[ad_1]
This is not because an animal is soft and spongy that it is not hard. Experiments at Rice University show that the humble hydra is a good example.
The hydra does not seem to age – and apparently never dies of old age. If you cut one out of two, you get hydrae. And everyone can eat animals twice his size.
These beasts are survivors, which makes them worthy of study, according to Jacob Robinson, Electrical and Computer Engineer
Robinson and his team developed methods for corral, Hydrae as a squid and perform the first comprehensive characterization of the relationships between neuronal activity and muscle movements in these creatures. Their results appear in the journal of the Royal Society of Chemistry Lab on a chip .
Researchers used several methods to reveal the basic neural models that drive hydra vulgaris activities in freshwater: They immobilized animals in, pbadages loaded with needles, deposited them in arenas one-tenth the size of a dime and let them explore large spaces. They expect their badysis to help them identify the patterns that have been preserved by evolution in larger brain architectures.
Robinson is a neuro-engineer specializing in microfluidics, fluid handling and small-scale content. His lab has developed a range of chip-based systems that allow scientists to control movement and even sequester biological systems – cells and small animals – for close study over long periods of time.
The laboratory has studied the above with its custom high throughput microfluidic systems, with worms representing the "animal" part.
But the hydras, which end about half a centimeter long, are of different sizes and change shape at will. This represented particular challenges for engineers
" C. elegans (round worms) and hydrae have similarities," Robinson said. "They are small and transparent and have relatively few neurons, which facilitates the observation of the activity of each brain cell at the same time." But there are huge biological differences, "he said, exactly 302 neurons, and we know exactly how it is wired.Hydrae can grow and shrink.They can be cut into pieces and form new animals, so the number of neurons inside can change by factors of 10.
"This means that there is a fundamental difference in the neurobiology of animals: where the worm must have an exact circuit, Hydra can have any number of circuits, rearrange in different ways and still have relatively similar behaviors, which makes them very fun to study. "
The microfluidic platform allows the laboratory to sequester a single hydra for 10 hours, activity during distinct behaviors such as body column and sprawling contraction, flexion, and translocation. others were modified to express fluorescent proteins or others.Because the best way to characterize a hydra is to watch it for about a week, the lab builds a range of microfluidic chips loaded with cameras to produce movies in time -lapse can hold up to 100 animals at a time.
to them at the naked eye, they sit there right there, "said Robinson." They are rather boring, but if you accelerate things with time-lapse imaging, they perform all kinds of interesting behaviors: they sample their environment, they move back and forth. "[196] 59003] Electrophysiology The tests were made possible by the laboratory development of Nano-SPEAR, microscopic probes that measure the electrical activity in the individual cells of small animals. The needles extend from the center of the hourglbad-shaped capture device and enter the cells of a hydra without causing permanent damage to the animal.
Nano-SPEARS do not seem to measure the activity of neurons inside the animal. sensitive proteins to trigger fluorescent signals in the cells of the hydra and produces temporal films in which the neurons illuminate as they contracted. "We use calcium as a proxy for electrical activity inside the cell," Robinson said. "When a cell becomes active, the electrical potential across its membrane changes. Ionic channels open up and allow calcium to enter." With this approach, the laboratory was able to identify models of neuronal activity that resulted in muscle contractions.
"Calcium imaging gives us spatial resolution, so I know where the cells are active," he said. "It's important to understand how the brain of this body works."
Manipulate hydrae is an acquired skill, according to graduate student and senior author Krishna Badhiwala. "If you manipulate them with pipettes, they are really easy, but they stay true to everything," she says.
"It's a bit difficult to get them stuck in microfluidics because they're really just" body-thick "cells, said Badhiwala." You can imagine that they're easily shredded we have finally come to insert them properly without much damage, it just requires dexterity and stability. "
With this study and future studies, the team hopes to connect the neural activity and muscle response to learn about similar connections in other members of the animal kingdom.
" C. elegans Drosophila (fruit flies), rats, mice, and humans are bilaterians, "said Robinson." We all have bilateral symmetry, that is, we shared a common ancestor, hundreds of millions of years ago. "Hydrae "belongs to another group of animals called" cn ideals ", radially symmetrical. "But the hydra and humans shared a common ancestor that we believe to be the first animal to have neurons," he says, "from this ancestor came all the nervous systems we see today. "
in different parts of the phylogenetic tree, we can think of what is common to all animals with nervous systems: why do we have a nervous system, what is it used for, what? can one hydra do? What are the things that they can not do?
"These types of questions will help us understand how we have evolved the nervous system that we have," Robinson said.
The co-authors are graduate students of Rice Daniel Gonzales and Benjamin Avants and alumnus Daniel Vercosa, now an engineer at Intel Corp. Robinson is an badistant professor of electrical and computer engineering.
Source link
