|
KMID : 1204320090250020119
|
|
Laboratory Animal Research
2009 Volume.25 No. 2 p.119 ~ p.125
|
|
|
Effects of Velocity on Spatial Frequency and Direction Tunings in Cat Visual Cortex Areas 17 and 18
|
|
Kim Jong-Nam
|
|
|
Abstract
|
|
|
|
Neurons in areas 17 and 18 of the visual cortex are important in processing information relating to the speed or spatial properties of a moving object. The effects of velocity on spatial frequency and direction tuning properties of neurons (n=260) of areas 17/18 were studied in three anaesthetized and paralyzed cats. The visual stimuli used were drifting sinusoidal gratings with varied spatial frequencies, directions and velocities. We confirmed that the spatial frequency tuning of neurons of areas 17 and 18 were independent of velocity. However, we also found that optimal spatial frequency was changed from low to high and spatial frequency bandwidth became broader in some neurons in area 17 when velocity was decreased. The optimal temporal frequency was not constant over a range of velocities in the case of these cells. This implies that these cells were affected not only by the velocity but also by the spatial frequency of the stimulus. We also found that optimal direction was changed by more than 30 degres in the case of 50 cells (19.2%) and directionality was changed as well over a range of velocities.
|
|
|
KEYWORD
|
|
|
Feline, electrophysiology, sinusoidal grating, visual cortex
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
 
|