagmus in response to a drum moving right compared to a drum moving left.3. Recordings were made from ganglion cells in the retina and their receptive fields were mapped. A total of 607 cells from deprived rabbits were analysed. The percentages of on-centre and off-centre centre-surround types, on-off directionally sensitive types, and on-directionally sensitive types were not significantly different from normal.4. The percentages of directionally sensitive cells responding in the anterior, posterior, superior and inferior directions were normal. The fall-off in sensitivity for these cells with change in direction from the preferred direction was normal.5. A few orientation sensitive cells were found responding to horizontally oriented bars.6. We conclude that this selective deprivation of rabbits had little effect on the optokinetic response and no effect on the organization of the retina.