Topographic reorganization in area 18 of adult cats following circumscribed monocular retinal lesions in adolescence

• Published in: The Journal of physiology Vol. 541; no. 2; pp. 601 - 612
• Main Authors: Young, J. M., Waleszczyk, W. J., Burke, W., Calford, M. B., Dreher, B.
• Format: Journal Article
• Language: English
• Published: Oxford, UK The Physiological Society 01-06-2002; Blackwell Publishing Ltd; Blackwell Science Inc
• Subjects: Algorithms; Animals; Cats; Functional Laterality - physiology; Neurons - physiology; Original; Photic Stimulation; Retina - anatomy & histology; Retina - cytology; Retina - physiology; Stereotaxic Techniques; Vision, Binocular - physiology; Vision, Monocular - physiology; Visual Cortex - anatomy & histology; Visual Cortex - cytology; Visual Cortex - physiology; Visual Pathways - anatomy & histology; Visual Pathways - cytology; Visual Pathways - physiology
• ISSN: 0022-3751; 1469-7793
• DOI: 10.1113/jphysiol.2001.016212

Circumscribed laser lesions were made in the nasal retinae of one eye in adolescent cats. Ten to sixteen months later, about
80 % of single neurones recorded in the lesion projection zone (LPZ) of contralateral area 18 (parastriate cortex, area V2)
were binocular but when stimulated via the lesioned eye had ectopic discharge fields (displaced to normal retina in the vicinity
of the lesion). Although the clear majority of binocular cells recorded from the LPZ responded with higher peak discharge
rates to stimuli presented via the non-lesioned eye, the orientation and direction selectivities as well as preferred and
upper cut-off velocities for stimuli presented through either eye were very similar. Furthermore, the sizes of the ectopic
discharge fields of binocular cells recorded from the LPZ were not significantly different from those of their counterparts
plotted via the non-lesioned eye. Thus, monocular retinal lesions performed in adolescent cats induce topographic reorganization
in the LPZ of area 18. Although a similar reorganization occurs in area 17 (striate cortex, area V1) of cats in which monocular
retinal lesions were made either in adulthood or adolescence, in view of the very different velocity response profiles of
ectopic discharge fields in areas 17 and those in area 18, it appears that ectopic discharge fields in area 17 are largely
independent of excitatory feedback input from area 18.