Periodic Reporting for period 3 - iNAPS (Illuminating Neuronal-Astrocytic Pathways for Sleep homeostasis)
Período documentado: 2020-04-01 hasta 2021-09-30
The overall objectives are: 1) identify the cell types and brain regions involved in sleep homeostasis; 2) determine how these cells affect sleep drive; and 3) evaluate the role of astrocytes, a special type of brain cell, in sleep homeostasis.
Once we have identified specific cell populations, we want to confirm the role of each group of cells, i.e. can we recapitulate aspects of sleep homeostasis by using specific tools that activate/inhibit those cells. For example, are certain cell types the engine driving sleep consolidation after sleep loss? We are currently optimising methodology required to target specific cell groups to assess their functionality.
Lastly, we are interested in how astrocytes – a specific type of brain cell – behave in sleep homeostasis. To do this we are using a mouse line that enables the expression of specific tags (e.g. fluorescent label or activity indicator) in astrocytes. We have observed marked morphological changes in astrocytes with sleep deprivation, and are exploring the functional consequences of this. We have also shown that astrocyte modulation affects the activity of cortical neurons of interest. Finally, we labeled astrocytes with a specific dye, facilitating the recording of their activity across sleep states.
• Performed intact-brain mapping of cellular activity in SD and RS. We are now expanding this dataset and performing unbiased quantitative analysis to prioritise regions of interest. Combined with the results from the above point, we expect to establish which brain regions are involved in sensing sleep need. Concomitantly, we have performed intact-brain mapping of NOS1 cells across sleep states. Preliminary results indicate region-specific alterations in cell morphology.
• Imaged signaling dynamics of cortical cells in brain slices. We are expanding this dataset with sleep perturbations and have planned parallel in vivo recordings. We expect to confirm the dynamic modulation of NOS1 cell activity across sleep states.
• Preliminary analysis indicates alteration in astrocyte morphology with sleep deprivation. Further replication is required to determine if this effect is robust, reproducible and region-dependent.