For more than 1 million years, independent cave populations that have been geographically and isolated from each other have evolved to include about 29 different populations. Among them, the small Mexican tetra, Astyanax mexicanus, consists of populations of river-dwelling surface fish and several independently ophthalmic caves. A number of behaviors differ between these cave populations, suggesting wide differences in brain structure and function. Although the symptoms of fishing in the cave have been studied for more than a century, little is known about how their brains are different. Furthermore, differences in brain activity have never been detected.
A groundbreaking study published in Science advance Charles E. of Florida Atlantic University Schmidt College of Science and Harriet L. Neuroscientists, in collaboration with Ramat-Gann at the Wilkes Honors College at Bar-Ilan University, Israel, are the first to identify large-scale differences of surface fish and cave fish populations. A. mexicanus, as well as among the cave’s various populations. Researchers extracted 18 anatomic regions throughout the brain and measured changes in neural activity in these areas. The whole-brain atlas generated from this study represent a comparative brain-wide study of intraspecies variation in a vertebrate model and provide a resource for studying the neural basis underlying behavioral development.
Alex c. “Cavefish have undergone many behavioral changes, including sleep deprivation, decreased social behaviors, extensive changes in sensory processing, and behavior changes,” said Kenney, PhD, lead author and an associate professor of biological audiences. FAU’s Charles E. Schmidt College of Science. “Despite a long focus on the character of differences in behavior and morphology among cave populations, little is known about the brain anatomy and neural circuits associated with these behavioral changes in cave populations unexpectedly. ”
a. To compare brain anatomy between independently developed populations of Maximus, researchers performed whole-brain confocal imaging in surface fish and fish from the Tinaja, Molino, and Pachon cavefish populations. They defined developmentally derived changes in brain function on 684 larval fish from which to generate neuroanatomical atlases. They performed manipulation analysis, imaging of neural circuits, and whole-brain activity mapping and development of three independently cave populations to generate standard brains for river-dwelling surface fish. Using these reference brains, they quantified defined neuroanatomical regions and specific neuronal populations that contribute to sleeping and feeding. They map patterns of neuronal activity to standard brains to generate brain-maps of activity differences using phosphorylated extracellular signal-regulated kinase (pERK) labeling in waking, feeding, and sleeping fish.
The results of the study indicate that hunting behavior led to all four a. Induced widespread changes in brain activity in the Mexican population and is likely to activate brain regions associated with sensory processing, satiety, and motivation. Sleep activity differs in the rostral region of the hypothalamus and tectum. The changes in the circuitry associated with the feeding identified in the study occurred early in development, stating that evolutionary changes are unique among populations of different caves. Analysis of brain area volume and neural circuits associated with behavioral regulation identified convergence on hindbrain and hypothalamic expansion, as well as changes in neurotransmitter systems including catecholamine and elevated numbers of hypocatrin or aurexin neurons in the cavfish population.
To characterize differences in brain anatomy between populations, the researchers each identified a. Maximus quantified the size of individual brain regions within the population. To determine if identifiable brain regions differed between populations, they identified select regions using standard regions, which they developed as a reference map, together with adult A. To determine whether there are changes in the size of brain regions that may be associated with developed behavioral differences, the researchers determined 13 additional brain regions, including the four regions of the tectum, cerebellum, pallium, and hypothalamus. In order to localize the pERK signal to different regions of the brain, they registered for the standard brains that had been developed.
“These fish have been studied for more than 80 years and there is widespread appreciation that they can tell us about what kind of behavior develops. Now, for the first time, we can find them with millimeter resolution. Can see inside the mind, ”said Ken. “We can begin to understand how individual neurons and brain regions behave complexly, including sleep and feeding. This work has broad implications for our understanding of how brains develop in many different animal models Is and we hope it will be widely used. Used by the scientific community. ”
Sleeveless in Latin America: Blind Cavefish, Extreme Environment and Insomnia
“Cavefish brain atlas reveal functional and physiological convergence in independently developed populations” Science advance (2020). In advance. sciencemag.org/lookup… .1126 / Sciadv.aba3126
Provided by Florida Atlantic University
Quotes: Mapping Caffeine Brains to the Neural Origins of Behavioral Development (2020, 16 September) from https://phys.org/news/2020-09-cavefish-brains-neural-behavioral-evolution.html on 17 September 2020 Retrieved.
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