Rhythmic building blocks of human attention: How network oscillations link perception and action

• Applicant: Randolph Helfrich, Ph.D.
• Subject Area: Human Cognitive and Systems Neuroscience
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 438570551

Attention is a fundamental mechanism needed to select and boost behaviorally relevant information to efficiently translate sensory experiences into goal-directed actions. Traditionally, attention has been conceptualized as a continuous process: Once it is allocated, it remains constant until the next environmental stimulus is attended. However, it is unclear how the brain implements constancy when its activity exhibits prominent waxing and waning patterns, also termed neuronal oscillations. Recently, several lines of inquiry probing attention on a fine-grained temporal scale revealed frequency-specific behavioral fluctuations during both covert sampling and overt exploration that aligned with ongoing brain oscillations. This evidence suggests that attention-guided perception might be a rhythmic and not a purely continuous process, where different phases of oscillatory brain activity provide distinct windows-of-opportunity to either covertly sample or overtly explore the environment. However, the functional and structural basis of these processing cycles remains to be determined. Furthermore, it is unknown if neuronal oscillations mediate the reciprocal interplay of covert sensory sampling and overt motor behaviors. Likewise, it is also unclear if neuronal oscillations reflect a general mechanism for predictive processing informing subsequent perception and action. Here, I will address these outstanding questions in three projects by combining detailed behavioral testing with both correlative and causal methodologies. In addition to non-invasive magnetoencephalography in healthy participants, I will take advantage of direct brain recordings in epilepsy patients, who are implanted with intracranial electrodes for seizure onset localization. This approach provides electrophysiological data with the necessary spatiotemporal resolution to better understand the neurophysiology of attention-guided human perception and action. In order to establish causality, I will utilize both the neuropsychological lesion approach as well as direct brain stimulation. Project 1 seeks to identify the structural and functional basis of attentional rhythmic fluctuations. Project 2 aims to determine if sensory and motor rhythms are distinct processes or if one sampling rhythm periodically re-weights their contributions to behavior. Finally, Project 3 will assess if oscillations provide a general mechanism for predictive processing. Taken together, I strive to understand how rhythmic brain activity mediates the interplay of attention-guided visual perception and goal-directed actions. The outcome of this project will provide detailed information on how attention is implemented at the network level and elucidate its role in guiding flexible human behavior.

• DFG Programme: Independent Junior Research Groups