Anatomical connections of the periaqueductal gray: specific neural substrates for different kinds of fear

Autor(es)

D.M.L. Vianna ; M.L. Brandão

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 36, n. 5, p. 557-566, Maio 2003.

Resumo

The periaqueductal gray (PAG) has been traditionally considered to be an exit relay for defensive responses. Functional mapping of its subdivisions has advanced our knowledge of this structure, but synthesis remains difficult mainly because results from lesion and stimulation studies have not correlated perfectly. After using a strategy that combined both techniques and a reevaluation of the available literature on PAG function and connections, we propose here that freezing could be mediated by different PAG subdivisions depending on the presence of immediate danger or exposure to related signaling cues. These subdivisions are separate functional entities with distinct descending and ascending connections that are likely to play a role in different defensive responses. The existence of ascending connections also suggests that the PAG is not simply a final common path for defensive responses. For example, the possibility that indirect ascending connections to the cingulate cortex could play a role in the expression of freezing evoked by activation of the neural substrate of fear in the dorsal PAG has been considered. (AU)

• Processo FAPESP: 98/11187-2 - Neurobiologia do medo e da ansiedade
• Beneficiário: Marcus Lira Brandão
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 97/00363-1 - Relação entre a matéria cinzenta periaquedutal e o complexo amigdalóide na organização do sistema motivacional de medo
• Beneficiário: Daniel Machado Luiz Vianna
• Linha de fomento: Bolsas no Brasil - Mestrado