"Cord" - what is it, definition of the term
A flexible strand made of twisted or braided fibers—natural (e.g., cotton, hemp) or synthetic (e.g., nylon, polyester)—is designed to bear tension, conduct electricity, or secure objects; in laboratory settings involving rats and mice, such a strand functions as a restraint device, allowing controlled limitation of movement while minimizing injury.
Detailed information
The central nervous conduit in rodents extends from the brainstem to the caudal vertebral region, encased by protective meninges and surrounded by cerebrospinal fluid. It consists of gray matter, white matter, and a central canal that transports fluid throughout the length of the structure.
During embryogenesis, the conduit originates from the neural plate, folds to form the neural tube, and differentiates into distinct regions. In rats, the formation completes by embryonic day 12, while mice reach a comparable stage by day 10. Morphological measurements show a proportional increase in diameter relative to body growth, with species‑specific scaling factors.
Signal transmission occurs via myelinated and unmyelinated fibers that connect peripheral sensory inputs to motor outputs. The conduit also houses autonomic nuclei that regulate visceral functions, such as cardiovascular and respiratory control. Mechanical protection is provided by vertebral arches and ligamentous attachments.
Research on this structure employs several standard techniques:
- Dissection under a stereomicroscope for isolation of the tissue segment.
- Cryosectioning followed by immunohistochemical staining to identify neuronal subpopulations.
- In vivo electrophysiological recording using microelectrode arrays.
- Magnetic resonance imaging for non‑invasive assessment of integrity and pathology.
Pathological conditions reported in laboratory rodents include traumatic compression, demyelinating lesions, and neurodegenerative changes. Experimental models replicate human spinal disorders by applying contusion injury, chemical neurotoxins, or genetic manipulation, enabling evaluation of therapeutic interventions.