Specific Glutamatergic Projection to Claustrum for Regulating Methamphetamine Abstinence Anxiety-Like Behaviors

Methamphetamine (METH) abstinence anxiety is a common METH abstinence symptom, which drives METH relapse. Our previous study found that claustrum (CL) is involved in coding abstinence anxiety-like behaviors caused by adolescent cocaine experiences. Here, we aim to investigate the role of CL in the development of METH abstinence-induced anxiety, especially exploring the related glutamatergic projections to CL. We found that 14 d of METH abstinence heightened anxiety-like behaviors in male mice, accompanied by hyperactivation of glutamatergic neurons (GNs) in the CL, as well as in several brain regions that project glutamatergic fibers to the CL, including the medial prefrontal cortex (mPFC) and the basolateral amygdala (BLA). Suppressing GNs within CL during the abstinence period, rather than solely before behavioral tests, alleviated anxiety-like behaviors in METH-abstinent mice. With virus-based pathway tracing tools, we found that the neurons in CL receiving glutamatergic inputs from mPFC and those from BLA were rarely crossed over, forming two relatively distinct subpopulations of GNs in CL. Most importantly, inhibiting the glutamatergic projections to CL from mPFC, but not that from BLA, efficiently reduced anxiety-like behaviors in METH-abstinent mice. These findings provide new insight into the specific population of CL neurons in the development of METH abstinence anxiety and suggest that mPFC-CL glutamatergic pathway might be a promising pharmacological target for the treatment of METH abstinence anxiety.