März 2011
34 Einträge
“Neuroscience describes the brain from the outside. It sees us through the prism of the third person, so that we are nothing but three pounds of electrical flesh. The paradox, of course, is that we don’t experience our matter. Self-consciousness, at least when felt from the inside, feels like more than the sum of its cells. “We’ve got all these tools for studying the cortex,” Markram says. “But none of these methods allows us to see what makes the cortex so interesting, which is that it generates worlds. No matter how much I know about your brain, I still won’t be able to see what you see.”
Some philosophers, like Thomas Nagel, have argued that this divide between the physical facts of neuroscience and the reality of subjective experience represents an epistemological dead end. No matter how much we know about our neurons, we still won’t be able to explain how a twitch of ions in the frontal cortex becomes the Technicolor cinema of consciousness.
Markram takes these criticisms seriously. Nevertheless, he believes that Blue Brain is uniquely capable of transcending the limits of “conventional neuroscience,” breaking through the mind-body problem. According to Markram, the power of Blue Brain is that it can transform a metaphysical paradox into a technological problem. “There’s no reason why you can’t get inside Blue Brain,” Markram says. “Once we can model a brain, we should be able to model what every brain makes. We should be able to experience the experiences of another mind.”
(…)
“Rendering cells is easy, at least for the supercomputer. It’s the transformation of those cells into experience that’s so hard. Still, Markram insists that it’s not impossible. The first step, he says, will be to decipher the connection between the sensations entering the robotic rat and the flickering voltages of its brain cells. Once that problem is solved—and that’s just a matter of massive correlation—the supercomputer should be able to reverse the process. It should be able to take its map of the cortex and generate a movie of experience, a first person view of reality rooted in the details of the brain. As the philosopher David Chalmers likes to say, “Experience is information from the inside; physics is information from the outside.” By shuttling between these poles of being, the Blue Brain scientists hope to show that these different perspectives aren’t so different at all. With the right supercomputer, our lucid reality can be faked.
“There is nothing inherently mysterious about the mind or anything it makes,” Markram says. “Consciousness is just a massive amount of information being exchanged by trillions of brain cells. If you can precisely model that information, then I don’t know why you wouldn’t be able to generate a conscious mind.” At moments like this, Markram takes on the deflating air of a magician exposing his own magic tricks. He seems to relish the idea of “debunking consciousness,” showing that it’s no more metaphysical than any other property of the mind. Consciousness is a binary code; the self is a loop of electricity. A ghost will emerge from the machine once the machine is built right.”
Courtesy of BBP/EPFL; rendering by Visualbiotech
Consciousness is typically construed as being explainable purely in terms of either private, raw feels or higher-order, reflective representations. In contrast to this false dichotomy, we propose a new view of consciousness as an interactive, plastic phenomenon open to sociocultural influence. We take up our account of consciousness from the observation of radical cortical neuroplasticity in human development. Accordingly, we draw upon recent research on macroscopic neural networks, including the “default mode,” to illustrate cases in which an individual’s particular “connectome” is shaped by encultured social practices that depend upon and influence phenomenal and reflective consciousness. On our account, the dynamically interacting connectivity of these networks bring about important individual differences in conscious experience and determine what is “present” in consciousness. Further, we argue that the organization of the brain into discrete anti-correlated networks supports the phenomenological distinction of prereflective and reflective consciousness, but we emphasize that this finding must be interpreted in light of the dynamic, category-resistant nature of consciousness. Our account motivates philosophical and empirical hypotheses regarding the appropriate time-scale and function of neuroplastic adaptation, the relation of high and low-frequency neural activity to consciousness and cognitive plasticity, and the role of ritual social practices in neural development and cognitive function.
Fresh heartbreak sparks a common montage: hibernating, thinking the world has ended, and keeping Kleenex in business, for starters. In a close relationship, you think of your partner as a part of you. “So when he or she pulls away, it feels like a part of your body was ripped off,” says Arthur Aron, a psychologist at SUNY at Stony Brook. The most reliable saving grace is time: As the days pass, activity diminishes in brain regions that register attachment.
Brain // Can’t stop checking your ex’s Facebook profile? Looking at photos of someone who recently let you go activates subcortical areas related to addiction - the same regions that make addicts crave cocaine. You pine for your partner, so seeing him feels rewarding.
Eyes // When everything reminds you of him, the crying spells don’t quit. “We’re built to hold on, not turn away,” says Lucy Brown, a neurologist at Einstein College of Medicine. Forming bonds is a deeply embedded need that was - and is - essential to our survival. The tears point you to what’s wrong so you can repair it, and, you know, keep our species alive.
Mouth // In a way, food is a substitute for your former flame. Hunger and the romantic drive share common reward systems in the brain, so when you feel empty, you may turn to two other men in your life: Ben & Jerry.
Heart // Feeling like you’ve been socked in the chest isn’t just a metaphor. After an extremely stressful situation, a days-long surge in adrenaline and other stress hormones can temporarily “stun” heart muscles, mimicking an actual heart attack (think chest pain and shortness of breath). Thankfully, your ticker should recover without long-term damage.
Limbs // When panic and anger subside, lethargy sets in. You can’t get out of bed and you withdraw from friends. The listlessness is a protective mechanism: It turns you into a shut-in so you can regroup mind and body.
[Psychology Today]
Do couples know each other less well as time goes on? Pairs who had spent an average of 40 more years together than younger participants were significantly worse at predicting a partner’s food, film, and kitchen-design preferences, a Journal of Consumer Psychology study found.
Researchers say older, long-term couples may pay less attention to each other, either because they view their relationship as already solid or because they think they know their partner well. Ask your honey what she’d like to do tonight - the answer may surprise you.
[Psychology Today]
A new study finds that memory reactivation during slow-wave sleep following learning can stabilize memories. Reactivation during wakefulness has the opposite effect, rendering memories labile and susceptible to modest modification.
For scientists studying how humans come to understand their world, the central challenge is this: How do our minds get so much from so little? We build rich causal models, make strong generalizations, and construct powerful abstractions, whereas the input data are sparse, noisy, and ambiguous—in every way far too limited. A massive mismatch looms between the information coming in through our senses and the ouputs of cognition.
SYNESTHESIA MAKES SENSE OF ART AND ART FROM SENSE:
Smilack has a rare form of synesthesia that involves all of her senses—the sound of one female voice looks like a thin, bending sheet of metal, and the sight of a certain fishing shack gives her a brief taste of Neapolitan ice cream—but her artistic leanings are shared by many other synesthetes. Scientists estimate that synesthesia is about seven times more common in poets, novelists, and artists than in the rest of the population. (Some of the most famous examples include artists David Hockney and Wassily Kandinsky and writer Vladimir Nabokov.)
In the last decade, this connection between synesthesia and art has drawn much attention from neuroscientists. And now several genetic and behavioral studies aim to pin down the biological mechanisms linking art and synesthesia, with hopes of answering even bigger questions about how every brain perceives art.