Differential modulation of hippocampal plasticity in a non-noxious conflict model for anxiety.
Modulation of synaptic strength may underlie stress-induced changes in cognitive ability. Long-term memory formation underpinning fear and anxiety behaviors, such as those seen in post-traumatic stress and phobic disorders, is thought to be dependent on amygdalo-hippocampal interactions. In most models, however, painful stimuli are used to induced stress and anxiety. Here, the effects of a novel conflict model, developed to generate a more naturalistic model of anxiety, utilizing two non-noxious stressors (predator (cat) odor and light), on hippocampus plasticity were determined. Exposure to the external stimuli elicited typical, stimulus-specific, anxiety-related behaviors. Dual presentation of the stressors evoked an increase in the variability of behaviors, suggesting that the animals were experiencing conflicting drives. Induction of long-term potentiation (LTP) within the CA1 region of the hippocampus was reduced following exposure to light stress, independent of presence, or absence, of odor. However, after a single presentation, LTP was reduced following either odor presentation or dual presentation of the stressors. Furthermore, LTP in ex vivo tissue obtained from conflict-exposed animals showed differential hemispheric responses, suggesting that long-term contextual-related components of anxiety behavior are dependent on modification of hippocampal circuitry.
Collins
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DR
Clinical Sciences Research Institute (UoW Campus), Warwick Medical School, University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK. dawn.collins@warwick.ac.uk
D000818:Animals; D001007:Anxiety / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D001522:Behavior, Animal; D002415:Cats; D003220:Conflict, Psychological; D004195:Disease Models, Animal; D006624:Hippocampus / Q000503:physiopathology*; D008027:Light; D017774:Long-Term Potentiation; D008297:Male; D009812:Odorants; D010775:Photic Stimulation; D011235:Predatory Behavior; D051381:Rats; D017207:Rats, Sprague-Dawley; D013315:Stress, Psychological / Q000209:etiology / Q000503:physiopathology / Q000523:psychology; D013569:Synapses / Q000502:physiology