How does the human brain deal with a spinal cord injury?

The primary sensorimotor cortex of the adult brain is capable of significant reorganization of topographic maps after deafferentation and de‐efferentation. Here we show that patients with spinal cord injury exhibit extensive changes in the activation of cortical and subcortical brain areas during hand movements, irrespective of normal (paraplegic) or impaired (tetraplegic patients) hand function. Positron emission tomography ([15O]‐H2O‐PET) revealed not only an expansion of the cortical ‘hand area’ towards the cortical ‘leg area’, but also an enhanced bilateral activation of the thalamus and cerebellum. The areas of the brain which were activated were qualitatively the same in both paraplegic and tetraplegic patients, but differed quantitatively as a function of the level of their spinal cord injury. We postulate that the changes in brain activation following spinal cord injury may reflect an adaptation of hand movement to a new body reference scheme secondary to a reduced and altered spino‐thalamic and spino‐cerebellar input.

[1]  M Hallett,et al.  Rapid reversible modulation of human motor outputs after transient deafferentation of the forearm , 1992, Neurology.

[2]  Michael B. Calford,et al.  Short-term expansion of receptive fields in rat primary somatosensory cortex after hindpaw digit denervation , 1991, Brain Research.

[3]  J C Rothwell,et al.  Reorganization of cortical blood flow and transcranial magnetic stimulation maps in human subjects after upper limb amputation. , 1994, Journal of neurophysiology.

[4]  Karl J. Friston,et al.  Comparing Functional (PET) Images: The Assessment of Significant Change , 1991, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[5]  M. Mishkin,et al.  Massive cortical reorganization after sensory deafferentation in adult macaques. , 1991, Science.

[6]  S. Bandinelli,et al.  Motor reorganization after upper limb amputation in man. A study with focal magnetic stimulation. , 1991, Brain : a journal of neurology.

[7]  G. E. Alexander,et al.  Parallel organization of functionally segregated circuits linking basal ganglia and cortex. , 1986, Annual review of neuroscience.

[8]  Jon H. Kaas,et al.  Central reorganization of sensory pathways following peripheral nerve regeneration in fetal monkeys , 1996, Nature.

[9]  T. Elbert,et al.  Phantom-limb pain as a perceptual correlate of cortical reorganization following arm amputation , 1995, Nature.

[10]  Yukio Mano,et al.  Central motor reorganization after anastomosis of the musculocutaneous and intercostal nerves following cervical root avulsion , 1995, Annals of neurology.

[11]  M Hallett,et al.  Reorganization of corticospinal pathways following spinal cord injury , 1991, Neurology.

[12]  A Curt,et al.  Influence of spinal cord injury on cerebral sensorimotor systems: a PET study. , 1997, Journal of neurology, neurosurgery, and psychiatry.

[13]  Michael B. Calford,et al.  Immediate and chronic changes in responses of somatosensory cortex in adult flying-fox after digit amputation , 1988, Nature.

[14]  L. Kempe.  Handbook of Physiology. Section I. The Nervous System , 1982 .

[15]  J C Mazziotta,et al.  Somatotopic mapping of the primary motor cortex in humans: activation studies with cerebral blood flow and positron emission tomography. , 1991, Journal of neurophysiology.

[16]  John Cadwell,et al.  Focal magnetic coil stimulation reveals motor cortical system reorganized in humans after traumatic quadriplegia , 1990, Brain Research.