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Neuronal stereoscopic processing following extraocular proprioception deafferentation
Y Trotter1, S Celebrini, J C Beaux
1Institut Des Neurosciences, Université P. et M. Curie, Paris, France.
Abstract:
In adult cats, after section of extraocular muscle proprioceptive (EOMP) afferents during the 'critical period', most cortical area 17 cells loose their ability to discriminate changes in binocular spatial disparity. After unilateral section this loss depends on whether or not cortical cells modulate their responses to the presentation of sinusoidal gratings linearly. For 'modulated cells', this loss is due to a reduction of binocular suppression while for 'unmodulated cells', it is due to a selective increase in the variability of the binocular response. These permanent neural dysfunctions show that balance in EOMP inflow plays a crucial role in cortical processing of binocular depth discrimination.
Insights
Disrupting sensory input from eye muscles during development permanently impairs a cat
Area of Science:
- Neuroscience
- Ophthalmology
- Developmental Biology
Background:
- Binocular depth discrimination is crucial for visual perception.
- The 'critical period' is a sensitive window for neural development.
- Extraocular muscle proprioceptive (EOMP) afferents provide sensory information about eye position.
Purpose of the Study:
- To investigate the long-term effects of disrupting EOMP afferents during the critical period on visual cortex function.
- To determine the mechanisms underlying the loss of binocular spatial disparity discrimination.
Main Methods:
- Unilateral section of EOMP afferents in adult cats during the critical period.
- Electrophysiological recordings from cortical area 17 cells.
- Analysis of cell responses to sinusoidal gratings and binocular suppression.
Main Results:
- Most cortical area 17 cells lost the ability to discriminate binocular spatial disparity after EOMP afferent section.
- The loss mechanism differed between 'modulated' and 'unmodulated' cells.
- 'Modulated cells' showed reduced binocular suppression; 'unmodulated cells' showed increased response variability.
Conclusions:
- Disruption of EOMP afferent input during the critical period causes permanent neural deficits in binocular processing.
- Balanced EOMP inflow is essential for normal cortical processing of binocular depth discrimination.
- These findings highlight the critical role of proprioception in visual development.