Postnatal Development of the Primate Hippocampal Formation

Abstract

The hippocampal formation is a multicomponent region of the medial temporal lobe preferentially involved in declarative and relational memory processing. Behavioral studies have suggested a protracted functional maturation of these structures in primates, and postnatal developmental abnormalities in the hippocampal formation are thought to contribute to neurodevelopmental disorders, such as autism, schizophrenia, epilepsy and Down syndrome. Despite all that we know about the functional organization of the adult hippocampal formation, notably absent is a systematic study of its postnatal maturation in primates. In this article, we review current knowledge of the structural development of the primate hippocampal formation and present new data on its postnatal neuroanatomical development. We summarize what is known about the neurobiological processes, such as the addition of new neurons, the establishment and elaboration of connectivity, and the neurochemical changes, that underlie the structural development and functional maturation of the primate hippocampal formation. We conclude that there is yet insufficient information to identify distinct developmental windows during which different hippocampal regions undergo specific maturational processes. For this reason, it is currently impossible to determine the ages at which specific hippocampal circuits become structurally mature and potentially capable of supporting defined, age-specific functional processes. Together with work in rodents, systematic studies of the structural development and functional maturation of the monkey hippocampal formation will be necessary to gain insight not only into the types of information processing that it subserves, but also into the specific maturational processes that might be affected in human neurodevelopmental disorders.

The cortisol awakening response in infants: Ontogeny and associations with development-related variables

“…This would result in gradually increasing pre-awakening inhibition of cortisol secretion and decreasing cortisol levels on awakening with infant development. Although being speculative, this interpretation is also in line with evidence showing that particularly the hippocampus is a structure undergoing major changes during the first nine months of life (see Arnold and Trojanowski, 1996;Lavenex et al, 2007).…”

The temporal stem in traumatic brain injury: preliminary findings

“…The fact that the hippocampus receives via the TS direct input from all of the primary and multi-modal sensory cortices of the brain (Lavenex et al 2007), suggests that any damage to the TS has the potential to disrupt input-output integrity of hippocampal function and MTL integration of the medial temporal lobe with the rest of the brain. Indeed, Gaffan (2005) argues that 'memory' impairment is not so much dependent upon damage specific to the hippocampus as it is to the disruption of pathways that interconnect the hippocampus to the rest of the brain (see also Diehl et al 2008;Taoka et al 2008;Wang et al 2008).…”

Developmental Age Differentially Mediates the Calcium-Binding Protein Parvalbumin in the Rat: Evidence for a Selective Decrease in Hippocampal Parvalbumin Cell Counts

“…However, developmental changes in baseline PV expression within typically developing behaviorally and pharmacologically naïve rats have not yet been systematically studied across the life span. Importantly, characterization of PV with respect to distinct HPC subregions and across the septotemporal extent, as well as in neocortical regions throughout development, is lacking [50]. In pilot studies, we have observed a roughly 10-20% decrease in PV cell counts in 6-month- compared to 1-month-old rats, with significant regional and septotemporal variation [51].…”