A distributed neural system for top-down face processing

Abstract

Evidence suggests that the neural system associated with face processing is a distributed cortical network containing both bottom-up and top-down mechanisms. While bottom-up face processing has been the focus of many studies, the neural areas involved in the top-down face processing have not been extensively investigated due to difficulty in isolating top-down influences from the bottomup response engendered by presentation of a face. In the present study, we used a novel experimental method to induce illusory face detection. This method allowed for directly examining the neural systems involved in top-down face processing while minimizing the influence of bottom-up perceptual input. A distributed cortical network of top-down face processing was identified by analyzing the functional connectivity patterns of the right fusiform face area (FFA). This distributed cortical network model for face processing includes both "core" and "extended" face processing areas. It also includes left anterior cingulate cortex (ACC), bilateral orbitofrontal cortex (OFC), left dorsolateral prefrontal cortex (DLPFC), left premotor cortex, and left inferior parietal cortex. These findings suggest that top-down face processing contains not only regions for analyzing the visual appearance of faces, but also those involved in processing low spatial frequency (LSF) information, decision making, and working memory.

Functional neural correlates of emotional expression processing deficits in behavioural variant frontotemporal dementia

“…13,30,31 Face perception tasks limiting ventral visual (bottom-up) input have detected increased activity in regions such as the infer ior parietal lobule, posterior cingulate cortex, dorsolateral prefrontal cortex and precuneus. 30,48 Following this model, in both patients with bvFTD and controls, high-intensity expressions would be expected to generate a greater limbic response than low-intensity expressions, leading to a reduced need for attentional compensation during the viewing of high-intensity faces. Supporting this model, patients with bvFTD showed greater recruitment of the parietal cortex when viewing low-than high-intensity expressions.…”

Face recognition under ambiguous visual stimulation: fMRI correlates of “encoding styles”

“…However, visual object recognition is not only affected by this bottom-up processing but also by top-down modulations. Such top-down processes are imposed, for example, by selectively attending to a specific stimulus or stimulus feature [Banich et al, 2000], expectations about the occurrence of specific objects [Li et al, 2009;Zhang et al, 2008], predictions about forthcoming objects [Fenske et al, 2006;Summerfield and Egner, 2009], or the monitoring of decision processes under uncertainty conditions [Ridderinkhof et al, 2004]. This higher level top-down modulation might facilitate the processing of attended, expected, or predicted objects though this facilitation might be based on different underlying brain mechanisms, such that attention might enhance and expectation might reduce visual processing in extrastriate object sensitive brain regions [see Summerfield and Egner, 2009].…”

“…However, these secondary schemata seem to be more transient in nature, but might, similar to primary schemata, figure as template against which incoming information is compared. Secondary schemata seem to originate predominantly in frontal brain regions and modulate the information flow and categorization processes in extrastriate visual processing regions [Fenske et al, 2006;Li et al, 2009;Summerfield et al, 2006a,b;Zhang et al, 2008], whereby the orbito-frontal cortex (OFC) in particular seems to signal subjectively successful object categorization [Fenske et al, 2006;Summerfield and Koechlin, 2008].…”

“…In the absence of strong top-down guidance by, for example, expectations or selective attention, a reliable object categorization of these ambiguous stimuli might be more strongly driven by the application of primary schemata as represented in object sensitive visual areas. Studies on object categorization of ambiguous stimuli in the absence of top-down control demonstrated a relation between activation in extrastriate object sensitive regions with the individual categorization behavior [Akrami et al, 2009;Li et al, 2009;Liu and Jagadeesh, 2008;Sterzer and Kleinschmidt, 2007;Summerfield et al, 2006b;Zhang et al, 2008]. However, besides stimulus properties top-down control is the second important factor during percept formation and top-down control is quite often represented in frontal brain regions.…”

“…However, besides stimulus properties top-down control is the second important factor during percept formation and top-down control is quite often represented in frontal brain regions. Top-down control by secondary schemata could be generated by context-related expectations [Fenske et al, 2006;Kveraga et al, 2007a] or by task instructions [Li et al, 2009;Zhang et al, 2008], and this top-down influence might affect the bottom-up processing and primary schema application in extra-striate brain regions. For example, object selective regions are active during task instructions to simply imagine specific objects for which these brain regions are sensitive without any sensory stimulation [O'Craven and Kanwisher, 2000].…”