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Abstract

Introduction:
Deficits in perception of emotional prosody have been described in patients with affective disorders at behavioral and neural level [1]. In the current study, we use an imaging genetics approach to examine the impact of CACNA1C, one of the most promising genetic risk factors for psychiatric disorders [2], on prosody processing on a behavioral, functional and microstructural level.
Methods:
Using functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) we examined key areas involved in prosody processing, i.e. the amygdala and voice areas, in a healthy population (N=51). The studied group contained 26 carriers of the CACNA1C rs1006737 risk allele (AA/AG) and 25 individuals homozygous for the non-risk genotype (GG). Participants were presented with positive, neutral and negative words and asked to judge the emotional valence of the prosody of those words.
Results:
We found stronger activation to emotional than neutral prosody in the voice areas and in the amygdala. CACNA1C rs1006737 genotype had no influence on behavioral and fMRI activity. However, significant microstructural differences (i.e. mean diffusivity) between CACNA1C rs1006737 risk allele carriers and non-carriers were found in the amygdala, but not the voice areas (Figure 1).
Conclusions:
This is the first study investigating the role of CACNA1C rs1006737 on prosody perception and processing on a behavioral, functional and structural level in a healthy population. Our findings reveal an effect of CACNA1C genotype on amygdalar microstructure with reduced MD in risk allele carriers indicating higher membrane density and thus cellularity within this region. These modifications in brain architecture associated with CACNA1C might reflect an endophenotype predisposing to affective disorders and concomitant alterations in emotion perception.