ELFT HÍRADÓ

[Balazs Dora <dora.balazs AT ttk.bme.hu>]

                         MEGHÍVÓ








     a Szilárd Leó-Kollokvium előadására:


                  Balázs Rózsa
                   (Femtonics)




"*FAST SIMULTANEOUS 3D ACOUSTO-OPTICAL IMAGING AND PHOTOSTIMULATION FOR 
VISUAL RESTORATION*"



Kivonat: The understanding of brain computations requires methods that 
read out neural activity on different spatial and temporal scales. 
Following signal propagation and integration across a neuron and 
recording the concerted activity of hundreds of neurons pose distinct 
challenges, and the design of imaging systems has been mostly focused on 
tackling one of the two operations. We developed a high-resolution, 
acousto-optic two-photon microscope with continuous three-dimensional 
(3D) trajectory and random-access scanning modes that reaches 
near-cubic-millimeter scan range and can be adapted to imaging different 
spatial scales. We performed 3D calcium and voltage imaging of action 
potential backpropagation and dendritic spike forward propagation at 
sub-millisecond temporal resolution in behaving mice.

Neural circuits support rapid visual learning. However, due to technical 
roadblocks, it is not known how visual circuits represent multiple 
features or how behaviorally relevant representations are selected for 
long-term memory. Here we developed Moculus, a head-mounted virtual 
reality platform for mice that covers the entire visual field, and 
allows binocular depth perception and full immersion. This controllable 
environment, combined with fast acousto-optical imaging, affords rapid 
visual learning and the uncovering of novel circuit substrates: both the 
control and reinforcement-associated visual cue coding neuronal 
assemblies are extended transiently to a near-saturating level. They 
formed partially orthogonal and overlapping clusters centered around hub 
cells with higher and earlier ramp-like responses, as well as locally 
increased connectivity. This temporally maximizes computational 
capability and allows competition between assemblies that encode 
behaviorally relevant information by stochastic fluctuation from 
trial-to-trial. The coding competition is driven by reinforcement 
feedback at the level of individual neurons.






Helye: BME Fizikai Intézet, Fizika Tanszék
Budafoki út 8. F-épület, 2. emelet, 13-as terem

Ideje: 2023. október 3. (kedd), 14:30.
Kapunyitás 14:15-től.
Program: http://physics.bme.hu/kollokvium


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Dóra Balázs és Zaránd Gergely