Attentional expectancies and their violation in the human brain in relation to cholinergic neurotransmission

• Applicant: Professorin Dr. Simone Vossel
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: from 2010 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 188326619

Recent work has shown that perceptual processing in the human brain strongly depends on attention and expectation, and that these influences are important for normal function and in various clinical disorders. For instance, expecting a stimulus to appear at a spatial location normally leads to preparatory biasing of sensory cortices by higher-level brain areas. Salient stimuli that unexpectedly occur outside the attentional focus engage distinct brain mechanisms to reorient attention to such targets. Predictive top-down control and reorienting of attention are thought to be mediated by distinct fronto-parietal networks and particular chemical pathways in the human brain, but many critical questions remain. Using novel cueing paradigms in combination with fMRI, MEG and pharmacological manipulations, I propose to investigate how the predictability of sensory events is dynamically encoded by the brain, and how this affects attention networks and performance. Importantly, both performance and neural activity will be modelled in relation to information-theoretic measures that allow a formal quantification of trial-by-trial predictability or surprise in terms of Bayesian learning. I shall test how probabilistic contexts affect different sensory modalities and may be integrated between them. Moreover, since the cholinergic neurotransmitter system is thought to affect the balance of expectation-guided versus bottom-up sensory processing, I shall test how the cholinesterase inhibitor physostigmine affects the impact of probabilistic contexts upon behavioural performance and neural responses. I shall investigate the effect of physostigmine on spatial attention in the visual modality as well as for multisensory spatial interactions. Taken together, the proposed studies will advance the understanding of the neural and neurochemical bases for uni- and multisensory attentional modulation in the human brain, in relation to probabilistic expectancies.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professor Dr. Jon Driver (†)