am also most grateful to Dame Sally Davies, former Chief Medical of Health for England and to Dr Elizabeth Davies, Reader in Cancer & Public Health, King’s College, London who reviewed and commented on my text.
References
1 Olesen J, Leonardi M. The burden of brain disease in Europe. Eur J Neurol 2003; 10: 471–477.
2 Wallace H, Shorvon SD, Tallis R. Age‐specific incidence and prevalence rates of treated epilepsy in an unselected population of 2,052,922 and age‐specific fertility rates of women with epilepsy. Lancet 1998; 26: 1970–1973.
Further Reading and Information
1 Shorvon S. Neurology worldwide: the epidemiology and burden of neurological disease. In Neurology A Queen Square Textbook, 2nd edn. Clarke C, Howard R, Rossor M, Shorvon S, eds. Wiley Blackwell, 2016. There are numerous references.
www.who.int/data/themes/mortality‐and‐global‐health‐estimates
1 Davies E, Clarke C, Hopkins A. Malignant cerebral glioma. I: Survival, disability and morbidity after radiotherapy. BMJ 1996; 313: 1507–1512.
2 Davies E, Clarke C, Hopkins A. Malignant cerebral glioma. II: Perspectives of patients and relatives on the value of radiotherapy. BMJ 1996; 313: 1512–1516.
Please visit https://www.drcharlesclarke.com for free updated notes, potential links and other references. You will be asked to log in, in a secure fashion, with your name and institution.
2 Movement, Sensation and The Silent Brain
Anatomical complexities of the nervous system became apparent in the late nineteenth century. Highlights were the pathways described by Santiago Ramón y Cajal in the 1890s and later the cortical mapping by Brodmann and the work of Alf Brodal. However, remarkably little neuroanatomy was required to practice sensibly and safely. To an extent this remains so. The neuroanatomy here is in excess of the needs of most general neurologists but further study is essential in many aspects of neuroscience.
First, here is an overview of the motor and sensory pathways of the brain and cord – the basic wiring that must be understood. I deal with this largely as illustrations. I also summarise what I call the Silent Brain, vital but less obvious – regions such as the thalamus. Cortical function is dealt with in Chapter 5. For neurones, nerves, glia and myelin see Chapter 10. Chapter 13 deals with the cranial nerves. Neuro‐ophthalmology is in Chapter 14, Neuro‐Otology in Chapter 15 and the autonomic nervous system in Chapter 24.
The overall anatomy of the brain is illustrated in Figure 2.1
ABC of Movement: Cortical, Extrapyramidal and Cerebellar Function
Movement – skilled, coordinated and fast – is highly developed in mammals. Rudimentary objectives are feeding, survival and reproduction and in Mankind, skilled use of tools, weapons and instruments of creative art.
1 Corticospinal (pyramidal) tracts originate in the motor cortex, somatosensory and limbic areas to reach cranial nerve nuclei and cord anterior horn cells. Dysfunction produces loss of skilled movement, weakness, spasticity and reflex change. Pyramidal describes the triangular cross‐section of the tract in the medulla. Pyramidal is used here interchangeably with corticospinal.
2 The striatal (a.k.a. extrapyramidal) system facilitates fast, fluid movement. Hallmarks of dysfunction are slowness (bradykinesia), stiffness (rigidity), rest tremor, all seen typically in Parkinson’s and some movement disorders. Broadly, these are basal ganglia functions.
3 The cerebellum coordinates smooth movement, and balance. Ataxia and action tremor are features of dysfunction.
Figure 2.1 Brain: overall anatomy (a) Lateral view (b) Midsagittal section (c) Ventral view.
Source: Champney (2016).
Cortex: Movement Force, Direction and Synergy
Movements are produced by neuronal groups in the motor cortex. These groups act synergistically to control force, direction and timing – and they communicate with sensation – to produce fine, skilled movements.
Pyramidal System Anatomy
Figure 2.2 outlines the principal motor pathway from cortex to anterior horn cells.
Note:
Pyramid: within rostral medulla
Decussation of the pyramids: within caudal medulla
Cortico‐spinal axons synapse on cord anterior horn cells.
Extrapyramidal System and Basal Ganglia Region
The word extrapyramidal is used in various ways. In neurology, extrapyramidal describes disorders such as Parkinson’s disease – the slowing, stiffness and/or tremor. Extrapyramidal is also sometimes used to include dyskinesias, such as chorea, hemiballismus or dystonia. In neuroanatomy, as a more general term, extrapyramidal relates to the basal ganglia region (Figure 2.3), that is:
Figure 2.2 Descending corticospinal pathways.
Source: Champney (2016).
