Parvalbumin Expression and Distribution in the Hippocampal Formation of Cebus apella

New World primates play an important role in biomedical research. However, the literature still lacks information on many structural features of the brain in these species, particularly structures of the hippocampal formation that are related to long-term memory storage. This study was designed to provide information, for the first time, about the distribution and number of neurons expressing parvalbumin-immunoreactivity (PV-I) in the subregions of the hippocampal formation in Cebus apella, a New World primate species commonly used in biomedical research. Our results revealed that for several morphometric variables, PV-I cells differ significantly among the subregions CA1, CA2, CA3, and the hilus. Based upon our findings and those of other studies, we hypothesize that the proportional increase from monkeys to humans in PV-I cell density within CA1 is a factor contributing to the evolution of increased memory formation and storage. Am. J. Primatol. 77:449-461, 2015. (c) 2014 Wiley Periodicals, Inc.Universidade Federal de São Paulo, Unifesp EPM, Dept Neurol & Neurocirurgia, Lab Neurociencias, São Paulo, BrazilHosp Israelita Albert Einstein, Inst Cerebro, BR-05652900 São Paulo, SP, BrazilCtr Nacl Primatas CENP, IEC, Ananindeua, BrazilUniversidade Federal de São Paulo, Unifesp EPM, Dept Med, Disciplina Endocrinol Clin, São Paulo, BrazilFac Ciencias Med Santa Casa São Paulo, São Paulo, BrazilUniversidade Federal de São Paulo, Unifesp EPM, Dept Neurol & Neurocirurgia, Lab Neurociencias, São Paulo, BrazilUniversidade Federal de São Paulo, Unifesp EPM, Dept Med, Disciplina Endocrinol Clin, São Paulo, BrazilWeb of Scienc