Electrophysiological properties of the medial mammillary bodies across the sleep-wake cycle

Dillingham, Christopher M., Wilson, Jonathan J. and Vann, Seralynne ORCID: https://orcid.org/0000-0002-6709-8773 2024. Electrophysiological properties of the medial mammillary bodies across the sleep-wake cycle. eNeuro 11 (4) , 0447-23. 10.1523/ENEURO.0447-23.2024

Preview

PDF - Published Version Available under License Creative Commons Attribution. Download (3MB) | Preview

Abstract

The medial mammillary bodies (MB) play an important role in the formation of spatial memories; their dense inputs from hippocampal and brainstem regions makes them well-placed to integrate movement-related and spatial information, that is then extended to the anterior thalamic nuclei and beyond to cortex. While the anatomical connectivity of the medial MBs has been well-studied, much less is known about their physiological properties, particularly in freely-moving animals. We therefore carried out a comprehensive characterization of medial MB electrophysiology across arousal states by concurrently recording from the medial MB and the CA1 field of the hippocampus in male rats. In agreement with previous studies, we found medial MB neurons to have firing rates modulated by running speed and angular head velocity, as well as theta-entrained firing. We extended the characterization of MB neuron electrophysiology in three key ways: 1) we identified a subset of neurons (25%) that exhibit dominant bursting activity; 2) we showed that ∼30% of theta-entrained neurons exhibit robust theta cycle skipping, a firing characteristic that implicates them in a network for prospective coding of position; 3) a considerable proportion of medial MB units showed sharp wave-ripple (SWR) responsive firing (∼37%). The functional heterogeneity of MB electrophysiology reinforces their role as an integrative node for mnemonic processing and identifies potential roles for the MBs in memory consolidation through propagation of SWR-responsive activity to the anterior thalamus and prospective coding in the form of theta-cycle skipping.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Psychology
Publisher:	Society for Neuroscience
ISSN:	2373-2822
Funders:	Wellcome Trust
Date of First Compliant Deposit:	4 April 2024
Date of Acceptance:	25 March 2024
Last Modified:	01 Jul 2024 10:41
URI:	https://orca.cardiff.ac.uk/id/eprint/167714

Actions (repository staff only)

Edit Item