Poster F135, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
The role of thalamo-striatal interactions in human behavioural flexibility.
Tiffany Bell1, Michael Lindner1, Angela Langdon2, Ying Zheng1, Anastasia Christakou1; 1University of Reading, UK, 2Princeton University, USA
Animal studies have shown that connections between the thalamic centromedian-parafascicular complex (CM-Pf) and dorsal medial striatum play a key role in behavioural flexibility. CM-Pf neurons fire in response to stimuli requiring an unpredicted reaction. This input elicits cholinergic modulation of striatal output, facilitating behavioural flexibility. However, evidence of this system in humans is difficult to obtain, given that the origin of the fMRI signal is difficult to disentangle. This study’s aim was to investigate the role of thalamo-striatal interactions in human reversal learning. Participants completed a multi-alternative probabilistic reversal learning task whilst undertaking a high resolution, multiband fMRI scan. Learning and reversal periods were modelled separately during analysis. Parametric modulation was used to assess the specificity of dorsal striatal involvement during reversal learning. Psychophysiological interaction (PPI) analysis was used to examine changes in functional connectivity between striatal and thalamic subdivisions. Dorsal striatal activation increased relative to the length of the perseverative period. Additionally, functional connectivity between the centro-medial thalamus and the dorsal striatum increased during the reversal period, and not initial learning. This effect was specific to this connection and was not seen between other thalamo-striatal pairs. These results are in line with prior evidence for the role of the dorsal striatum in behavioural flexibility. Moreover, we demonstrate for the first time that communication between the centro-medial thalamus and the dorsal striatum is important specifically for reversal learning. This is in line with evidence from the animal literature, providing further support for the role of thalamo-striatal input in behavioural flexibility.
Topic Area: THINKING: Decision making