Naturally occurring variations in defensive burying behavior are associated with differences in vasopressin, oxytocin, and androgen receptors in the male rat.

Largely ignored in tests of defensive burying is the capacity for individual animals to display marked variations in active coping behaviors. To expose the neurobiological correlates of this behavioral differentiation rats were exposed to a mousetrap that was remotely triggered upon approach to remove the quality of pain. Relative to animals showing no significant levels of defensive burying activity, rats showing sustained elevations in defensive burying displayed higher levels of arginine vasopressin (AVP) mRNA and increased numbers of androgen receptor positive cells in the medial amygdala and posterior bed nuclei of the stria terminalis, brain regions that integrate emotional appraisal and sensory information.

Effects of expectation on amygdala-kindled convulsions and interictal behaviour in rats: confirmation of a Pavlovian mechanism.

We found evidence that the effects of exposure to the stimulation environment on the convulsions and interictal behaviour of basolateral amygdala (BA)-kindled rats are the result of Pavlovian conditioning. In Experiment 1, the rats first received 45 BA stimuli in one environment (CS+) and 45 sham stimuli in another environment (CS-). During this first phase of the experiment, the CS+ and CS- began to exert differential effects on interictal behaviour and convulsions.

Antidepressant effects of exercise: evidence for an adult-neurogenesis hypothesis?

It has been hypothesized that a decrease in the synthesis of new neurons in the adult hippocampus might be linked to major depressive disorder (MDD). This hypothesis arose after it was discovered that antidepressant medications increased the synthesis of new neurons in the brain, and it was noted that the therapeutic effects of antidepressants occurred over a time span that approximates the time taken for the new neurons to become functional. Like antidepressants, exercise also increases the synthesis of new neurons in the adult brain: a 2-3-fold increase in hippocampal neurogenesis has been observed in rats with regular access to a running wheel when they are compared with control animals.

Conditioned effects of kindling three different sites in the hippocampal complex of the rat.

Rats received kindling stimulations to the perirhinal cortex (PRh), ventral hippocampus (VH), or dorsal hippocampus (DH) in 1 environment and an equivalent number of sham stimulations in a 2nd environment. The PRh-kindled rats displayed rapid kindling and a swift emergence of conditioned interictal defensiveness. In contrast, the VH- and DH-kindled rats displayed much slower kindling and slow or no conditioning, respectively.

Serotonin receptor binding and mRNA expression in the hippocampus of fearful amygdala-kindled rats.

Amygdala kindling in rats increases fear behavior. The neural correlates of this fear are not well understood. In this experiment, we investigated the relation between serotonin receptor binding and mRNA expression and fearful behavior in amygdala-kindled rats.

Long-term kindling of the basolateral amygdala impairs copulatory behavior in male rats.

This experiment examined the consequences of long-term kindling of the basolateral amygdala on male sexual behavior and the frequency of both spontaneous wet dog shakes (WDS) and those induced by the 5-HT2A receptor agonist DOI. Results demonstrated that following 60 stimulations of the left basolateral amygdala over a 4-week period, male Long-Evans rats exhibited decrements in every aspect of sexual behavior. Specifically, latencies to mount, intromit and ejaculate were all prolonged following long-term kindling, and ejaculation frequencies were significantly reduced.

Anticipating the attack: temporal conditioning during amygdala kindling in rats.

The present study showed that amygdala-kindled rats use short-interval timing superimposed on phase or ordinal timing to predict when a convulsion will occur. In 2 experiments, rats received 1 stimulation and 1 sham stimulation each day, always at the same times (conditioned stimulus [CS]+ and CS- times, respectively) and 150 s after rats had been placed in the testing chamber (the preadministration interval). As kindling progressed, the rats displayed more defensive behavior at the CS+ time than at the CS- time.

Stimulation site determines the conditioned effects of kindling in rats: anterior neocortex versus amygdala.

Rats received 53 stimulations to either the left basolateral amygdala (BA) or left anterior neocortex (AN) in one environment (CS+) and 53 sham stimulations (the stimulation lead was attached but no current was delivered) in another environment (CS-), quasirandomly over 54 days. Confirming a previous report [Barnes, S.J.

Conditioning of a flavor aversion in rats by amygdala kindling.

Rats received 30 stimulations and 30 sham stimulations (the lead was attached to the subjects but no current was delivered) to the left basolateral amygdala in a quasirandom sequence. Stimulations were preceded by the presentation of 1 flavored solution conditional stimulus (CS+); sham stimulations were preceded by the presentation of another flavored solution, CS-. As kindled motor seizures developed, the rats began to consume significantly less of the CS+ than the CS-.