Research Methodologies

We employ a variety of molecular, anatomical, cellular, and behavioral techniques to study the ways in which the central nervous system detects and codes challenging environmental stimulation. Many of these techniques help to determine how the brain is modified upon repeated stressful exposures, and how these underlying modifications can further change later behaviors. We have recently begun to employ virally-mediated gene transfer in rat brains to gain better control over circuits of interests, especially at the level of the hypothalamus; techniques such as chemogenetics, and fiber photometry help measure neurotransmitter or calcium release, while neural excitation or inhibition of specific neural phenotypes within regions of interest can be achieved with various intersectional methods.

Neuroanatomical Methods

In situ hybridization histochemistry is employed to detect, visualize and quantify messenger ribonucleic acids (mRNA) and heteronuclear ribonucleic acids (hnRNA) in specific areas of the brain.

Example of radioisotopic in situ hybridization histochemistry against c-fos mRNA (reversed picture from obtained autoradiogram)

brain image section

Double Fluorescent in situ hybridization (Fish) histochemistry is employed to help determine the colocalization of mRNAs in different regions of the brain.

Example of double FISH against c-fos mRNA (Fluorescein – green) and the vesicular glutamate transporter 2 mRNA (CY3 – red), also counterstained with DAPI in the auditory thalamus (blue). Courtesy, Sarah K. Sasse, 2008.

FISH neuronal image

Immunohistochemistry is employed to detect, visualize and quantify cellular protein expression in different brain regions.

Example of double immunohistochemical staining against the protein CRH (blue) and the anterograde tracer PHA-l (brown; brightfield view)

double-stained immunohistochemical image

Anterograde and retrograde tract tracing techniques are used extensively to assess the connections between different parts of the brain.

Example of anterograde tract tracing (Biotinylated Dextran-amines); darkfield view.

darkfield neuronal image