The role of the anterior nuclei of the thalamus in human memory processing

Abstract:

Extensive neuroanatomical connectivity between the anterior thalamic nuclei (ATN) and hippocampus and neocortex renders them well-placed for a role in memory processing, and animal, lesion, and neuroimaging studies support such a notion. The deep location and small size of the ATN have precluded their real-time electrophysiological investigation during human memory processing. However, ATN electrophysiological recordings from patients receiving electrodes implanted for deep brain stimulation for pharmacoresistant focal epilepsy have enabled high temporal resolution study of ATN activity. Theta frequency synchronization of ATN and neocortical oscillations during successful memory encoding, enhanced phase alignment, and coupling between ATN local gamma frequency activity and frontal neocortical and ATN theta oscillations provide evidence of an active role for the ATN in memory encoding, potentially integrating information from widespread neocortical sources. Greater coupling of a broader gamma frequency range with theta oscillations at rest than during memory encoding provides additional support for the hypothesis that the ATN play a role in selecting local, task-relevant high frequency activity associated with particular features of a memory trace.

Authors:

• Catherine M Sweeney-Reed

• Lars Buentjen

• Jürgen Voges

• Friedhelm C Schmitt

• Tino Zaehle

• Julia WY Kam

• Jörn Kaufmann

• Hans-Jochen Heinze

• Hermann Hinrichs

• Robert T Knight

• Michael D Rugg

Date: 2021

DOI: https://doi.org/10.1016/j.neubiorev.2021.02.046

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Phase-amplitude cross-frequency coupling in the human nucleus acumbens tracks action monitoring during cognitive control

Authors:

• S. Durschmid

• Tino Zaehle

• Klaus Kopitzki

• Jürgen Voges

• Friedhelm Schmitt

• Hans-Jochen Heinze

• Robert T. Knight

• Hermann Hinrichs

Date: 2013

DOI: 10.3389/fnhum.2013.00635

PubMed: 24586885

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Abstract:

The Nucleus Accumbens (NAcc) is an important structure for the transfer of information between cortical and subcortical structures, especially the prefrontal cortex and the hippocampus. However, the mechanism that allows the NAcc to achieve this integration is not well understood. Phase-amplitude cross-frequency coupling (PAC) of oscillations in different frequency bands has been proposed as an effective mechanism to form functional networks to optimize transfer and integration of information. Here we assess PAC between theta and high gamma oscillations as a potential mechanism that facilitates motor adaptation. To address this issue we recorded intracranial field potentials directly from the bilateral human NAcc in three patients while they performed a motor learning task that varied in the level of cognitive control needed to perform the task. As in rodents, PAC was observable in the human NAcc, transiently occurring contralateral to a movement following the motor response. Importantly, PAC correlated with the level of cognitive control needed to monitor the action performed. This functional relation indicates that the NAcc is engaged in action monitoring and supports the evaluation of motor programs during adaptive behavior by means of PAC.