Activating positive memory engrams suppresses depression-like behaviour.

Stress is considered a potent environmental risk factor for many behavioural abnormalities, including anxiety and mood disorders. Animal models can exhibit limited but quantifiable behavioural impairments resulting from chronic stress, including deficits in motivation, abnormal responses to behavioural challenges, and anhedonia. The hippocampus is thought to negatively regulate the stress response and to mediate various cognitive and mnemonic aspects of stress-induced impairments, although the neuronal underpinnings sufficient to support behavioural improvements are largely unknown.

Assessing contributions of nucleus accumbens shell subregions to reward-seeking behavior.

Background: The nucleus accumbens (NAc) plays a key role in brain reward processes including drug seeking and reinstatement. Several anatomical, behavioral, and neurochemical studies discriminate between the limbic-associated shell and the motor-associated core regions. Less studied is the fact that the shell can be further subdivided into a dorsomedial shell (NAcDMS) and an intermediate zone (NAcINT) based on differential expression of transient c-Fos and long-acting immediate-early gene ΔFosB upon cocaine sensitization.

Predator odor-evoked BOLD activation in the awake rat: modulation by oxytocin and V₁a vasopressin receptor antagonists.

Modulators of unconditioned fear are potential targets for developing treatments for anxiety disorders. We used blood oxygen level dependent (BOLD) MRI to investigate the pattern of brain activity during the presentation of a predator odor (cat fur) and a repulsive novel odor, butyric acid (BA), to awake rats. We further tested whether odor-evoked BOLD activation involved oxytocin (OT) and vasopressin V(1a) receptors.