Abstract
1. This paper reviews Alpern, Rushton & Torii's (1970a-d) derivation of the size of the inhibitory nerve signal arising from after flashes in the metacontrast experiment. 2. Their geometric argument is recast in terms of simple functional equations. This form of argument clearly displays the role of their assumptions in obtaining their main conclusion: nerve signal is linear in intensity over a range of 3-4 log units. 3. Two disadvantages of their approach are discussed. First, it is noted that in the presence of the data the assumption they employ in their analysis is logically equivalent to their conclusion. 4. Secondly, accepting their claim that the nerve signal generated by the after flash is linear over a broad range of intensities, and that this inhibitory signal simply cancels the excitatory signal of the test flash, leads to the conslusion that over this same intensity range the excitatory nerve signal is a power function with an exponent of close to two. This is incompatible with the suggestion that photoreceptor signals have been measured.
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Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Alpern M., Rushton W. A., Torii S. Signals from cones. J Physiol. 1970 Apr;207(2):463–475. doi: 10.1113/jphysiol.1970.sp009073. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Alpern M., Rushton W. A., Torii S. The attenuation of rod signals by backgrounds. J Physiol. 1970 Jan;206(1):209–227. doi: 10.1113/jphysiol.1970.sp009007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Alpern M., Rushton W. A., Torii S. The attenuation of rod signals by bleachings. J Physiol. 1970 Apr;207(2):449–461. doi: 10.1113/jphysiol.1970.sp009072. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Alpern M., Rushton W. A., Torii S. The size of rod signals. J Physiol. 1970 Jan;206(1):193–208. doi: 10.1113/jphysiol.1970.sp009006. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kahneman D. Method, findings, and theory in studies of visual masking. Psychol Bull. 1968 Dec;70(6):404–425. doi: 10.1037/h0026731. [DOI] [PubMed] [Google Scholar]
- RAAB D. H. Backward masking. Psychol Bull. 1963 Mar;60:118–129. doi: 10.1037/h0040543. [DOI] [PubMed] [Google Scholar]
