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Background on neuronal tracing

A key aspect to understanding the brain’s function is knowing its architecture, in particular the connections between different brain regions. For example, communication between the hippocampus and the prefrontal cortex brain regions is involved in the formation of episodic memory, a special type of memory which includes autobiographical events (see Jin & Maren, 2015). Directional flow of information between different parts of the brain is mediated via individual neurons. Neurons are composed of a cell body, with dendrites receiving incoming information, and a projecting axon sending information onwards to other neuronal cells. Synapses at the terminals of axons form connections to dendrites of proximal neuronal cells. In the specific example of episodic memory, a subset of hippocampal neurons projects axons directly to the prefrontal cortex, but also indirectly via synapses to neurons in other brain regions. Further, the connections between regions are often reciprocal, forming a neuronal loop which is activated and strengthened during memory formation and memory retrieval.

It was by serendipity that I got into the field of gene therapy, more specifically AAV-based retinal gene therapy. The year was 2001 and I started a job as a technician in a lab using adeno-associated viral vectors (AAVs) to treat an inherited retinal degenerative disease called Retinitis Pigmentosa. I quickly became fascinated by this emerging technology and its potential for the treatment of some genetic diseases.

As part of our partnership with the Penn Vector Core, we will be expanding our inventory of tools for calcium sensing. In this post, we’ll review the main categories of sensors we’ll have available.

Guest blogger Todd Waldman, Professor at Georgetown University, contributed to this post.

Adeno-associated viruses (AAVs) make fantastic gene delivery vehicles for episomal gene expression and are particularly useful for gene delivery to the nervous system. For many years they have also been used to enhance the efficiency of genome editing. In this post we'll walk through a variety of ways you can use AAVs to improve your genome editing experiments (with and without targeted nucleases).

In a previous blog post we discussed how fluorescent proteins can be used to construct biosensors, biological tools that monitor processes or detect molecules. Here we’ll be diving into the details surrounding SF-iGluSnFr, a recently upgraded biosensor designed to detect glutamate.