Directional sensitivity, invariance and variability of tectal T5 neurons in response to moving configurational stimuli in the toadBufo bufo (L.)
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- Ewert, J.P., Borchers, H.W. & Wietersheim, A.. J. Comp. Physiol. (1979) 132: 191. doi:10.1007/BF00614490
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Different configurational visual stimuli traversed, at constant angular velocity, the centers of the receptive fields of single tectal T5 neurons (n= 42) in various directions of thex-y coordinates. The neuronal responses were recorded extracellularly in paralyzed toadsBufo bufo (L.). All data were processed by a computer, in part on-line and off-line.
Some of the T5 neurons showed no obvious change in their discharge rate when a stimulus traversed their receptive fields in different directions. Other neurons of the T5 group exhibited directional sensitivity which could be correlated with the shape of the moving stimulus.
T5(2) neurons, as described previously, were activated strongly by a stripe moving along its axis (worm-like), but they responded weakly, if the stripe axis was oriented perpendicular to the direction of movement (antiworm-like). The selective responsiveness was found to be invariant for the stimulus movement direction.
In other types of T5 neurons the selective response to the configurational stimuli tested (worms, antiworms) was a function of the movement direction. Various subtypes with different kinds of correlation between stimulus configuration and movement direction have been identified. Some of these neurons obviously correspond to the previously recorded T5(1) neurons.
Longterm recordings from the same neuron indicated that the response property — at least in some T5(1) neurons — can change, when identical series of stimuli were repeatedly presented over a period of several hours.
excitatory receptive field