It is now possible to map the activity of nearly all the neurons in a vertebrate brain at cellular resolution. What does this mean for neuroscience research and projects like the Brain Activity Map proposal?
In an Article that just went live in Nature Methods, Misha Ahrens and Philipp Keller from HHMI’s Janelia Farm Research Campus used high-speed light sheet microscopy to image the activity of 80% of the neurons in the brain of a fish larva at speeds of a whole brain every 1.3 seconds. This represents—to our knowledge—the first technology that achieves whole brain imaging of a vertebrate brain at cellular resolution with speeds that approximate neural activity patterns and behavior.
Brain activity imaging of a whole zebrafish brain at single-cell resolution.
Interestingly, the paper comes out at a time when much is being discussed and written about mapping brain activity at the cellular level. This is one of the main proposals of the Brain Activity Map—a project that is being discussed at the White House and could be NIH’s next ‘big science’ project for the next 10-15 years. [Just for clarity, the authors of this work are not formally associated with the BAM proposal].
If you want to know people’s politics, tradition said to study their parents. In fact, the party affiliation of someone’s parents can predict the child’s political leanings about around 70 percent of the time.
But new research, published yesterday in the journal PLOS ONE, suggests what mom and dad think isn’t the endgame when it comes to shaping a person’s political identity. Ideological differences between partisans may reflect distinct neural processes, and they can predict who’s right and who’s left of center with 82.9 percent accuracy, outperforming the “your parents pick your party” model. It also out-predicts another neural model based on differences in brain structure, which distinguishes liberals from conservatives with 71.6 percent accuracy.
The study matched publicly available party registration records with the names of 82 American participants whose risk-taking behavior during a gambling experiment was monitored by brain scans. The researchers found that liberals and conservatives don’t differ in the risks they do or don’t take, but their brain activity does vary while they’re making decisions.
The idea that the brains of Democrats and Republicans may be hard-wired to their beliefs is not new. Previous research has shown that during MRI scans, areas linked to broad social connectedness, which involves friends and the world at large, light up in Democrats’ brains. Republicans, on the other hand, show more neural activity in parts of the brain associated with tight social connectedness, which focuses on family and country.
Other scans have shown that brain regions associated with risk and uncertainty, such as the fear-processing amygdala, differ in structure in liberals and conservatives. And different architecture means different behavior. Liberals tend to seek out novelty and uncertainty, while conservatives exhibit strong changes in attitude to threatening situations. The former are more willing to accept risk, while the latter tends to have more intense physical reactions to threatening stimuli.
I have long known the Brain is an associative computer: It reminds you of things similar to the topics of discussion/observations….hint: Think of higher things and your Brain will assist you in thinking higher things…what the article says from the other side of the coin….
Do you hate it when people complain? It turns out there’s a good reason: Listening to too much complaining is bad for your brain in multiple ways, according to Trevor Blake, a serial entrepreneur and author of Three Simple Steps: A Map to Success in Business and Life. In the book, he describes how neuroscientists have learned to measure brain activity when faced with various stimuli, including a long gripe session.
“The brain works more like a muscle than we thought,” Blake says. “So if you’re pinned in a corner for too long listening to someone being negative, you’re more likely to behave that way as well.”
Advocates of free will can rest easy, for now. A 30-year-old classic experiment that is often used to argue against free will might have been misinterpreted.
In the early 1980s, Benjamin Libet, a neuroscientist at the University of California in San Francisco, used electroencephalography (EEG) to record the brain activity of volunteers who had been told to make a spontaneous movement. With the help of a precise timer that the volunteers were asked to read at the moment they became aware of the urge to act, Libet found there was a 200 millisecond delay, on average, between this urge and the movement itself.
But the EEG recordings also revealed a signal that appeared in the brain even earlier, 550 milliseconds, on average, before the action. Called the readiness potential, this has been interpreted as a blow to free will, as it suggests that the brain prepares to act well before we are conscious of the urge to move.
