Aging is associated with changes in the neural circuits underlying empathy.

Although the neurodevelopment of empathy from childhood to adolescence has been documented, no study has yet examined it across a life span aging perspective. Sixty-five healthy participants from 3 age groups (young, middle-aged, old) underwent functional magnetic resonance imaging while presented with visual stimuli depicting body parts being injured, either accidentally by oneself or intentionally by another, thus isolating pain and agency as 2 variables of interest. Older adults reported less dispositional emotional empathy as assessed by the interpersonal reactivity index, and their unpleasantness ratings were more sensitive to intentional harm.

Behavioural phenotyping of dopamine transporter knockdown mice using local small interference RNA.

The objective of this study was to evaluate basic behavioural phenotypes and methamphetamine-induced hyperactivity in dopamine transporter (DAT) knockdown and control mice after local injections of small interference RNA into ventral tegmental area/substantia nigra once every other day for 14 days. Local knockdown of DAT expression in the mouse brain did not affect basic behavioural functions, but these mice displayed elevated depression-like immobility and a approximately 35% reduction of methamphetamine-induced hyperactivity.

Dopamine receptor antagonists impair place conditioning after acute stress in rats.

An immediate and robust release of dopamine appears in the brain under an acute stressor, but the functional role of dopamine under stress remains elusive. We recently showed conditioned place preference (CPP) induced by the acute application of a stressor such as being placed on an elevated stand or immobilized in a restraint holder. This study tested whether dopamine is involved in such CPP.