bims-climfi Biomed News
on Cerebellar cortical circuitry
Issue of 2019‒10‒13
two papers selected by
Jun Maruta
Mount Sinai Health System

  1. Acta Neurobiol Exp (Wars). 2019 ;79(3): 238-250
      The present study examined temporal activation patterns of rat cerebellar cortical neurons in 4-aminopyridine induced seizures, using c-fos protein as a marker of neuronal activity. C-fos-containing cells were counted in each cerebellar cortical layer, and cell count was compared between zebrin II positive and zebrin II negative bands of the lobules of the vermis and cerebellar hemispheres. We found significant activation of granule cells and interneurons of the molecular layer in zebrin II positive bands. The Purkinje cells, in contrast, exhibited non-significant, scattered c-fos immunoreactivity across all bands. Fluctuation of synaptophysin expression in the mossy fibre rosettes of the granular layer was determined via light microscopic immunohistochemistry. We detected a transient, significant decrease in synaptophysin staining density following 4-aminopyridine seizures, which may indicate short-term synaptic depression. We also identified different timing of increased c-fos expression in the neurons of the cerebellar cortex in different cortical zones. In particular, the activation pattern of the interneurons of the molecular layer reflected the climbing fibre distribution, reflecting the zonal olivo-cortico-nuclear organization. Seizure-induced activation of the granule cells corresponded with the zebrin II positive zones. This observation raises the possibility that zebrin II positive compartments may be more susceptible to cerebellar convulsions.
  2. Elife. 2019 Oct 09. pii: e47021. [Epub ahead of print]8
      The cerebellum has a parasagittal modular architecture characterized by precisely organized climbing fiber (CF) projections congruent with alternating aldolase C/zebrin II expression. However, behavioral relevance of CF inputs to individual modules remains poorly understood. Here, we used two-photon calcium imaging in the cerebellar hemisphere Crus II in mice performing an auditory go/no-go task to investigate the functional differences in CF inputs to modules. CF signals in medial modules show anticipatory decreases, early increases, secondary increases, and reward-related increases or decreases, which represent quick motor initiation, go cues, fast motor behavior, and positive reward outcomes. CF signals in lateral modules show early increases and reward-related decreases, which represent no-go and/or go cues and positive reward outcomes. The boundaries of CF functions broadly correspond to those of aldolase C patterning. These results indicate that spatially segregated CF inputs in different modules play distinct roles for execution of goal-directed behavior.
    Keywords:  mouse; neuroscience