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cygnu-s:

Women of National Geographic

Jane Goodall - studied chimpanzees and has created community-centered conservation programs that not only protect chimpanzees of Gombe National Park in Tanzania, but also take into account the needs of the people crucial to their protection

Hayat Sindi - created low-tech diagnostic tools to aid in the improvement of healthcare in the world’s poorest communities, has a Cambridge University Ph.D. in biotechnology

Kakenya Ntaiya - teacher building the first school for girls in her rural Kenyan village, refuses to accept Maasai woman’s traditionally subservient role, hopes that expanding education and leadership opportunities for girls will also improve life for the entire village

Nalini Nadkarni - uses mountain climbing gear to climb into the rainforest canopies of Costa Rica and researches the threats of global warming

Sarah McNair-Landry - youngest person to ski to the South Pole, sledged to the North Pole, and crossed ~1,400 miles of the Greenland ice cap to draw attention to the dangers of global warming

Dian Fossey - studied endangered gorillas in the Virunga Volcanoes of Rwanda, her devotion to their care and protection cost her her life and she was probably murdered by poachers who she fought relentlessly.

I hope that one day I can be added to this list of incredible and inspiring women.

Photographs by Hugo Van Lawick, Kris Krug, Philip Scott Andrews, Michael and Patricia Fogden, John Stetson, Robert I. M. Campbell

neurosciencestuff:

Watching neurons fire from a front-row seat 
They are with us every moment of every day, controlling every action we make, from the breath we breathe to the words we speak, and yet there is still a lot we don’t know about the cells that make up our nervous systems. When things go awry and nerve cells don’t communicate as they should, the consequences can be devastating. Speech can be slurred, muscles stop working on command and memories can be lost forever.
Better understanding of how neurons and brains work could lead to new prevention, diagnostic and treatment techniques, but the brain is complex and difficult to study. If you were to hold your brain, you would likely marvel at how much it feels and moves like Jell-O. This tissue is composed of neurons and other supporting cells with tiny cell bodies, which generate electrical signals that determine how the brain and the nervous system function.
Those signals can be recorded and measured if a suitably small electrode is in the vicinity, but that presents challenges. Brain tissue is always moving in response to the body’s movement and breathing patterns. In addition, the nerve tissue is incredibly sensitive. If disrupted by a foreign body, the cells trigger an immune response to encapsulate the intruder and barricade it from the electrical signal it’s trying to capture and understand.
Working to develop intelligent neural interfaces
That challenge led Jit Muthuswamy, an associate professor of biomedical engineering at Arizona State University, Tempe (ASU), to pursue a robotic electrode system that would seek and maintain contact with neurons of interest autonomously in a subject going through normal behavioral routines. That led him to Sandia National Laboratories.
“We are working to develop chronic, reliable, intelligent neural interfaces that will communicate with single neurons in a variety of applications, some of which are emerging and others that are closer to market,” Muthuswamy said. “Applications like brain prostheses are critically dependent on us being able to interface and communicate with single neurons reliably over the course of a patient’s life. Such reliable neural interfaces are also critical to help us understand the dynamic changes in the wiring diagram of the brain.”
Key to the success of that robotic approach are the microscale actuators needed to reposition the electrodes. This led Muthuswamy in 2000 to seek out Sandia engineer Murat Okandan and the unique microsystems engineering capabilities available at Sandia’s Microsystems and Engineering Sciences Applications facility.
“The process flow we use to make these isn’t available anywhere else in the world, so the level of complexity and mechanical design space we had to design and fabricate these was immensely larger than what other researchers might have,” Okandan said. He has been working with Muthuswamy’s research team since that initial contact to find a suitable method to track individual neurons as they fire.
Earlier probes were made of a sharpened metal wire inserted in the tissue. The closer the probe is to the neuron, the stronger the signal, so experimenters ideally try to get as close as possible without disrupting surrounding tissue. The problem is that even a thin wire is too big; such a probe can take measurements around the neuron, but is far too cumbersome to be reliable over time.
Equally important is capturing the signals from an awake animal. Given their size and rigidity, current probes aren’t suited to gather recordings as the animal responds to its environment. Those units aren’t self-contained, so they keep the animals from moving around freely.
Microscale key to capturing signals from awake, moving animals
Microscale actuators and microelectrodes are critical to addressing both of those issues so probes can interact with individual nerve cells while doing minimal damage to surrounding tissue. The microscale actuators and associated packaging system developed at ASU and Sandia let a probe move autonomously in and out of the areas surrounding the cell, collecting measurements while compensating for any movement in the neuron or brain tissue.
About the size of a thumbnail, the self-contained unit has three microelectrodes and associated micro actuators. When a current runs through the thermal actuator, it expands and pushes the microelectrodes outward over the edge of the unit, which is flat to fit against the tissue. Because the actuator is so small, it can be heated to several hundred degrees Celsius and cooled again 1,000 times per second. It takes 540 cycles to fully extend the probe, but that can be done quickly – in a second or less.
The probes were implanted in the somatosensory cortex of rodents and rigorously tested in numerous experiments, both in acute and long-term conditions, Muthuswamy said. Animal procedures were carried out with the approval of ASU’s Institute of Animal Care and Use Committee, and experiments were done in accordance with National Institute of Health guidelines.
Muthuswamy said the neural probes demonstrated significant improvement in the quality and reliability of the signals when the probes were moved with precision using the Sandia microactuators in response to loss of neural signals. Further, he said, adding autonomous closed-loop controls to compensate for microscale perturbations in brain tissue significantly improved the stability of neural recordings from the brain.
Scale of this system is unique
Thermal actuators have been used for years at Sandia and elsewhere, but the scale of this system is unique. “The idea that we could build this system to achieve multiple millimeters of total displacement out of a micron-scaled device was a significant milestone,” said Sandia engineer Michael Baker, who designed the actuator. “We used electrostatic actuators in the past, but the thermal actuator provides much higher force, which is needed to move the probe in tissue.”
The microelectrodes are made of highly conductive polysilicon, which the team discovered has a number of advantages. It is almost metal-like in its conductivity, but durable enough for millions of cycles. It provides a signal-to-noise ratio much greater than previous wire probes and provides high-quality measurement signals.
Muthuswamy and Okandan currently are seeking to produce richer data with resolution in the submicron range to be able to go inside cells and take measurements there. They also are working on stacking the existing neural probe chips and decreasing the spaces between probes. Muthuswamy’s Neural Microsystems lab at ASU has developed a unique stacking approach for creating three-dimensional arrays of actuated microelectrodes.
“By building a three-dimensional array, we would have access to significantly more information, rather than just a slice,” Okandan said. “We’re very encouraged by the progress we have made, and are looking forward to building on that progress.”
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neurosciencestuff:

