We investigate dopaminergic modulation of perceptual and rule-based judgments in the prefrontal cortex. Perceptual decisions refer to the monitoring of (often ambiguous) sensory evidence to detect or discriminate sensations in order to guide appropriate actions, e.g. the detection of a stimulus at perceptual threshold. Rule-based decisions reflect principles or algorithms that map input to actions, such as “greater than/less than”-decisions applied to numerical magnitudes. The neurotransmitter dopamine is thought to influence the stability and transition from one decision state to the other. This hypothesis will be tested in monkeys performing decision tasks while recording single cell activity in combination with iontophoretic drug application. This will allow exploring dopaminergic modulation of neuronal coding related to decisions. Selectively targeting D1 and D2 receptor types will help to unravel the respective contributions of dopamine receptor-mediated effects on the neurons’ coding reliability. To assess the impact of dopamine in larger association cortical networks, recordings will be extended to other associative regions, such as the premotor or the posterior parietal cortices. Better insight into the impact of dopaminergic modulation in the fronto-parietal network will also be instrumental in understanding and refining the effects of antipsychotic drugs targeting dopamine receptors.

Jacob S, Stalter M, Nieder A (2016) Cell-type specific modulation of targets and distractors by dopamine D1 receptors in primate prefrontal cortex. Nature Communications, in press.

Ott T, Nieder A (2016) Dopamine D2 receptors enhance population dynamics in primate prefrontal working memory circuits. Cerebral Cortex, DOI:10.1093/cercor/bhw244 [Epub ahead of print]

Ott T, Jacob SN, Nieder A (2014) Dopamine receptors differentially enhance rule coding in primate prefrontal cortex neurons. Neuron 84(6):1317-28, doi: 10.1016/j.neuron.