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Repetitive visual cortex transcranial random noise stimulation in adults with amblyopia.

Author(s): Donkor R, Silva AE, Teske C, Wallis-Duffy M, Johnson AP, Thompson B

We tested the hypothesis that five daily sessions of visual cortex transcranial random noise stimulation would improve contrast sensitivity, crowded and uncrowded visual acuity in adults with amblyopia. Nineteen adults with amblyopia (44.2?±?14.9 years, 10 ...

Article GUID: 33542265
Assessing optimal colour and illumination to facilitate reading.

Author(s): Morrice E, Murphy C, Soldano V, Addona C, Wittich W, Johnson AP

PURPOSE: This study examined the effectiveness of the LuxIQ, the Apple iPad and a smart bulb in assessing optimal colour and illumination to facilitate reading in younger, older and visually impaired adults. METHODS: Participants read standardised texts at ...

Article GUID: 33533095
Congenital Deafness Leads to Altered Overt Oculomotor Behaviors.

Author(s): Sharp A, Turgeon C, Johnson AP, Pannasch S, Champoux F, Ellemberg D

Front Neurosci. 2020;14:273 Authors: Sharp A, Turgeon C, Johnson AP, Pannasch S, Champoux F, Ellemberg D

Article GUID: 32327967
Music predictability and liking enhance pupil dilation and promote motor learning in non-musicians.

Author(s): Bianco R, Gold BP, Johnson AP, Penhune VB

Sci Rep. 2019 Nov 19;9(1):17060 Authors: Bianco R, Gold BP, Johnson AP, Penhune VB

Article GUID: 31745159
Spatial summation of broadband contrast.

Author(s): Richard B, Hansen BC, Johnson AP, Shafto P

J Vis. 2019 May 01;19(5):16 Authors: Richard B, Hansen BC, Johnson AP, Shafto P

Article GUID: 31100132
Title:Spatial summation of broadband contrast.
Authors:Richard B,  Hansen BC,  Johnson AP,  Shafto P
Link:https://www.ncbi.nlm.nih.gov/pubmed/31100132?dopt=Abstract
Category:J Vis
PMID:31100132
Dept Affiliation: PSYCHOLOGY
1 Department of Mathematics and Computer Science, Rutgers University, Newark, NJ, USA.
2 Department of Psychological and Brain Sciences, Neuroscience Program, Colgate University, Hamilton, NY, USA.
3 Department of Psychology, Concordia University, Montreal, Quebec, Canada.

Description:

Spatial summation of broadband contrast.

J Vis. 2019 May 01;19(5):16

Authors: Richard B, Hansen BC, Johnson AP, Shafto P

Abstract

Spatial summation of luminance contrast signals has historically been psychophysically measured with stimuli isolated in spatial frequency (i.e., narrowband). Here, we revisit the study of spatial summation with noise patterns that contain the naturalistic 1/fa distribution of contrast across spatial frequency. We measured amplitude spectrum slope (a) discrimination thresholds and verified if sensitivity to a improved according to stimulus size. Discrimination thresholds did decrease with an increase in stimulus size. These data were modeled with a summation model originally designed for narrowband stimuli (i.e., single detecting channel; Baker & Meese, 2011; Meese & Baker, 2011) that we modified to include summation across multiple-differently tuned-spatial frequency channels. To fit our data, contrast gain control weights had to be inversely related to spatial frequency (1/f); thus low spatial frequencies received significantly more divisive inhibition than higher spatial frequencies, which is a similar finding to previous models of broadband contrast perception (Haun & Essock, 2010; Haun & Peli, 2013). We found summation across spatial frequency channels to occur prior to summation across space, channel summation was near linear and summation across space was nonlinear. Our analysis demonstrates that classical psychophysical models can be adapted to computationally define visual mechanisms under broadband visual input, with the adapted models offering novel insight on the integration of signals across channels and space.

PMID: 31100132 [PubMed - in process]