(a) CIE transiently retarded extinction acquisition (higher fear on trial-block 2) and significantly impaired extinction retrieval, relative to air controls (air n=10, CIE n=12). (b) CIE did not affect anxiety-like behavior in the light-dark exploration test (transitions: air=19.8±10.1, CIE=13.8±2.2, p>.05), or produce tolerance to the effects of acute alcohol challenge, as measured by rotarod ataxia (=pre versus post acute alcohol) (Fig. S2: rotarod training) and the loss of righting reflex (air n=10, CIE n=12). b=baseline, Con=conditioning, RT=retrieval, RN=renewal. Data are Means ±SEM. *P<.05 CIE versus air

(a) Coronal cartoon of PL. Examples of reconstructed neurons. (b) CIE increased overall length of PL apical dendrites at non-terminal branches (air n=7, CIE n=9, n=6-8 neurons/mouse for b,c). (c) Sholl analysis revealed that PL apical dendritic length was lesser close to the soma and greater farther from the soma after CIE. (d) Coronal cartoon of IL. Examples of reconstructed neurons (scale bar=50 μm). (e) CIE did not alter overall IL apical length (air n=14, CIE n=12, n=6-8 neurons/mouse for e,f). (f) Sholl analysis found no alcohol-induced change in IL dendritic length as a function of distance from the soma. Data are Means ±SEM. *P<.05 CIE versus air

(a) In vivo freely moving recordings of IL neurons demonstrated CIE decreased neuronal activity during the first 100 milliseconds (redrawn in insets) of CS onset during late extinction (trial-block 10) and extinction retrieval (air n=7, CIE n=7, n=69-85 neurons, for a-c). (b) Coronal cartoon showing electrode placements in IL. Example extracellular waveforms and principal components separation of simultaneously recorded neurons. (c) CIE decreased CS-related IL neuronal bursting during extinction retrieval. (d) CIE decreased stimulation-evoked synaptic NMDAR-mediated currents in IL neurons, with example traces (air n=7, CIE n=8). (e) Coronal cartoon showing cannula placements in IL. (f) NMDAR antagonist AP5 infused into IL immediately after extinction training impaired extinction retrieval in alcohol-naive mice (air n=8, CIE n=7). Data are Means ±SEM. *P<.05 CIE versus air