Frequency matters: how changes in hippocampal theta frequency can influence temporal coding, anxiety-reduction, and memory

• DOI: 10.3389/fnsys.2022.998116
• Publication Date: 2023-02-03T13:55:08Z
• Authors: Miranda Hines; Steven Poulter; Vincent Douchamps; Francesca Pibiri; Anthony McGregor; Colin Lever
• Keywords: memory; theta frequency; theta slope and y-intercept; 0303 health sciences; 03 medical and health sciences; temporal coding; hippocampus; 600; Neurosciences. Biological psychiatry. Neuropsychiatry; anxiety; RC321-571; Neuroscience

Hippocampal theta frequency is a somewhat neglected topic relative to power, phase, coherence, and cross-frequency coupling. Accordingly, here we review present new data on variation in hippocampal frequency, focusing functional associations (temporal coding, anxiety reduction, learning, memory). Taking the rodent running-speed relationship as model, identify two doubly-dissociable components: (a) slope component of frequency-to-stimulus-rate ("theta slope"); (b) its y-intercept intercept"). We three tonic determinants frequency. (1) Hotter temperatures increase potentially consistent with time intervals being judged shorter when hot. Initial evidence suggests this occurs via "theta slope" component. (2) Anxiolytic drugs widely-different post-synaptic pre-synaptic primary targets share effect reducing intercept" component, supporting notions final common pathway reduction involving hippocampus. (3) Novelty reliably decreases, familiarity increases, acting upon The reliability latter finding, special status novelty for prompts us propose Elicits Slowing Theta (NEST) hypothesis, following elements: slowing formation generalised response different types modalities; Novelty-elicited hippocampal-formation-wide adaptive functioning accommodate additional need learning entailed by novelty; Lengthening cycle enhances associativity; (4) Even part-cycle lengthening may boost (5) Artificial stimulation aimed at enhancing should employ low-end frequencies.