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1. The properties of interneurones located in the 4th lumbar segment of the cat spinal cord (L4 interneurones) have been investigated by intracellular and extracellular recording from individual neurones. The study focused on interneurones projecting to hind-limb motor nuclei and/or interposed in pathways from group II muscle afferents. The projection to(More)
Postnatal development of the corticospinal system was investigated in 13 macaques using noninvasive transcranial magnetic stimulation (TMS) of the motor cortex and direct electrical stimulation of corticospinal axons in the medullary pyramid and spinal cord. The latency of antidromic corticospinal volleys evoked from the pyramid and recorded from the motor(More)
1. A powerful projection from group II muscle afferents of hind-limb muscles to the 3rd, 4th and 5th segments of the lumbar spinal cord has been demonstrated by focal synaptic field potential recording. 2. Field potentials were found at two locations: one in the dorsal horn (Rexed's laminae IV and V) and the other in the intermediate zone and ventral horn(More)
To illuminate the action of non-invasive stimuli on the human cerebral cortex, responses of corticospinal axons and of plantar alpha-motor neurons following transcranial magnetic (TMS) and electrical stimulation (TES) were recorded in the lumbosacral cord in the anaesthetized macaque monkey. A round coil was used for TMS, and the anode was located at the(More)
1. Extracellular recordings have been obtained from 134 units in the paravermal cortex of lobule V in the anterior lobe of the cerebellum in free-to-move cats. Each unit discharged action potentials in a characteristic pattern with no complex spikes. Previous investigators have described such discharges and have assigned them to Golgi cells. We provide(More)
Although the reticulospinal tract is a major descending motor pathway in mammals, its contribution to upper limb control in primates has received relatively little attention. Reticulospinal connections are widely assumed to be responsible for coordinated gross movements primarily of proximal muscles, whereas the corticospinal tract mediates fine movements,(More)
While the synaptic properties of Golgi cell-mediated inhibition of granule cells are well studied, less is known of the afferent inputs to Golgi cells so their role in information processing remains unclear. We investigated the responses of cerebellar cortical Golgi cells and Purkinje cells in Crus I and II of the posterior lobe cerebellar hemisphere to(More)
Strong experimental evidence implicates the corticospinal tract in voluntary control of the contralateral forelimb. Its potential role in controlling the ipsilateral forelimb is less well understood, although anatomical projections to ipsilateral spinal circuits are identified. We investigated inputs to motoneurons innervating hand and forearm muscles from(More)
Extracellular recordings were made from 124 Purkinje cells in the paravermal part of lobule V of the cerebellum in cats walking steadily at a speed of 0.5 m/s on a moving belt. All cells tested had a tactile receptive field from which simple spikes could be evoked and 96% of these were on the ipsilateral forelimb. Seventy-six of the cells were also studied(More)
We recently showed that the activity of cerebellar Golgi cells can be powerfully modulated by stimulation of peripheral afferents, in a pattern different to local Purkinje cells. Here we have examined the pathways underlying these responses. Graded electrical stimulation of muscle and cutaneous nerves revealed that long-lasting depressions and short-lasting(More)