|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1993 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1992 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Visual stimulator was made using a slide projector and an x-y stage with 2 axs program controler. This stimulator enabled us to give visual patterns on discrete grid positions on the screen or to make continuous moving patterns.
Using this stimulator, intracelluar responses of tectal neurons of the frog were recorded intracellulary. There are 4 classes of retinal fibers (R1, R2, R3 and R4) and they directly projet to optic tecum. When on-off stimulation was given on grid points, it was possible to distinguish contribution of R3 from R4 (R1 and R2 produces no response). By measuring the amplitude of the responses at different time, spatial distribution of excitation and inhibition was obtained.
In order to overcome the difficulty of intracellular recording, in vivo whole cell recording technique was established. Applying this method, synaptic potentials from tectal neurons was recorded simultaneously with impulses from a single optic nerve fiber. Application of pulse-triggered correlation method, EPSPs elicited by R1/R2, R3 and R4 could be identified. We measured rize time and amplitude of EPSPs, and identified unitary EPSPs. Mesurement of latency, monosynaptice and disynaptic EPSP could be difined.