Optical imaging

Autofluorescence imaging (AFI) is another, perhaps less commonly known, technique used to measure neuronal activity. It relies on the detection of changes in fluorescence from endogenous mitochondrial proteins inside neurons, named flavoproteins. During aerobic energy metabolism, these flavoproteins are oxidized which is translated by an increase in the molecule’s autofluorescence. Therefore, this signal can be used to measure neuronal activity given that an increase in neuronal responses is directly linked to an increase in its metabolic rate. In this blog, we explore the mouse primary somatosensory cortex function using both intrinsic and autofluorescence imaging techniques.

When we think about how we use our senses to interact with the surrounding environment, the sense of smell might not be the first to come to mind. However, evidence indicates that olfaction plays a crucial role in our species, influencing several aspects of our social interactions, such as mate choice and mother-infant bonding (Boesveldt and Parma 2021).
One study estimated that humans can discriminate more than a trillion different odors (Bushdid et al. 2014). This remarkable capability is due to the presence of a large number of olfactory sensory neurons in the back of our nasal cavity. Each neuron expresses a single type of olfactory receptor protein, which has a distinct affinity for specific odorant molecules.