ISSN:
1432-1106
Keywords:
Lateral geniculate nucleus
;
Orientation sensitivity
;
Visual cortical areas 17 and 18
;
Corticogeniculate projection
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Orientation sensitivity was tested, using moving bars as stimuli, in 136 LGN cells in normal cats and 82 LGN cells in cats with areas 17 and 18 lesioned. The responses of most neurones showed some dependence on the orientation of the line stimulus. The orientation bias was more pronounced for long, narrow bars moving at rather slow velocities. Length-response curves revealed less end-inhibition along the optimum orientation than along the nonoptimum orientation. Thirty-two percent of the cells in the normal cats and 50% in the lesioned animals responded best to orientations within 10 ° of the vertical or horizontal. The oblique orientations were represented poorly in the lesioned group. Thus the corticogeniculate feedback may serve to confer a more uniform distribution of orientation preferences on the LGN. It is suggested that the orientation biases of LGN neurones may play a role in building orientation-selective cells in the visual cortex. Further, the preferences for horizontal and vertical orientations in the LGN may explain the preferences for these orientations reported for visual cortical cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00237172
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