In this talk, I will describe our efforts to use light in order to understand information processing in the brain using light. I will start with an established tool of using light for 3D brain imaging via multi-photon microscopy, where within fundamental optical limits, provides a good spatial range for studying single neurons up to interconnected neurons in a circuit. Within this spatial range, I will also talk about using patterned light to photo-induce synaptic inputs and analyse how the spatio-temporal organisation of these inputs cause the neuron to fire an output.
We use a dynamically programmable hologram to produce 3D light patterns that can induce targeted and highly localised synaptic inputs along the dendritic tree of a neuron. Such technique can also be used for light-based recording of responses from multiple neurons – leading to an all-optical method for stimulating and recording neuronal activity. To target neurons deep within brain tissue, the hologram can be added with an adaptive phase-pattern to correct for optical aberrations caused by the brain tissue.