RT Journal Article
T1 Dynamic gamma frequency feedback coupling between higher and lower order visual cortices underlies perceptual completion in humans
A1 Moratti, Stephan
A1 Mendez Bertolo, Constantino
A1 Pozo Guerrero, Francisco del
A1 Strange, Bryan
AB To perceive a coherent environment, incomplete or overlapping visual forms must be integrated into meaningful coherent percepts, a process referred to as "Gestalt" formation or perceptual completion. Increasing evidence suggests that this process engages oscillatory neuronal activity in a distributed neuronal assembly. A separate line of evidence suggests that Gestalt formation requires top-down feedback from higher order brain regions to early visual cortex. Here we combine magnetoencephalography (MEG) and effective connectivity analysis in the frequency domain to specifically address the effective coupling between sources of oscillatory brain activity during Gestalt formation. We demonstrate that perceptual completion of two-tone "Mooney" faces induces increased gamma frequency band power (55-71Hz) in human early visual, fusiform and parietal cortices. Within this distributed neuronal assembly fusiform and parietal gamma oscillators are coupled by forward and backward connectivity during Mooney face perception, indicating reciprocal influences of gamma activity between these higher order visual brain regions. Critically, gamma band oscillations in early visual cortex are modulated by top-down feedback connectivity from both fusiform and parietal cortices. Thus, we provide a mechanistic account of Gestalt perception in which gamma oscillations in feature sensitive and spatial attention-relevant brain regions reciprocally drive one another and convey global stimulus aspects to local processing units at low levels of the sensory hierarchy by top-down feedback. Our data therefore support the notion of inverse hierarchical processing within the visual system underlying awareness of coherent percepts.
PB Elsevier
SN 1095-9572
YR 2014
FD 2014
LK https://hdl.handle.net/20.500.14352/35113
UL https://hdl.handle.net/20.500.14352/35113
LA eng
NO Ministerio de Economía y Competitividad (MINECO)
NO Ministerio de Educación y Ciencia
DS Docta Complutense
RD 29 mar 2026