Purkinje cells

Purkinje neuron

Simple spikes.

The cerebellar cortex contains 20-30 million Purkinje cells (some estimates point to double the number). On each Purkinje cell there are, in round numbers, 2-3 thousand (!!) grain cells .

The Purkinje cells are inhibitory with GABA as the transmitter substance. They belong to the group of cerebellar cortex nerve cell types.

Purkinje cells are the largest nerve cells of the cerebellar cortex. They stretch with their different parts throughout the bark.

The cell bodies of the Purkinje cells are pear-shaped, 40-80 μm in size, are closely clustered side by side and form the middle layer of the cerebellar cortex: the Purkinje cell layer.

The dendritetrees of the Purkinje cells are very extensive and strangely flattened laterally. They form rows of densely packed sagittal discs which make up the bulk of the molecular layer of the cerebellar cortex. Dendrites are provided with dendrite tags, often in such quantities that a single dendrite tree carries more than 300,000 dendrite tags. The dendrite tree of Purkinje cells is penetrated by hundreds of thousands of parallel threads. These form excitatory synaptic complexes with the dendrite spines.

The axons of the Purkinje cells run down through the grain cell layer and have their inhibitory termini in the cerebellar nuclei (in some cases in the vestibular nuclei). The purkinje axone emits within its proximala parts a large number of collaterals up in the molecular layer.

The Purkinje cells are excited partly by the parallel filaments of the grain cells and partly by climbing filaments from the lower olive kernel complex with great impact.

Purkinje cells are inhibited partly by themselves (proximal axon claterals) and partly by the basket and star cells.

The Purkinje cells discharge spontaneously in the frequency range 30-50/second with so-called simple action potentialser (cf. with complex spike).