Université de Fribourg

Intrinsic connections of the macaque monkey hippocampal formation: II. CA3 connections

Kondo, Hideki ; Lavenex, Pierre ; Amaral, David G.

In: The Journal of Comparative Neurology, 2009, vol. 515, no. 3, p. 349 - 377

We examined the topographic organization of the connections of the CA3 field of the macaque monkey hippocampus. Discrete anterograde and retrograde tracer injections were made at various positions within CA3 and CA1. The projections from CA3 to CA1 (Schaffer collaterals), which terminate in the strata radiatum, pyramidale, and oriens, are present throughout the entire transverse extent of CA1....

Université de Fribourg

Postmortem changes in the neuroanatomical characteristics of the primate brain: Hippocampal formation

Lavenex, Pierre ; Lavenex, Pamela Banta ; Bennett, Jeffrey L. ; Amaral, David G.

In: The Journal of Comparative Neurology, 2009, vol. 512, no. 1, p. 27 - 51

Comparative studies of the structural organization of the brain are fundamental to our understanding of human brain function. However, whereas brains of experimental animals are fixed by perfusion of a fixative through the vasculature, human or ape brains are fixed by immersion after varying postmortem intervals. Although differential treatments might affect the fundamental characteristics of the...

Université de Fribourg

Intrinsic connections of the macaque monkey hippocampal formation: I. Dentate gyrus

Kondo, Hideki ; Lavenex, Pierre ; Amaral, David G.

In: The Journal of Comparative Neurology, 2008, vol. 511, no. 4, p. 497 - 520

We have carried out a detailed analysis of the intrinsic connectivity of the Macaca fascicularis monkey hippocampal formation. Here we report findings on the topographical organization of the major connections of the dentate gyrus. Localized anterograde tracer injections were made at various rostrocaudal levels of the dentate gyrus, and we investigated the three-dimensional organization of the...

Université de Fribourg

Spatial memory and the monkey hippocampus: not all space is created equal

Lavenex, Pamela Banta ; Lavenex, Pierre

In: Hippocampus, 2009, vol. 19, no. 1, p. 8-19

Studies of the role of the monkey hippocampus in spatial learning and memory, however few, have reliably produced inconsistent results. Whereas the role of the hippocampus in spatial learning and memory has been clearly established in rodents, studies in nonhuman primates have made a variety of claims that range from the involvement of the hippocampus in spatial memory only at relatively longer...

Université de Fribourg

Effects of neonatal amygdala or hippocampus lesions on resting brain metabolism in the macaque monkey: A microPET imaging study

Machado, Christopher J. ; Snyder, Abraham Z. ; Cherry, Simon R. ; Lavenex, Pierre ; Amaral, David G.

In: NeuroImage, 2008, vol. 39, no. 2, p. 832-846

Longitudinal analysis of animals with neonatal brain lesions enables the evaluation of behavioral changes during multiple stages of development. Interpretation of such changes, however, carries the caveat that permanent neural injury also yields morphological and neurochemical reorganization elsewhere in the brain that may lead either to functional compensation or to exacerbation of behavioral...

Université de Fribourg

The dentate gyrus: fundamental neuroanatomical organization (dentate gyrus for dummies)

Amaral, David G. ; Scharfman, Helen E. ; Lavenex, Pierre

In: Progress in Brain Research, 2007, vol. 163, p. 3-22, 788-790

The dentate gyrus is a simple cortical region that is an integral portion of the larger functional brain system called the hippocampal formation. In this review, the fundamental neuroanatomical organization of the dentate gyrus is described, including principal cell types and their connectivity, and a summary of the major extrinsic inputs of the dentate gyrus is provided. Together, this...

Université de Fribourg

Spatial relational learning persists following neonatal hippocampal lesions in macaque monkeys

Lavenex, Pierre ; Lavenex, Pamela Banta ; Amaral, David G.

In: Nature Neuroscience, 2006, vol. 10, no. 2, p. 234 - 239

The hippocampus is important for the acquisition of spatial representations of the environment and consequently in contextual memory. This suggests that the neural substrates underlying spatial cognition might be essential for remembering specific life episodes. Indeed, hippocampal lesions prevent spatial relational learning in adult rodents and monkeys, and result in profound amnesia in adult...

Université de Fribourg

Postnatal development of the primate hippocampal formation

Lavenex, Pierre ; Lavenex, Pamela Banta ; Amaral, David G.

In: Developmental Neuroscience, 2007, vol. 39, no. 1-2, p. 179-192

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...

Université de Fribourg

The expression of social dominance following neonatal lesions of the amygdala or hippocampus in rhesus monkeys (Macaca mulatta)

Bauman, M. D. ; Toscano, J. E. ; Mason, W. A. ; Lavenex, Pierre ; Amaral, David G.

In: Behavioral Neuroscience, 2006, vol. 120, no. 4, p. 749-760

As part of ongoing studies on the neurobiology of socioemotional behavior in the nonhuman primate, the authors examined the social dominance hierarchy of juvenile macaque monkeys (Macaca mulatta) that received bilateral ibotenic acid lesions of the amygdala or the hippocampus or a sham surgical procedure at 2 weeks of age. The subjects were reared by their mothers with daily access to large...

Université de Fribourg

Spatial relational memory in 9-month-old macaque monkeys

Lavenex, Pierre ; Lavenex, Pamela Banta

In: Learning & Memory, 2006, vol. 13, p. 84-96

This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys (Macaca mulatta). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in one of two sets of three distinct locations....