Why Optogenetics Needs in Vivo Neurochemistry

In neuroscience, the consequences of optogenetic manipulation are often studied using in vivo electrophysiology and by observing behavioral changes induced by light stimulation in genetically targeted rodents. In contrast, reports on the in vivo neurochemical effects of optogenetic stimulation are scarce despite the improving quality of analytical techniques available to monitor biochemical compounds involved in neurotransmission. This intriguing lack of neurochemical information suggests the existence of unknown or misunderstood factors hampering the expected rise of a novel specialty putatively be termed "neurochemical optogenetics".