Tag Archives: brain

Rat Brain Cells, in a Dish, Flying a Plane

Adaptive Flight Control With Living Neuronal Networks on Microelectrode Arrays (open access paper) by Thomas B. DeMarse and Karl P. Dockendorf Department of Biomedical Engineering, University of Florida

investigating the ability of living neurons to act as a set of neuronal weights which were used to control the flight of a simulated aircraft. These weights were manipulated via high frequency stimulation inputs to produce a system in which a living neuronal network would “learn” to control an aircraft for straight and level flight.

A system was created in which a network of living rat cortical neurons were slowly adapted to control an aircraft’s flight trajectory. This was accomplished by using high frequency stimulation pulses delivered to two independent channels, one for pitch, and one for roll. This relatively simple system was able to control the pitch and roll of a simulated aircraft.

When Dr. Thomas DeMarse first puts the neurons in the dish, they look like little more than grains of sand sprinkled in water. However, individual neurons soon begin to extend microscopic lines toward each other, making connections that represent neural processes. “You see one extend a process, pull it back, extend it out — and it may do that a couple of times, just sampling who’s next to it, until over time the connectivity starts to establish itself,” he said. “(The brain is) getting its network to the point where it’s a live computation device.”

To control the simulated aircraft, the neurons first receive information from the computer about flight conditions: whether the plane is flying straight and level or is tilted to the left or to the right. The neurons then analyze the data and respond by sending signals to the plane’s controls. Those signals alter the flight path and new information is sent to the neurons, creating a feedback system.

“Initially when we hook up this brain to a flight simulator, it doesn’t know how to control the aircraft,” DeMarse said. “So you hook it up and the aircraft simply drifts randomly. And as the data come in, it slowly modifies the (neural) network so over time, the network gradually learns to fly the aircraft.”

Although the brain currently is able to control the pitch and roll of the simulated aircraft in weather conditions ranging from blue skies to stormy, hurricane-force winds, the underlying goal is a more fundamental understanding of how neurons interact as a network, DeMarse said.

New Neurons are Needed for New Memories

New neurons are needed for new memories

Around 15 years ago, researchers discovered that the adult rodent brain contains discrete populations of stem cells which continue to divide and produce new cells throughout life. This discovery was an important one, as it overturned a persistent dogma in neuroscience which held that the adult mammalian brain cannot regenerate.
..
This study shows that inhibiting neurogenesis has strikingly different consequences in two distinct regions of the brain. In the olfactory bulb, it leads to significant shrinkage but apparently does not alter smell-related behaviour. In the hippocampus, the effect on structure is not so marked, but it is clear that newly-generated neurons are necessary for the processes of learning and memory. Exactly how the new cells contribute to memory formation is still unknown.

More interesting stuff. Related: How The Brain Rewires Itself – Scientists Witness the Birth of a Brain Cell – New Neurons in Old Brains – No Sleep, No New Brain Cells

Asymmetrical Brains Aid Multi-tasking

Asymmetrical brains help fish (and us) to multi-task:

In the animal world, the ability to multi-task is a matter of life and death. Many species must be ever-watchful for food, while simultaneously looking out for predators who would view them in the same way Like too many open applications that slow down a computer, these multiple tasks compete for the brain’s finite resources. Those who survive life’s challenges are those with an edge at efficiently dealing with multiple demands.

One way of doing this is to use parallel processing – to delegate different parts of a problem to different pieces of hardware. This is exactly the situation found in the human brain, with two asymmetric hemispheres associated with different mental abilities. And this ‘lateralisation’ is not unique to us, but seems to be present in all back-boned animals, from fish to apes. An explanation for this asymmetry now becomes obvious – it may allow animals to multi-task, acting as a sort of cerebral division of labour.
…
In these cases, regardless of parallel processing power, an asymmetric brain is clearly a disadvantage. The two scientists believe that the tipping point between these pros and cons comes when an animal has to perform difficult mental tasks.

Other studies have shown that asymmetrical brains endow wild chimpanzees with superior termite-fishing skills, and (equally wild) human children with better mathematical and verbal abilities than their classmates. It may be that over the course of evolution, our brain’s halves started to work together more effectively as they became more different and specialised. It is ironic and sad then, that the opposite seems to hold true for the divergence of human cultures.

Do Dolphins Sleep?

Do dolphins sleep?, MIT:

Dolphins do sleep, but not quite in the same way that people do. They sleep with one half of the brain at a time and with one eye closed. Dolphins rest this way on and off throughout the day, switching which side of the brain they shut down. During these periods, everything inside the dolphin slows down, and the mammal moves very little.

How Humans Got So Smart

Cooking and Cognition: How Humans Got So Smart

For a long time, we were pretty dumb. Humans did little but make “the same very boring stone tools for almost 2 million years,” he said. Then, only about 150,000 years ago, a different type of spurt happened — our big brains suddenly got smart. We started innovating. We tried different materials, such as bone, and invented many new tools, including needles for beadwork. Responding to, presumably, our first abstract thoughts, we started creating art and maybe even religion.

To understand what caused the cognitive spurt, Khaitovich and colleagues examined chemical brain processes known to have changed in the past 200,000 years. Comparing apes and humans, they found the most robust differences were for processes involved in energy metabolism.

The finding suggests that increased access to calories spurred our cognitive advances, said Khaitovich, carefully adding that definitive claims of causation are premature.

Nice example of scientific discovery in action. The direct link from cooking to brain development is far from proven but it is interesting. I also like “the same very boring stone tools for almost 2 million years” – maybe that is because I am too cynical (but while evolution is amazing – sometimes it is amazing how slow progress is).

