Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.
The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit https://cc.nih.gov.
Updates regarding government operating status and resumption of normal operations can be found at https://opm.gov.

Ante la falta de fondos del gobierno federal, no se actualizará este sitio web y la organización no responderá a transacciones ni consultas hasta que se aprueben los fondos.
 El Centro Clínico de los Institutos Nacionales de la Salud  (el hospital de investigación) permanecerá abierto. Consulte https://cc.nih.gov(en inglés)
Infórmese sobre el funcionamiento del gobierno federal y el reinicio de las actividades en https://opm.gov.

Year of Publication: 2024
Project: BOLD Connectivity Dynamics
FIM Authors:
Authors:
  • Cambria Revsine
  • Javier Gonzalez-Castillo
  • Elisha Merriam
  • Peter Bandettini
  • Fernando Ramirez
Abstract:

Our ability to recognize faces regardless of viewpoint is a key property of the primate visual system. Traditional theories hold that facial viewpoint is represented by view-selective mechanisms at early visual processing stages and that representations become increasingly tolerant to viewpoint changes in higher-level visual areas. Newer theories, based on single-neuron monkey electrophysiological recordings, suggest an additional intermediate processing stage invariant to mirror-symmetric face views. Consistent with traditional theories, human studies combining neuroimaging and multivariate pattern analysis (MVPA) methods have provided evidence of view-selectivity in early visual cortex. However, contradictory results have been reported in higher-level visual areas concerning the existence in humans of mirror-symmetrically tuned representations. We believe these results reflect low-level stimulus confounds and data analysis choices. To probe for low-level confounds, we analyzed images from two popular face databases. Analyses of mean image luminance and contrast revealed biases across face views described by even polynomials, - i.e., mirror-symmetric. To explain major trends across human neuroimaging studies of viewpoint selectivity, we constructed a network model that incorporates three biological constraints: cortical magnification, convergent feedforward projections, and interhemispheric connections. Given the identified low-level biases, we show that a gradual increase of interhemispheric connections across network layers is sufficient to replicate findings of mirror-symmetry in high-level processing stages, as well as view-tuning in early processing stages. Data analysis decisions - pattern dissimilarity measure and data recentering - accounted for the variable observation of mirror-symmetry in late processing stages. The model provides a unifying explanation of MVPA studies of viewpoint selectivity. We also show how common analysis choices can lead to erroneous conclusions.


Code
Journal: Journal of Neuroscience
Volume: 44
URL: https://www.jneurosci.org/content/44/17/e0296232024.abstract
DOI: https://doi.org/10.1523/JNEUROSCI.0296-23.2024