Further characterisation of the functional neuroanatomy associated with prosodic emotion decoding.
BACKGROUND
Current models of prosodic emotion comprehension propose a three stage cognition mediated by temporal lobe auditory regions through to inferior and orbitofrontal regions. Cumulative evidence suggests that its mediation may be more flexible though, with a facility to respond in a graded manner based on the need for executive control. The location of this fine-tuning system is unclear, as is its similarity to the cognitive control system.


METHODS
In the current study, need for executive control was manipulated in a block-design functional MRI study by systematically altering the proportion of incongruent trials across time, i.e., trials for which participants identified prosodic emotions in the face of conflicting lexico-semantic emotion cues. Resultant Blood Oxygenation Level Dependent contrast data were analysed according to standard procedures using Statistical Parametric Mapping v8 (Ashburner et al., 2009).


RESULTS
In the parametric analyses, superior (medial) frontal gyrus activity increased linearly with increased need for executive control. In the separate analyses of each level of incongruity, results suggested that the baseline prosodic emotion comprehension system was sufficient to deal with low proportions of incongruent trials, whereas a more widespread frontal lobe network was required for higher proportions.


CONCLUSIONS
These results suggest an executive control system for prosodic emotion comprehension exists which has the capability to recruit superior (medial) frontal gyrus in a graded manner and other frontal regions once demand exceeds a certain threshold. The need to revise current models of prosodic emotion comprehension and add a fourth processing stage are discussed.
Department of Psychology, Durham University, UK. r.l.c.mitchell@durham.ac.uk
Rachel L C
RL
Mitchell
D000161:Acoustic Stimulation; D000704:Analysis of Variance; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology; D032882:Comprehension; D003220:Conflict, Psychological; D003627:Data Interpretation, Statistical; D004644:Emotions / Q000502:physiology*; D056344:Executive Function; D005149:Facial Expression; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D011597:Psychomotor Performance / Q000502:physiology; D012938:Social Perception; D013238:Stereotaxic Techniques; D013702:Temporal Lobe / Q000502:physiology; D055815:Young Adult