Spatial frequency rows in area 18 of the cat [proceedings].
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Biomedical subjects
N Berardi
Publications and source records attributed to N Berardi.
Nerve growth factor preserves behavioral visual acuity in monocularly deprived kittens.
Recent electrophysiological and anatomical experiments in rats and cats have shown that treatment with the neurotrophic factor-nerve growth factor (NGF)-prevents the effects of monocular deprivation (MD) at the level of visual cortex and lateral geniculate nucleus. We tested whether NGF treatment was effective in preventing MD effects on visual behavior of monocularly deprived kittens. Behavioral visual acuity was measured in kittens that had been monocularly deprived and treated intraventricularly with NGF for 2 weeks during the critical postnatal period. The detrimental effects of MD on behavioral visual acuity were found to be largely prevented by NGF treatment.
Animals↗
Postnatal development of functional properties of visual cortical cells in rats with excitotoxic lesions of basal forebrain cholinergic neurons.
In the rat, visual cortical cells develop their functional properties during a period termed as critical period, which is included between eye opening, i.e. postnatal day (PD) 15, and PD40. The present investigation was aimed at studying the influence of cortical cholinergic afferents from the basal forebrain (BF) on the development of functional properties of visual cortical neurons. At PD15, rats were unilaterally deprived of the cholinergic input to the visual cortex by stereotaxic injections of quisqualic acid in BF cholinergic nuclei projecting to the visual cortex. Cortical cell functional properties, such as ocular dominance, orientation selectivity, receptive-field size, and cell responsiveness were then assessed by extracellular recordings in the visual cortex ipsilateral to the lesioned BF both during the critical period (PD30) and after its end (PD45). After the recording session, the rats were sacrificed and the extent of both cholinergic lesion in BF and cholinergic depletion in the visual cortex was determined. Our results show that lesion of BF cholinergic nuclei transiently alters the ocular dominance of visual cortical cells while it does not affect the other functional properties tested. In particular, in lesioned animals recorded during the critical period, a higher percentage of visual cortical cells was driven by the contralateral eye with respect to normal animals. After the end of the critical period, the ocular dominance distribution of animals with cholinergic deafferentation was not significantly different from that of controls. Our results suggest the possibility that lesions of BF cholinergic neurons performed during postnatal development only transiently interfere with cortical competitive processes.
Animals↗