Most alumni magazines are sad attempts to buff up the prestige of the institution which have suffered from low budgets and bad writing. MIT’s is quite different — it has become an excellent general science magazine. The July/August issue succeeds in being almost uniformly excellent and interesting in covering new neuroscience. Unfortunately the content is now behind a paywall, but here’s some good bits (which should make you want to subscribe to their RSS feed or the magazine itself.)
With the invention of optogenetics and other technologies, researchers can investigate the source of emotions, memory, and consciousness for the first time….
Optogenetics had its origins in 2000, in late-night chitchat at Stanford University. There, neuroscientists Karl Deisseroth and Edward Boyden began to bounce ideas back and forth about ways to identify, and ultimately manipulate, the activity of specific brain circuits. Deisseroth, who had a PhD in neuroscience from Stanford, longed to understand (and someday treat) the mental afflictions that have vexed humankind since the era of Hippocrates, notably anxiety and depression (see “Shining Light on Madness”). Boyden, who was pursuing graduate work in brain function, had an omnivorous curiosity about neurotechnology. At first they dreamed about deploying tiny magnetic beads as a way to manipulate brain function in intact, living animals. But at some point during the next five years, a different kind of light bulb went off.
Since the 1970s, microbiologists had been studying a class of light-sensitive molecules known as rhodopsins, which had been identified in simple organisms like bacteria, fungi, and algae. These proteins act like gatekeepers along the cell wall; when they detect a particular wavelength of light, they either let ions into a cell or, conversely, let ions out of it. This ebb and flow of ions mirrors the process by which a neuron fires: the electrical charge within the nerve cell builds up until the cell unleashes a spike of electrical activity flowing along the length of its fiber (or axon) to the synapses, where the message is passed on to the next cell in the pathway. Scientists speculated that if you could smuggle the gene for one of these light-sensitive proteins into a neuron and then pulse the cell with light, you might trigger it to fire. Simply put, you could turn specific neurons in a conscious animal on—or off—with a burst of light.
In 2004, Deisseroth successfully inserted the gene for a light-sensitive molecule from algae into mammalian neurons in a dish. Deisseroth and Boyden went on to show that blue light could induce the neurons to fire. At about the same time, a graduate student named Feng Zhang joined Deisseroth’s lab. Zhang, who had acquired a precocious expertise in the techniques of both molecular biology and gene therapy as a high school student in Des Moines, Iowa, showed that the gene for the desired protein could be introduced into neurons by means of genetically engineered viruses. Again using pulses of blue light, the Stanford team then demonstrated that it could turn electrical pulses on and off in the virus-modified mammalian nerve cells. In a landmark paper that appeared in Nature Neuroscience in 2005 (after, Boyden says, it was rejected by Science), Deisseroth, Zhang, and Boyden described the technique. (No one would call it “optogenetics” for another year.)
Neuroscientists immediately seized on the power of the technique by inserting light-sensitive genes into living animals. Researchers in Deisseroth’s own lab used it to identify new pathways that control anxiety in mice, and both Deisseroth’s team and his collaborators at Mount Sinai Hospital in New York used it to turn depression on and off in rats and mice. And Susumu Tonegawa’s lab at MIT recently used optogenetics to create false memories in laboratory animals.
This issue has many terrific overview articles, but I’ll just point out this interview of Antonio Damasio (whose results on the importance of emotions to decisionmaking I quoted in Bad Bayfriends) by Jason Pontin. “Q+A: Antonio Damasio”:
For decades, biologists spurned emotion and feeling as uninteresting. But Antonio Damasio demonstrated that they were central to the life-regulating processes of almost all living creatures.
Damasio’s essential insight is that feelings are “mental experiences of body states,” which arise as the brain interprets emotions, themselves physical states arising from the body’s responses to external stimuli. (The order of such events is: I am threatened, experience fear, and feel horror.) He has suggested that consciousness, whether the primitive “core consciousness” of animals or the “extended” self-conception of humans, requiring autobiographical memory, emerges from emotions and feelings.
His insight, dating back to the early 1990s, stemmed from the clinical study of brain lesions in patients unable to make good decisions because their emotions were impaired, but whose reason was otherwise unaffected–research made possible by the neuroanatomical studies of his wife and frequent coauthor, Hanna Damasio. Their work has always depended on advances in technology. More recently, tools such as functional neuroimaging, which measures the relationship between mental processes and activity in parts of the brain, have complemented the Damasios’ use of neuroanatomy.
A professor of neuroscience at the University of Southern California, Damasio has written four artful books that explain his research to a broader audience and relate its discoveries to the abiding concerns of philosophy. He believes that neurobiological research has a distinctly philosophical purpose: “The scientist’s voice need not be the mere record of life as it is,” he wrote in a book on Descartes. “If only we want it, deeper knowledge of brain and mind will help achieve … happiness.”
Antonio Damasio talked with Jason Pontin, the editor in chief of MIT Technology Review.
When you were a young scientist in the late 1970s, emotion was not thought a proper field of inquiry.
We were told very often, “Well, you’re going to be lost, because there’s absolutely nothing there of consequence.” We were pitied for our poor choice.