The Brain Hides Information From Us To Prevent Mistakes

“The main finding of the study is that it has enabled us to confirm that tactile sensations are initially located unconsciously in anatomical coordinates, but they reach our awareness only when the brain has formed an image of their origin in the spatial coordinates, external to the body,” explained Salvador Soto-Faraco. The coexistence of different spatial reference frames in the brain has been known for some time. So has the fact that confusions between them may result in some cases, such as when we invert the usual anatomical position of some body parts (e.g. when crossing our arms over the body midline). “The brain sorts out problems of this kind rapidly, in a matter of tenths of a second. To do so, however, it has to integrate information arriving in formats that are quite disparate”, Sotoa-Faraco added. “Our research has helped us understand how this process works and how the brain manages spatial realignment when faced with conflict”, he concluded.

Interesting. I think my brain might be hiding more from me lately (like right now where the key to my shed is) 🙂

Scientists Witness the Birth of a Brain Cell

The Birth of a Brain Cell: Scientists Witness Neurogenesis

For the first time, researchers have developed a way to view stem cells in the brains of living animals, including humans—a finding that allows scientists to follow the process neurogenesis (the birth of neurons). The discovery comes just months after scientists confirmed that such cells are generated in adult as well as developing brains.
…
The key ingredient in this process is a substance unique to immature cells that is neither found in mature neurons nor in glia, the brain’s nonneuronal support cells. Maletic-Savatic and her colleagues collected samples of each of the three cell types from rat brains (stem cells from embryonic animals, the others from adults) and cultured the varieties separately in the lab. They were able to determine the chemical makeup of each variety – and isolate the compound unique to stem cells – with nuclear magnetic resonance (NMR) spectroscopy. (NMR helps to determine a molecule’s structure by measuring the magnetic properties of its subatomic particles.) Although the NMR could identify the biomarker, but not its makeup, Maletic-Savatic speculates it is a blend of fatty acids in a lipid (fat) or lipid protein.

Bird Brain Language Research

Molecular Mapping of Movement-Associated Areas in the Avian Brain: A Motor Theory for Vocal Learning Origin

Vocal learning is a critical behavioral substrate for spoken human language. It is a rare trait found in three distantly related groups of birds-songbirds, hummingbirds, and parrots. These avian groups have remarkably similar systems of cerebral vocal nuclei for the control of learned vocalizations that are not found in their more closely related vocal non-learning relatives. These findings led to the hypothesis that brain pathways for vocal learning in different groups evolved independently from a common ancestor but under pre-existing constraints. Here, we suggest one constraint, a pre-existing system for movement control.

Using behavioral molecular mapping, we discovered that in songbirds, parrots, and hummingbirds, all cerebral vocal learning nuclei are adjacent to discrete brain areas active during limb and body movements. Similar to the relationships between vocal nuclei activation and singing, activation in the adjacent areas correlated with the amount of movement performed and was independent of auditory and visual input.
…
Based upon these findings, we propose a motor theory for the origin of vocal learning, this being that the brain areas specialized for vocal learning in vocal learners evolved as a specialization of a pre-existing motor pathway that controls movement.

Scientists Reconsider Autism

Webcast – In My Language – about what gets considered thought, intelligence, personhood, language, and communication, and what does not.

Scientists Reconsider What They Think They Know

This movement is being fueled by a small but growing cadre of neuropsychological researchers who are taking a fresh look at the nature of autism itself. The condition, they say, shouldn’t be thought of as a disease to be eradicated. It may be that the autistic brain is not defective but simply different — an example of the variety of human development. These researchers assert that the focus on finding a cure for autism — the disease model — has kept science from asking fundamental questions about how autistic brains function.

A cornerstone of this new approach — call it the difference model — is that past research about autistic intelligence is flawed, perhaps catastrophically so, because the instruments used to measure intelligence are bogus. “If Amanda Baggs had walked into my clinic five years ago,” says Massachusetts General Hospital neuroscientist Thomas Zeffiro, one of the leading proponents of the difference model, “I would have said she was a low-functioning autistic with significant cognitive impairment. And I would have been totally wrong.”
…
And that hurts autistic people, Dawson says. She makes a comparison with blindness. Of course blind people have a disability and need special accommodation. But you wouldn’t give a blind person a test heavily dependent on vision and interpret their poor score as an accurate measure of intelligence. Mottron is unequivocal: Because of recent research, especially the Raven paper, it’s clearer than ever that so-called low-functioning people like Amanda Baggs are more intelligent than once presumed.The Dawson paper was hardly conclusive, but it generated buzz among scientists and the media. Mottron’s team is now collaborating with Massachusetts General Hospital’s Zeffiro, a neuroimaging expert, to dig deeper.

Continue reading →

Virus Engineered To Kill Deadly Brain Tumors

Yale Lab Engineers Virus That Can Kill Deadly Brain Tumors

A laboratory-engineered virus that can find its way through the vascular system and kill deadly brain tumors has been developed by Yale School of Medicine researchers, it was reported this week in the Journal of Neuroscience.

Each year 200,000 people in the United States are diagnosed with a brain tumor, and metastatic tumors and glioblastomas make up a large part of these tumors. There currently is no cure for these types of tumors, and they generally result in death within months.
…
“Three days after inoculation, the tumors were completely or almost completely infected with the virus and the tumor cells were dying or dead,” van den Pol said. “We were able to target different types of cancer cells. Within the same time frame, normal mouse brain cells or normal human brain cells transplanted into mice were spared. This underlines the virus’ potential therapeutic value against multiple types of brain cancers.”

Pretty cool. Too bad these press releases never quite live up to the initial promise. Still this one is very cool, if it can succeed in helping even a small percentage of people it will be a great breakthrough. It is also just cool – using a virus to kill tumors – how cool is that?