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Abstract

Introduction:
Veridical body language reading is indispensable for successful social cognition and interaction (Pavlova 2012). Healthy individuals can reliably recognize emotions expressed through body motion in point-light displays (Pollick et al. 2001; Sokolov et al. 2011). Despite potential implications for understanding and treatment of neuropsychiatric disease (Nackaerts et al. 2012) related to impairments in body language reading (Pavlova 2012), characteristics of the brain circuitry underpinning body language remain largely unknown.
Methods:
Functional MRI (3T Trio, Siemens Medical Solutions, Erlangen, Germany) was performed in 17 healthy adults (mean age 26.7 years) during emotion recognition in displays portraying a point-light arm knocking on a door with different emotional expressions (happy, neutral, and angry). Data pre-processing and analysis were conducted with Statistical Parametric Mapping (SPM12, Wellcome Institute of Cognitive Neuroscience, London, UK, http://www.fil.ion.ucl.ac.uk/spm). Standard procedures were applied for slice timing and realignment corrections, segmentation and normalization to MNI space. Statistical analysis based on a general linear model was run on the resulting individual fMRI data. The individual whole-brain images for the contrast happy versus neutral and angry versus neutral motion were included in a second-level random effects whole-brain analysis.
Results:
Happy as compared to neutral knocking resulted in higher activations in the right caudate nucleus and right posterior superior temporal sulcus (STS). The inferior insula, and anterior and medial cingulate cortex in the left hemisphere exhibited higher activation for angry as compared to neutral knocking. In addition, the left cerebellar lobules VIII and IX, and right amygdala were more strongly activated by neutral than emotional body motion.
Conclusions:
The outcome suggests differential involvement of cortical and subcortical "social brain" components in visual recognition of emotions expressed by bodily movement. Processing of emotional body language appears to be lateralized, depending on the emotional content. Left midline cerebellar structures and the right amygdala may interact in signalling a lack of emotional expression. This is in line with recent data on cerebellar involvement in visual processing of body motion (Sokolov et al. 2010, 2012, 2014). Further research is required to examine pathophysiological significance of this circuitry in patients with brain lesions and neuropsychiatric conditions, such as schizophrenia and autistic spectrum disorders.