This conclusion assumes that the readiness potential is the signature of the brain planning and preparing to move. “Even people who have been critical of Libet’s work, by and large, haven’t challenged that assumption,” says Aaron Schurger of the National Institute of Health and Medical Research in Saclay, France.
One attempt to do so came in 2009. Judy Trevena and Jeff Miller of the University of Otago in Dunedin, New Zealand, asked volunteers to decide, after hearing a tone, whether or not to tap on a keyboard. The readiness potential was present regardless of their decision, suggesting that it did not represent the brain preparing to move. Exactly what it did mean, though, still wasn’t clear.
Crossing a threshold
Now, Schurger and colleagues have an explanation.
How the human auditory system extracts perceptually relevant acoustic features of speech is unknown. To address this question, we used intracranial recordings from nonprimary auditory cortex in the human superior temporal gyrus to determine what acoustic information in speech sounds can be reconstructed from population neural activity. We found that slow and intermediate temporal fluctuations, such as those corresponding to syllable rate, were accurately reconstructed using a linear model based on the auditory spectrogram. However, reconstruction of fast temporal fluctuations, such as syllable onsets and offsets, required a nonlinear sound representation based on temporal modulation energy. Reconstruction accuracy was highest within the range of spectro-temporal fluctuations that have been found to be critical for speech intelligibility. The decoded speech representations allowed readout and identification of individual words directly from brain activity during single trial sound presentations. These findings reveal neural encoding mechanisms of speech acoustic parameters in higher order human auditory cortex.
An early symptom of autism might be found in a baby’s gaze, researchers reported Thursday.
Diagnosing autism as early as possible is of critical importance. Studies show the earlier therapy begins, the more likely the child can overcome the deficits linked to the brain disorder.
The new study, published online in the journal Current Biology, examined babies 6 months to 10 months of age who were at higher risk of developing autism because they had an older sibling with autism. Researchers from Birkbeck College, University of London, placed sensors on the scalp to register brain activity while the babies viewed faces. During the exam, the faces sometimes looked at the babies and other times looked away. This was key because earlier studies show that eye contact in babies is important to their social interaction and that children with autism tend to avoid eye contact.
The study found that babies who went on to develop autism had different brain activity during the eye-contact test compared with babies who did not develop autism. In other words, the babies destined to develop autism were already processing social information differently.
The mysterious origin of the female orgasm hasn’t yet been solved, but now the world’s first movie of the brain during sexual climax maps activity before, during and after the event. Created by animators from theVisualMD, it’s based on brain scans captured by Barry Komisaruk of Rutgers University, New Jersey, and his team as a woman stimulated herself inside an fMRI machine.
The animation uses a colour scale that varies from red to white, where yellow and white are linked to highest levels of activity. The first sequence uses snapshots of 20 moments during the 7-minute scan.
Initially, genital touching fires up a region of the sensory cortex but signals quickly spread to the limbic system, an area linked to emotion, behaviour and long-term memory. Then the cerebellum and frontal cortex light up as muscles become tense before climax. During orgasm, almost the whole brain becomes highly active, as demonstrated by the bright yellow colours. This stage is highlighted in the second part of the animation. Activity then returns to lower levels.
Komisaruk hopes that this map of the brain will help explain conditions where women have difficulty achieving orgasm, by showing where the process breaks down. He’s also developing a technique where people can watch their brain activity while inside an fMRI scanner, allowing them to learn how to change brain patterns. This could help treat a range of conditions such as pain, anxiety and depression.
Previously, Komisaruk has compared brain activity during stimulation of the vagina, clitoris and cervix.
The animation was presented this week at the Society for Neuroscience annual meeting in Washington DC.
If you enjoyed this clip, check out the first video of a couple having sex in an MRI scanner.
