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MEMP - Thesis Defense - Vicente Parot

Thursday, May 9, 2019

All-optical neurophysiology using high-speed wide-area optical sectioning

All-optical stimulation and recording of neural activity has the potential to characterize brain function over large areas, but requires spectrally orthogonal optogenetic actuators and reporters, and optical systems for stimulation and optically sectioned imaging in turbid tissue. Two-photon (2P) all-optical neurophysiology is limited to <100 cells in parallel due to the high laser power required. To stimulate and record neural activity with one photon (1P), we paired a trafficking-optimized blue shifted channelrhodopsin (eTsChR) with a nuclear-localized red-shifted calcium indicator (H2B-jRGECO1a). To image cellular-resolution activity in large areas (4.6 mm FOV) of acute brain slices, we devised a computational optical sectioning method using a digital micromirror device (DMD) to illuminate neighboring sample locations with orthogonal functions of time based on Hadamard codes. To record high-speed neuronal activity (500 Hz), we designed a compressed sensing strategy for Hadamard microscopy with analytic solution, obtaining one optical section every two camera frames. We made wide-area functional maps spanning cortex and striatum, of the effects of antiepileptic drugs on neural excitability and of the effects of AMPA and NMDA receptor blockers on synaptic transmission. Together, these optogenetic and optical tools provide a powerful capability for wide-area mapping of neuronal excitability and functional connectivity in acute brain slices. 

Thesis Supervisor:
Adam E. Cohen, PhD
Professor of Chemistry and Chemical Biology and of Physics, Harvard University
Howard Hughes Medical Institute Investigator

Thesis Committee Chair:
James M. Hogle, PhD
Edward S. Harkness Professor, Department of Biological Chemistry & Molecular Pharmacology,
Harvard University
 
Thesis Readers:
Bence P. Ölveczky, PhD
Professor of Organismic and Evolutionary Biology, Harvard University
 
David A. Boas, PhD
Professor of Biomedical Engineering, Boston University
 
Florian Engert, PhD
Professor of Molecular and Cellular Biology, Harvard University

 

 
Date and Time: 
Thursday, May 9, 2019 - 2:00pm to 4:00pm
Location: 
The Pfizer Lecture Hall, Mallinckrodt Building, Room B23
12 Oxford Street, Harvard Cambridge Campus