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Spaceflight induces changes in the synaptic circuitry of the postnatal developing neocortex.
J DeFelipe1, J I Arellano, A Merchán-Pérez
1Instituto Cajal (CSIC), Avenida Dr Arce 37, 28002 Madrid, Spain. defelipe@cajal.csic.es
Cerebral Cortex (New York, N.Y. : 1991)
|July 18, 2002
Summary
Spaceflight during development alters rat neocortical circuitry, changing synapse number and shape. Some changes were temporary, while others persisted or emerged after returning to Earth, indicating gravity
Area of Science:
- Neuroscience
- Developmental Biology
- Space Biology
Background:
- Neocortical circuitry development is influenced by intrinsic and extrinsic factors.
- Altered development can lead to changes in cortical organization and function.
Purpose of the Study:
- To investigate the effects of microgravity on the developing neocortical hindlimb synaptic circuitry in rats.
- To determine if observed changes persist or resolve after re-adaptation to terrestrial gravity.
Main Methods:
- Rats were exposed to 16 days of spaceflight (postnatal days 14-30).
- Synaptic density and morphology in specific neocortical layers were analyzed.
- Changes were assessed after spaceflight and after a 4-month re-adaptation period.
Main Results:
- Microgravity exposure altered synaptic number and morphology in a laminar-specific manner.
- Synaptic lengths increased, and densities decreased in layers II/III, IV, and Va.
- Changes were transient for some layers but persistent or new differences emerged in layer IV after re-adaptation.
- Only excitatory (asymmetrical) synapses were affected.
Conclusions:
- Terrestrial gravity is essential for normal cortical synaptogenesis.
- Development in microgravity causes lasting alterations in neocortical circuitry.
- Findings are crucial for planning long-duration space missions.