Attractor models of working memory and their modulation by reward.
This work reports an empirical examination of two key issues in theoretical neuroscience: distractibility in the context of working memory (WM) and its reward dependence. While these issues have been examined fruitfully in isolation (e.g. Macoveanu et al. in Biol Cybern 96(4): 407-19, 2007), we address them here in tandem, with a focus on how distractibility and reward interact. In particular, we parameterise an observation model that embodies the nonlinear form of such interactions, as described in a recent neuronal network model (Gruber et al. in J Comput Neurosci 20:153-166, 2006). We observe that memory for a target stimulus can be corrupted by distracters in the delay period. Interestingly, in contrast to our theoretical predictions, this corruption was only partial. Distracters do not simply overwrite target; rather, a compromise is reached between target and distracter. Finally, we observed a trend towards a reduced distractibility under conditions of high reward. We discuss the implications of these findings for theoretical formulations of basal and dopamine (DA)-modulated neural bump- attractor networks of working memory.
Chumbley
Justin R
JR
Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, 12 Queen Square, London, WC1N 3BG, UK. j.chumbley@fil.ion.ucl.ac.uk
Dolan
Raymond J
RJ
Friston
Karl J
KJ
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008954:Models, Biological; D010775:Photic Stimulation / Q000379:methods; D012201:Reward; D055815:Young Adult