The large-scale organization of shape processing in the ventral and dorsal pathways
- Carnegie Mellon University, United States
- University of Western Ontario, Canada
Abstract
Although shape perception is considered a function of the ventral visual pathway, evidence suggests that the dorsal pathway also derives shape-based representations. In two psychophysics and neuroimaging experiments, we characterized the response properties, topographical organization and perceptual relevance of these representations. In both pathways, shape sensitivity increased from early visual cortex to extrastriate cortex but then decreased in anterior regions. Moreover, the lateral aspect of the ventral pathway and posterior regions of the dorsal pathway were sensitive to the availability of fundamental shape properties, even for unrecognizable images. This apparent representational similarity between the posterior-dorsal and lateral-ventral regions was corroborated by a multivariate analysis. Finally, as with ventral pathway, the activation profile of posterior dorsal regions was correlated with recognition performance, suggesting a possible contribution to perception. These findings challenge a strict functional dichotomy between the pathways and suggest a more distributed model of shape processing.
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Article and author information
Author details
Funding
Israel Science Foundation (grant No. 65/15)
- Erez Freud
Yad Hanadiv Postdoctoral Fellowship
- Erez Freud
National Science Foundation (BCS-1354350)
- David C Plaut
- Marlene Behrmann
Pennsylvania Department of Health (Commonwealth Universal Research Enhancement Program)
- David C Plaut
Canadian Institutes of Health Research (MOP 130345)
- Jody C Culham
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Nicholas Turk-Browne, Princeton University, United States
Ethics
Human subjects: As detailed in the manuscript, all subjects had normal or corrected-to-normal vision and were financially compensated for their participation. Informed consent and consent to publish was obtained in accordance with ethical standards set out by the Declaration of Helsinki (1964) and with procedures approved by the IRB committee of Carnegie Mellon University.
Version history
- Received: April 7, 2017
- Accepted: September 29, 2017
- Accepted Manuscript published: October 5, 2017 (version 1)
- Version of Record published: October 27, 2017 (version 2)
- Version of Record updated: December 20, 2017 (version 3)
Copyright
© 2017, Freud et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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The large-scale organization of shape processing in the ventral and dorsal pathways
eLife 6:e27576.
https://doi.org/10.7554/eLife.27576
Further reading
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- Neuroscience
The central tendency bias, or contraction bias, is a phenomenon where the judgment of the magnitude of items held in working memory appears to be biased toward the average of past observations. It is assumed to be an optimal strategy by the brain and commonly thought of as an expression of the brain’s ability to learn the statistical structure of sensory input. On the other hand, recency biases such as serial dependence are also commonly observed and are thought to reflect the content of working memory. Recent results from an auditory delayed comparison task in rats suggest that both biases may be more related than previously thought: when the posterior parietal cortex (PPC) was silenced, both short-term and contraction biases were reduced. By proposing a model of the circuit that may be involved in generating the behavior, we show that a volatile working memory content susceptible to shifting to the past sensory experience – producing short-term sensory history biases – naturally leads to contraction bias. The errors, occurring at the level of individual trials, are sampled from the full distribution of the stimuli and are not due to a gradual shift of the memory toward the sensory distribution’s mean. Our results are consistent with a broad set of behavioral findings and provide predictions of performance across different stimulus distributions and timings, delay intervals, as well as neuronal dynamics in putative working memory areas. Finally, we validate our model by performing a set of human psychophysics experiments of an auditory parametric working memory task.
