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DTSTAMP:20260404T025848Z
UID:5e1451b13ad2b958774976@ist.ac.at
DTSTART:20200117T130000
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DESCRIPTION:Speaker: Steven A. Kushner\nhosted by Gaia Novarino\nAbstract: 
 Cortical GABAergic fast-spiking parvalbumin-positive (PV) interneurons are
  frequently myelinated with a proximally-biased topography and account for
  a substantial fraction of neocortical myelin. Conversely\, somatostatin-p
 ositive (SOM) interneurons contribute only modestly to myelin content in t
 he cerebral cortex. Previous studies have demonstrated that myelinating gl
 ia are sensitive to fiber caliber for initiating axonal wrapping\, however
  the majority of studies have focused on the peripheral nervous system or 
 have been performed in cell culture settings. Given the substantial differ
 ences in axonal morphology between local PV+ and SOM+ interneurons\, we th
 erefore sought to examine whether cortical interneuron myelination might b
 e related to axonal morphology in vivo. We now demonstrate that segmental 
 axonal myelination of cortical interneurons is strongly predicted by the j
 oint combination of interbranch-point distance and local axon caliber in b
 oth mouse and human neocortex. We further explored the robustness of this 
 model by either increasing PV+ interneuron size with cell-type specific de
 letion of Tsc1 or reducing PV+ interneuron size by cell-type specific dele
 tion of Ube3a. In both cases\, although the frequency of myelinated segmen
 ts was significantly altered\, the joint combination of interbranch-point 
 distance and local axon caliber remained highly predictive of myelin topog
 raphy. Lastly\, we considered regular-spiking SOM+ cells\, which normally 
 have relatively shorter interbranch distances and thinner axon diameters t
 han PV+ cells\, and are rarely myelinated. Enlargement of SOM+ cell size b
 y cell type-specific deletion of Tsc1 dramatically increased the frequency
  of myelinated axonal segments and with a topography accurately predicted 
 by the model. Together\, our results suggest that local axonal morphology 
 is an important determinant underlying the topography of cortical GABAergi
 c interneuron myelination.
LOCATION:Seminar Room\, Lab Building East\, ISTA
ORGANIZER:lmarr@ist.ac.at
SUMMARY:Steven A. Kushner: Morphological determinants of cortical GABAergic
  interneuron myelination
URL:https://talks-calendar.ista.ac.at/events/2471
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