Watching neurons fire from a front-row seat

They are with us every moment of every day, controlling every action we make, from the breath we breathe to the words we speak, and yet there is still a lot we don’t know about the cells that make up our nervous systems. When things go awry and nerve cells don’t communicate as they should, the consequences can be devastating. Speech can be slurred, muscles stop working on command and memories can be lost forever.

Better understanding of how neurons and brains work could lead to new prevention, diagnostic and treatment techniques, but the brain is complex and difficult to study. If you were to hold your brain, you would likely marvel at how much it feels and moves like Jell-O. This tissue is composed of neurons and other supporting cells with tiny cell bodies, which generate electrical signals that determine how the brain and the nervous system function.

Those signals can be recorded and measured if a suitably small electrode is in the vicinity, but that presents challenges. Brain tissue is always moving in response to the body’s movement and breathing patterns. In addition, the nerve tissue is incredibly sensitive. If disrupted by a foreign body, the cells trigger an immune response to encapsulate the intruder and barricade it from the electrical signal it’s trying to capture and understand.

Working to develop intelligent neural interfaces

That challenge led Jit Muthuswamy, an associate professor of biomedical engineering at Arizona State University, Tempe (ASU), to pursue a robotic electrode system that would seek and maintain contact with neurons of interest autonomously in a subject going through normal behavioral routines. That led him to Sandia National Laboratories.

“We are working to develop chronic, reliable, intelligent neural interfaces that will communicate with single neurons in a variety of applications, some of which are emerging and others that are closer to market,” Muthuswamy said. “Applications like brain prostheses are critically dependent on us being able to interface and communicate with single neurons reliably over the course of a patient’s life. Such reliable neural interfaces are also critical to help us understand the dynamic changes in the wiring diagram of the brain.”

