Long-Term Dysfunctions of Neural Stereoscopic Mechanisms After Unilateral Extraocular Muscle Proprioceptive Deafferentation

摘要: 1. Neural correlates of the permanent deficits in depth perception that occur when extraocular muscle proprioceptive (EMP) afferents are interrupted unilaterally kittens were investigated by performing extracellular recordings primary visual cortex (area 17) adulthood. Unilateral section ophthalmic branch trigeminal nerve (V1 nerve) performed 11 cats they between 5 and 12 weeks age (uni-V1 group). Electrophysiological results compared with those obtained 17 normal adult (control 2. Binocular interactions assessed testing sensitivity cortical neurons to dichoptic presentations moving sine-wave gratings whose interocular positional phase relationship was randomly varied. The amplitude modulation minimum maximum binocular responses defined dynamic range. degree suppression or facilitation comparing these response limits optimal monocular evoked through either eye at best spatial frequency. variability both estimated using variation coefficient. 3. In uni-V1 cats, range significantly less pronounced than controls, whereas not affected. increased, unlike responses, similar control values. 4. From Fourier analysis poststimulus time histograms, two clear-cut categories cells emerged differentially affected group. "modulated" showed "unmodulated" had more variable controls. Results from "simple" modulated cells, "complex" unmodulated cells. However, population, which composed simple complex it shown increase due 5. A nonparametric statistical test applied on shift tuning curves determine stimulus change necessary elicit a significant neural response. Two determined: "discriminative" (80% controls but 45% cats) combined relatively low variability. reverse true case "nondiscriminative" (20% 55% cats). 6. about half monocularly activated.(ABSTRACT TRUNCATED AT 400 WORDS)