A computational gateway for astrocytic calcium imaging
Dipartimento
BIOLOGIA
Corso di studi
NEUROSCIENCE
Relatori
relatore Dott. Ratto, Gian Michele correlatore Dott. Origlia, Nicola correlatore Dott. Maya-Vetencourt, José Fernando
Parole chiave
2-photon microscopy
astrocytes
BDNF
calcium
calcium imaging
computational neuroscience
matlab
memory
perirhinal cortex
Data inizio appello
22/03/2022
Consultabilità
Non consultabile
Data di rilascio
22/03/2092
Riassunto
Calcium ion (Ca2+) is a second messenger that plays a pivotal role in the physiology of the cell. Excitable cells, such as neurons and glia, are known to finely regulate their intracellular Ca2+ concentration with a very precise spatio-temporal resolution, giving rise to complex signals. Being able to decipher these signals implies the opportunity to exploit a full-fledged "window with a view" on the life of the brain. During my internship, I contributed to the development of a novel MATLAB-written software, named Image Gateway, that has been devised with the simple aim of allowing unbiased, virtually ROI-free analyses of calcium imaging acquisitions. The two main purposes of Image Gateway are, in extreme synthesis, that of (i) automatically extracting "interesting" clusters of Ca2+ activity – conceived as spatio-temporal columns that encompass high fluctuations of Ca2+ ΔF/F activity –, and (ii) automatically computing a cross-correlation analysis on the ΔF/F time series extracted from these clusters. A very wide range of different parameters and diverse pipelines are at the user’s disposal, making the overall analysis process highly customizable and quite fast. On top of that, Image Gateway is virtually independent of the neurobiological problem. The software can in fact be launched regardless of the kind of microscopy, and it can carry out analyses either at the single-cell level or at multiple-cells level – virtually on any cell type. For this thesis, I report the use of Image Gateway for the study and the characterization of intracellular Ca2+ microdomains present within the thin processes of astrocytes – a type of glial cells which is known to finely oversee the neuronal computation, as well as plasticity phenomena – whose activity was recorded in slices of mouse perirhinal cortex by means of two- photon microscopy. The results allowed to unveil the stochastic, virtually neuronal-independent behaviour of perirhinal cortex astrocytic Ca2+ microdomains, which were previously shown to be necessary for synaptic LTP stabilization and maintainance through pro-BDNF/BDNF recycling. These findings suggest the importance of auto-regulatory mechanisms, operated within the astrocytic peri-synaptic territory itself, which might subtend an unexpected functional drive at the basis of episodic memory formation.