Biology subjects

Luettgau, L.

Publications and source records attributed to Luettgau, L..

2 recordsLinked to original sources

bioRxiv2019

Dissociable roles of cortical excitation-inhibition balance during patch-leaving versus value-guided decisions

In a dynamic world, it is essential to decide when to leave an exploited resource. Such patch-leaving decisions involve balancing the cost of moving against the gain expected from the alternative patch. This is in contrast with value-guided decisions that typically involve maximizing reward by selecting the current best option. Patterns of neuronal activity pertaining to patch-leaving decisions have been reported in the dorsal anterior cingulate cortex (dACC), whereas competition via mutual inhibition in the ventromedial prefrontal cortex (vmPFC) is thought to underlie value-guided choice. Here, we show that the balance between cortical excitation and inhibition (E/I balance), measured by the ratio of GABA and glutamate concentrations, plays a dissociable role for the two kinds of decisions. Patch-leaving decision behaviour was related to E/I balance in dACC. In contrast, value-guided decision making was related to E/I balance in vmPFC. These results support previous mechanistic accounts of value-guided choice and provide novel evidence for a role of dACC E/I balance in patch-leaving decisions.

neuroscience↗

bioRxiv2019

Decisions bias future choices by modifying hippocampal associative memories

Decision making is guided by memories of option values. However, retrieving items from memory renders them malleable. Here, we show that merely retrieving values from memory and making a choice between options is sufficient both to induce changes to stimulus-reward associations in the hippocampus and to bias future decision making. After allowing participants to make repeated choices between reward-conditioned stimuli, in the absence of any outcome, we observed that participants preferred stimuli they had previously chosen, and neglected previously unchosen stimuli, over otherwise identical-valued options. Using functional brain imaging, we show that decisions induced changes to hippocampal representations of stimulus-outcome associations. These changes were correlated with future decision biases. Our results indicate that choice-induced preference changes are partially driven by choice-induced modification of memory representations and suggest that merely making a choice - even without experiencing any outcomes - induces associative plasticity.

neuroscience↗