Anorexia Accelerates the Development of the Rat Hippocampus

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This image stack was used in the study to analyze spine density. Image courtesy of Tara Chowdhury, Ph.D. first author of the study.

To find out how anorexia nervosa changes the brain, scientists at New York University are studying a rat model of the disease called activity-based anorexia (ABA). Previously, they discovered that ABA rats develop unusually robust dendritic branching of neurons in part of the hippocampus. Their new study takes those findings a step further, illuminating more differences between the brains of healthy versus ABA rats, and offering evidence that ABA rats may be developing too early, closing a critical period of development too soon.

But before making any conclusions about ABA brains, the researchers made some interesting discoveries about normal brain development. Using Neurolucida to analyze CA1 pyramidal cells in the stratum radiatum layer of the ventral hippocampus, they found that after puberty, around postnatal day 51, dendrites go through a growth spurt, more than doubling the number of branches seen seven days earlier. This growth spurt is followed by a decrease, or a pruning, which the researchers say is part of the normal maturation process.

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Scientists Discover Anorexia-Driven Changes to Dendrites With Neurolucida

A digital reconstruction of a CA1 pyramidal cell from the ventral hippocampus, traced using Neurolucida with Sholl spheres at 20 micron intervals. Cells in this region featured greater dendritic length and branching versus controls.

A digital reconstruction of a CA1 pyramidal cell from the ventral hippocampus of a rat with activity-based anorexia, traced using Neurolucida with Sholl spheres at 20 micron intervals. Cells in this region featured greater dendritic length and branching versus controls.

Gaunt facial features and a frighteningly thin figure are physical hallmarks of anorexia nervosa, an eating disorder that predominantly affects adolescent girls. But in addition to extreme weight loss, changes take place that aren’t as visually apparent. For the first time, scientists in New York have found evidence of brain plasticity in the activity-based anorexia (ABA) mouse model.

Led by Dr. Chiye Aoki of New York University, the research team used Neurolucida to analyze pyramidal neurons in the rat brain. Since anorexia is linked to elevated stress hormones and anxiety, the researchers focused on the hippocampus, a region that regulates anxiety and is known to change structurally in response to hormones and stress.

“Using Neurolucida, we were able to collect, store, and analyze large amounts of data with more precision and accuracy than would have been possible without the digital interface,” said Tara Chowdhury, a graduate student working in Dr. Aoki’s lab, and first author of the paper.

“Additionally, with its very approachable interface, the software allowed us to trace dendrites, get precise thickness measurements, and categorize spine types easily during tracing. The built-in Sholl analysis and spine analysis tools resulted in quick quantification of all the measurements that would have taken hours to achieve without Neurolucida.”

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