Chronic stress is among the most common environmental factors leading to the development of neuropsychiatric disorders.The psychopathologies by chronic stress are closely associated with the enduring hypertrophy of basolateral amygdala(BLA)neurons.Research in recent years has revealed that although widely intermingled,the BLA neurons are highly heterogeneous in terms of their afferent/efferent targets and their engagements in amygdala-related tasks.How chronic stress alters the structure of these different subsets of basoamygdala(BA)neurons remains largely elusive.Here,by using combined approach of retrograde tracing and biocytin staining,we explored the influence of chronic immobilization stress on the morphology of BA neurons projecting or not projecting to medial prefrontal cortex(mPFC).While both neuron groups showed considerable dendritic hypertrophy following CIS,clear differences emerged in the specific location where dendritic hypertrophy occurred.In non-mPFC-projecting BA neurons,the hypertrophy was observed in both the distal and proximal dendrites.By contrast,it was only seen in the proximal but not distal dendrites of mPFC-projecting BA ones.CIS also caused distinct changes in the spines of these two neuronal groups.Although having little influence on the overall spine density of both neuron groups,it greatly increased the density of mature mushroom spines and decreased that of immature thin spines in non-mPFC projecting BA neurons,but leaving both unaltered in mPFC projecting neurons.The neuron-specific remodeling by chronic stress may suggest that BA neurons are differently recruited to mediate the adversity of chronic stress on emotion.