Flexible top-down modulation in human ventral temporal cortex

Visual neuroscientists have long characterized attention as inducing a scaling or additive effect on fixed parametric functions describing neural responses (e.g., contrast response functions). Here, we instead propose that top-down effects are more complex and manifest in ways that depend not only o...

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Bibliographic Details
Published in:NeuroImage (Orlando, Fla.) Fla.), 2020-09, Vol.218, p.116964-116964, Article 116964
Main Authors: Zhang, Ru-Yuan, Kay, Kendrick
Format: Article
Language:English
Subjects:
Adult
Attention
Bottom-up processing
Brain Mapping
Cognition
Cognition & reasoning
Cognitive ability
Cortex (temporal)
Decision making
Experiments
Face
Functional magnetic resonance imaging
Fusiform face area
Human ventral temporal cortex
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
Photic Stimulation
Psychomotor Performance - physiology
Studies
Temporal Lobe - diagnostic imaging
Top-down processing
Visual Perception - physiology
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Summary:Visual neuroscientists have long characterized attention as inducing a scaling or additive effect on fixed parametric functions describing neural responses (e.g., contrast response functions). Here, we instead propose that top-down effects are more complex and manifest in ways that depend not only on attention but also other cognitive processes involved in executing a task. To substantiate this theory, we analyze fMRI responses in human ventral temporal cortex (VTC) in a study where stimulus eccentricity and cognitive task are varied. We find that as stimuli are presented farther into the periphery, bottom-up stimulus-driven responses decline but top-down attentional enhancement increases substantially. This disproportionate enhancement of weak responses cannot be easily explained by conventional models of attention. Furthermore, we find that attentional effects depend on the specific cognitive task performed by the subject, indicating the influence of additional cognitive processes other than attention (e.g., decision-making). The effects we observe replicate in an independent experiment from the same study, and also generalize to a separate study involving different stimulus manipulations (contrast and phase coherence). Our results suggest that a quantitative understanding of top-down modulation requires more nuanced characterization of the multiple cognitive factors involved in completing a perceptual task.
ISSN:1053-8119
1095-9572
DOI:10.1016/j.neuroimage.2020.116964