ISSN:
1432-1106
Keywords:
Cat
;
Visual cortex
;
Deprivation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The effects of monocular deprivation from contour vision were investigated in the striate cortex of cats. In addition to the receptive field (RF) properties of single cells responses to electrical stimulation of the deprived and the experienced optic nerve were analyzed: Evoked potentials as well as intra- and extracellularly recorded single unit responses were evaluated. The main goals were: 1. to determine to what extent the responses to electrical stimulation reflected the shift in ocular dominance apparent from the RF analysis, 2. to determine the relative effects of deprivation on excitatory and inhibitory responses and 3. to locate the site of impaired transmission in the pathway from the deprived eye. The results show that the responses to electrical stimulation reflect precisely the shift in ocular dominance apparent from the RF analysis. The evoked potentials elicited from the deprived nerve further indicate that deprivation had also affected the afferent system at the LGN level or (and) at the terminal field of the thalamo-cortical fibers. In contrast to the reduction of short latency excitatory responses to stimulation of the deprived nerve, oligosynaptic inhibition with latencies of 4–6 msec was equally well elicited by stimulation of either eye. The same was true for delayed excitatory responses which frequently occur with latencies between 40 and 80 msec after nerve stimulation. It is concluded from these results 1. that transmission between thalamic afferents and inhibitory interneurones in the cortex is less affected by deprivation than transmission in those pathways which relay cortical excitation, 2. that there is another deprivation resistant indirect pathway from the retina to the visual cortex which is probably relayed through mesencephalic structures and 3. that deprivation effects are not confined to transmission failure at the thalamo-cortical synapses but include alterations already at the presynaptic level.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00237856
