Journal Article

Redefining the cerebellar cortex as an assembly of non-uniform Purkinje cell microcircuits

Lang, Eric J., Apps, Richard, Cerminara, Nadia L., Sillitoe, Roy V.

2015

Overview

Key Points A widely held assumption is that the same neural computation is performed throughout a uniform circuitry in the adult mammalian cerebellar cortex, and differences in function can be explained primarily by distinct patterns of input and output connectivity. Anatomical, genetic and physiological evidence suggests, however, that the cerebellar cortex is not uniform. Regional differences include variations in cell type, morphology and expression of various molecular markers, most notably zebrin II expression by Purkinje cells. Purkinje cells are considered to be key players within the cerebellar cortex because they provide the sole signal output from the cortex to the cerebellar nuclei. Differences related to zebrin II expression include variations in intrinsic and synaptic physiology and patterns of activity of simple spikes and complex spikes. Mouse mutant models also show that Purkinje cell death occurs in restricted patterns that are related to both motor and potentially non-motor dysfunction. Variations in gene expression and related anatomical and physiological differences therefore result in an assembly of non-uniform cerebellar cortical microcircuits that have different information processing capabilities. The cerebellar cortex drives smooth goal-directed movement as well as a range of other functions. Apps and colleagues describe studies that have revealed variations in the cytoarchitecture, molecular composition, physiological properties and vulnerability to cell death of different cerebellar cortical regions, and discuss the idea that these underlie different forms of information processing. The adult mammalian cerebellar cortex is generally assumed to have a uniform cytoarchitecture. Differences in cerebellar function are thought to arise primarily through distinct patterns of input and output connectivity rather than as a result of variations in cortical microcircuitry. However, evidence from anatomical, physiological and genetic studies is increasingly challenging this orthodoxy, and there are now various lines of evidence indicating that the cerebellar cortex is not uniform. Here, we develop the hypothesis that regional differences in properties of cerebellar cortical microcircuits lead to important differences in information processing.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 13/51 / 631/378/1697 / 631/378/2632/1368 / 64/110 / 9/74 / Animal Genetics and Genomics / Animals / Behavioral Sciences / Biological Techniques / Biomedicine / Cerebellar ataxia / Cerebellar Cortex - physiology / Climbing / Cognition / Genetic aspects / Humans / Nerve Net - physiology / Neurobiology / Neurons / Neurosciences / Physiological aspects / Physiology / Purkinje Cells - physiology / review-article / Synapses - physiology