Striatal and thalamic GABA level concentrations play differential roles for the modulation of response selection processes by proprioceptive information

Shalmali Dharmadhikari, Ruoyun Ma, Chien-Lin Yeh, Ann-Kathrin Stock, Sandy Snyder, S. Elizabeth Zauber, Ulrike Dydak, Christian Beste
2015 NeuroImage  
The selection of appropriate responses is a complex endeavor requiring the integration of many different sources of information in fronto-striatal-thalamic circuits. An often neglected but relevant piece of information is provided by proprioceptive inputs about the current position of our limbs. This study examines the importance of striatal and thalamic GABA levels in these processes using GABA-edited magnetic resonance spectroscopy (GABAMRS) and a Simon task featuring proprioception-induced
more » ... terference in healthy subjects. As a possible model of deficits in the processing of proprioceptive information, we also included Parkinson's disease (PD) patients in this study. The results show that proprioceptive information about unusual postures complicates response selection processes in controls, but not in PD patients. The well-known deficits of PD patients in processing proprioceptive information can turn into a benefit when altered proprioceptive information would normally complicate response selection processes. Striatal and thalamic GABA levels play dissociable roles in the modulation of response selection processes by proprioceptive information: Striatal GABA levels seem to be important for the general speed of responding, most likely because striatal GABA promotes response selection. In contrast, the modulation of response conflict by proprioceptive information is closely related to thalamic GABA concentrations with higher concentration being related to a smaller response conflict effect. The most likely explanation for this finding is that the thalamus is involved in the integration of sensorimotor,
doi:10.1016/j.neuroimage.2015.06.066 pmid:26142275 pmcid:PMC4589476 fatcat:ob4nvl4pkjb63nwsj6evkgq26m