3D two-photon imaging
Circuits of neuronal network that compute information in real- time span across the brain tissue in 3D. To understand the computational mechanisms of the brain, we need methods that read out neural activity in large cell populations simultaneously, on both the somatic and dendritic scales. Following signal propagation and integration across a single neuron and recording the activity of hundreds of neurons pose challenges that not many imaging systems has been designed to tackle at once. To overcome this problem, we developed a high- resolution, acousto- optic (AO) two- photon microscope with continuous 3D trajectory and random- access scanning modes, that reaches a near cubic millimeter scan range, and can be adapted to imaging different spatial scales. With our technology, neuronal activity can be followed even in behaving animals in large scanning volumes, with a measurement speed and signal- to noise ratio (SNR) increased by several orders of magnitude. This feat, in combination with the exceptional penetration depth characteristic of two- photon imaging, makes our methodology very convenient for in vivo measurements of neuronal populations.