Key to the success of that robotic approach are the microscale actuators needed to reposition the electrodes. This led Muthuswamy in 2000 to seek out Sandia engineer Murat Okandan and the unique microsystems engineering capabilities available at Sandia’s Microsystems and Engineering Sciences Applications facility.

“The process flow we use to make these isn’t available anywhere else in the world, so the level of complexity and mechanical design space we had to design and fabricate these was immensely larger than what other researchers might have,” Okandan said. He has been working with Muthuswamy’s research team since that initial contact to find a suitable method to track individual neurons as they fire.

Earlier probes were made of a sharpened metal wire inserted in the tissue. The closer the probe is to the neuron, the stronger the signal, so experimenters ideally try to get as close as possible without disrupting surrounding tissue. The problem is that even a thin wire is too big; such a probe can take measurements around the neuron, but is far too cumbersome to be reliable over time.

Equally important is capturing the signals from an awake animal. Given their size and rigidity, current probes aren’t suited to gather recordings as the animal responds to its environment. Those units aren’t self-contained, so they keep the animals from moving around freely.

Microscale key to capturing signals from awake, moving animals

Microscale actuators and microelectrodes are critical to addressing both of those issues so probes can interact with individual nerve cells while doing minimal damage to surrounding tissue. The microscale actuators and associated packaging system developed at ASU and Sandia let a probe move autonomously in and out of the areas surrounding the cell, collecting measurements while compensating for any movement in the neuron or brain tissue.

About the size of a thumbnail, the self-contained unit has three microelectrodes and associated micro actuators. When a current runs through the thermal actuator, it expands and pushes the microelectrodes outward over the edge of the unit, which is flat to fit against the tissue. Because the actuator is so small, it can be heated to several hundred degrees Celsius and cooled again 1,000 times per second. It takes 540 cycles to fully extend the probe, but that can be done quickly – in a second or less.

The probes were implanted in the somatosensory cortex of rodents and rigorously tested in numerous experiments, both in acute and long-term conditions, Muthuswamy said. Animal procedures were carried out with the approval of ASU’s Institute of Animal Care and Use Committee, and experiments were done in accordance with National Institute of Health guidelines.

Muthuswamy said the neural probes demonstrated significant improvement in the quality and reliability of the signals when the probes were moved with precision using the Sandia microactuators in response to loss of neural signals. Further, he said, adding autonomous closed-loop controls to compensate for microscale perturbations in brain tissue significantly improved the stability of neural recordings from the brain.

Scale of this system is unique

Thermal actuators have been used for years at Sandia and elsewhere, but the scale of this system is unique. “The idea that we could build this system to achieve multiple millimeters of total displacement out of a micron-scaled device was a significant milestone,” said Sandia engineer Michael Baker, who designed the actuator. “We used electrostatic actuators in the past, but the thermal actuator provides much higher force, which is needed to move the probe in tissue.”

The microelectrodes are made of highly conductive polysilicon, which the team discovered has a number of advantages. It is almost metal-like in its conductivity, but durable enough for millions of cycles. It provides a signal-to-noise ratio much greater than previous wire probes and provides high-quality measurement signals.

Muthuswamy and Okandan currently are seeking to produce richer data with resolution in the submicron range to be able to go inside cells and take measurements there. They also are working on stacking the existing neural probe chips and decreasing the spaces between probes. Muthuswamy’s Neural Microsystems lab at ASU has developed a unique stacking approach for creating three-dimensional arrays of actuated microelectrodes.