William James had tackled emotion richly and intelligently. But his ideas [mainly that emotions are the brain’s mapping of body states, ideas that Damasio revived and experimentally verified] had led to huge controversies in the beginning of the 20th century that ended nowhere. Somehow researchers had the sense that emotion would not, in the end, be sufficiently distinctive–because animals had emotions, too. But what animals don’t have, researchers told themselves, is language like we do, nor reason or creativity–so let’s study that, they thought. And in fact, it’s true that most creatures on the face of the earth do have something that could be called emotion, and something that could be called feeling. But that doesn’t mean we humans don’t use emotions and feelings in particular ways.
Because we have a conscious sense of self?
Yes. What’s distinctive about humans is that we make use of fundamental processes of life regulation that include things like emotion and feeling, but we connect them with intellectual processes in such a way that we create a whole new world around us.
What made you so interested in emotions as an area of study?
There was something that appealed to me because of my interest in literature and music. It was a way of combining what was important to me with what I thought was going to be important scientifically.
What have you learned?
There are certain action programs that are obviously permanently installed in our organs and in our brains so that we can survive, flourish, procreate, and, eventually, die. This is the world of life regulation–homeostasis–that I am so interested in, and it covers a wide range of body states. There is an action program of thirst that leads you to seek water when you are dehydrated, but also an action program of fear when you are threatened. Once the action program is deployed and the brain has the possibility of mapping what has happened in the body, then that leads to the emergence of the mental state. During the action program of fear, a collection of things happen in my body that change me and make me behave in a certain way whether I want to or not. As that is happening to me, I have a mental representation of that body state as much as I have a mental representation of what frightened me.
And out of that “mapping” of something happening within the body comes a feeling, which is different from an emotion?
Exactly. For me, it’s very important to separate emotion from feeling. We must separate the component that comes out of actions from the component that comes out of our perspective on those actions, which is feeling. Curiously, it’s also where the self emerges, and consciousness itself. Mind begins at the level of feeling. It’s when you have a feeling (even if you’re a very little creature) that you begin to have a mind and a self.
But that would imply that only creatures with a fully formed sense of their minds could have fully formed feelings–
No, no, no. I’m ready to give the very teeny brain of an insect—provided it has the possibility of representing its body states–the possibility of having feelings. In fact, I would be flabbergasted to discover that they don’t have feelings. Of course, what flies don’t have is all the intellect around those feelings that could make use of them: to found a religious order, or develop an art form, or write a poem. They can’t do that; but we can. In us, having feelings somehow allows us also to have creations that are responses to those feelings.
But humans are certainly conscious of being responsive.
Yes. We’re aware of our feelings and are conscious of the pleasantness or unpleasantness associated with them. Look, what are the really powerful feelings that you deal with every day? Desires, appetites, hunger, thirst, pain–those are the basic things.
How much of the structure of civilization is devoted to controlling those basic things?- Spinoza says that politics seeks to regulate such instincts for the common good.
We wouldn’t have music, art, religion, science, technology, economics, politics, justice, or moral philosophy without the impelling force of feelings.
Do people emote in predictable ways regardless of their culture? For instance, does everyone hear the Western minor mode in music as sad?
We now know enough to say yes to that question.
At the Brain and Creativity Institute [which Damasio directs], we have been doing cross-cultural studies of emotion. At first we thought we would find very different patterns, especially with social emotions. In fact, we don’t. Whether you are studying Chinese, Americans, or Iranians, you get very similar responses. There are lots of subtleties and lots of ways in which certain stimuli elicit different patterns of emotional response with different intensities, but the presence of sadness or joy is there with a uniformity that is strongly and beautifully human.
Could our emotions be augmented with implants or some other brain-interfacing technology?
Inasmuch as we can understand the neural processes behind any of these complex functions, once we do, the possibility of intervening is always there. Of course, we interface with brain function all the time: with diet, with alcohol, and with medications. So it’s not that surgical interventions will be any great novelty. What will be novel is to make those interventions cleanly so that they are targeted. No, the more serious issue is the moral situations that might arise.
Because it really depends on what the intervention is aimed at achieving.
Suppose the intervention is aimed at resuscitating your lost ability to move a limb, or to see or hear. Do I have any moral problem? Of course not. But what if it interferes with states of the brain that are influential in how you make your decisions? Then you are entering a realm that should be reserved for the person alone.
What has been the most useful technology for understanding the biological basis of consciousness?
Imaging technologies have made a powerful contribution. At the same time, I’m painfully aware that they are limited in what they give us.
If you could wish into existence a better technology for observing the brain, what would it be?
I would not want to go to only one level, because I don’t think the really interesting things occur at just one level. What we need are new techniques to understand the interrelation of levels. There are people who have spent a good part of their lives studying systems, which is the case with my wife and most of the people in our lab. We have done our work on neuroanatomy, and gone into cells only occasionally. But now we are actually studying the state of the functions of axons [nerve fibers in the brain], and we desperately need ways in which we can scale up from what we’ve found to higher and higher levels.
What would that technology look like?
I don’t know. It needs to be invented.
It looks like neuroscience now has the basic tools to sense and control individual neurons; the massive complexity of using all that data to detect how meaning and sensory input are coded will be daunting, but it’s likely we will eventually see direct optic nerve interfaces, “augments” (networked computers embedded in the brain itself and allowing direct communication and access to information), and perhaps the ability for human thought to be transferred to a new substrate — uploading of people into the cloud, a form of immortality.