Neuroscience Never Ceases to Amaze

Student examines neurons at the University of New England Imaging Core
“Wow!” is the first word uttered by those who see the complexity and beauty of neurons under the microscope. Students participating in the iXplore Summer Program had this opportunity at the University of New England’s Histology and Imaging Core. Here, students investigated the nervous system using a variety of histologic techniques. Students stained mouse brain tissue and found that neurons (black dots, below left) are clustered in symmetrical regions of the brain. Higher magnification showed neurons with long branching projections (dendrites and axons), which aid in communication between neurons.
Are all 75 million neurons in the mouse brain alike? To answer this question, students examined brains stained by immunohistochemistry, a method highlighting specific molecules, and concluded all neurons are not alike, since dopamine (a neurotransmitter, staining red) is produced in varying amounts in the brain (below).

Sagittal section of mouse brain. Nuclei (blue) and dopamine-making regions (red). [Tyrosine-Hydroxylase (TH), DAPI, 100X. P. Caradonna, UNE.]

Mouse brain tissue showing cell nuclei (blue) and dopamine-making neurons (red). [DAPI, TH, 400X. Peter Caradonna, UNE.]
Do neurons form patterns outside of the brain? Students looked at cornea slides stained for a neuron receptor called TRPV. This receptor was found on neurons throughout the cornea (green). With higher magnification, TRPV staining (red), shows neurons form a swirling pattern in the cornea. These receptors respond to injury — like a poke in the eye — and send signals to the tear ducts to produce tears.