The cortical and subcortical correlates of face pareidolia in the macaque brain.

Face detection is a foundational social skill for primates. This vital function is thought to be supported by specialized neural mechanisms; however, although several face-selective regions have been identified in both humans and nonhuman primates, there is no consensus about which region(s) are involved in face detection. Here, we used naturally occurring errors of face detection (i.e. objects with illusory facial features referred to as examples of 'face pareidolia') to identify regions of the macaque brain implicated in face detection. Using whole-brain functional magnetic resonance imaging to test awake rhesus macaques, we discovered that a subset of face-selective patches in the inferior temporal cortex, on the lower lateral edge of the superior temporal sulcus, and the amygdala respond more to objects with illusory facial features than matched non-face objects. Multivariate analyses of the data revealed differences in the representation of illusory faces across the functionally defined regions of interest. These differences suggest that the cortical and subcortical face-selective regions contribute uniquely to the detection of facial features. We conclude that face detection is supported by a multiplexed system in the primate brain.

The paradoxical association between tension-reduction alcohol outcome expectancies and tension following alcohol consumption.

Background: Behavioral models suggest that strong tension-reduction alcohol-outcome expectancies (TREs) among drinkers should be associated with greater tension reduction after drinking. Yet, the few studies investigating this have found either no relationship or the opposite relationship.Objectives: We sought to explore this relationship by building upon the limitations of past studies and employing a placebo-controlled, within-subject experimental design.Methods: Sixty social drinkers (26 M, 34 F) visited the lab on two occasions spaced one week apart. Each participant was randomly assigned to receive alcoholic drinks targeting a BAC of 0.05% on one testing day and placebo drinks on the other, with the order counter-balanced. On both testing days, participants completed measures of state anxiety and fear both before drinking and following a drinking/absorption period. While completing the self-report measures, participants were anticipating an impending, mildly stressful heartbeat perception task.Results: Multilevel modeling revealed that the more strongly individuals believed that alcohol reduces tension, the less the pharmacologic properties of alcohol did so (p = .02 for the state anxiety outcome measure; p = .001 for the fear outcome measure). This was the case even with anxiety sensitivity - a known predictor of stress-response dampening - controlled for.Conclusions: These results provide further evidence for the paradoxical association of TREs and the dampening of anxiety. Additionally, the findings are consistent with the basis of expectancy challenges that aim to reframe inaccurate TREs among drinkers.

Parallel Processing of Facial Expression and Head Orientation in the Macaque Brain.

When we move the features of our face, or turn our head, we communicate changes in our internal state to the people around us. How this information is encoded and used by an observer's brain is poorly understood. We investigated this issue using a functional MRI adaptation paradigm in awake male macaques. Among face-selective patches of the superior temporal sulcus (STS), we found a double dissociation of areas processing facial expression and those processing head orientation. The face-selective patches in the STS fundus were most sensitive to facial expression, as was the amygdala, whereas those on the lower, lateral edge of the sulcus were most sensitive to head orientation. The results of this study reveal a new dimension of functional organization, with face-selective patches segregating within the STS. The findings thus force a rethinking of the role of the face-processing system in representing subject-directed actions and supporting social cognition.SIGNIFICANCE STATEMENT When we are interacting with another person, we make inferences about their emotional state based on visual signals. For example, when a person's facial expression changes, we are given information about their feelings. While primates are thought to have specialized cortical mechanisms for analyzing the identity of faces, less is known about how these mechanisms unpack transient signals, like expression, that can change from one moment to the next. Here, using an fMRI adaptation paradigm, we demonstrate that while the identity of a face is held constant, there are separate mechanisms in the macaque brain for processing transient changes in the face's expression and orientation. These findings shed new light on the function of the face-processing system during social exchanges.