Acute psychosocial stress reduces cell survival in adult hippocampal neurogenesis without altering proliferation.

Factors modulating neurogenesis may contribute to the pathophysiology of affective disorders such as major depression. Environmental stressors in animal models have been proposed to alter neurogenesis, suggesting a mechanism for this contribution. The effect of an acute psychosocial stressor on either proliferation or survival (immediate, short term, and long term) was examined along with subsequent neuronal differentiation in the hippocampus of adult male Sprague Dawley rats.

Extracellular glutamate levels in prefrontal cortex during the expression of associative responses to cocaine related stimuli.

We conducted studies to examine the potential role of glutamate in the prefrontal cortex (PFC) during conditioned responses to stimuli (flashing light and metronome) previously associated with cocaine administration. During training, PAIRED subjects received cocaine injections (15 mg/kg) during stimuli sessions while UNPAIRED subjects received saline injections (but received cocaine in the home cage an hour later). We showed previously that PAIRED subjects exhibit conditioned locomotion when tested with the stimuli alone.

Conditioned locomotion is not correlated with behavioral sensitization to cocaine: an intra-laboratory multi-sample analysis.

Pre-clinical and clinical studies have demonstrated the importance of associative factors in regulating craving for drugs of abuse. To model these conditioned effects, we have examine cue-induced conditioned locomotion in rodents. The present study involved analysis of several of our prior studies to evaluate the relationship between conditioned locomotion and behavioral sensitization using a within-subjects analysis.

Dissociation of conditioned locomotion and Fos induction in response to stimuli formerly paired with cocaine.

A discrete stimulus (flashing light) was paired with cocaine (20 mg/kg) to induce conditioned locomotion. To identify brain regions activated during this response, Fos was measured with immunohistochemistry. Although paired subjects displayed robust conditioned locomotion, Fos was not increased in any limbic brain regions analyzed.