alcoholism is frequently co - morbid with posttraumatic stress disorder ( ptsd ) but it is unclear how alcohol impacts neural circuits mediating recovery from trauma . 
 we found that chronic intermittent ethanol ( cie ) impaired fear extinction and remodeled the dendritic arbor of medial prefrontal cortical ( mpfc ) neurons in mice . 
 cie impaired extinction encoding by infralimbic ( il ) mpfc neurons in vivo , and functionally downregulated burst - mediating nmda glun1 receptors . 
 these findings suggest alcohol may increase risk for trauma - related anxiety disorders by disrupting mpfc - mediated extinction of fear .