Fiber-bundle imaging

Imaging and manipulating single neurons in freely behaving rats

Long-term imaging and optogenetic manipulation of neuronal activity can help to reveal the underlining circuitry of the brain. Moreover, correlating the optical measurements with behavioral observations can shed light on the specific function of each neuron. To this end, multiple groups have developed 1- and 2-photon fiberscopes for the imaging and holographic photoactivation in freely behaving mice. Yet, there are no reports of behavioral experiments using a fiberscope.

In pursuit of this idea we are developing a novel system for imaging single neurons in freely-behaving rats while photoactivating or inhibiting them in collaboration with Hiroshi Ito. 1-photon wide-field fluorescence of GCaMP7f or jRGECO1 expressing cells is recorded with a camera together with an image fiber and a gradient-index (GRIN) lens. By employing a spatial-light-modulator (SLM) we are planning on selectively photoactivating or inhibiting single neurons. To overcome the stress-induced tension in the fiber while the animals are moving we are building a commutator which renders the field-of-view invariant over rotation.