Probing inter-areal computations with a cellular resolution two-photon holographic mesoscope

Abstract

SummaryBrain computation depends on intricately connected yet highly distributed neural networks. Due to the absence of the requisite technologies, causally testing fundamental hypotheses on the nature of inter-areal processing have remained largely out-of-each. Here we developed the first two photon holographic mesoscope, a system capable of simultaneously reading and writing neural activity patterns with single cell resolution across large regions of the brain. We demonstrate the precise photo-activation of spatial and temporal sequences of neurons in one brain area while reading out the downstream effect in several other regions. Investigators can use this new platform to understand feed-forward and feed-back processing in distributed neural circuits with single cell precision for the first time.

Rapid learning of neural circuitry from holographic ensemble stimulation enabled by model-based compressed sensing

“…While in our experiments we typically mapped connectivity from several hundred neurons, this was only limited by factors outside of the influence of NWD and CAVIaR, such as the number of neurons targetable by our SLM or the rate at which phase masks could be computed. Our simulations predict that the scale and throughput of compressive connectivity mapping will only grow with the adoption of experimental steps to increase the targetable field of view (e.g., by translating the microscope or SLM stimulation field), with larger commercially available SLMs, with the use of holographic mesoscopes [Abdeladim et al, 2023], or with even more potent opsins enabling stimulation of more targets for the same laser power. Such advances would allow for precise, low-latency holographic control over larger neural ensembles or for mapping larger population sizes than those used here.…”

Closed-loop experiments and brain machine interfaces with multiphoton microscopy

“… 97 A combination of 3D-SHOT and ChroME2s realized targeted photostimulation of more than 600 cells per second. 98 3D-SHOT can be used with large FOV two-photon microscopy, 99 which should enable the control of more neural activities.…”

“…How many neurons can be stimulated per second with the current level of technology? Let us assume that each cell needs to be stimulated with a laser of about 10 mW for about 10 ms. 28 , 97 – 101 The upper limit of total laser power would be about 200 mW due to the problem of overheating caused by water absorption. 102 Thus the limit would be 100 patterns of 20 populations, a total of 2000 neurons/s.…”

“…To increase total number of photostimulated neurons, incorporating two or more SLMs within the same microscope would be useful 96 in addition to using a large FOV two-photon microscope. 20 , 99 …”

“…A combination of imaging and stimulation with two-photon microscopy, i.e., an all-optical experiment in which activity is monitored by two-photon imaging and simultaneously controlled by two-photon stimulation of opsin, has been realized. 27 , 29 , 30 , 54 , 96 , 99 – 101 , 106 – 113 What is possible when we can record and stimulate at the same time? In the case of whole-cell patch-clamp recording for monitoring and stimulating the cell, one can hold the membrane potential according to the negative feedback of the operational amplifier.…”