“By building a three-dimensional array, we would have access to significantly more information, rather than just a slice,” Okandan said. “We’re very encouraged by the progress we have made, and are looking forward to building on that progress.”

currentsinbiology:

Octopus supermom sets egg-brooding record

A female deep-sea octopus has broke the record for egg brooding. The mom, a Graneledone boreopacifica, held her eggs in her arms for 4.5 years, until they hatched—and she apparently died. Scientists first spotted her and her eggs in 2007 during one of their regular visits, via a remotely operated vehicle (ROV), to the deep-sea habitat of Monterey Submarine Canyon off the coast of California. She was perched on a rocky outcrop 1397 meters below the ocean’s surface, with her arms curled around her clutch (see video above). Over the next 53 months, the scientists returned to the outcrop 18 times—and each time, there was the female, still patiently guarding her eggs, they report today in PLOS ONE. During their visits, they noticed that she never ate; rather than hunting crabs and shrimp, she pushed them away anytime they got too close to her eggs. She even ignored a tempting bit of crabmeat the scientists extended to her by means of one of the ROV’s arms. They suspect that she may have ingested damaged or unfertilized eggs to stay alive, but the marathon egg brooding took its toll. When the scientists first saw her, she was a pale purple, but over time she turned a ghostly white, her mantle shrank, her skin slackened, and her eyes grew cloudy. The researchers last saw her in September 2011. On their next visit the following month, she was gone; female octopuses invariably die after brooding. Only the tattered remnants of her empty egg capsules remained, indicating a successful hatch.

This female octopus grew frail during the years she spent brooding her eggs.

neurosciencestuff:

Noise-Induced Hearing Loss Alters Brain Responses to Speech

Prolonged exposure to loud noise alters how the brain processes speech, potentially increasing the difficulty in distinguishing speech sounds, according to neuroscientists at The University of Texas at Dallas.

In a paper published this week in Ear and Hearing, researchers demonstrated for the first time how noise-induced hearing loss affects the brain’s recognition of speech sounds.

Noise-induced hearing loss (NIHL) reaches all corners of the population, affecting an estimated 15 percent of Americans between the ages of 20 and 69, according to the National Institute of Deafness and Other Communication Disorders (NIDCD).

Exposure to intensely loud sounds leads to permanent damage of the hair cells, which act as sound receivers in the ear. Once damaged, the hair cells do not grow back, leading to NIHL.

“As we have made machines and electronic devices more powerful, the potential to cause permanent damage has grown tremendously,” said Dr. Michael Kilgard, co-author and Margaret Fonde Jonsson Professor in the School of Behavioral and Brain Sciences. “Even the smaller MP3 players can reach volume levels that are highly damaging to the ear in a matter of minutes.”

Before the study, scientists had not clearly understood the direct effects of NIHL on how the brain responds to speech.

To simulate two types of noise trauma that clinical populations face, UT Dallas scientists exposed rats to moderate or intense levels of noise for an hour. One group heard a high-frequency noise at 115 decibels inducing moderate hearing loss, and a second group heard a low-frequency noise at 124 decibels causing severe hearing loss.

For comparison, the American Speech-Language-Hearing Association lists the maximum output of an MP3 player or the sound of a chain saw at about 110 decibels and the siren on an emergency vehicle at 120 decibels. Regular exposure to sounds greater than 100 decibels for more than a minute at a time may lead to permanent hearing loss, according to the NIDCD.

Researchers observed how the two types of hearing loss affected speech sound processing in the rats by recording the neuronal response in the auditory cortex a month after the noise exposure. The auditory cortex, one of the main areas that processes sounds in the brain, is organized on a scale, like a piano. Neurons at one end of the cortex respond to low-frequency sounds, while other neurons at the opposite end react to higher frequencies.

In the group with severe hearing loss, less than one-third of the tested auditory cortex sites that normally respond to sound reacted to stimulation. In the sites that did respond, there were unusual patterns of activity. The neurons reacted slower, the sounds had to be louder and the neurons responded to frequency ranges narrower than normal. Additionally, the rats could not tell the speech sounds apart in a behavioral task they could successfully complete before the hearing loss.

In the group with moderate hearing loss, the area of the cortex responding to sounds didn’t change, but the neurons’ reaction did. A larger area of the auditory cortex responded to low-frequency sounds. Neurons reacting to high frequencies needed more intense sound stimulation and responded slower than those in normal hearing animals. Despite these changes, the rats were still able to discriminate the speech sounds in a behavioral task.

