Thalamo-hippocampal pathway determines aggression and self-harm.

Aggression and self-harm are maladaptive coping strategies that often occur in individuals with a history of early life trauma (ELT), yet their underlying neural mechanisms remain unclear. Here, we identify L-type calcium channel (LTCC)-expressing thalamic nucleus reuniens (RE) as a critical component regulating both behaviors. ELT-induced excessive LTCC activity in vesicular glutamate transporter 2 (vGlut2) RE neurons and its corresponding effects on persistent neuronal activation contribute to increasing susceptibility to aggression and self-harm. Activation of vGlut2 RE neurons projecting to ventral hippocampus (vCA1), but not medial prefrontal cortex, promotes these behaviors in control mice. Furthermore, we found that RE neurons modulate two distinct subsets of vCA1 neurons, with one projecting to the hypothalamus to drive aggression and another to the basal amygdala to mediate self-harm. Our findings uncover how LTCC functions in the RE-to-vCA1 neural pathway increase the risk of aggression and self-harm, highlighting potential therapeutic targets for mitigating destructive behaviors following early adversity.