Encoding of emotion-paired spatial stimuli in the rodent hippocampus
MetadataShow full item record
AbstractRats can acquire the cognitive component of CS-US associations between sensory and aversive stimuli without a functional basolateral amygdala (BLA). Thus, other brain regions should support such associations. Some septal/dorsal CA1 (dCA1) neurons respond to both spatial stimuli and footshock, suggesting that dCA1 could be one such region. We report that, in both dorsal and ventral hippocampus, different neuronal ensembles express immediate-early genes (IEGs) when a place is experienced alone vs. when it is associated with foot shock. We assessed changes in the size and overlap of hippocampal neuronal ensembles activated by two behavioral events using a cellular imaging method, Arc/Homer1a catFISH. The control group (A-A) experienced the same place twice, while the experimental group (A-CFC) received the same training plus two foot shocks during the second event. During fear conditioning, A-CFC, compared to A-A, rats had a smaller ensemble size in dCA3, dCA1, and vCA3, but not vCA1. Additionally, A-CFC rats had a lower overlap score in dCA1 and vCA3. Locomotion did not correlate with ensemble size. Importantly, foot shocks delivered in a training paradigm that prevents establishing shock-context associations, did not induce significant Arc expression, rejecting the possibility that the observed changes in ensemble size and composition simply reflect experiencing a foot shock. Combined with data that Arc is necessary for lasting synaptic plasticity and long-term memory, the data suggests that Arc/H1a+ hippocampal neuronal ensembles encode aspects of fear conditioning beyond space and time. Rats, like humans, may use the hippocampus to create integrated episodic-like memory during fear conditioning.
CitationFront Behav Neurosci. 2012 Jun 14; 6:27
- Altered hippocampal function before emotional trauma in rats susceptible to PTSD-like behaviors.
- Authors: Nalloor R, Bunting KM, Vazdarjanova A
- Issue date: 2014 Jul
- Acute systemic MK-801 induced functional uncoupling between hippocampal areas CA3 and CA1 with distant effect in the retrosplenial cortex.
- Authors: Buchtová H, Fajnerová I, Stuchlík A, Kubík Š
- Issue date: 2017 Feb
- Temporal dynamics of Arc gene induction in hippocampus: relationship to context memory formation.
- Authors: Pevzner A, Miyashita T, Schiffman AJ, Guzowski JF
- Issue date: 2012 Mar
- Functional interaction of ventral hippocampal CA1 region and prelimbic cortex contributes to the encoding of contextual fear association of stimuli separated in time.
- Authors: Santos TB, Wallau AE, Kramer-Soares JC, Oliveira MGM
- Issue date: 2020 May
- Differential expression of the immediate early genes c-Fos, Arc, Egr-1, and Npas4 during long-term memory formation in the context preexposure facilitation effect (CPFE).
- Authors: Heroux NA, Osborne BF, Miller LA, Kawan M, Buban KN, Rosen JB, Stanton ME
- Issue date: 2018 Jan