Optogenetic Stimulation of the Anterior Thalamic Nuclei Ameliorates Impaired Spatial Memory in Rats With Mammillothalamic Tract Lesions

Barnett, S.C. , Young, C.K., Perry, B.A.L., McNaughton, N., Hughes, S.M., Parr-Brownlie, L.C. and Dalrymple-Alford, J.C. (2019) Optogenetic Stimulation of the Anterior Thalamic Nuclei Ameliorates Impaired Spatial Memory in Rats With Mammillothalamic Tract Lesions. 37th International Australasian Winter Conference on Brain Research, Queenstown, New Zealand, 31 Aug - 04 Sep 2019.

Full text not currently available from Enlighten.

Publisher's URL: https://www.otago.ac.nz/awcbr/proceedings/

Abstract

The mammillothalamic tract (MTT) provides a unidirecƟ onal pathway from the mammillary bodies to the anterior thalamic nuclei (ATN). MTT lesions produce severe spaƟ al memory impairments and negaƟ vely impact other memory-related structures that receive ATN eff erents. We tested if optogeneƟ c theta sƟ mulaƟ on of the ATN would ameliorate the memory defi cits produced by MTT lesions. Without sƟ mulaƟ on, rats with MTT lesions showed impaired performance in a radial-arm maze task (RAM). When making correct arm choices, sham rats (N=9) exhibited peak theta (4-12 Hz) power at 8.5 Hz in the ATN; MTT-lesioned rats (N=11) exhibited peak theta above 9 Hz. SpaƟ al memory was improved in MTT-lesioned rats given a regular paƩ ern of theta-burst sƟ mulaƟ on (TBS) at 8.5 Hz using blue light (465 nm) in the opsin-transduced ATN (LV-CaMKIIa-ChR2 (H134R)-mCherry) during RAM performance, whereas control sƟ mulaƟ on (orange, 620 nm) had no eff ect (blue vs orange: Cohen’s d = 1.71 (95%CI, 0.75,2.64) and 2.0 (95%CI, 0.94,3.03) for two separate replicaƟ ons). No light sƟ mulaƟ on eff ects were found in sham rats given the opsin construct or in two MTT-lesioned rats given LV-CaMKIIa-mCherry (i.e. no opsin construct). Blue light using an irregular paƩ ern of closed-loop 8.5 Hz TBS, but derived from the rat’s own hippocampal theta rhythm, had no eff ect. Viral vector histology awaits compleƟ on, but memory funcƟ on appears to be improved by regular optogeneƟ c TBS of the ATN aŌ er MTT injury.

Item Type:Conference or Workshop Item
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Barnett, Dr Sophie
Authors: Barnett, S.C., Young, C.K., Perry, B.A.L., McNaughton, N., Hughes, S.M., Parr-Brownlie, L.C., and Dalrymple-Alford, J.C.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
ISSN:1176-3183

University Staff: Request a correction | Enlighten Editors: Update this record