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A link between synaptic plasticity and reorganization of brain activity in Parkinson's disease.

ABSTRACT: The link between synaptic plasticity and reorganization of brain activity in health and disease remains a scientific challenge. We examined this question in Parkinson's disease (PD) where functional up-regulation of postsynaptic D₂ receptors has been documented while its significance at the neural activity level has never been identified. We investigated cortico-subcortical plasticity in PD using the oculomotor system as a model to study reorganization of dopaminergic networks. This model is ideal because this system reorganizes due to frontal-to-parietal shifts in blood oxygen level-dependent (BOLD) activity. We tested the prediction that functional activation plasticity is associated with postsynaptic dopaminergic modifications by combining positron emission tomography/functional magnetic resonance imaging to investigate striatal postsynaptic reorganization of dopamine D₂ receptors (using ¹¹C-raclopride) and neural activation in PD. We used covariance (connectivity) statistics at molecular and functional levels to probe striato-cortical reorganization in PD in on/off medication states to show that functional and molecular forms of reorganization are related. D₂ binding across regions defined by prosaccades showed increased molecular connectivity between both caudate/putamen and hyperactive parietal eye fields in PD in contrast with frontal eye fields in controls, in line with the shift model. Concerning antisaccades, parietal-striatal connectivity dominated in again in PD, unlike frontal regions. Concerning molecular-BOLD covariance, a striking sign reversal was observed: PD patients showed negative frontal-putamen functional-molecular associations, consistent with the reorganization shift, in contrast with the positive correlations observed in controls. Follow-up analysis in off-medication PD patients confirmed the negative BOLD-molecular correlation. These results provide a link among BOLD responses, striato-cortical synaptic reorganization, and neural plasticity in PD.

SUBMITTER: Rebelo D

PROVIDER: S-EPMC7826364 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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A link between synaptic plasticity and reorganization of brain activity in Parkinson's disease.

Rebelo Diliana D Oliveira Francisco F Abrunhosa Antero A Januário Cristina C Lemos João J Castelo-Branco Miguel M

Proceedings of the National Academy of Sciences of the United States of America 20210101 3

The link between synaptic plasticity and reorganization of brain activity in health and disease remains a scientific challenge. We examined this question in Parkinson's disease (PD) where functional up-regulation of postsynaptic D<sub>2</sub> receptors has been documented while its significance at the neural activity level has never been identified. We investigated cortico-subcortical plasticity in PD using the oculomotor system as a model to study reorganization of dopaminergic networks. This m ...[more]

PMID: 33431672

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A link between synaptic plasticity and reorganization of brain activity in Parkinson's disease.

Publications

A link between synaptic plasticity and reorganization of brain activity in Parkinson's disease.

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