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Sugihara, I.

Publications and source records attributed to Sugihara, I..

3 recordsLinked to original sources
bioRxiv2020

Heterogeneity of intrinsic excitability in Purkinje cells linked with longitudinal zebrin zones in the mouse cerebellum

Heterogeneous populations of Purkinje cells (PCs), classified into zebrin-positive (Z+) and - negative (Z-) types, are arranged into separate longitudinal zones and are involved in different types of cerebellar learning. However, the electrophysiological phenotype that is brought about by the zebrin expression has not been much clarified in PCs. We compared electrophysiological characteristics in the soma and parallel fiber (PF)-PC synapse in Z+ and Z- PCs located in identified vermal and hemispheric zones in cerebellar slices in zebrin-reporter mice. Intrinsic excitability, intrinsic plasticity and PF-PC synaptic long term potentiation (LTP) occurred more strongly in Z- Purkinje cells than in Z+ PCs. The enhanced intrinsic plasticity was correlated with the reduction of medium-time-course after-hyperpolarization (mAHP) only in Z- PCs. These differences, which seem to be produced by the zebrin-linked expression of other functional molecules, may tune Z+ and Z- PCs to zone-specific cerebellar functions.

neuroscience↗
bioRxiv2020

Striped distribution pattern of Purkinje cells of different birthdates in the mouse cerebellar cortex studied with the Neurog2-CreER transgenic line

Heterogeneity of Purkinje cells (PCs) that are arranged into discrete longitudinal stripes in the cerebellar cortex is related to the timing of PC generation. To understand the cerebellar compartmental organization, we mapped the PC birthdate (or differentiation timing) in the entire cerebellar cortex. We used the birthdate-tagging system of neurog2-CreER (G2A) mice hybridized with the AldocV strain which clarifies the zebrin (aldolase C) longitudinal striped pattern. The pattern of the birthdate-dependent PC distribution was arranged consistently into longitudinally-oriented stripes throughout almost all lobules except for the nodulus, paraflocculus and flocculus, in which distinct stripes were observed.Boundaries of the PC birthdate stripes were found either in the middle or coincided with that of the zebrin stripes. PCs in each birthdate stripe were born in various periods between embryonic day (E) 10.0 and E 13.5. In the vermis, PCs were chronologically distributed from lateral to medial stripes. In the paravermis, PCs of early birthdates were distributed in the long lateral zebrin-positive stripe (stripe 4+//5+) and the medially neighboring narrow zebrin-negative substripe (3d-//e2-), while PCs of late birthdates were distributed in the rest of all paravermal areas. In the hemisphere, PCs of early and late birthdates were intermingled in the majority of areas. The results indicate that the birthdate of a PC is a partial determinant for the zebrin compartment in which it is located. However, the correlation between the PC birthdate and the zebrin compartmentalization is not simple, and distinct among the vermis, paravermis, hemisphere, nodulus, and flocculus. HighlightsBirthdates of Purkinje cells (PCs) were mapped on the cerebellar zebrin striped pattern by using Neurog2-CreER (G2A) mice. The vermis, paravermis, hemisphere, nodulus, and flocculus had distinct longitudinally-striped patterns of PC birthdate distribution. PCs in each birthdate stripe were born in various periods between embryonic day (E) 10.0 and E 13.5. Boundaries of PC birthdate distributions were located at the boundaries of zebrin stripes or in the middle of a zebrin stripe. The results indicate that the PC birthdate is a partial determinant for the zebrin compartment in which a PC is located.

neuroscience↗
bioRxiv2019

Convergence of unisensory-evoked signals via multiple pathways to the cerebellum

The cerebellum receives signals directly from peripheral sensory systems and indirectly from the neocortex. To reveal how these different types of signals are processed in the cerebellar cortex, in vivo whole-cell recordings from granule cells and unit recordings from Purkinje cells were performed in mice in which primary somatosensory cortex (S1) could be optogenetically inhibited. Tactile stimulation of the upper lip produced two-phase granule cell responses (with latencies of [~] 8 ms and 28 ms), for which only the late phase was S1 dependent. Complex spikes and the late phase of simple spikes in Purkinje cells were also S1 dependent. These results indicate that individual granule cells integrate convergent inputs from the periphery and neocortex, and send their outputs to Purkinje cells, which then combine those signals with climbing fiber signals from the neocortex.

neuroscience↗