Rapid Fear Detection Relies on High Spatial Frequencies

Abstract

Signals of threat--such as fearful faces--are processed with priority and have privileged access to awareness. This fear advantage is commonly believed to engage a specialized subcortical pathway to the amygdala that bypasses visual cortex and processes predominantly low-spatial-frequency information but is largely insensitive to high spatial frequencies. We tested visual detection of low- and high-pass-filtered fearful and neutral faces under continuous flash suppression and sandwich masking, and we found consistently that the fear advantage was specific to high spatial frequencies. This demonstrates that rapid fear detection relies not on low- but on high-spatial-frequency information--indicative of an involvement of cortical visual areas. These findings challenge the traditional notion that a subcortical pathway to the amygdala is essential for the initial processing of fear signals and support the emerging view that the cerebral cortex is crucial for the processing of ecologically relevant signals.

Facial emotion processing in patients with social anxiety disorder and Williams–Beuren syndrome: an fMRI study

“…51,52 The information from facial features and finegrained details might be critical not only for accurate processing of facial expressions, 46 but also for the rapid detection of threat-related signals, such as fearful faces. 53,54 Deficient input from visual areas may also have contributed to the absence of an amygdala response to threat-related faces observed in our study. Interestingly, Sarpal and colleagues 55 reported significant reductions in functional connectivity between the FFA and the amygdala during the presentation of threatening faces.…”

Preferential awareness of protofacial stimuli in autism

“…For example, it has been found that suppression durations are influenced by facial properties that may be too subtle to be processed by a coarse subcortical pathway, such as a face's race, age (Stein, End, & Sterzer, 2014), or a face's familiarity to the observer (Gobbini et al, 2013). Also, detection of stimuli containing high spatial frequencies that are thought to be processed by cortical areas overcome CFS relatively quickly (Stein, Seymour, Hebart, & Sterzer, 2014;Yang & Blake, 2012). Furthermore, whereas earlier neuroimaging studies indicated that neural activity under interocular suppression is largely confined to subcortical areas (Jiang & He, 2006;Pasley, Mayes, & Schultz, 2004;Troiani & Schultz, 2013;Williams, Morris, McGlone, Abbott, & Mattingley, 2004), the extent and location of residual neural processing in cortical areas -especially in the dorsal visual processing stream -is still a matter of debate (Ludwig & Hesselmann, 2015;Sterzer, Stein, Ludwig, Rothkirch, & Hesselmann, 2014), with some imaging studies showing preserved cortical responses despite interocular suppression (e.g.…”

Unconscious processing under interocular suppression: getting the right measure

“…A rapidly growing body of literature using b-CFS now suggests that interocular suppression allows for a much greater extent of high-level unconscious processing than previously thought (for a review, see Gayet et al, submitted). For example, b-CFS is sensitive to various features of face stimuli (Jiang et al, 2007; Yang et al, 2007; Zhou et al, 2010; Stein et al, 2011b,c, 2012b, 2014; Chen and Yeh, 2012; Stein and Sterzer, 2012; Stewart et al, 2012; Gobbini et al, 2013a,b), and can even be influenced by semantic stimulus properties (Costello et al, 2009; Mudrik et al, 2011; Sklar et al, 2012). These findings demonstrate that b-CFS is highly sensitive to differences between complex stimuli in their potency to gain access to awareness.…”