Squint affects synchronization of oscillatory responses in cat visual cortex

TY - JOUR

T1 - Squint affects synchronization of oscillatory responses in cat visual cortex

AU - König, P

AU - Engel, A K

AU - Löwel, S

AU - Singer, W

PY - 1993/5/1

Y1 - 1993/5/1

N2 - As shown previously, neurons in various areas of the cat's visual cortex respond to appropriate visual stimuli with oscillatory activity in the frequency range of 30-70 Hz. It has been suggested that synchronization of such responses serves to define assemblies of coherently active cells which represent individual visual objects. In this study, we have investigated this putative binding mechanism in the visual cortex of strabismic cats. We used six adult cats in which divergent squint had been induced surgically at the age of 3 weeks. Multiunit activity was recorded from area 17 with arrays of four or five closely spaced microelectrodes. Subsequently, auto- and cross-correlation functions were computed for all spike trains. To quantify the oscillatory nature of the responses and the strength of synchronization between spatially remote sites, damped sine wave functions were fitted to the correlograms. Analysis of responses obtained from 202 recording sites showed that the vast majority of cells had become monocular. Auto-correlation analysis revealed that the proportion of oscillatory firing patterns was similar to that observed in normal cats. However, cross-correlation analysis of 153 response pairs demonstrated that synchronization was reduced significantly between cells dominated by different eyes while it was as frequent and strong as in normal cats between cells dominated by the same eye. These findings indicate that strabismus not only causes a reorganization of afferent inputs but also affects intracortical interactions.(ABSTRACT TRUNCATED AT 250 WORDS)

AB - As shown previously, neurons in various areas of the cat's visual cortex respond to appropriate visual stimuli with oscillatory activity in the frequency range of 30-70 Hz. It has been suggested that synchronization of such responses serves to define assemblies of coherently active cells which represent individual visual objects. In this study, we have investigated this putative binding mechanism in the visual cortex of strabismic cats. We used six adult cats in which divergent squint had been induced surgically at the age of 3 weeks. Multiunit activity was recorded from area 17 with arrays of four or five closely spaced microelectrodes. Subsequently, auto- and cross-correlation functions were computed for all spike trains. To quantify the oscillatory nature of the responses and the strength of synchronization between spatially remote sites, damped sine wave functions were fitted to the correlograms. Analysis of responses obtained from 202 recording sites showed that the vast majority of cells had become monocular. Auto-correlation analysis revealed that the proportion of oscillatory firing patterns was similar to that observed in normal cats. However, cross-correlation analysis of 153 response pairs demonstrated that synchronization was reduced significantly between cells dominated by different eyes while it was as frequent and strong as in normal cats between cells dominated by the same eye. These findings indicate that strabismus not only causes a reorganization of afferent inputs but also affects intracortical interactions.(ABSTRACT TRUNCATED AT 250 WORDS)

KW - Animals

KW - Cats

KW - Electrophysiology

KW - Functional Laterality

KW - Neurons

KW - Ocular Physiological Phenomena

KW - Oscillometry

KW - Reaction Time

KW - Strabismus

KW - Vision, Monocular

KW - Visual Cortex

M3 - SCORING: Journal article

C2 - 8261125

VL - 5

SP - 501

EP - 508

JO - EUR J NEUROSCI

JF - EUR J NEUROSCI

SN - 0953-816X

IS - 5

ER -