Structural plasticity in the entorhinal and perirhinal cortices following hippocampal lesions in rhesus monkeys
- Villard, Justine ORCID University of Lausanne
- Chareyron, Loïc J. (Contributor) ORCID University of Lausanne
- Piguet, Olivia (Contributor) ORCID University of Lausanne
- Lambercy, Pauline (Contributor) ORCID University of Lausanne
- Lonchampt, Gianni (Contributor) ORCID University of Lausanne
- Banta Lavenex, Pamela A. (Contributor) ORCID UniDistance Suisse
- Amaral, David G. (Contributor) ORCID University of California, Davis
- Lavenex, Pierre (Contributor) ORCID University of Lausanne
- 2023
Published in:
- Hippocampus. - 2023, p. 1-19
amnesia
development
immature neurons
medial temporal lobe
memory
neurodevelopmental disorders
open access
English
Immature neurons expressing the Bcl2 protein are present in various regions of the
mammalian brain, including the amygdala and the entorhinal and perirhinal cortices.
Their functional role is unknown but we have previously shown that neonatal and
adult hippocampal lesions increase their differentiation in the monkey amygdala.
Here, we assessed whether hippocampal lesions similarly affect immature neurons in
the entorhinal and perirhinal cortices. Since Bcl2-positive cells were found mainly in
areas Eo, Er, and Elr of the entorhinal cortex and in layer II of the perirhinal cortex,
we also used Nissl-stained sections to determine the number and soma size of immature
and mature neurons in layer III of area Er and layer II of area 36 of the perirhinal
cortex. We found different structural changes in these regions following hippocampal
lesions, which were influenced by the time of the lesion. In neonate-lesioned monkeys,
the number of immature neurons in the entorhinal and perirhinal cortices was
generally higher than in controls. The number of mature neurons was also higher in
layer III of area Er of neonate-lesioned monkeys but no differences were found in
layer II of area 36. In adult-lesioned monkeys, the number of immature neurons
in the entorhinal cortex was lower than in controls but did not differ from controls in
the perirhinal cortex. The number of mature neurons in layer III of area Er did not differ
from controls, but the number of small, mature neurons in layer II of area 36 was
lower than in controls. In sum, hippocampal lesions impacted populations of mature
and immature neurons in discrete regions and layers of the entorhinal and perirhinal
cortices, which are interconnected with the amygdala and provide major cortical
inputs to the hippocampus. These structural changes may contribute to some functional
recovery following hippocampal injury in an age-dependent manner.
mammalian brain, including the amygdala and the entorhinal and perirhinal cortices.
Their functional role is unknown but we have previously shown that neonatal and
adult hippocampal lesions increase their differentiation in the monkey amygdala.
Here, we assessed whether hippocampal lesions similarly affect immature neurons in
the entorhinal and perirhinal cortices. Since Bcl2-positive cells were found mainly in
areas Eo, Er, and Elr of the entorhinal cortex and in layer II of the perirhinal cortex,
we also used Nissl-stained sections to determine the number and soma size of immature
and mature neurons in layer III of area Er and layer II of area 36 of the perirhinal
cortex. We found different structural changes in these regions following hippocampal
lesions, which were influenced by the time of the lesion. In neonate-lesioned monkeys,
the number of immature neurons in the entorhinal and perirhinal cortices was
generally higher than in controls. The number of mature neurons was also higher in
layer III of area Er of neonate-lesioned monkeys but no differences were found in
layer II of area 36. In adult-lesioned monkeys, the number of immature neurons
in the entorhinal cortex was lower than in controls but did not differ from controls in
the perirhinal cortex. The number of mature neurons in layer III of area Er did not differ
from controls, but the number of small, mature neurons in layer II of area 36 was
lower than in controls. In sum, hippocampal lesions impacted populations of mature
and immature neurons in discrete regions and layers of the entorhinal and perirhinal
cortices, which are interconnected with the amygdala and provide major cortical
inputs to the hippocampus. These structural changes may contribute to some functional
recovery following hippocampal injury in an age-dependent manner.
- Language
-
- English
- Classification
- Psychology
- License
-
CC BY
- Open access status
- hybrid
- Identifiers
-
- DOI 10.1002/hipo.23567
- ARK ark:/51647/srd1325384
- Persistent URL
- https://n2t.net/ark:/51647/srd1325384
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