Mesoscale Ca²⁺imaging reveals networks of Purkinje cell dendritic and somatic modulation, with divergent roles of activity versus correlation during behavior

Abstract

A major challenge in cerebellar physiology is determining how the stereotypic, conserved circuitry of the cerebellar cortex, with its dominant parasagittal and transverse architectures, underlies its fundamental computations and contributions to behavior. To interrogate Purkinje cell dynamics at this parasagittal and transverse spatial scale, we implemented a novel approach for awake, chronic, wide-field Ca2+imaging of the cerebellar cortex. We observe two functionally and spatially distinct Purkinje cell networks, reflecting their dendritic and somatic activities, respectively. Both dendritic and somatic networks exhibit bilateral, widespread activation during behavior, but with diverse patterns of spatial correlations occurring primarily along the parasagittal and transverse directions, consistent with the main geometry of the cerebellar cortex. Somatic network correlation dynamics are robustly modulated by prediction errors, and even reflect ultimate behavioral outcomes. These results provide a novel link between cerebellar structure and function, with the correlation dynamics of Purkinje cell activity a key feature.

Early and widespread engagement of the cerebellum during hippocampal epileptiform activity Format: Brief Communication

“…Mice expressing the Ca 2+ indicator GCaMP6s selectively in Purkinje cells were generated by crossing mice expressing Cre selectively in Purkinje cells in the cerebellum (B6.Cg-Tg(Pcp2-cre)3555Jdhu/J; Jackson Laboratory stock 010536) 21 with floxed-STOP GCaMP6s mice (B6.Cg-Igs7tm162.1(tetO-GCaMP6s,CAG-tTA2)Hze/J; Jackson Laboratory stock 031562) 22 . The resulting PcP2-GCaMP6s crosses had expression of GCaMP6s restricted to Purkinje cells, and in a sparse manner, as reported previously 23 . This allowed for single cell resolution of Purkinje cells at the wide-field level.…”

“…We therefore adapted conformant See-Shell 15 technology to allow chronic, widefield, monitoring of the cerebellar cortex 16 , including lobules IV-VII ( Supplementary Figure 1 ). Sparse expression of GCaMP6s selectively in Purkinje cells allowed single cell resolution, and 1-photon imaging allowed simultaneous monitoring of both somatic and dendritic aspects 16 ( Supplementary Fig. 1 ).…”

“…Unsupervised spatial independent component analysis provided unbiased segregation of the widefield Ca 2+ signals into functional domains, which appeared as parasagittal bands and, separately, Purkinje cell somata ( Supplementary Fig. 1 , Supplementary Methods) 16 .…”

“…Cerebellar imaging windows were fabricated as described previously 23 . Implants consist of a small section of PET film affixed to a 3D-printed window frame, designed to conform to the contours of the skull, and a separate 3D-printed head fixation implant, which contained three holes tapped using an 0-80 hand tap for securing to a titanium headplate during the implantation surgery.…”

“…Implants consist of a small section of PET film affixed to a 3D-printed window frame, designed to conform to the contours of the skull, and a separate 3D-printed head fixation implant, which contained three holes tapped using an 0-80 hand tap for securing to a titanium headplate during the implantation surgery. A minimum of 2 weeks post KA injection, mice underwent implantation procedures 23 under isoflurane anesthesia. Buprenorphine ER (1mg/kg) and Dexamethasone (2mg/kg) were administered subcutaneously for analgesia and inflammation, respectively.…”