Fig. 2

Adolescent THC exposure altered the dendritic arborization, spine density, and developmental trajectory of layer III prelimbic (PrL) pyramidal neurons. a Adolescent THC significantly increased distal apical dendritic arborization in early adolescence (24 h after drug treatment). b In early adulthood (2 weeks after drug treatment), a significant allostatic reversal resulting in atrophy was observed in distal apical trees accompanied by the emergence of significantly increased proximal branching. c Between time points, vehicle-treated animals (VEH) exhibited no difference in apical arbor complexity while THC-treated animals (THC) exhibited a significant decrease in distal apical branching complexity. d Adolescent THC exposure significantly increased basal dendritic arborization 24 h after drug treatment. e Two weeks after drug treatment, a non-significant allostatic reversal was observed in basal trees. f Vehicle-treated animals exhibited significantly increased basal arbor complexity between time points, whereas THC-treated animals exhibited significantly decreased basal apical branching complexity. g Representative dendrograms of traced PrL pyramidal neurons. h No significant differences were observed in total apical dendritic spine density. i Vehicle-treated subjects exhibited significant pruning of stubby apical dendritic spines between time points, whereas THC-treated subjects exhibited premature pruning. j No significant differences in apical mushroom spine density were observed. k No significant differences in apical thin spine density were observed. l Vehicle-treated subjects exhibited significant pruning of total basal dendritic spines between time points, whereas THC-treated subjects exhibited premature pruning. m Vehicle-treated subjects exhibited significant pruning of stubby basal dendritic spines between time points, whereas THC-treated subjects exhibited premature pruning. n No significant differences in basal mushroom spine density were observed. o No significant differences in basal thin spine density were observed. p Representative deconvolved basal dendritic branches from all treatment conditions. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001. Data shown as mean + SEM a–b, d–e, h–o. Data represent the difference between 2 weeks and 24 h, shown as mean + standard error of the difference between treatments c, f. Scale bar = 2 μm p