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Influential models on visual perception assume that there is a precedence of low over high spatial frequencies (SFs) in the processing time course of the visual input, that is, a coarse-to-fine (CtF) encoding. Additionally, hemispheric asymmetries for strategies of SF processing have been shown. A CtF processing would be favored in the right hemisphere, whereas the reverse fine-to-coarse (FtC) processing would be favored in the left hemisphere. In the current article, we aimed to behaviorally investigate which temporal strategy, that is, CtF or FtC, each brain hemisphere performs to integrate SF information of human faces. To address this issue, we conducted a male–female categorization task using the divided visual field paradigm; CtF and FtC brief dynamic sequences of faces were presented in the left, right, and central visual fields. Results of the correct response time and the inverse efficiency score showed an overall advantage of CtF processing for face categorization, irrespective of the visual field of presentation. Error rate data also highlights the role of the right hemisphere in CtF processing. Here, we provide evidence at the behavioral level for a general and nonlateralized precedence of the default CtF strategy carried out by the visual system to encode faces, a complex stimulus with ecological value.

About 20% to 30% of patients diagnosed with major depressive disorder do not respond to conventional pharmacotherapy or psychotherapy. Repetitive transcranial magnetic stimulation (rTMS) has been established as an effective alternative to treat depression. The most widely used protocol and with more evidence of efficacy for major depression consists of high frequency stimulation targeting the left dorsolateral prefrontal cortex (DLPFC). However, it is unclear how and which basic psychological processes are modulated by such setup. The literature shows that the DLPFC is hyperactivated in response to facial expressions of happiness in depressed individuals, probably because they need more attentional resources to process mood-incongruent visual stimuli. The present study investigated recognition of emotional faces pre and post 15 Hz rTMS (real or sham) over the left DLPFC in participants diagnosed with major depression, and healthy controls. A double staircase design presented morphed faces and calculated the absolute threshold for the 6 basic emotions (i.e., anger, disgust, fear, happiness, sadness, and surprise). There was a significant difference only for the depression group that received rTMS: an increased sensitivity for happy faces after stimulation. We conclude that high frequency rTMS over the left DLPFC might reduce major depression typical lower bias to recognize positive valence stimuli, and hence explains the increased sensitivity for happy faces observed in the depression group.

The present study psychophysically investigated the laterality of low spatial frequencies (LSFs) and high spatial frequencies (HSFs) during face recognition at different exposure times. Spatial frequency–filtered faces were presented in a divided visual field at high and low temporal constraints in 2 tasks: face recognition (Experiment 1) and face gender recognition (Experiment 2). Both experiments revealed general primacy in the recognition of LSF over HSF faces. In Experiment 1, LSF and HSF facial information was more efficiently processed in the right and left hemispheres, respectively, and exposure time had no effect. Experiment 2 showed right hemisphere asymmetry for LSF faces at a low temporal constraint. These results suggest that the spatial frequency processing for face recognition is lateralized in the brain hemispheres. However, the contributions of LSFs and HSFs depend on the task and exposure time.