One-way avoidance learning in female inbred Roman high- and low-avoidance rats: effects of bilateral electrolytic central amygdala lesions.
Female inbred Roman high- (RHA-I) and low- (RLA-I) avoidance rats show differences in one-way avoidance learning only when the task implies a highly aversive situation (1s in the "non-shock"-associated safe compartment, as opposed to 30s). These between-strain differences seem to depend on strain differences in emotionality, given that: (i) they are abolished by IP administration of the GABAergic anxiolytic diazepam (Torres et al. [32]) and (ii) avoidance responding appears to correlate with cellular density in the basolateral amygdala (Gómez et al. [9]). In the present study we further analyzed whether the implication of the amygdala in one-way avoidance depends on the experimental situation aversiveness (30s vs. 1s in safety). After bilateral electrolytic lesions (1mA; 20s) of the central amygdala (CeA), RHA-I and RLA-I rats were exposed to a danger compartment (where they received a warning signal - 88dB tone - followed by a 1mA electric foot-shock), and a safe compartment, where these stimuli were not presented. The number of trials needed to reach 5 consecutive avoidance responses was used as dependent variable. Sham lesioned RLA-I rats showed poorer performance than sham lesioned RHA-I rats only under the 1s condition. The CeA lesion disrupted the avoidance response only in 1s groups, abolishing the between-strain performance differences observed under this condition. These results indicate the implication of CeA in one-way avoidance performance, and suggest a reciprocal modulation of fear and reinforcement (i.e. fear relief) in this form of aversive learning.
Morón
Ignacio
I
Faculty of Psychology, University of Granada, 18071, Granada, Spain.
Gómez
M A José
MA
Escarabajal
M A Dolores
MA
de la Torre
Lourdes
L
Cándido
Antonio
A
Maldonado
Antonio
A
Tobeña
Adolf
A
Fernández-Teruel
Alberto
A
Torres
Carmen
C
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001362:Avoidance Learning; D004572:Electrolysis; D005239:Fear; D005260:Female; D051381:Rats; D011919:Rats, Inbred Strains; D012054:Reinforcement, Psychology; D013045:Species Specificity; D013997:Time Factors