Showing posts with label fmri. Show all posts
Showing posts with label fmri. Show all posts

Saturday, August 24, 2013

How to reconstruct from brain images which letter a person was reading | KurzweilAI

How to reconstruct from brain images which letter a person was reading | KurzweilAI: The researchers “taught” the model how 1200 voxels (volumetric pixels) of 2x2x2 mm from the brain scans correspond to individual pixels in different versions of handwritten letters...
“In our further research we will be working with a more powerful MRI scanner,” said Sanne Schoenmakers, who is working on a thesis about decoding thoughts. “Due to the higher resolution of the scanner, we hope to be able to link the model to more detailed images. We are currently linking images of letters to 1200 voxels in the brain; with the more powerful scanner we will link images of faces to 15,000 voxels.”

Monday, April 15, 2013

Many Neuroscience Studies May Be Based on Bad Statistics | Wired Science | Wired.com

Many Neuroscience Studies May Be Based on Bad Statistics | Wired Science | Wired.com: Many researchers consider a statistical power of 80 percent to be a desirable goal in designing a study. At that level, if an effect of a particular size were genuine, the study would detect it 80 percent of the time.

But roughly half of the neuroscience studies Munafò and colleagues included in their analysis had a statistical power below 20 percent. Those studies would fail to detect a genuine effect at least 80 percent of the time...

“It was already clear that fMRI studies were almost always very underpowered, but this paper shows that just about everything except a set of studies described as “neurological” are also underpowered,” Pashler said.

Wednesday, April 10, 2013

Brain imaging spots our abstract choices before we do

Brain imaging spots our abstract choices before we do:  Kreiman discovered that electrical activity in the supplementary motor area, involved in initiating movement, and in the anterior cingulate cortex, which controls attention and motivation, appeared up to 5 seconds before a volunteer was aware of deciding to press the button (Neuron, doi.org/btkcpz). This backed up earlier fMRI studies by John-Dylan Haynes of the Bernstein Center for Computational Neuroscience in Berlin, Germany, that had traced the origins of decisions to the prefrontal cortex a whopping 10 seconds before awareness...

If this kind of "mind-reading" is possible, a new study by Haynes, published this week and also presented at the meeting, suggests that it may not be restricted to decisions about moving a finger. Using fMRI, Haynes has found that the very brain areas involved in deciding to move are also active several seconds before a more abstract decision, like whether to add or subtract a series of numbers.

Monday, December 12, 2011

Download Knowledge Directly to Your Brain, Matrix-Style

Download Knowledge Directly to Your Brain, Matrix-Style: Led by BU neuroscientist Takeo Watanabe, researchers used a method called decoded fMRI neurofeedback to stimulate the visual cortex. First they showed participants circles at different orientations. Then they used fMRI to watch the participants’ brain activity. The researchers were then able to train the participants to recreate this visual cortex activity.

The volunteers were again placed in MRI machines and asked to visualize shapes of certain colors. The participants were asked to “somehow regulate activity in the posterior part of the brain” to make a solid green disc as large as they could. They were told they would get a paid bonus proportional to the size of this disc, but they weren’t told anything about what the disc meant. The researchers watched the participants’ brain activity and monitored the activation patterns in their visual cortices.

Friday, February 25, 2011

Brain imaging provides window into consciousness | KurzweilAI

Brain imaging provides window into consciousness | KurzweilAI: While progress has been made in elucidating the range of brain function in those who are severely injured, Dr. Schiff urges caution. “Although everyone wants to use a tool like this, fMRI is not yet capable of making clear measurements of cognitive performance. There will be a range of possible responses reflecting different capabilities in these patients that we have to further explore and understand,” he says.

Tuesday, January 18, 2011

Functional boost for magnetic resonance imaging

Functional boost for magnetic resonance imaging: "Their approach side-steps to some extent the problems inherent in current approaches to fMRI, namely low signal-to-noise ratio, high data volumes, differences between patients or subjects and artifacts caused by the movement of the person being scanned. Their approach allows them to turn large amounts of often noisy data into discrete sequences of neural activity events. The team has demonstrated how well their approach works by analyzing data from fMRI scans on volunteers involved in the simple activities of drinking a glass of water or a glass of glucose solution."

Wednesday, January 5, 2011

Advance makes MRI scans more than seven times faster

Advance makes MRI scans more than seven times faster: The faster scans are made possible by combining two technical improvements invented in the past decade that separately boosted scanning speeds two to four times over what was already the fastest MRI technique, echo planar imaging (EPI). Physical limitations of each method prevented further speed improvements, "but together their image accelerations are multiplied," Feinberg said...
"Other techniques which capture signals derived from neuronal activity, EEG or MEG, have much higher temporal resolution; hundred microsecond neuronal changes. But MRI has always been very slow, with 2 second temporal resolution," Feinberg said. "Now MRI is getting down to a few hundred milliseconds to scan the entire brain, and we are beginning to see neuronal network dynamics with the high spatial resolution of MRI."

Tuesday, November 23, 2010

How to Train Your Own Brain - Technology Review

How to Train Your Own Brain - Technology Review: "In addition, focusing on a limited region adds extra noise to the system—much like looking too closely at just one swatch of a Pointillist painting—the mix of odd colors doesn't make sense until you step back and see how the dots fit together. Psychologist Anna Rose Childress, Jeremy Magland, and their colleagues at the University of Pennsylvania have overcome this issue by designing a new system of whole-brain imaging and pairing it with an algorithm that let them determine which regions of the brain are most centrally involved in a certain thought process."

Wednesday, August 25, 2010

Thought-controlled computers on the way: Intel

Thought-controlled computers on the way: Intel: "Pomerlau said words produce activity in parts of the brain associated with what the word represents. So thinking of a word for a type of food, such as apple, results in activity in the parts of the brain associated with hunger, while a word with a physical association such as spade produces activity in the areas of the motor cortex related to making the physical movements of digging. In this way the computer can infer attributes of a word to narrow it down and identify it quickly.
A working prototype can already detect words like house, screwdriver and barn, but as brain scanning becomes more advanced the computer's ability to understand thoughts will improve."

Monday, July 26, 2010

We humans can mind-meld too - New Scientist - New Scientist

We humans can mind-meld too - New Scientist - New Scientist: The scans showed that the listeners' brain patterns tracked those of the storyteller almost exactly, though trailed 1 to 3 seconds behind. But in some listeners, brain patterns even preceded those of the storyteller.

"We found that the participants' brains became intimately coupled during the course of the 'conversation', with the responses in the listener's brain mirroring those in the speaker's"

Tuesday, July 6, 2010

Stanford-led team validates, extends fMRI research on brain activity

Stanford-led team validates, extends fMRI research on brain activity - “It was often assumed that a positive fMRI BOLD signal can represent increased activity of excitatory neurons, but this was never really known and, in fact, became much more controversial over the years,” said Deisseroth. Now, the new study confirms those earlier assumptions.