The Historical Evolution of Topographical Mapping and Nomenclature of the Lateral Cervical and Lateral Spinal Nuclei

The intricate organization of nuclei within the dorsolateral funiculus of the spinal cord has long been an area of interest in the field of neuroanatomy. Numerous researchers have endeavored to determine the morphology, neurochemistry, connections, and physiology of the lateral cervical nucleus and lateral spinal nucleus throughout history. This manuscript charts the historical progression in the mapping, naming, and comprehension of the lateral cervical nucleus and lateral spinal nucleus across a variety of species, such as rats, mice, marmosets, rhesus monkeys, and humans. It synthesizes significant research spanning decades, which together shed light on the nuanced topography of these nuclei, starting from Theodor Ziehen's foundational work in 1903, through Molander's precise mappings, to the detailed contemporary mappings by modern scholars. Despite the wealth of research elucidating the mappings of these nuclei, there remains a need for further investigation into their roles and neurochemical characteristics.

The seminal contributions of Benedict Stilling (1810-1879) to neuroanatomy

Benedict Stilling (1810-1879), was a prolific, prominent, and ambitious anatomist, who performed works on the organization of the nervous system for many years. He made numerous observations on the anatomy of the nervous system in various animal species. Stilling contributed to the establishment of significant foundations in the anatomy of the spinal cord, brainstem, and cerebellum. Stilling paved the way for future researchers by describing the techniques he used in his diligent studies published in his published books. In his books, which include many drawings and cadaveric images, he revealed the relationships between the structures in the nervous system. He also made significant contributions to neuroanatomy terminology by coining terms in these books. At the same time, some nuclei in the anatomy of the nervous system were later named after him as an eponym by many researchers. Therefore, Stilling's neuroanatomical works, which are still important today, should be appreciated. This article aims to emphasize his pioneering work in neuroanatomy.

Bror Rexed (1914-2002) and His Pioneer Works on Spinal Cord Cytoarchitecture

Swedish neuroscientist Bror Anders Rexed lived between 1914 and 2002. He was a renowned neuroscientist and a politician who packed a lot into his 88-year life. Bror Rexed is best known for his works on the description of the cytoarchitectonic organization of the cat spinal cord. Rexed laminae as an eponym is a historical landmark for the spinal cord cytoarchitecture. Rexed's name (particularly his surname) has also been linked to the du-reform in Swedish. In this article, we focus on his works on the central and peripheral nervous systems and translational approaches for neurosurgery, as well as his influence on health policies in Sweden.

Odor Enrichment Increases Hippocampal Neuron Numbers in Mouse

The hippocampus and olfactory bulb incorporate new neurons migrating from neurogenic regions in the brain. Hippocampal atrophy is evident in numerous neurodegenerative disorders, and altered hippocampal neurogenesis is an early pathological event in Alzheimer's disease. We hypothesized that hippocampal neurogenesis is affected by olfactory stimuli through the neural pathway of olfaction-related memory. In this study, we exposed mice to novel pleasant odors for three weeks and then assessed the number of neurons, non-neuronal cells (mainly glia) and proliferating cells in the hippocampus and olfactory bulb, using the isotropic fractionator method. We found that the odor enrichment significantly increased the neuronal cell numbers in the hippocampus, and promoted cell proliferation and neurogenesis in the olfactory bulb. In contrast, the glial cell numbers remained unchanged in both of the regions. Our results suggest that exposure to novel odor stimuli promotes hippocampal neurogenesis and support the idea that enriched environments may delay the onset or slow down the progression of neurodegenerative disorders.

Subcortical Parenchymal and Right Lentiform Nucleus Haemorrhages in a Lightning Victim

We report a 12-year-old lightning victim with right subcortical parenchymal and right lentiform nucleus haemorrhages documented by computed tomography (CT) and magnetic resonance imaging (MRI). A linear entry burn with an area of singed hair on the scalp was obvious. Neurological examination did not show any lateralized deficit. Cranial nerves were intact. A laceration on the right external auditory canal, elevated cardiac enzymes and electrocardiographic changes were also recorded. The boy was discharged on the sixth day. Prolonged loss of consciousness in lightning victims may suggest intracranial injury. Although brain CT can demonstrate intracranial haemorrhages, MRI is mandatory to show subcortical parenchymal haemorrhage in lightning victims.

Vertebral landmarks for the identification of spinal cord segments in the mouse

Accurate identification of spinal cord segments in relation to vertebral landmarks is essential to surgery aimed at experimental spinal cord injury. We have analyzed a complete series of high-resolution magnetic resonance (MR) images from the mouse spine in order to delineate the boundaries of spinal cord segments in relation to vertebral landmarks. The resulting atlas can be used to plan experimental approaches that require the accurate identification of a target spinal cord segment.

