Spatial-frequency tuning in the pooling of one-and two- dimensional motion signals

Date

2009

Authors

Amano, Kaoru
Edwards, Mark
Badcock, David Russell
Nishida, Shin'ya

Journal Title

Journal ISSN

Volume Title

Publisher

Pergamon-Elsevier Ltd

Abstract

Cortical neurons that initially extract motion signals have small receptive-fields, and narrow orientation- and bandpass-spatial-frequency tuning. Accurate extraction of the veridical motion of objects typically requires the global pooling of the output of multiple local-motion units across orientation and space. We examined whether the narrow spatial-frequency tuning present at the local-motion level is preserved at the global-motion-pooling stage. Stimuli consisted of numerous drifting Gabor or plaid elements that were either signal (carrier drift-speed consistent with a given global-motion vector) or noise (drift speed consistent with a random, noise vector). The carrier spatial-frequencies of the signal and noise elements were independently varied. Regardless of the frequency of the signal elements, broad low-pass masking functions were obtained for both Gabor (one-dimensional) and Plaid (two-dimensional) conditions when measuring the threshold signal ratio for identification of the global-motion direction. For the Gabor stimuli, this pattern of results was also independent of the relative orientations of the signal and noise elements. These results indicate that in the global-motion pooling of one-dimensional and two-dimensional signals, local-motion signals of all spatial frequencies are pooled into a single system that exhibits broadband, low-pass tuning.

Description

Keywords

Keywords: article; brain cortex; grating; human; human experiment; luminance; motion; normal human; orientation; priority journal; receptive field; signal transduction; space; spatial frequency discrimination; visual acuity; visual stimulation; visual system; Cereb Direction-discrimination; Gabor; Global-motion; Motion integration; Spatial frequency

Citation

Source

Vision Research

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

DOI

10.1016/j.visres.2009.08.026

Restricted until

2037-12-31