“Although the ear is critical to hearing, it is just the first step of many processing stages needed to hold a conversation,” Kilgard said. “We are beginning to understand how hearing damage alters the brain and makes it hard to process speech, especially in noisy environments.”

neurosciencestuff:

The Dopamine Transporter

Recent published research in the Journal of Clinical Investigation demonstrates how changes in dopamine signaling and dopamine transporter function are linked to neurological and psychiatric diseases, including early-onset Parkinsonism and attention deficit hyperactivity disorder (ADHD).

"The present findings should provide a critical basis for further exploration of how dopamine dysfunction and altered dopamine transporter function contribute to brain disorders" said Michelle Sahai, a postdoctoral associate at the Weill Cornell Medical College of Cornell University, adding "it also contributes to research efforts developing new ways to help the millions of people suffering."

Sahai is also studying the effects of cocaine, a widely abused substance with psychostimulant effects that targets the dopamine transporter. She and her colleagues expect to release these specific findings within the next year.

Losing Control

Dopamine is a neurotransmitter that plays an important role in our cognitive, emotional, and behavioral functioning. When activated from outside stimuli, nerve cells in the brain release dopamine, causing a chain reaction that releases even more of this chemical messenger.

To ensure that this doesn’t result in an infinite loop of dopamine production, a protein called the dopamine transporter reabsorbs the dopamine back into the cell to terminate the process. As dopamine binds to its transporter, it is returned to the nerve cells for future use.

However, cocaine and other drugs like amphetamine, completely hijack this well-balanced system.

"When cocaine enters the bloodstream, it does not allow dopamine to bind to its transporter, which results in a rapid increase in dopamine levels," Sahai explained.

The competitive binding and subsequent excess dopamine is what causes euphoria, increased energy, and alertness. It also contributes to drug abuse and addiction.

To further understand the effects of drug abuse, Sahai and other researchers in the Harel Weinstein Lab at Cornell are delving into drug interactions on a molecular level.

Using supercomputer resources, she is able to observe the binding of dopamine and various drugs to a 3D model of the dopamine transporter on a molecular level. According to Sahai, the work requires very long simulations in terms of microseconds and seconds to understand how drugs interact with the transporters.

Through the Extreme Science and Engineering Discovery Environment (XSEDE), a virtual cyberinfrastructure that provides researchers access to computing resources, Sahai performs these simulations on Stampede, the world’s 7th fastest supercomputer, at the Texas Advanced Computing Center (TACC).

"XSEDE-allocated resources are fundamental to helping us understand of how drugs work. There’s no way we could perform these simulations on the machines we have in house. Through TACC as an XSEDE service provider, we can also expect an exponential increase in computational results, and good customer service and feedback."

Ultimately, Sahai’s research will contribute to an existing body of work that is attempting to develop a cocaine binding inhibitor without suppressing the dopamine transporter.

"If we can understand how drugs bind to the dopamine transporter, then we can better understand drug abuse and add information on what’s really important in designing therapeutic strategies to combat addiction," Sahai said.

A Common Link in the Research

While Sahai is still working to understand drug abuse, her simulations of the dopamine transporter have contributed to published research on Parkinson’s disease and other neurological disorders.

In a collaborative study with the University of Copenhagen, Copenhagen University Hospital, and other research groups in the U.S. and Europe, researchers revealed the first known link between de novo mutations in the dopamine transporter and Parkinsonism in adults.

The study found that mutations can produce typical effects including debilitating tremors, major loss of motor control, and depression. The study also provides additional support for the idea that dopamine transporter mutations are a risk factor for attention deficit hyperactivity disorder (ADHD).

After identifying the dopamine transporter as the mutated gene linked to Parkinson’s, researchers once again turned to the Harel Weinstein Lab due to its long-standing interest and investment in studying the human dopamine transporter.

Sahai’s simulations using XSEDE and TACC’s Stampede supercomputer supported clinical trials by offering greater insight into how the dopamine transporter is involved in neurological disorders.

"This research is very important to me," Sahai said. "I was able to look at the structure of the dopamine transporter on behalf of experimentalists and understand how irregularities in this protein are harming an actual person, instead of just looking at something isolated on a computer screen."

While there is currently no cure for Parkinson’s disease, a deeper understanding of the specific mechanisms behind it will help the seven to ten million people afflicted with the disease.

"Like my work on drug abuse, the end goal is thinking about how we can help people. And it all comes back to drug design," Sahai said.

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