Modulação da amígdala basolateral sobre o colículo inferior no condicionamento clássico ao medo

• Ano de defesa: 2020
• Autor(a) principal: Cristiano Soares Simões
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - INSTITUTO DE CIÊNCIAS BIOLOGICAS; Programa de Pós-Graduação em Neurociências; UFMG
• Palavras-chave em Português: Condicionamento ao medo auditivo; Amígdala basolateral; Colículo inferior; Muscimol; Respostas evocadas auditivas em regime permanente; Eletrofisiologia; Neurociências; Medo; Complexo nuclear basolateral da amígdala
• Link de acesso: http://hdl.handle.net/1843/35506

It has been shown that fear conditioning improves the steady-state evoked potentials driven by a long-lasting amplitude-modulated tone in the inferior colliculus. In this work, we tested the hypothesis that the amygdala modulates this effect since it plays a crucial role in assessing the biological relevance of environmental stimuli. We inhibited the basolateral nucleus of the amygdala of rats by injecting a GABAa receptor agonist (muscimol) before the recall test session of an auditory fear conditioning paradigm and recorded the evoked activity in the central nucleus of the inferior colliculus. According to our results, the treatment with muscimol decreased the expression of freezing behavior during the recall test session but increased the entrainment of the modulation envelope in the activity of the inferior colliculus. We repeated the injection protocol with another group of rats but without pairing the tone to an aversive stimulus and observed that the enhancement of the stimulus-driven activity in the inferior colliculus is a result of the inhibition of the basolateral amygdala, regardless of the conditioning task. Our findings suggest that this structure exerts a tonic inhibitory control over the encoding of sensory information at the early stages of the sensory pathway.