Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by BLYTHE, I. M.
Right arrow Articles by TRAUB, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by BLYTHE, I. M.
Right arrow Articles by TRAUB, M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Brain, Vol. 109, No. 4, 661-675, 1986
© 1986 Guarantors of Brain

research-article

A STUDY OF SYSTEMATIC VISUAL PERSEVERATION INVOLVING CENTRAL MECHANISMS

I. M. BLYTHE, J. M. BROMLEY, K. H. RUDDOCK, C. KENNARD and M. TRAUB

Department of Physics (Biophysics) and Pure and Applied Biology, Imperial College London Department of Neurology, The London Hospital, Whitechapel London

Correspondence to: Reprint requests and correspondence to: Dr K. H. Ruddock, Department of Physics (Biophysics), Imperial College, London SW7 2BZ.

SUMMARY

The subject of this investigation experiences vivid after-images which persist for tens of seconds following stimulation by light insufficiently intense to produce after-images in normal subjects. The after-images occur at all points in the visual field, and have spatial structure closely similar to that of the stimuli which elicit them, the only distortion being the absence of high (> 10 cycles deg-1) spatial frequencies. The duration of the after image is dependent on the spatial structure and spectral content of the eliciting stimulus, being maximum for low, nonzero spatial frequencies (1-2 cycles deg–1) and yellow or green wavelengths. The after-images appear ‘khaki’ or ‘mustard-green’ in colour, regardless of the spectral composition of the light stimulus, and those produced by flickering or moving targets do not themselves exhibit temporal fluctuations, although movement produces a streak along the path described by the moving object. After six weeks of treatment with the anticonvulsant drug, carbamazepine, the duration of the after-images fell by about 30%, but no further reduction occurred over the following three months. In spite of the prolonged after-images, the subject has normal sensitivity for detection of flicker and movement, but that for detection of a single flash is raised abnormally at low background illumination. Neither CT nor MRI brain scans revealed any abnormality. These responses are discussed in relation to those found in other subjects suffering visual perseveration or pahnopsia, and we examine their possible causes.

Received May 7, 1985. Revised October 22, 1985. Accepted November 22, 1985.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J. Neurol. Neurosurg. PsychiatryHome page
D Chan, S J Crutch, and E K Warrington
A disorder of colour perception associated with abnormal colour after-images: a defect of the primary visual cortex
J. Neurol. Neurosurg. Psychiatry, October 1, 2001; 71(4): 515 - 517.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.