1. neurosciencestuff:

Turning science on its head
Harvard neuroscientists have made a discovery that turns 160 years of neuroanatomy on its head.
Myelin, the electrical insulating material in the body long known to be essential for the fast transmission of impulses along the axons of nerve cells, is not as ubiquitous as thought, according to new work led by Professor Paola Arlotta of the Harvard Stem Cell Institute (HSCI) and the University’s Department of Stem Cell and Regenerative Biology, in collaboration with Professor Jeff Lichtman of Harvard’s Department of Molecular and Cellular Biology.
“Myelin is a relatively recent invention during evolution,” says Arlotta. “It’s thought that myelin allowed the brain to communicate really fast to the far reaches of the body, and that it has endowed the brain with the capacity to compute higher-level functions.”
In fact, loss of myelin is a feature in a number of devastating diseases, including multiple sclerosis and schizophrenia.
But the new research shows that despite myelin’s essential roles in the brain, “some of the most evolved, most complex neurons of the nervous system have less myelin than older, more ancestral ones,” said Arlotta, co-director of the HSCI neuroscience program.
What this means, she said, is that the higher one looks in the cerebral cortex — closer to the top of the brain, which is its most evolved part — the less myelin one finds.  Not only that, but “neurons in this part of the brain display a brand-new way of positioning myelin along their axons that has not been previously seen. They have ‘intermittent myelin’ with long axon tracts that lack myelin interspersed among myelin-rich segments.”
“Contrary to the common assumptions that neurons use a universal profile of myelin distribution on their axons, the work indicates that different neurons choose to myelinate their axons differently,” Arlotta said. “In classic neurobiology textbooks, myelin is represented on axons as a sequence of myelinated segments separated by very short nodes that lack myelin. This distribution of myelin was tacitly assumed to be always the same, on every neuron, from the beginning to the end of the axon. This new work finds this not to be the case.”
The results of the research by Arlotta and postdoctoral fellow Giulio Srubek Tomassy, the first author on the report, are published in the latest edition of the journal Science.
The paper is accompanied by a “perspective” by R. Douglas Fields of the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the National Institutes of Health, who said that Arlotta and Tomassy’s findings raise important questions about the purpose of myelin, and “are likely to spark new concepts about how information is transmitted and integrated in the brain.”
Arlotta and Tomassy collaborated closely on the new work with postdoctoral fellow Daniel Berger of the Lichtman lab, which generated one of the two massive electron microscopy databases that made the work possible.
“The fact that it is the most evolved neurons, the ones that have expanded dramatically in humans, suggest that what we’re seeing might be the ‘future.’ As neuronal diversity increases and the brain needs to process more and more complex information, neurons change the way they use myelin to achieve more,” said Arlotta.
Tomassy said it is possible that these profiles of myelination “may be giving neurons an opportunity to branch out and ‘talk’ to neighboring neurons.” For example, because axons cannot make synaptic contacts when they are myelinated, one possibility is that these long myelin gaps may be needed to increase neuronal communication and synchronize responses across different neurons. He and Arlotta postulate that the intermittent myelin may be intended to fine-tune the electrical impulses traveling along the axons, in order to allow the emergence of highly complex neuronal behaviors.

    neurosciencestuff:

    Turning science on its head

    Harvard neuroscientists have made a discovery that turns 160 years of neuroanatomy on its head.

    Myelin, the electrical insulating material in the body long known to be essential for the fast transmission of impulses along the axons of nerve cells, is not as ubiquitous as thought, according to new work led by Professor Paola Arlotta of the Harvard Stem Cell Institute (HSCI) and the University’s Department of Stem Cell and Regenerative Biology, in collaboration with Professor Jeff Lichtman of Harvard’s Department of Molecular and Cellular Biology.

    “Myelin is a relatively recent invention during evolution,” says Arlotta. “It’s thought that myelin allowed the brain to communicate really fast to the far reaches of the body, and that it has endowed the brain with the capacity to compute higher-level functions.”

    In fact, loss of myelin is a feature in a number of devastating diseases, including multiple sclerosis and schizophrenia.

    But the new research shows that despite myelin’s essential roles in the brain, “some of the most evolved, most complex neurons of the nervous system have less myelin than older, more ancestral ones,” said Arlotta, co-director of the HSCI neuroscience program.

    What this means, she said, is that the higher one looks in the cerebral cortex — closer to the top of the brain, which is its most evolved part — the less myelin one finds.  Not only that, but “neurons in this part of the brain display a brand-new way of positioning myelin along their axons that has not been previously seen. They have ‘intermittent myelin’ with long axon tracts that lack myelin interspersed among myelin-rich segments.”

    “Contrary to the common assumptions that neurons use a universal profile of myelin distribution on their axons, the work indicates that different neurons choose to myelinate their axons differently,” Arlotta said. “In classic neurobiology textbooks, myelin is represented on axons as a sequence of myelinated segments separated by very short nodes that lack myelin. This distribution of myelin was tacitly assumed to be always the same, on every neuron, from the beginning to the end of the axon. This new work finds this not to be the case.”

