Distinct cerebellar lobules encode arousal and valence in specific time windows: an MEG study Charis Styliadis Laboratory of Medical Physics, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece OHBM Meeting, Hamburg, June 2014

Cerebellum and Emotions Cerebellar Anatomy and Lobule Grouping

Cerebellum and Emotions Different levels of arousal and valence activate distinct cerebellar lobules within specific time windows in a sequence determined by the arousal and valence content of the affective experience. Hypothesis

Cerebellum and Emotions  Subjects: 10 healthy adults (5 females; 21 to 40 years; 28.5; S.D., 5.94)  Stimuli: 160 stimuli from International Affective Picture System (IAPS).  4 groups of stimuli manipulating the level of arousal within pleasant and unpleasant pictures: (i) pleasant with high arousal (PHA, (ii) pleasant with low arousal (PLA), (iii) unpleasant with high arousal (UHA) and (iv) unpleasant with low arousal (ULA). Balanced for gender differences and perceptual features. Materials Overview

Cerebellum and Emotions Experimental Task  Stimuli and inter-stimuli (fixation cross) were centred on screen.  The fixation cross was presented for a pseudo-randomized interval of 1500±200 ms.  Trials were presented for 1000 ms along with the fixation cross

Cerebellum and Emotions  MEG recordings: 151-channel CTF whole head system (VSM MedTech Ltd, B.C., Canada) at a sampling rate of 1250 Hz.  Time frequency Analysis: Wavelet analysis (factor 3) applied on single trials for revealing induced activity.  Source reconstruction: Dual state Synthetic Aperture Magnetometry (SAM) for an active time window of ms after stimulus onset at the gamma frequency band ( Hz).  Statistical analysis: 2x2 repeated measures of ANOVA using SPM with a statistical threshold of p<0.001 uncorrected.  Virtual Sensors: Virtual sensors on significant cerebellar lobules. Analysis Overview

Cerebellum and Emotions MEG Sensor Space Group-averaged time frequency of induced activity of arousal after onset. Changes significant at p<0.05 level (cluster correction) are indicated within dotted lines.

Cerebellum and Emotions Analysis Pipeline

Cerebellum and Emotions SAM Analysis Static Window Analysis Sliding Window Analysis

Cerebellum and Emotions Results-Static Window Analysis ( p<0.001 uncor.) High Arousal High Arousal and Pleasant Valence

Cerebellum and Emotions Results-Sliding window analysis High ArousalUnpleasant Valence High Arousal and Pleasant Valence

Cerebellum and Emotions Results-MEG Virtual Sensor Space Group-averaged time frequency of induced activity of arousal after onset for Left Crus II (-16, -86, -35). Changes significant at p<0.05 level (cluster correction) are indicated within dotted lines.

Cerebellum and Emotions (i)arousal, valence, and their interaction are functionally represented on anatomically distinct cerebellar lobules (ii)the processing of arousal, valence, and their interaction unfolds at well-defined latencies relative to stimulus onset and evolve in parallel within the cerebellum (iii)emotion-related cerebellar responses are hierarchically organized into an early prioritization of high arousal, followed by an unpleasant valence effect and later a pleasant valence by high arousal interaction effect. Conclusions

Thank you! Christos Papadelis, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, USA Panagiotis D. Bamidis, Laboratory of Medical Physics, Aristotle University of Thessaloniki, Greece Andreas A. Ioannides, Laboratory for Human Brain Dynamics, AAI Scientific Cultural Services Ltd., Nicosia, Cyprus People that made this possible Funded by the Operational Program “Education and Lifelong Learning” of the Greek Ministry of Education and Religious Affairs, Culture and Sports (ref. number 2012ΣΕ ).