Properties of bilateral spinocerebellar activation of cerebellar cortical neurons.
We aimed to explore the cerebellar cortical inputs from two spinocerebellar pathways, the spinal border cell-component of the ventral spinocerebellar tract (SBC-VSCT) and the dorsal spinocerebellar tract (DSCT), respectively, in the sublobule C1 of the cerebellar posterior lobe. The two pathways were activated by electrical stimulation of the contralateral lateral funiculus (coLF) and the ipsilateral LF (iLF) at lower thoracic levels. Most granule cells in sublobule C1 did not respond at all but part of the granule cell population displayed high-intensity responses to either coLF or iLF stimulation. As a rule, Golgi cells and Purkinje cell simple spikes responded to input from both LFs, although Golgi cells could be more selective. In addition, a small population of granule cells responded to input from both the coLF and the iLF. However, in these cases, similarities in the temporal topography and magnitude of the responses suggested that the same axons were stimulated from the two LFs, i.e., that the axons of individual spinocerebellar neurons could be present in both funiculi. This was also confirmed for a population of spinal neurons located within known locations of SBC-VSCT neurons and dorsal horn (dh) DSCT neurons. We conclude that bilateral spinocerebellar responses can occur in cerebellar granule cells, but the VSCT and DSCT systems that provide the input can also be organized bilaterally. The implications for the traditional functional separation of VSCT and DSCT systems and the issue whether granule cells primarily integrate functionally similar information or not are discussed.
Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University Lund, Sweden.
Pontus
P
Geborek
Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University Lund, Sweden.
Fredrik
F
Bengtsson
Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University Lund, Sweden.
Henrik
H
Jörntell
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001703:Biophysics; D002415:Cats; D002525:Cerebellar Cortex / Q000166:cytology*; D004558:Electric Stimulation; D004569:Electroencephalography; D007839:Functional Laterality / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D009474:Neurons / Q000145:classification / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology; D020824:Spinocerebellar Tracts / Q000502:physiology*
Golgi cells; Purkinje cell; granule cells; in vivo whole cell recording; mossy fiber; sensorimotor control; spinocerebellar tracts