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Neuroanatomy
Published in Ibrahim Natalwala, Ammar Natalwala, E Glucksman, MCQs in Neurology and Neurosurgery for Medical Students, 2022
Ibrahim Natalwala, Ammar Natalwala, E Glucksman
ii – Fasciculus gracilis. The dorsal columns consist of the fasciculus gracilis and fasciculus cuneatus, both consisting of neurones which convey proprioception, vibration, discriminative touch and pressure. Afferent sensory neurones entering the spinal cord below vertebral level T6 go on to form the fasciculus gracilis, and those entering above T6 form the fasciculus cuneatus.
Fertilization and normal embryonic and early fetal development
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Asim Kurjak, Ritsuko K. Pooh, Aida Salihagic-Kadic, Iva Lausin, Lara Spalldi-Barisic
Cerebral hemispheres continue with development during the 9th and 10th weeks of pregnancy. Visible are lateral ventricles containing hyperechoic choroid plexuses. The head is clearly divided from the body by the neck. External ear is sometimes depicted in the 3D surface image. Herniation of the midgut is present. Dorsal column, the early spine, can be examined in its whole length. The arms with elbow and legs with knee are now visible. Feet can be seen approaching the midline (Fig. 15).
Spinal CordAnatomical and Physiological Features
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The three main ascending spinal tracts are (i) dorsal column medial lemniscus pathway, (ii) spinothalamic tract and (iii) spinocerebellar tract. The dorsal column medial lemniscus conveys information for the perception of pressure, vibration and texture via Aα/β fibres to facilitate discriminative touch. The spinothalamic tract conveys pain and temperature modalities via Aδ/C fibres. Proprioception is conveyed via Aα fibres which terminate at the cerebellum by the spinocerebellar tract. Details of the course of the ascending tracts are described in Chapter 8.
A systematic review of disease prevalence, health-related quality of life, and economic outcomes associated with Friedreich’s Ataxia
Published in Current Medical Research and Opinion, 2022
Katharina Buesch, Rongrong Zhang
Friedreich’s ataxia (FA) is a rare, autosomal recessive genetic condition that accounts for the majority of inherited ataxia cases1. In FA, the production of the mitochondrial protein frataxin is reduced, which adversely affects iron metabolism and results in the accumulation of iron within certain tissues. Published evidence suggests that toxicity caused by iron accumulation may play a role in the pathophysiology associated with FA, although this has not been definitively established2. Affected areas primarily include the dorsal columns of the spinal cord, peripheral nerves, and the cerebellum. As a result, FA is consistently characterized by progressive gait and limb ataxia, dysarthria, and loss of lower limb reflexes; other clinical features are variable1,3. The myocardium and endocrine pancreas are also frequently affected by the disease process, which can result in the development of cardiomyopathy and diabetes mellitus, respectively3. FA affects those of European, North African, Middle Eastern or Indian origin. Cases are very rarely, if at all, observed in sub-Saharan Africa, China, Japan, and Southeast Asia4,5.
Adaptive, personalized closed-loop therapy for Parkinson’s disease: biochemical, neurophysiological, and wearable sensing systems
Published in Expert Review of Neurotherapeutics, 2021
Lazzaro di Biase, Gerd Tinkhauser, Eduardo Martin Moraud, Maria Letizia Caminiti, Pasquale Maria Pecoraro, Vincenzo Di Lazzaro
Similarly, spinal cord stimulation (SCS) has been proposed as a viable, less invasive approach for the symptomatic treatment of gait impairments in PD. Leveraging widely established experience in SCS for alleviating chronic pain, most studies to date have applied stimulation epidurally over the dorsal aspect of the upper-thoracic spinal cord. Pre-clinical experiment in rodent [167,168] and non-human primate [169] models of PD showed efficacy to reduce akinesia and restore mobility. Concurrent neural recordings of brain activity patterns confirmed that SCS disrupts pathological low-frequency synchronization across various brain structures, including basal ganglia and motor cortex, and reduced the coupling between them. These observations reinforced the view that SCS recruits ascending sensory fibers in the dorsal columns, which reach brainstem, thalamic and cortical structures. These modulated afferent inputs help correct the excessive synchrony in the cortico-basal ganglia-thalamo-cortical loops [170], and in turn improve motor symptoms.
Fooled by the fragments: vitamin B12 deficiency masquerading as thrombotic thrombocytopenic purpura
Published in Journal of Community Hospital Internal Medicine Perspectives, 2021
Pegah Jahangiri, Rachel Hicks, Prabjot K. Batth, Christopher J. Haas
Classically, vitamin B12 deficiency is associated with subacute combined degeneration, a condition characterized by damage to the dorsal columns of the spinal cord with resultant loss of vibration sense/proprioception, spastic paresis, and gait abnormalities. Mechanistically, this occurs due to lack of conversion of the three-carbon methylmalonyl-CoA to four-carbon succinyl-CoA, causing a subsequent accumulation of three-carbon proprionate. Some suggest this results in the formation and incorporation of 15- and 17-carbon fatty acids into neuronal lipids, predisposing to myelin and neuronal breakdown [12]. Notably, individuals with inherited deficits in methylmalonyl coenzyme-A mutase have highly variable neurological phenotypes without evidence of predisposition to SCD [13], purporting an alternative role of cobalamin in this symptomatology.