Saccadic latency is modulated by emotional content of spatially filtered face stimuli.

Abstract

Models of attention and emotion assign a special status to the processing of threat. While evidence for threat-related attentional bias in highly anxious individuals is robust, effects in the normal population are mixed. An important explanation for the absence of threat-related attentional bias in nonanxious individuals may relate to the spatial frequency components of stimuli. Here we report behavioral data from two experiments examining the relationship between spatial frequency components of emotional and neutral faces and fast saccadic orienting behavior. In Experiment 1 participants had to saccade toward a single face, filtered to include mostly low, high or broad spatial frequencies (LSF, HSF or BSF), posing a fearful, happy or neutral expression presented for 20 ms in the periphery. At BSF a general emotional effect was found whereby saccadic responses were faster for fearful and happy faces relative to neutral, with no significant differences between fearful and happy faces. At LSF both fearful and happy faces had shorter saccadic latencies in comparison to neutral, demonstrating an emotional bias consistent with the BSF data. However, at LSF fearful faces resulted in significantly faster saccades than happy faces indicating that this bias was stronger for threat-related faces. There was no difference in saccadic responses between any emotions at HSF. Experiment 2 showed that the emotional bias diminished for inverted stimuli suggesting that the results were not attributable to low-level image properties. The findings suggest an overall advantage in the oculomotor system for orientation to emotional stimuli and at LSF in particular, a significantly faster localization of threat conveyed by the face stimuli in all individuals.

Inefficient search strategies in simulated hemianopia.

“…ii In homonymous hemianopia, residual discrimination appears to rely on low spatial frequency visual information (Bannerman et al, 2012;Sahraie et al, 2013). Faces are complex visual stimuli with different information contained at different spatial frequencies, while oriented line segments are far simpler, containing the same orientation information at high and low frequencies.…”

“…With a view to extend the present method to hemianopic patients in future studies, in the first experiment we selected experimental conditions that are more likely to drive saccadic eye movement in the patient group, namely, the detection of emotional information present in low spatial frequency components of faces (Bannerman et al, 2012;Sahraie et al, 2013). The search items to one side of the point of gaze a) were removed entirely, b) had high spatial frequency information removed, c) were replaced with dots to mark their locations, or d) were unmodified (control).…”

“…The low spatial frequency cut-off was 2 cycles per degree (for the exact method of filtering and normalizing images refer to Bannerman et al, 2012). We decided to include the 2 c/° cut-off because the remaining information was in the range of the optimal frequencies for detection and awareness in blindsight reported by Sahraie et al (2010Sahraie et al ( , 2013) and comparable to the parameters applied in previous studies by Vuilleumier, Armony, Driver and Dolan (2003) and Bannerman et al (2012). Previous work also indicated that participants were able to correctly classify the emotion expression at this low spatial frequency range (Bannerman et al, 2012).…”

“…In addition, significant detection of stimuli of social significance such as facial expressions of fear and anger have been reported for stimuli presented within the field defect (Pegna, Khateb, Lazeyras, & Seghier, 2005) and it is claimed that such expressions predominantly rely on low spatial frequencies (Bannerman, Hibbard, Chalmers, & Sahraie, 2012). Blindsight is thought to be subserved by secondary visual pathways bypassing the geniculo-striate projection, such as the retinotectal pathway that projects from the retina directly to the superior colliculus of the midbrain, a structure involved in eye movement control.…”

Dissociating retrieval success from incidental encoding activity during emotional memory retrieval, in the medial temporal lobe

“…It is well known that emotion enhances the magnitude of early and late neural markers of stimulus processing, as shown by ERP studies (Olofsson et al, 2008), although shifts in the latency of ERP components indexing sensory and cognitive processes influenced by emotion are not commonly found (e.g., though this may be the result of event-related averaging vs. single-trial variability for ERP data). Also, negative emotions can produce faster responses of the oculomotor system resulting in quicker localization of threat (Bannerman et al, 2009, 2012). As also shown in the present results, fMRI studies of emotion processing can show differences in the temporal dynamics of the BOLD response between experimental conditions.…”