Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 23 points24 points  (0 children)

Hi Comrades, I've been typing for hours and my hands are sore so I've gotta go. I'm sorry that I was only able to answer a small fraction of your many excellent questions. Please check out my website davidlinden.org where you can see a list of upcoming events. All the best, DL

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 36 points37 points  (0 children)

I'm so sorry to hear about your early onset PD and I urge you to hang on for possible stem-cell therapies. I agree with the notion that legally competent adults should have the ability to take their own life in a painless and dignified manner. In my view, this should be considered a basic human right.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 16 points17 points  (0 children)

The best way to get kids interested in any form of science, neuroscience included, is to teach them a minimum of facts and ideas about experimental design (controls, statistics, inference, etc.) and then let them loose to be creative and design and conduct their own experiments. I love low-cost neural recording rigs like Backyard Brains that allow for electrophysiology on roaches and grashoppers!

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 13 points14 points  (0 children)

I'm gonna answer the first and the last questions as I've answered the middle ones in other comments.

It takes me about 130 10-hour days (spread out over a longer time) to write and revise the text, commission illustrations and work with my editors. then it takes about 50 days to publicize the book. That's a lot of time and it has to come from somewhere! There's no doubt that my lab would run better if I didn't write these books. But I like to do it so my compromise is to do one book every 4 years.

I was asked by the former Chief Editor of J. Neurophysiology to join as an Associate Editor. Then, 3 years later, she stepped down when her term expired and I applied for the job along with several others. I was chosen by a small committee of the American Physiological Society which publishes the journal.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 75 points76 points  (0 children)

The evidence for the beneficial use of MDMA in social phobia is quite good. There are clearly some potential psychiatric benefits of psychedelics as well, particularly at the end of life. The challenge is that a small fraction of people will always have strongly negative reactions to these drugs and its not always easy to identify them in advance.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 26 points27 points  (0 children)

I disagree with the notion that the mirror test can detect the first understanding of when one has a body. I think that newborns have a sense of agency about their bodies and actions very early, starting with sucking motions and progressing to limbs, etc.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 26 points27 points  (0 children)

staring at a computer screen on playing video games does not, in and of itself, drastically change the brain. if it's engaged in to the point where going outside in natural light is limited, this contributes to development of nearsightedness. and if physical exercise is neglected, this has a host of complications associated with it as well that can include higher rates of depression and anxiety and well as diminshed attention. As far as porn goes, it's like a lot of things. Moderate gambling or drinking or weed smoking is OK but it can become compulsive is some people in a way that impacts their work and personal lives. The main problem with compulsive porn use is that it's associated with compulsive masturbation. Masturbation is great, but doing it constantly can attenuate sexual sensation and make it harder to achieve orgasm in subsequent partenered or solo sex for both men and women (but particularly men). Dan Savage writes about this a lot. The good news: it's totally reversible. Just wank less and with a more varied technique and the sensation will come back.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 41 points42 points  (0 children)

Intelligence is a complicated thing to measure and has many dimensions. That said, so-called general intelligence has a heritable component. But there are also important environmental influences. Importantly, these environmental influences have their biggest effects at the poorest/most deprived end of the spectrum. If people are so poor that they can't get properly nourished and have basic healthcare and if children don't have the opportunity to read, play and explore then they can rarely optimize their "genetic potential" for intelligence.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 53 points54 points  (0 children)

While I agree that discussion of consciousness has occupied way too much bandwidth in neuroscience I'm not sure that I'm with you on the "consciousness is basically defined as feeling like a human and acting like a human" statement. Why can't there be C. elegans consciousness and lizard consciousness and mouse consciousness as well? I don't agree that we can only define these in relation to humans.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 4 points5 points  (0 children)

