Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- Part I Physiology and pathophysiology of nerve fibres
- Part II Pain
- Part III Control of central nervous system output
- 18 Synaptic transduction in neocortical neurones
- 19 Cortical circuits, synchronization and seizures
- 20 Physiologically induced changes of brain temperature and their effect on extracellular field potentials
- 21 Fusimotor control of the respiratory muscles
- 22 Cerebral accompaniments and functional significance of the long-latency stretch reflexes in human forearm muscles
- 23 The cerebellum and proprioceptive control of movement
- 24 Roles of the lateral nodulus and uvula of the cerebellum in cardiovascular control
- 25 Central actions of curare and gallamine: implications for reticular reflex myoclonus?
- 26 Pathophysiology of upper motoneurone disorders
- 27 Modulation of hypoglossal motoneurones by thyrotropin-releasing hormone and serotonin
- 28 Serotonin and central respiratory disorders in the newborn
- 29 Are medullary respiratory neurones multipurpose neurones?
- 30 Reflex control of expiratory motor output in dogs
- 31 Abnormal thoraco-abdominal movements in patients with chronic lung disease
- 32 Respiratory rhythms and apnoeas in the newborn
- 33 Cardiorespiratory interactions during apnoea
- 34 Impairment of respiratory control in neurological disease
- 35 The respiratory muscles in neurological disease
- Part IV Development, survival, regeneration and death
- Index
26 - Pathophysiology of upper motoneurone disorders
from Part III - Control of central nervous system output
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- List of contributors
- Preface
- Part I Physiology and pathophysiology of nerve fibres
- Part II Pain
- Part III Control of central nervous system output
- 18 Synaptic transduction in neocortical neurones
- 19 Cortical circuits, synchronization and seizures
- 20 Physiologically induced changes of brain temperature and their effect on extracellular field potentials
- 21 Fusimotor control of the respiratory muscles
- 22 Cerebral accompaniments and functional significance of the long-latency stretch reflexes in human forearm muscles
- 23 The cerebellum and proprioceptive control of movement
- 24 Roles of the lateral nodulus and uvula of the cerebellum in cardiovascular control
- 25 Central actions of curare and gallamine: implications for reticular reflex myoclonus?
- 26 Pathophysiology of upper motoneurone disorders
- 27 Modulation of hypoglossal motoneurones by thyrotropin-releasing hormone and serotonin
- 28 Serotonin and central respiratory disorders in the newborn
- 29 Are medullary respiratory neurones multipurpose neurones?
- 30 Reflex control of expiratory motor output in dogs
- 31 Abnormal thoraco-abdominal movements in patients with chronic lung disease
- 32 Respiratory rhythms and apnoeas in the newborn
- 33 Cardiorespiratory interactions during apnoea
- 34 Impairment of respiratory control in neurological disease
- 35 The respiratory muscles in neurological disease
- Part IV Development, survival, regeneration and death
- Index
Summary
The pyramidal syndrome
The hallmark of lesions of the motor cortex or its descending fibres in the human is the pyramidal syndrome. It is characterized by deficient force generation and impairment of selective control of the fingers. Recovery is better in proximal than in distal muscles, which almost regain their former capacity, even in cases with complete pyramidal tract (PT) transection. Within the remaining range, force control is good as is sensory guidance. There is no disturbance of movement initiation, preparation or of specifications such as movement direction, and there are no apractic phenomena.
It is an old controversy whether the increase in tone and reflexes, which is often regarded as part of the pyramidal syndrome, is due to the damage of motor cortex and its descending fibres or whether it indicates the impairment of more rostral areas. Ablation studies in monkeys and apes showed that excisions restricted to area 4 led to an initially flaccid paresis, later resolving into a state of approximately normal tonus. Hines (1929) found spasticity only after excisions involving the anterior part of area 4 and called this ‘suppressor strip’ or area 4s. Electrical stimulation of this strip yielded muscle relaxation. For the mediation of this inhibitory action McCulloch, Graf & Magoun (1946) described a separate non-pyramidal cortico-reticular pathway projecting from area 4s to the brainstem. Although such an inhibitory zone has not been confirmed by subsequent studies, other authors have associated spasticity with more anterior lesions centring on the superior precentral sulcus in the premotor area of the macaque cortex (Fulton & Kennard, 1934; Denny-Brown & Botterell, 1948; Woolsey et al., 1952).
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- The Neurobiology of DiseaseContributions from Neuroscience to Clinical Neurology, pp. 276 - 282Publisher: Cambridge University PressPrint publication year: 1996