Novel Optical Probe for Multi-Region Fiber Photometry in Mouse Brain

Animal behavior is driven by the simultaneous activation of neurons within networks that are distributed across various brain areas. The complexity of neuronal networks, involving various brain regions and different types of neurons, necessitates the ability to record the activity of specific neuronal subpopulations simultaneously. For this purpose the multi-fiber photometry systems have been proposed in several previous studies. Here we developed a new optical probe that combines two optic fibers with different length. We implanted the probes bilaterally addressing two different brain area in each hemisphere. We further applied this technique for calcium activity registration simultaneously in four brain areas during associative learning. We showed that the basolateral amygdala and primary somatosensory cortex become more active towards a previously neutral stimulus, implying their roles in associative memory formation during learning. Altogether, we showed the new optic-fiber probe for four-site calcium activity registration in brain of behaving mouse.