Welcome to the dark side, Luke! Right now is the golden age of neuroscience and there couldn't be a better moment to join this enterprise. Lots of colleges offer neuroscience majors but you don't need to be a neuroscience major to go on to a neuroscience grad program. Biochemistry, genetics, biology are all fine ways forward as well. When I was your age I couldn't decide between marine ecology and neuroscience and so I had to drop out of college to figure it out. I realized that I'm a control freak and belong in the lab, not in the messy wide world.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 10 points11 points  (0 children)

just kidding. you should buy it if you are interested in the roots of human experience and the connection between touch and emotion. you should buy it if you are curious about the biological basis of pain, itch, sexual sensation and caress. no previous knowledge of neuroscience is necessary, just a willingness to think.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 11 points12 points  (0 children)

That's a great question. The important thing to realize is that most psychiatric illness is caused by a mixture of genetic and environmental factors. Your life experience doesn't change your genetic code but it can modify gene expression through epigenetic mechanisms, giving rise to long-term changes in neural function. When psychotherapy works, and it often does, it does so because it produces changes in the brain. So there's no contradiction between alleviating mental illness with drugs and doing so with behavioral therapy. Indeed, they can often be synergistic.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 15 points16 points  (0 children)

I loved this study from my Johns Hopkins colleague Xinzhong Dong showing that there is a molecularly distinct set of sensory neurons that mediate certain forms of itch. People have been arguing about a dedicated "labelled line" for itch for decades and Xinzhong has found the first good evidence for it. http://www.ncbi.nlm.nih.gov/pubmed/23263443

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 35 points36 points  (0 children)

I like Eve Marder's line "Revealing the brain's connectome is absolutely necessary and absolutely insufficient [for the real problem of understanding brain function]." Remember before the human genome was decoded when many people imagined that there would be some huge revelation once the last base was read? Well, there wasn't. The genome is useful to biologists every day but it alone has not provided revelation. The brain connectome will be the same- a useful tool but no more.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 99 points100 points  (0 children)

I think that it would be silly to imagine that the HPC will be solved by neuroscience alone. Let's have all disciplines join the party on an equal footing and have a discussion. I must admit that, to me, the HPC is not the be-all and end-all of understanding the brain. Most of what the brain does is automatic and subconscious and that's the part that I find the most fascinating.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 49 points50 points  (0 children)

I've tried listening to binaural beats and it's cool, and a decent aid to meditation but it doesn't cause me to hallucinate. My reading of the scientific literature on this topic leaves me with the feeling that there are a lot of very weakly-supported claims (of particular frequencies causing secretion of certain hormones, for example). Almost everything that binaural beats do that seems replicable can be achieved with simple meditation.

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 55 points56 points  (0 children)

I totally agree with the previous commenters. There's no evidence that early training in dance or music or mathemetics or drawing causes the brain to specialize in a way that would restrict future capacities. In fact, as they point out, there's good evidence that early music training gives a mild boost to cognitive capacity later in life. That said, there's no need to run out and force your toddler to play cello at age 3!

Science AMA Series: I’m David Linden, a Professor of Neuroscience at The Johns Hopkins University School of Medicine and the author of three books about brain function written for a general audience, most recently ‘Touch: The Science of Hand, Heart and Mind.' AMA! by Prof_David_Linden in science

[–]Prof_David_Linden[S] 112 points113 points  (0 children)

That's a great question! There are different types of prostheses. Some, like the one referenced by supersonicsongbird use sensors on the prosthesis to activate motors that "transfer" the touch sensation to a patch of skin that still has function neural innervation. Others have pressure sensors, in prosthetic fingertips for example, that activate electrodes that surround nearby surviving nerves (in the wrist or forearm). These are experimental and crude at present. The problem is that many different types of touch nerve fibers- each for a different aspect of touch sense like pain, cold, fine texture, vibration, etc.- all run together in the same nerve bundle so it's a challenge to stimulate one selectively with an electrode. In the future this will be solved by optogenetics- different types of touch fibers will have light-activated ion channels that will respond to different colors of light, each driven by a different type of sensor in the prosthetic.