Neurochemical control of patch-leaving decisions via modulation of network dynamics

点击翻译按钮获取中文摘要

Should I spend a lot of time, effort and money to move to a different city for a new job? Or should I stay where I am and stick with my current job? This kind of stay-switch decision, in behavioural ecology often termed patch-leaving (a subclass of foraging decisions), is an important decision problem that we often face in everyday life. Because of the sequential nature of patch-leaving, any decision has consequences that last beyond the current trial - after having moved to a different habitat, one cannot simply move back to the previous location without having to pay a cost again. This makes patch-leaving different from standard reward-guided choice, in which this strategic sequential component is not present. Research on human foraging is a rather new field, but it has already been shown that this kind of decision relies on neural circuitry that is distinct from (albeit overlapping) that supporting simple reward-guided choice. While the evidence so far suggests a crucial role for a network of brain regions centred on the anterior cingulate cortex (ACC), little is known about the temporal dynamics of neural activity underlying patch-leaving decisions. The studies conducted so far hint at the possibility that the key decision variable (DV) for foraging may be represented in cortical oscillatory activity in ACC in the theta and gamma range. Likewise, a few studies and theoretical proposal suggest a key role for neuromodulatory systems in the relevant computations. The present project will test a number of novel hypotheses. Using MEG and concurrent EEG-fMRI, it will be investigated how the key DV for patch-leaving is represented in cortical oscillatory activity in a number of candidate cortical regions, most importantly in the ACC. Furthermore, neurochemical activity will either be measured with MR spectroscopy or manipulated with pharmacological challenges. This will elucidate how neurochemical systems govern patch-leaving decisions by controlling the temporal dynamics of neural activity. If interference with neurochemical systems should perturb both oscillatory representations and associated behaviour, these studies would also provide evidence to what extent these patterns are causally relevant for patch-leaving.