The ability to dream is a fascinating aspect of the human mind. However, how the images and emotions that we experience so intensively when we dream form in our heads remains a mystery. Up to now it has not been possible to measure dream content. Max Planck scientists working with colleagues from the Charité hospital in Berlin have now succeeded, for the first time, in analysing the activity of the brain during dreaming. They were able to do this with the help of lucid dreamers, i.e. people who become aware of their dreaming state and are able to alter the content of their dreams. The scientists measured that the brain activity during the dreamed motion matched the one observed during a real executed movement in a state of wakefulness.
Figure legend: Activity in the motor cortex during the movement of the hands while awake (left) and during a dreamed movement (right). Blue areas indicate the activity during a movement of the right hand, which is clearly demonstrated in the left brain hemisphere, while red regions indicate the corresponding left-hand movements in the opposite brain hemisphere..
Methods like functional magnetic resonance imaging have enabled scientists to visualise and identify the precise spatial location of brain activity during sleep. However, up to now, researchers have not been able to analyse specific brain activity associated with dream content, as measured brain activity can only be traced back to a specific dream if the precise temporal coincidence of the dream content and measurement is known. Whether a person is dreaming is something that could only be reported by the individual himself.
Scientists from the Max Planck Institute of Psychiatry in Munich, the Charité hospital in Berlin and the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig availed of the ability of lucid dreamers to dream consciously for their research. Lucid dreamers were asked to become aware of their dream while sleeping in a magnetic resonance scanner and to report this “lucid” state to the researchers by means of eye movements. They were then asked to voluntarily “dream” that they were repeatedly clenching first their right fist and then their left one for ten seconds.
This enabled the scientists to measure the entry into REM sleep – a phase in which dreams are perceived particularly intensively – with the help of the subject’s electroencephalogram (EEG) and to detect the beginning of a lucid phase. The brain activity measured from this time onwards corresponded with the arranged “dream” involving the fist clenching. A region in the sensorimotor cortex of the brain, which is responsible for the execution of movements, was actually activated during the dream. This is directly comparable with the brain activity that arises when the hand is moved while the person is awake. Even if the lucid dreamer just imagines the hand movement while awake, the sensorimotor cortex reacts in a similar way.
The coincidence of the brain activity measured during dreaming and the conscious action shows that dream content can be measured. “With this combination of sleep EEGs, imaging methods and lucid dreamers, we can measure not only simple movements during sleep but also the activity patterns in the brain during visual dream perceptions,” says Martin Dresler, a researcher at the Max Planck Institute for Psychiatry.
The researchers were able to confirm the data obtained using MR imaging in another subject using a different technology. With the help of near-infrared spectroscopy, they also observed increased activity in a region of the brain that plays an important role in the planning of movements. “Our dreams are therefore not a ‘sleep cinema’ in which we merely observe an event passively, but involve activity in the regions of the brain that are relevant to the dream content,” explains Michael Czisch, research group leader at the Max Planck Institute for Psychiatry.
Martin Dresler, Stefan P. Koch, Renate Wehrle, Victor I. Spoormaker, Florian Holsboer, Axel Steiger, Philipp G. Sämann, Hellmuth Obrig, Michael Czisch
Dreamed Movement Elicits Activation in the Sensorimotor Cortex
Current Biology, D-11-00137R3, October 2011
I read this article three times and the whole thing is still going *WHOOSH* right over my head. I’m posting it here in the hopes that one of you science minded members will explain the significance to me.
Here’s the first clip:
A group at Berkeley has just published (£) the first successful attempt to reconstruct imagery from the mind using an fMRI brain scanner. The results are startling, encouraging and a little bit scary.
The method used called fMRI is known for its high spacial resolution (3D imaging ability) but notoriously low temporal resolution (measurements with respect to time – effectively a slow shutter speed). In the past this has been a barrier to research such as this on the visual cortex because of the incredibly high rate that information is processed in the visual system. Now a new encoding method has been developed which allows for the modelling of brain activity in the visual system at a faster rate. […]