Spatial Light Modulator Multiplexing for Neural Stimulation
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Solution Overview
Problem
Current methods lack the capability to precisely and efficiently stimulate large populations of light-responsive neurons with the temporal and spatial resolution needed to mimic natural neural activity patterns, especially in awake behaving animals, for studying causal roles in circuit dynamics and behavior.
Innovation Solution
A light projection system that uses holographic images generated by a combination of light sources, optical adjustment components, and spatial light modulators to selectively stimulate light-responsive neurons at a rate greater than 1 kHz, allowing for precise manipulation of neural activity patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple spatial light modulators are used to stimulate large populations of neurons, then the spatial coverage and number of addressable neurons increase, but the temporal resolution and stimulation rate decrease due to sequential operation limitations
Solution Approach 1:
The patent employs time-multiplexed operation where multiple spatial light modulators are sequentially activated in periodic cycles. Each SLM operates at its full refresh rate during its allocated time slot, and the system cycles through multiple SLMs rapidly. This periodic switching enables the system to address thousands of neurons across multiple SLMs while maintaining high temporal resolution within each time slot, resolving the contradiction between covering large neuronal populations and maintaining high stimulation rates.
2Speed
If the refresh rate of spatial light modulators is increased to improve temporal precision, then the temporal resolution of neural activation patterns improves, but the complexity and cost of the system increases
Solution Approach 1:
The patent divides the system into multiple spatial light modulator units, each operating at standard refresh rates. By segmenting the overall stimulation task across multiple SLMs that operate in parallel time slots, the system achieves high effective temporal resolution without requiring any single SLM to operate at excessively high refresh rates. This segmentation approach maintains temporal precision while managing individual component complexity and cost.
3Manufacturing precision
If holographic images are projected at high rates to mimic natural neural activity patterns, then the fidelity of neural pattern reproduction improves, but the energy consumption and heat generation increase
Solution Approach 1:
The patent uses periodic time-multiplexed projection where high-fidelity holographic images are projected at high rates within each time slot, but the overall system operates by cycling through multiple SLMs sequentially. This periodic operation allows high instantaneous projection rates for fidelity while the duty cycle across the entire system manages average power consumption and heat generation, resolving the contradiction between pattern fidelity and energy usage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables kHz manipulation of thousands of neurons in a 3D volume with high spatial resolution, improving temporal precision of neural activation patterns and allowing for precise measurement and replay of natural activity, thereby enhancing our understanding of neural networks and behavior.
Implementation Method 1
irradiating a sample comprising a plurality of light-responsive neurons with a plurality of holographic images that are each configured to stimulate one or more light-responsive neurons in the sample, wherein the holographic images are created by light projection system that includes: a plurality of light sources; a plurality of optical adjustment components; a plurality of spatial light modulators
Implementation Method 2
Optogenetic methods of manipulating the activity of excitable cells, such as neurons, by altering the membrane potential of excitable cells expressing light-activated proteins that depolarize orhyperpolarize cells in response to light
Implementation Method 3
direct each of the holographic images to a projection location; and project the holographic images onto the sample at a rate greater than 1 kHz
Data Source
AI summary
Methods for selectively stimulating a plurality of light-responsive neurons in a sample are provided. Methods according to certain embodiments include irradiating a sample comprising a plurality of light-responsive neurons with a plurality of holographic images that are each configured to stimulate one or more light-responsive neurons in the sample, wherein the holographic images are created by light projection system that includes a plurality of light sources; a plurality of optical adjustment components; a plurality of spatial light modulators; a controller; a processor; and a computer-readable medium comprising instructions that, when executed by the processor, cause the controller to operate the light sources, optical adjustment components and spatial light modulators to generate and display a plurality of holographic images; direct each of the holographic images to a projection location; and project the holographic images onto the sample at a rate greater than 1 kHz. Light projection systems for irradiating a sample having light-responsive neurons with holographic images are also described.