Early-life pain may leave a lasting mark on social behavior by tipping the balance between excitation and inhibition in the brain. In mice, restoring that balance, including with deep brain stimulation, reversed the resulting social deficits.

Animal studies have described “low road” pathways that rush sensory information from the thalamus to the amygdala. A brain imaging study of 113 people now maps several such routes in humans, with some far more consistent than others.

Petting a dog after a stressful task didn’t speed recovery, but in a new experiment it was followed by calmer brain and heart responses when dog owners faced a second stress test soon after.

Children with ADHD process unexpected sounds differently than their peers, but these brain responses change as they grow. New research shows heightened sensitivity to sudden noises in early childhood gives way to blunted responses in middle childhood.

Cannabis is often a group activity in college, but the pattern looks different among heavier users. Students who used more often shared less in a hypothetical sharing task and were less likely to use mostly with others.