Quantification and Comparison of Cell Properties in Cat's Striate Cortex Determined by Different Types of Stimuli

Abstract

Direction and orientation tuning elicited by moving bars, flashing bars and a moving noise field were compared in cells in area 17 of the cat. Fourier analysis of tuning curves (SDO-analysis) was applied to quantify the general sensitivity (S) to visual stimulation, tuning strength to direction(D) and orientation (O), as well as the preferred direction (PD) and orientation (PO). Results from SDO-analysis were compared with the commonly used direction index and half-width-at-half-height orientational tuning parameter and it is demonstrated that the commonly used parameters can be replaced and are superseded by the results from SDO-analysis. The comparison of the responses elicited by the different types of stimuli showed that a linear correlation between D (or O) components was mainly found in simple cells, while in most cases no correlation was obtained for complex cells. Since several of the simple cells also showed no linear relationship, a direct mutual prediction of the S, D and O components can only be achieved for approximately 50% of the cortical cells applying commonly used stimulus types. The general responsiveness (S) shows that flashing bar stimuli are at least as effective as moving bars, whereas moving noise stimulates cortical cells more weakly. A moving bar tends to increase the orientation tuning (O) in most cells and with a moving noise stimulus predominantly the directional tuning (D) of complex cells is strongly enhanced. In conclusion, Fourier analysis of tuning curves (SDO-analysis) provides a valuable and simple tool for the quantification of direction and orientation specificity. Motion enhances the cortical response specificity which indicates the involvement of facilitation or inhibition exclusively induced by movement.

Spectral integration plasticity in cat auditory cortex induced by perceptual training

“…Wörgötter & Eysel 1987;Wörgötter et al 1990;DeValois & DeValois 1990). These studies provide evidence that generalized stimuli covering large portions of the receptor surface can be well suited to predict responses to specific and/or more spatially restricted stimuli.…”

Interocular suppression in the visual cortex of strabismic cats

“…The sharpness of orientational tuning was quantitatively assessed, for a sample of cells dominated by each eye in all strabismic cats, by performing a Fourier analysis of the responses to drifting gratings varied pseudorandomly in drift direction (see Wijrgijtter et al, 1990). Curves were fitted to the data points, taking into account the 0-8th order Fourier components, and tuning widths were calculated.…”

Quantification of directional and orientational selectivities of visual neurons to moving stimuli

“…It may be predicted that the values for S and O(0) derived with a stationary flashing bar which contains no directional 289 element differ from those values derived with moving bars, due to the superimposition of a directional element on the latter (Worgotter et al 1990). Moving noise fields, and also small moving spots, have been regarded as patterns without an orientational element, i.e., O(0) = 0 (Worgotter et al 1990).…”

“…Recently, based on the periodicity of directional and orientational selectivities, some new schemes, e.g., circular statistics (Levick and Thibos 1982;Thibos and Levick 1985) and the SDO-analysis based on Fast Fourier Transform (Worgotter and Eysel 1987;Worgotter et al 1990), have been suggested. It can be proven theoretically that the two schemes result in equivalent algorithms despite different primary ideas and mathematical tools adopted (cf.…”