    The results of the research by Arlotta and postdoctoral fellow Giulio Srubek Tomassy, the first author on the report, are published in the latest edition of the journal Science.

    The paper is accompanied by a “perspective” by R. Douglas Fields of the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the National Institutes of Health, who said that Arlotta and Tomassy’s findings raise important questions about the purpose of myelin, and “are likely to spark new concepts about how information is transmitted and integrated in the brain.”

    Arlotta and Tomassy collaborated closely on the new work with postdoctoral fellow Daniel Berger of the Lichtman lab, which generated one of the two massive electron microscopy databases that made the work possible.

    “The fact that it is the most evolved neurons, the ones that have expanded dramatically in humans, suggest that what we’re seeing might be the ‘future.’ As neuronal diversity increases and the brain needs to process more and more complex information, neurons change the way they use myelin to achieve more,” said Arlotta.

    Tomassy said it is possible that these profiles of myelination “may be giving neurons an opportunity to branch out and ‘talk’ to neighboring neurons.” For example, because axons cannot make synaptic contacts when they are myelinated, one possibility is that these long myelin gaps may be needed to increase neuronal communication and synchronize responses across different neurons. He and Arlotta postulate that the intermittent myelin may be intended to fine-tune the electrical impulses traveling along the axons, in order to allow the emergence of highly complex neuronal behaviors.

  2. "Too many young women I think are harder on themselves than circumstances warrant. They are too often selling themselves short. They too often take criticism personally instead of seriously. You should take criticism seriously because you might learn something, but you can’t let it crush you. You have to be resilient enough to keep moving forward, whatever the personal setbacks and even insults that come your way might be. That takes a sense of humor about yourself and others. Believe me, this is hard-won advice I’m putting forth. It’s not like you wake up and understand this. It’s a process."

    Hillary Clinton on how to handle criticism & other advice for young women, The Cut (via thatkindofwoman)

    Yes.  Criticism does not mean you should stop.  It does mean you need to stop and think.

    (via engrprof)
  3. Learn by doing

    gradnessmadness:

    “Most of life is on-the-job training. Some of the most important things can only be learned in the process of doing them. You do something and you get feedback — about what works and what doesn’t. If you don’t do anything for fear of doing it wrong, poorly, or badly, you never get any feedback, and therefore you never get to improve.”

    -Jack Canfield  

    Forever relevant.

  4. neurosciencestuff:

Researchers uncover why there is a mapping between pitch and elevation
Have you ever wondered why most natural languages invariably use the same spatial attributes – high versus low – to describe auditory pitch? Or why, throughout the history of musical notation, high notes have been represented high on the staff? According to a team of neuroscientists from Bielefeld University, the Max Planck Institute for Biological Cybernetics in Tübingen and the Bernstein Center Tübingen, high pitched sounds feel ‘high’ because, in our daily lives, sounds coming from high elevations are indeed more likely to be higher in pitch. This study has just appeared in the science journal PNAS.
Dr. Cesare Parise and colleagues set out to investigate the origins of the mapping between sound frequency and spatial elevation by combining three separate lines of evidence. First of all, they recorded and analyzed a large sample of sounds from the natural environment and found that high frequency sounds are more likely to originate from high positions in space. Next, they analyzed the filtering of the human outer ear and found that, due to the convoluted shape of the outer ear – the pinna – sounds coming from high positions in space are filtered in such a way that more energy remains for higher pitched sounds. Finally, they asked humans in a behavioural experiment to localize sounds with different frequency and found that high frequency sounds were systematically perceived as coming from higher positions in space.
The results from these three lines of evidence were highly convergent, suggesting that all such diverse phenomena as the acoustics of the human ear, the universal use of spatial terms for describing pitch, or the reason why high notes are represented higher in musical notation ultimately reflect the adaptation of human hearing to the statistics of natural auditory scenes. ‘These results are especially fascinating, because they do not just explain the origin of the mapping between frequency and elevation,’ says Parise, ‘they also suggest that the very shape of the human ear might have evolved to mirror the acoustic properties of the natural environment. What is more, these findings are highly applicable and provide valuable guidelines for using pitch to develop more effective 3D audio technologies, such as sonification-based sensory substitution devices, sensory prostheses, and more immersive virtual auditory environments.’
The mapping between pitch and elevation has often been considered to be metaphorical, and cross-sensory correspondences have been theorized to be the basis for language development. The present findings demonstrate that, at least in the case of the mapping between pitch and elevation, such a metaphorical mapping is indeed embodied and based on the statistics of the environment, hence raising the intriguing hypothesis that language itself might have been influenced by a set of statistical mappings between naturally occurring sensory signals.
Besides the mapping between pitch and elevation, human perception, cognition, and action are laced with seemingly arbitrary correspondences, such as that yellow–reddish colors are associated with a warm temperature or that sour foods taste sharp. This study suggests that many of these seemingly arbitrary mappings might in fact reflect statistical regularities to be found in the natural environment.

