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Rats were trained to locate food in a response, direction, or place problem on an open field located at 2 positions. In Experiment 1, both the response and direction groups solved the problem. The place group failed to solve the task in approximately 300 trials. Experiment 2 demonstrated that rats need distinguishable start points to solve a place problem(More)
In order to relate noradrenaline-dependent potentiation in the dentate gyrus to behavioural events, rats were made to explore an environment in which their encounters with novel stimuli could be strictly controlled and monitored. Previous experiments have shown that an encounter with novel objects in a holeboard elicits a burst response in a large(More)
In the present study we assess a new model for classical conditioning of odor preference learning in rat pups. In preference learning beta(1)-adrenoceptors activated by the locus coeruleus mediate the unconditioned stimulus, whereas olfactory nerve input mediates the conditioned stimulus, odor. Serotonin (5-HT) depletion prevents odor learning, with(More)
Estrogen has been reported to enhance CA1 functional plasticity in adult rats, as measured by the induction of long-term potentiation (LTP). In the present study, the effects of androgens on CA1 LTP were assessed in adult male Sprague-Dawley rats in vivo following peripubertal castration. Castrated rats with cholesterol implants showed significantly greater(More)
Short Abstract Arousal sometimes enhances and sometimes impairs perception and memory. In our Glutamate Amplifies Noradrenergic Effects (GANE) model, glutamate at active synapses interacts with norepinephrine released by the locus coeruleus to create local 'hot spots' of activity that enable the selective effects of arousal. This hot spot mechanism allows(More)
Research on cognitive aging has focused on how decline in various cortical and hippocampal regions influence cognition. However, brainstem regions play essential modulatory roles, and new evidence suggests that among these, the integrity of the locus coeruleus-norepinephrine system plays a key role in determining late life cognitive abilities. The locus(More)
BACKGROUND β-adrenoceptor activation in the hippocampus is sufficient to induce heterosynaptic long-term potentiation of perforant path input to the dentate gyrus. However, in vitro and in vivo studies suggest the plasticity effects of β-adrenoceptor activation may vary depending on the level of receptor activation. METHODS The present experiments use an(More)
It was hypothesized that 5-HT2 receptors in the olfactory bulb prime the bulbar response to a beta adrenoceptor mediated unconditioned stimulus (UCS) during odor preference learning in 1-week-old rat pups. The ability of 4 mg/kg of isoproterenol + stroking and 6 mg/kg of isoproterenol + no stroking to induce normal odor preference learning in pups depleted(More)
The effects of superfusion of norepinephrine (NE) on perforant path (PP) evoked potentials in the dentate gyrus were evaluated in the rat hippocampal slice preparation. Superfusion of NE (10 microM) produced a facilitation of the PP evoked responses. Facilitation of the synaptically-evoked responses was expressed in the field potential as an increase in(More)
Norepinephrine, acting through beta-adrenergic receptors, is implicated in mammalian memory. In in vitro and in vivo studies, norepinephrine produces potentiation of the perforant path-dentate gyrus evoked potential; however, the duration and dynamics of norepinephrine-induced potentiation have not been explored over extended time periods. To characterize(More)