Reconstruction of cone-system contributions to responses of colour-opponent neurones in monkey lateral geniculate.

Responses of colour-opponent X-cells to intensity-modulation at various wavelengths were obtained in the lateral geniculate nucleus (LGN) of the anaesthetized (N2O/O2) rhesus monkey. The gaussian white noise (GWN) analysis method was used to describe the stimulus-response relationship. Two different methods were used to estimate sign and relative strength of the response contribution of each of the three known cone systems as a function of time.

Characterization of spatial and temporal properties of monkey LGN Y-cells.

LGN Y-cells in 3 anaesthetized (N2O/O2) and paralyzed rhesus monkeys were investigated with stimuli, intensity modulated by gaussian white noise, and with moving and counterphase modulated spatial sine wave gratings. The results support the model, postulated on the base of electrophysiological recordings in the retina cat and mudpuppy, which consists of a linear centre and surround mechanism whose responses are modified in a frequency-selective multiplicative way by a nonlinear mechanism in the receptive field. This nonlinear mechanism is also held responsible for the second-order harmonic responses, which are the defining characteristic of Y-cells.

Responses of single units in the monkey superior colliculus to moving stimuli.

1. Single unit responses of pan-directional cells to moving and stationary flashing stimuli were studied in the superficial layers of the superior colliculus in paralysed, anaesthetized rhesus monkeys. The aim of this study was to see how far cell responses to moving stimuli fit in with what would be expected from their responses to stationary flashing stimuli.