title: Social buffering suppresses fear-associated activation of the lateral amygdala in male rats: behavioral and neurophysiological evidence.
abstract: In social mammals, the presence of an affiliative conspecific reduces stress responses, a phenomenon referred to as "social buffering."In a previous study, we found that the presence of a conspecific animal ameliorated a variety of stress responses to an aversive conditioned stimulus (CS), including freezing and Fos expression in the lateral amygdala (LA) of male rats. Although these findings suggest that the presence of a conspecific animal suppresses neural activity in the LA, direct neurophysiological evidence of suppressed activity in the LA during social buffering is still lacking. In the present study, we analyzed freezing behavior and local field potentials in the LA of fear-conditioned rats in response to the CS, in the presence or absence of a conspecific. After auditory aversive conditioning, the CS was presented to the conditioned rats in the presence or absence of a conspecific animal, on 2 successive days. The presence of a conspecific animal significantly decreased the mean peak amplitudes of auditory evoked field potentials, gamma oscillations (25-75 Hz) and high frequency oscillations (100-300 Hz) in the LA. Furthermore, magnitudes of these neural responses positively correlated with freezing duration of the fear-conditioned rats. The results provide the first electrophysiological evidence that social buffering suppresses CS-induced activation in the LA, which consequently reduces conditioned fear responses.
authors: System Emotional Science, University of Toyama Sugitani, Toyama, Japan.
authors: Felipe
authors: F
authors: Fuzzo
authors: System Emotional Science, University of Toyama Sugitani, Toyama, Japan.
authors: Jumpei
authors: J
authors: Matsumoto
authors: Laboratory of Veterinary Ethology, The University of Tokyo Tokyo, Japan.
authors: Yasushi
authors: Y
authors: Kiyokawa
authors: Laboratory of Veterinary Ethology, The University of Tokyo Tokyo, Japan.
authors: Yukari
authors: Y
authors: Takeuchi
authors: System Emotional Science, University of Toyama Sugitani, Toyama, Japan.
authors: Taketoshi
authors: T
authors: Ono
authors: System Emotional Science, University of Toyama Sugitani, Toyama, Japan.
authors: Hisao
authors: H
authors: Nishijo
keywords: gamma oscillation; high frequency oscillation; lateral amygdala; male rat; social buffering