*sigh* my last experiment was looking at this association and found nothing. I need to figure out why….

    neurosciencestuff:

    Researchers uncover why there is a mapping between pitch and elevation

    Have you ever wondered why most natural languages invariably use the same spatial attributes – high versus low – to describe auditory pitch? Or why, throughout the history of musical notation, high notes have been represented high on the staff? According to a team of neuroscientists from Bielefeld University, the Max Planck Institute for Biological Cybernetics in Tübingen and the Bernstein Center Tübingen, high pitched sounds feel ‘high’ because, in our daily lives, sounds coming from high elevations are indeed more likely to be higher in pitch. This study has just appeared in the science journal PNAS.

    Dr. Cesare Parise and colleagues set out to investigate the origins of the mapping between sound frequency and spatial elevation by combining three separate lines of evidence. First of all, they recorded and analyzed a large sample of sounds from the natural environment and found that high frequency sounds are more likely to originate from high positions in space. Next, they analyzed the filtering of the human outer ear and found that, due to the convoluted shape of the outer ear – the pinna – sounds coming from high positions in space are filtered in such a way that more energy remains for higher pitched sounds. Finally, they asked humans in a behavioural experiment to localize sounds with different frequency and found that high frequency sounds were systematically perceived as coming from higher positions in space.

    The results from these three lines of evidence were highly convergent, suggesting that all such diverse phenomena as the acoustics of the human ear, the universal use of spatial terms for describing pitch, or the reason why high notes are represented higher in musical notation ultimately reflect the adaptation of human hearing to the statistics of natural auditory scenes. ‘These results are especially fascinating, because they do not just explain the origin of the mapping between frequency and elevation,’ says Parise, ‘they also suggest that the very shape of the human ear might have evolved to mirror the acoustic properties of the natural environment. What is more, these findings are highly applicable and provide valuable guidelines for using pitch to develop more effective 3D audio technologies, such as sonification-based sensory substitution devices, sensory prostheses, and more immersive virtual auditory environments.’

    The mapping between pitch and elevation has often been considered to be metaphorical, and cross-sensory correspondences have been theorized to be the basis for language development. The present findings demonstrate that, at least in the case of the mapping between pitch and elevation, such a metaphorical mapping is indeed embodied and based on the statistics of the environment, hence raising the intriguing hypothesis that language itself might have been influenced by a set of statistical mappings between naturally occurring sensory signals.

    Besides the mapping between pitch and elevation, human perception, cognition, and action are laced with seemingly arbitrary correspondences, such as that yellow–reddish colors are associated with a warm temperature or that sour foods taste sharp. This study suggests that many of these seemingly arbitrary mappings might in fact reflect statistical regularities to be found in the natural environment.

    *sigh* my last experiment was looking at this association and found nothing. I need to figure out why….

  5. "This is an anatomically-realistic 3D brain visualization depicting real-time source-localized activity (power and "effective" connectivity) from EEG (electroencephalographic) signals. Each color represents source power and connectivity in a different frequency band (theta, alpha, beta, gamma) and the golden lines are white matter anatomical fiber tracts. Estimated information transfer between brain regions is visualized as pulses of light flowing along the fiber tracts connecting the regions…

    The final visualization is done in Unity and allows the user to fly around and through the brain with a gamepad while seeing real-time live brain activity from someone wearing an EEG cap…” 


    Team:
    - Gazzaley Lab / Neuroscape lab, UCSF: Adam Gazzaley, Roger Anguera, Rajat Jain, David Ziegler, John Fesenko, Morgan Hough
    - Swartz Center for Computational Neuroscience, UCSD: Tim Mullen & Christian Kothe

    More brain animations

  6. I was kindly asked to be the ‘Lady Scientist Spotlight’ for this week over on the Scientific Women of Tumblr blog, so if you want to read a bit about me and my research, click here and go check it out.

  7. "The math is the easiest part… I don’t know if that makes it better or worse…"

    "The math is the easiest part… I don’t know if that makes it better or worse…"

  8. nonojojofoto:

Drying neural tissue.

Such a good blog.

    nonojojofoto:

    Drying neural tissue.

    Such a good blog.

  9. I think this top hat suits my brain wonderfully. 

    I think this top hat suits my brain wonderfully. 

About me

Hi, and welcome to my blog!

This is where I write about and reblog things that I find interesting about the brain, psychology, neuroscience and grad school.

I have a B.Sc. (Hons) in Psychology and I am now a first year Ph.D. student. Right now I investigate the underlying predictive neural mechanisms of multisensory perception, using functional imaging, psychophysics and computational modelling. I tag things that are related to my PhD or any of my side projects here.


If you have a question, please click the “Ask Me” button above and I will do my best to answer you. If you prefer me to answer privately, please mention it in your ask.


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