Binocular integration of binocular neurons in striate cortex of Kitten / 中华实验眼科杂志

ABSTRACT

Background The integration of segregated pathways from the two eyes first appears in V1 neurons,where it not only plays a critical role in the generation of a three-dimensional visual representation.Abnormal visual experiences in critical period usually lead to amblyopia and binocular integration defects.Objective Present study was to investigate how neurons of kitten coordinate their activity patterns in response to synchronous dichoptic stimulus inputs in striate cortex.Methods Spike rate and local field potential(LFP) gamma band(20-90Hz) power of three kitten(1-1.2Kg,8-10 weeks old) to monocular and synchronous dichoptic presented gratings were assessed for 28 binocular neurons in V1 of kitten by in vivo extracellular record method under anaesthesia and paralysis.Ocular dominance index(ODI) and binocular integration index(BII) were assessed and the correlation between these two indexes were analyzed.Results In 28 cells with binocular characteristic,the absolute value of spike-ODI was significant larger than that of LFP-ODI(t=2.606,P=0.021).A positive linear correlation between the ocular preferences of spike and LFP was found(R2=0.513,F=27.423,P=0.003).In dichotic trails,binocular facilitation with BII for spike was 2.348±0.996,showing a significant reduce in comparison with BII for LFP(3.678±1.974)(t=2.671,P=0.019).Binocular integration index for two signals were greater when monocular responses of both eyes were similar(P=0.035 and P=0.124,respectively).Conclusion Both spike rate and gamma band power of LFP exhibited binocular facilitation to synchronous presented dichotic stimuli with significant facilitation induced by balanced monocular responses.Spiking activity and LFP reflect neural activities of different spatial scales and source components.