We will conduct the first study to investigate changes in excitatory glutamate and inhibitory GABA neurotransmitter concentrations during a social processing task, as well as the relationship between glutamate and GABA concentrations and social processing ability. Social processing ability will be assessed using tools outlined by the gold-standard National Institute of Mental Health Research Domain Criteria (RDoC) of Social Processes (Insel, 2010). We will also investigate the extent to which glutamate changes during the social processing task are associated with autism and schizophrenia spectrum traits.
Glutamate and GABA concentrations will be quantified from the right superior temporal sulcus (STS), a well validated social processing region (Deen, Koldewyn, Kanwisher, & Saxe, 2015; Pitcher, Dilks, Saxe, Triantafyllou, & Kanwisher, 2011), and a control region in the visual cortex for comparison. Furthermore, we will establish the relationship between functional glutamate and GABA and brain activity associated with social processing as indicated by blood oxygen level depletion (BOLD) signal, measured using functional MRI (fMRI).
**Primary objective:**
To investigate the neurochemical processes involved in social processing among healthy adults using a novel neuroimaging technique, fMRS; specifically, changes in Glx and GABA concentrations in the social processing regions of right STS.
**Secondary objectives:**
1) To investigate the relationship between task-based glutamate and GABA concentrations and social processing ability, as well as autism and schizophrenia spectrum traits;
2) To establish the relationship between functional Glx and GABA and BOLD signal during social processing;
3) To identify differences in functional Glx and GABA and BOLD signal during social processing between the current 3T Siemens Trio MRI scanner at Swinburne Neuroimaging and the new 3T Siemens Prisma.
Forty healthy adults aged 18-40 (20 male, 20 female) will be recruited for in this study. Male and female participants will be matched on age and handedness, and will be free from psychiatric (e.g., schizophrenia, depression), neurological (e.g., epilepsy, seizures) and genetic (e.g., Fragile x syndrome) conditions.
