Brain circuitry
This image summarizes the findings through coronal histologic sections, MR images and intensity measurements.

Scientists now can watch the vast and complex network of interconnections within the brain in action by injecting manganese into animal models and observing neurological pathways through specialized high-powered Magnetic Resonance Imaging (MRI) technology.

In a paper published in "NeuroImage," researchers explain that by injecting a solution of manganese and water with precision into specific locations within the hippocampus, they are able to observe through 3D MRI scans the transmission of neuronal impulses throughout the brain related to memory and retrieval.

“This is the first time we’ve been able to observe functional connections across a living brain in real time,” says lead author and UNM second-year medical student Christopher S. Medina. “We’re excited about documenting networks that are involved in mental functions, like consciousness, cognition, emotion, thinking and more. We’ll be collecting data on the time, intensity, speed and location of transmissions as they race through this brain-network system.”

Within the brain, neurons extend processes across long distances to reach outlying targets. The axonal transport system, which depends on microtubule-based motors and proteins, carries information and building blocks within these long processes to create and maintain distant synapses. With manganese-enhanced imaging, researchers can gain important new insights into normal versus damaged neurological function in disorders like Alzheimer’s disease, Down syndrome and PTSD.

“I liken it to a national rail system of hubs, tracks and switches delivering information to specific destinations,” says Elaine Bearer, MD, PhD, professor and Harvey Family Professor in Pathology, UNM Department of Pathology. Bearer is the senior author and mentor to Medina. She directs the lab working on the study. “With this new process, we’re looking at patterns of connection and key components of the system that we haven’t been able to understand.”

By introducing stimuli, like predator scents or cold or heat, a baseline neurological response can be established and then compared to responses gone awry. Bearer adds that the ability to map neurological connections throughout the brain can someday provide specific information for treatment of a host of diseases, including Alzheimer’s.

The UNM team worked closely with faculty from Brown University, California Institute of Technology, Universidad de Buenos Aires and the Marine Biological Laboratory in Massachusetts. Their findings were published in NeuroImage Journal at http://www.sciencedirect.com/science/article/pii/S1053811916304979.

For more information about UNM’s Department of Pathology, visit http://pathology.unm.edu/.