Musculotopic organization of the motor neurons supplying forelimb and shoulder girdle muscles in the mouse

We identified the motor neurons (MNs) supplying the shoulder girdle and forelimb muscles in the C57BL/6J mouse spinal cord using Fluoro-Gold retrograde tracer injections. In spinal cord transverse sections from C2 to T2, we observed two MN columns (medial and lateral) both with ventral and dorsal subdivisions. The dorsolateral column consisted of the biceps brachii, forearm extensors, forearm flexors, and hand MNs, and the ventrolateral column consisted of the latissimus dorsi, trapezius, teres major, deltoid, and triceps MNs. The supraspinatus muscle MNs were located in the dorsomedial column, and pectoralis major and serratus anterior MNs were located in the ventromedial columns. MNs of the dorsolateral column innervated the biceps brachii in mid-C4 to mid-C7, forearm extensors in caudal C4 to mid-T1, forearm flexors in rostral C5 to mid-T1, and hand muscles in mid-C8 to mid-T2 segments. The MNs innervating the trapezius were located in mid-C2 to mid-C4, triceps brachii in mid-C6 to rostral T1, deltoid in rostral C4 to mid-C6, teres major in rostral C5 to mid-C8, and latissimus dorsi in mid-C5 to caudal C8. In addition, MNs innervating the supraspinatus were located from rostral C4 to caudal C8, pectoralis major in mid-C6 to mid-T2, and serratus anterior in rostral C5 to caudal C7/rostral C8 segments. While the musculotopic pattern of MN groups was very similar to that documented for other species, we found differences in the position and cranio-caudal extent of some MN pools compared with previous reports. The identification of mouse forelimb MNs can serve as an anatomical reference for studying degenerative MN diseases, spinal cord injury, and developmental gene expression.

NADPH-d and Fos reactivity in the rat spinal cord following experimental spinal cord injury and embryonic neural stem cell transplantation

AIMS

The aim of this study is to determine the role of nitric oxide (NO) in neuropathic pain and the effect of embryonic neural stem cell (ENSC) transplantation on NO content in rat spinal cord neurons following spinal cord injury (SCI).

MAIN METHODS

Ninety adult male Sprague-Dawley rats were divided into 3 groups (n=30, each): control (laminectomy), SCI (hemisection at T12-T13 segments) and SCI+ENSC. Each group was further divided into sub-groups (n=5 each) based on the treatment substance (L-NAME, 75 mg/kg/i.p.; L-arginine, 225 mg/kg/i.p.; physiological saline, SF) and duration (2h for acute and 28 days for chronic groups). Pain was assessed by tail flick and Randall-Selitto tests. Fos immunohistochemistry and NADPH-d histochemistry were performed in segments 2 cm rostral and caudal to SCI.

KEY FINDINGS

Tail-flick latency time increased in both acute and chronic L-NAME groups and increased in acute and decreased in chronic L-arginine groups. The number of Fos (+) neurons decreased in acute and chronic L-NAME and decreased in acute L-arginine groups. Following ENSC, Fos (+) neurons did not change in acute L-NAME but decreased in the chronic L-NAME groups, and decreased in both acute and chronic L-arginine groups. NADPH-d (+) neurons decreased in acute L-NAME and increased in L-arginine groups with and without ENSC transplantation.

SIGNIFICANCE

This study confirms the role of NO in neuropathic pain and shows an improvement following ENSC transplantation in the acute phase, observed as a decrease in Fos(+) and NADPH-d (+) neurons in spinal cord segments rostral and caudal to injury.

Therapeutic effect of vitamin D3 in a rat diffuse axonal injury model

We investigated the therapeutic effect of vitamin D3 in a rat diffuse axonal injury model. A total of 60 male Sprague-Dawley rats weighing 175-200 g were anaesthetized and subjected to head trauma using Marmarou's impact-acceleration model. The rats were then separated into two groups; one group was treated with vitamin D3 and the other with saline for up to 4 days after the head trauma. Rats from both groups were killed 1, 3 or 8 days post-injury. The brains were examined histopathologically and scored according to the level of neuronal, vascular and axonal damage. There were no significant differences between the groups after 1 or 3 days, but evaluation after 8 days revealed a significant improvement in the group treated with vitamin D3. Our data indicate that vitamin D3 has a beneficial effect in diffuse axonal injury and may be useful in the management of this condition.