Hippocampal electrical stimulation disrupts associative learning when targeted at dentate spikes
Nokia, M., Gureviciene, I., Waselius, T., Tanila, H., & Penttonen, M. (2017). Hippocampal electrical stimulation disrupts associative learning when targeted at dentate spikes. Journal of Physiology, 595(14), 4961-4971. https://doi.org/10.1113/JP274023
Published inJournal of Physiology
DisciplinePsykologiaMonitieteinen aivotutkimuskeskusPsychologyCentre for Interdisciplinary Brain Research
© 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society. This is a final draft version of an article whose final and definitive form has been published by Blackwell. Published in this repository with the kind permission of the publisher.
Hippocampal electrophysiological oscillations, namely theta and ripples, have been implicated in encoding and consolidation of new memories, respectively. According to existing literature, hippocampal dentate spikes are prominent, short‐duration (<30 ms), large‐amplitude (∼2–4 mV) fluctuations in hilar local‐field potentials that take place during awake immobility and sleep. Interestingly, previous studies indicate that during dentate spikes dentate gyrus granule cells increase their firing while firing of CA1 pyramidal cells are suppressed, thus resulting in momentary uncoupling of the two hippocampal subregions. To date, the behavioural significance of dentate spikes is unknown. Here, to study the possible role of dentate spikes in learning, we trained adult male Sprague–Dawley rats in trace eyeblink classical conditioning. For 1 h immediately following each conditioning session, one group of animals received hippocampal stimulation via the ventral hippocampal commissure (vHC) contingent on dentate spikes to disrupt the uncoupling between the dentate gyrus and the CA1 subregions. A yoked control group was stimulated during immobility, irrespective of brain state, and another control group was not stimulated at all. As a result, learning was impaired only in the group where vHC stimulation was administered contingent on dentate spikes. Our results suggest dentate spikes and/or the associated uncoupling of the dentate gyrus and the CA1 play a significant role in memory consolidation. Dentate spikes could possibly reflect reactivation and refinement of a memory trace within the dentate gyrus triggered by input from the entorhinal cortex. ...
ISSN Search the Publication Forum0022-3751
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Related funder(s)Academy of Finland
Funding program(s)Academy Project, AoF; Academy Research Fellow, AoF; Research costs of Academy Research Fellow, AoF
Additional information about fundingThis study was supported by the Academy of Finland (grant no. 139767 to M.P. and grant nos. 275954, 284155 and 286384 to M.S.N.).
Showing items with similar title or keywords.
Dentate spikes and learning : Disrupting hippocampal function during memory consolidation can improve pattern separation Lensu, Sanna; Waselius, Tomi; Penttonen, Markku; Nokia, Miriam (American Physiological Society, 2019)Hippocampal dentate spikes (DSs) are short-duration, large-amplitude fluctuations in hilar local field potentials and take place while resting and sleeping. During DSs, dentate gyrus granule cells increase firing while CA1 ...
Hippocampal responses to electrical stimulation of the major input pathways are modulated by dentate spikes Lehtonen, Suvi‐Maaria; Waselius, Tomi; Penttonen, Markku; Nokia, Miriam S. (John Wiley & Sons, 2022)Dentate gyrus (DG) is important for pattern separation and spatial memory, and it is thought to gate information flow to the downstream hippocampal subregions. Dentate spikes (DSs) are high-amplitude, fast, positive ...
Effects of post-training hippocampal dentate spike - contingent stimulation on learning after trace fear conditioning in rats Kullberg, Nina; Tiri, Sonja (2015)Tutkimuksemme tarkoituksena oli selvittää, miten hippokampuksen dentate poimun (dentate gyrus) alueella ilmentyvien dentate-piikkien stimulointi vaikuttaa oppimiseen rotilla. Aiemmin on tutkittu dentate-piikkien vaikutuksia ...
Disrupting neural activity related to awake-state sharp wave-ripple complexes prevents hippocampal learning Nokia, Miriam; Mikkonen, Jarno; Penttonen, Markku; Wikgren, Jan (Frontiers Media, 2012)Oscillations in hippocampal local-field potentials (LFPs) reflect the crucial involvement of the hippocampus in memory trace formation: theta (4–8 Hz) oscillations and ripples (~200 Hz) occurring during sharp waves are ...
Hippocampal theta activity is selectively associated with contingency detection but not discrimination in rabbit discrimination-reversal eyeblink conditioning Nokia, Miriam; Wikgren, Jan (Wiley, 2010)The relative power of the hippocampal theta-band (∼6 Hz) activity (theta ratio) is thought to reflect a distinct neural state and has been shown to affect learning rate in classical eyeblink conditioning in rabbits. We ...