How the human thalamus guides navigation and memory: a common coding framework built on direct thalamic recordings

Project Information

DirectThalamus

Grant agreement ID: 802681

DOI

10.3030/802681

Project closed

EC signature date 29 January 2019

Start date 1 July 2019

End date 31 January 2025

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 499 914,00

EU contribution

€ 1 499 914,00

Coordinated by

LUDWIG-MAXIMILIANS-UNIVERSITAET MUENCHEN
Germany

Periodic Reporting for period 4 - DirectThalamus (How the human thalamus guides navigation and memory: a common coding framework built on direct thalamic recordings)

Reporting period: 2024-01-01 to 2025-01-31

Summary of the context and overall objectives of the project

Our project examines how a specific area deep within the brain, the thalamus, contributes to memory and navigation processes in humans. The thalamus has long been thought of as a simple relay station without much impact on cognitive processes beyond transmitting signals to neocortical areas of the brain. Recent findings challenge this view and suggest that the thalamus is crucially involved in higher cognitive functions. Obtaining neural signals from the thalamus in humans with high spatial and temporal accuracy is challenging, due to its location and structure. We overcome these challenges by recording neural activity directly from the thalamus in a rare population of epilepsy patients. To treat their epilepsy, electrodes are implanted directly into the thalamus (deep brain stimulation therapy). With the electrophysiological data obtained from these electrodes, we are aiming to answer the following research questions: How does the human thalamus code and communicate information? And how does this contribute to spatial navigation and the formation and consolidation of memories?
Answering these questions is important because it will push the boundaries of the state of the art in cognitive neuroscience towards a comprehensive understanding of human cognition and will inspire new lines of research in fundamental and clinical neuroscience.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We have developed and set up multiple experimental paradigms and successfully conducted intracranial recordings in patients, as well as stimulation of the thalamus in patients. We implemented analyses pipelines to investigate the multimodal data (intracranial & scalp EEG, eye and motion tracking, behavioral data, etc.). The obtained results were summarized in manuscripts and communicated in scientific presentations as well through media coverage. We published several papers that provide important insight into the neural underpinnings of thalamic and thalamocortical processing.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Several major breakthroughs have been made:

We identify a robust electrophysiological signature that predicts changes in veridical head orientation, similar but not identical to what has been shown in animal models.

We show that rhythmic neural activity in the human thalamus predicts perceptual performance. These results suggest that it is interactions between the neocortex and the thalamus, rather than neocortical activity alone, that is important for human perception.

We discover a novel brain-state-specific oscillation in the human thalamus. This discovery might have implications for deep brain stimulation therapy.

We show that slow oscillations in the human anterior thalamus precede slow oscillations in the neocortex. Our results thus challenge the traditional view of how cardinal brain oscillations are coordinated during sleep, highlighting the importance of thalamic contributions. This is important, since sleep oscillations are thought to be essential for the offline strengthening of memories.

We show a key role of spindle-locked ripples in human sleep-based memory reactivation. This is an important step twoards understanding the neural mechanisms underlying memory consolidation during sleep.

Together, our findings broadly challenge current views on the neural basis of human cognition that are centered on neocortical processes without accounting for thalamic contributions and ultimately ask for a more comprehensive, thalamocortical model of cognition. A

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