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Neuroimaging Clinics of North America Aug 2022The 12 cranial nerves (CNs) all have important functions. All, except the accessory nerve, arise solely within the cranial vault. We will discuss each CN function along... (Review)
Review
The 12 cranial nerves (CNs) all have important functions. All, except the accessory nerve, arise solely within the cranial vault. We will discuss each CN function along with its entire CN course. The modality of choice for evaluation of the CN itself is typically MRI, however, CT is very important to access the bony foramina and CN boundaries..
Topics: Accessory Nerve; Cranial Nerves; Humans; Magnetic Resonance Imaging
PubMed: 35843663
DOI: 10.1016/j.nic.2022.04.004 -
Cell Aug 2020Piloerection (goosebumps) requires concerted actions of the hair follicle, the arrector pili muscle (APM), and the sympathetic nerve, providing a model to study...
Piloerection (goosebumps) requires concerted actions of the hair follicle, the arrector pili muscle (APM), and the sympathetic nerve, providing a model to study interactions across epithelium, mesenchyme, and nerves. Here, we show that APMs and sympathetic nerves form a dual-component niche to modulate hair follicle stem cell (HFSC) activity. Sympathetic nerves form synapse-like structures with HFSCs and regulate HFSCs through norepinephrine, whereas APMs maintain sympathetic innervation to HFSCs. Without norepinephrine signaling, HFSCs enter deep quiescence by down-regulating the cell cycle and metabolism while up-regulating quiescence regulators Foxp1 and Fgf18. During development, HFSC progeny secretes Sonic Hedgehog (SHH) to direct the formation of this APM-sympathetic nerve niche, which in turn controls hair follicle regeneration in adults. Our results reveal a reciprocal interdependence between a regenerative tissue and its niche at different stages and demonstrate sympathetic nerves can modulate stem cells through synapse-like connections and neurotransmitters to couple tissue production with demands.
Topics: Accessory Nerve; Animals; Cell Cycle; Cold Temperature; Female; Fibroblast Growth Factors; Forkhead Transcription Factors; Gene Expression Profiling; Hair; Hair Follicle; Hedgehog Proteins; Humans; Male; Mice; Mice, Inbred C57BL; Norepinephrine; Piloerection; RNA-Seq; Receptors, Adrenergic, beta-2; Repressor Proteins; Signal Transduction; Smoothened Receptor; Stem Cell Niche; Stem Cells; Sympathetic Nervous System; Synapses
PubMed: 32679029
DOI: 10.1016/j.cell.2020.06.031 -
Muscle & Nerve Jun 2022The aim of this study was to describe a new method for studying the supraclavicular nerve (SCN) conduction and to report four cases with SCN lesions.
INTRODUCTION/AIMS
The aim of this study was to describe a new method for studying the supraclavicular nerve (SCN) conduction and to report four cases with SCN lesions.
METHODS
The SCN was antidromically recorded with a pair of self-adhesive electrodes located in the middle of the clavicle. Stimulation (<5 mA) was delivered 7 cm proximally with a bar electrode. To facilitate recording, it was explained to the participant that they would feel a very faint electrical sensation locally and an electrical tingle upward (ear) or downward (shoulder/clavicle). Each participant was asked to say when the tingling moved downward.
RESULTS
In normal subjects, median values were 16 μV (range: 9-33) for sensory nerve action potential (SNAP) amplitude; 1.2 ms (range: 1-1.5) for onset latency; and 1.25 (range: 1-1.7) for side-to-side amplitude ratio. In the four patients, the SCN SNAP was absent on the pathological side and normal on the healthy side. All four patients complained of unilateral neuropathic hypoesthesia on the anterior aspect of the neck, chest, and shoulder that occurred after radical neck surgery for thyroid or larynx cancer (x3) and first rib resection (x1).
DISCUSSION
A comparison with previous reports shows that this simple method provides similar or highest SNAP amplitudes. SCN lesions are rare, and rarely referred for electrodiagnosis, and often overlooked. However, the SCN conduction study, which causes very slight inconvenience (low-intensity stimulation), allows a better understanding of the origin of the complaints and permits the patient to benefit of more suitable treatment.
Topics: Cervical Plexus; Electrodes; Electrodiagnosis; Humans; Neural Conduction; Neurologic Examination
PubMed: 35366347
DOI: 10.1002/mus.27547