Neurophysiology of Vision

Abstract

High resolution monitoring of stimulus-evoked retinal neural activities is important for understanding retinal neural mechanisms, and can be a powerful tool for retinal disease diagnosis and treatment outcome evaluation. Fast intrinsic optical signals (IOSs), which have the time courses comparable to that of electrophysiological activities in the retina, hold the promise for high resolution imaging of retinal neural activities. However, application of fast IOS imaging has been hindered by the contamination of slow, high magnitude optical responses associated with transient hemodynamic and metabolic changes. In this paper we demonstrate the feasibility of separating fast retinal IOSs from slow optical responses by combining flicker stimulation and dynamic (temporal) differential image processing. A near infrared flood-illumination microscope equipped with a high-speed (1000 Hz) digital camera was used to conduct concurrent optical imaging and ERG measurement of isolated frog retinas. High spatiotemporal resolution imaging revealed that fast IOSs could follow flicker frequency up to at least 6 Hz. Comparable time courses of fast IOSs and ERG kinetics provide evidence that fast IOSs are originated from stimulus activated retinal neurons.

<title>Modeling and investigation of some spatio-temporal aspects of visual information processing in the retinal neural network</title>

“…Some psychophysical facts are in agreement [13] and related neurophysiological data [4,111 are not in contradiction with these predictions. Both these predictions will be verified by theory-guided neurophysiological experiments.…”

The Timing of Response Onset and Offset in Macaque Visual Neurons

“…Several studies have shown that neurons with stronger inhibition or lower spontaneous rates have more specific trigger features, i.e., are more narrowly tuned (Pettigrew et al, 1968;Creutzfeldt and Sakmann, 1969;Snodderly and Gur, 1995;Carandini and Ferster, 2000). Similar observations were reported for the auditory nerve: cells with high intensity thresholds have less spontaneous activity (Kiang et al, 1965(Kiang et al, , 1976.…”

Comparison of normalization theory and neural enhancement explanation of negative aftereffects.

“…Cells which are selectively responsive to the direction in which contours move across the visual field have been measured with many species (see Creutzfeldt & Sakmann, 1969).…”