The Neurology of Eye Movements, Edition 5, by R. John Leigh, M.D. and David S. Zee MD Foreword Chapter 1: A Survey of Eye Movements: Characteristics and Teleology Chapter 2: The Ocular Motor Periphery Chapter 3: The Vestibular-Optokinetic System Chapter 4: The Saccadic System Chapter 5: Smooth Visual Tracking and Fixation Chapter 6: Gaze Holding and The Neural Integrator Chapter 7: The Neural Basis for Conjugate Eye Movements Chapter 8: Eye-Head Movements Chapter 9: Vergence Eye Movements Chapter 10: Diagnosis of Peripheral Ocular Motor Palsies And Strabismus Chapter 11: Diagnosis of Nystagmus and Saccadic Intrusions Chapter 12: Diagnosis and Management of Vestibular Disorders Chapter 13: Disorders of Ocular Motility Due To Disease of the Brainstem, Cerebellum and Diencephalon Chapter 14: Disorders of Ocular Motility With Disease Affecting The Basal Ganglia, Cerebral Cortex, And In Systemic Conditions Appendix A: A Summary Scheme for the Bedside Ocular Motor Examination Appendix B: A Summary of Methods for Measuring Eye Movements Appendix C: Tables of Ocular Motor Findings in Hereditary Ataxias Appendix D: Table of Videos and their Legends

The neurology of eye movements

1. Single unit impulses were recorded with percutaneously inserted tungsten needle electrodes from the median nerve in conscious human subjects. 2. A sample of 334 low threshold mechanoreceptive units innervating the glabrous skin area of the hand were studied. In accordance with earlier investigations, the units were separated into four groups on the basis of their adaptation and receptive field properties: RA, PC, SA I and SA II units. 3. The locations of the receptive fields of individual units were determined and the relative unit densities within various skin regions were calculated. The over-all density was found to increase in the proximo-distal direction. There was a slight increase from the palm to the main part of the finger and an abrupt increase from the main part of the finger to the finger tip. The relative densities in these three regions were 1, 1.6, 4.2. 4. The differences in over-all density were essentially accounted for by the two types of units characterized by small and well defined receptive fields, the RA and SA I units, whereas the PC and SA II units were almost evenly distributed over the whole glabrous skin area. 5. The spatial distribution of densities supports the idea that the RA and SA I units account for spatial acuity in psychophysical tests. This capacity is known to increase in distal direction along the hand. 6. On the basis of histological data regarding the number of myelinated fibres in the median nerve, a model of the absolute unit density was proposed. It was estimated that the density of low threshold mechanoreceptive units at the finger tip is as high as 241 u./cm2, whereas in the palm it is only 58 u./cm2.

https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/jphysiol.1979.sp012619

Tactile sensibility in the human hand: relative and absolute densities of four types of mechanoreceptive units in glabrous skin.

Functional recovery from peripheral nerve injury and repair depends on a multitude of factors, both intrinsic and extrinsic to neurons. Neuronal survival after axotomy is a prerequisite for regeneration and is facilitated by an array of trophic factors from multiple sources, including neurotrophins, neuropoietic cytokines, insulin-like growth factors (IGFs), and glial-cell-line-derived neurotrophic factors (GDNFs). Axotomized neurons must switch from a transmitting mode to a growth mode and express growth-associated proteins, such as GAP-43, tubulin, and actin, as well as an array of novel neuropeptides and cytokines, all of which have the potential to promote axonal regeneration. Axonal sprouts must reach the distal nerve stump at a time when its growth support is optimal. Schwann cells in the distal stump undergo proliferation and phenotypical changes to prepare the local environment to be favorable for axonal regeneration. Schwann cells play an indispensable role in promoting regeneration by increasing their synthesis of surface cell adhesion molecules (CAMs), such as N-CAM, Ng-CAM/L1, N-cadherin, and L2/HNK-1, by elaborating basement membrane that contains many extracellular matrix proteins, such as laminin, fibronectin, and tenascin, and by producing many neurotrophic factors and their receptors. However, the growth support provided by the distal nerve stump and the capacity of the axotomized neurons to regenerate axons may not be sustained indefinitely. Axonal regenerations may be facilitated by new strategies that enhance the growth potential of neurons and optimize the growth support of the distal nerve stump in combination with prompt nerve repair.

The cellular and molecular basis of peripheral nerve regeneration.

The hippocampus and behavior.

Recent studies in the rat (Guillery, 1956; Nauta, 1956) have confirmed much earlier descriptions of widespread distributions of the fornix system to the diencephalon and the rostral mid-brain regions. Besides the well-known massive hippocampal projections to the septal region (Ganser, 1882) and the mammillary body (Gudden, 1881), fornix components have been traced from the hippocampus to the preoptic region and the hypothalamus (Cajal, 1911), to the anterior nuclear complex and rostral intralaminar nuclei of the thalamus (Gudden, 1881; Vogt, 1898; Cajal, 1911), and to the rostral part of the central grey mid-brain substance (Edinger and Wallenberg, 1902).

Hippocampal projections and related neural pathways to the mid-brain in the cat

A classification of peripheral nerve injuries producing loss of function

The intraneural topography of the radial, median and ulnar nerves

The connective tissues of peripheral nerves

Stress-strain phenomena in human peripheral nerve trunks

A knowledge of neurovascular relations and anomalies at the base of the brain is of importance both for an understanding of certain obscure cranial nerve palsies accompanying diseased vascular states or expanding intracranial lesions, and for an appreciation of cranial nerve topography for the purposes of intracranial surgery. The object of this paper is to direct attention to some normal anatomical features which appear to have been neglected and to record certain anomalous arrangements of a highly practical character which have not hitherto been described. The observations are based on an examination of the brains of 210 dissecting-room subjects in which the anatomical relations at the base of the brain were studied during and following their removal from the cranial cavity. An advantage of this material was that all the brains were hardened iln situ, so that the configuration of the parts was pirserved. Clinical records of the cases examined were unfortunately rarely available so that it was not possible to correlate the anatomical findings with any ante-mortem symptomatology where signs of nerve compression might have been expected. The author is aware that this considerably limits the scope of the present study, since in themselves the observations advance no conclusive evidence that the neurovascular relations of the type here described were, or are, responsible for nerve palsies. There is, on the contrary, abundant evidence that nerves may be grossly stretched, compressed, and deformed without the development of any signs or symptoms of disordered function. All that is claimed is that these observations demonstrate that, even when the normal arrangement obtains, large arteries are on occasion so related to nerves that they may press upon, displace, and deform them. -In this way they could conceivably impair their function. This possibility is further increased by the presence in some cases of certain anomalous arrangements, and in others, where the vessels are the subject of atheromatous changes or are abnormally large, tortuous, or pulsating. There is already a voluminous literature relating to the association between intracranial aneurysms and the signs and symptoms of nerve compression (Peacock, 1876; Beadles, 1907; Fearnsides, 1916; Symonds, 1923; Jefferson, 1937; Dandy, 1944; and others). The present report, however, is not concerned with the excursions and possible effects of such arterial lesions.

https://jnnp.bmj.com/content/jnnp/11/4/243.full.pdf

Sydney Sunderland

Papers

A classification of peripheral nerve injuries producing loss of function

The intraneural topography of the radial, median and ulnar nerves

The connective tissues of peripheral nerves

Stress-strain phenomena in human peripheral nerve trunks

Neurovascular relations and anomalies at the base of the brain.