Tag: fMRI

Synaptic Sunday #9 – Vivid Memory Edition

by hkatz, posted in Neuroscience, Research, Synaptic Sunday

1) Why Does a Vivid Memory ‘Feel So Real?’

Researchers found that vivid memory and real perceptual experience share “striking” similarities at the neural level, although they are not “pixel-perfect” brain pattern replications.

and

“Our study has confirmed that complex, multi-featured memory involves a partial reinstatement of the whole pattern of brain activity that is evoked during initial perception of the experience. This helps to explain why vivid memory can feel so real.”

Are vivid memories more accurate than non-vivid memories? Less vulnerable to fabrication and distortion? A memory can feel quite vivid but could be made up in part. Maybe there are certain aspects of a scene that we remember more accurately and other parts that we fill-in, even for a memory that feels like a powerfully accurate recording playing in our minds.

As always, it’s important to distinguish between the accuracy of the memory and the confidence people have in the accuracy of the memory. Are we good judges of how accurately we’ve remembered something?

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2) Psychologists Link Emotion to Vividness of Perception and Creation of Vivid Memories

Have you ever wondered why you can remember things from long ago as if they happened yesterday, yet sometimes can’t recall what you ate for dinner last night?

Synaptic Sunday #7 – Mind-Controlled Robotics edition

by hkatz, posted in Neuroscience, Research, Synaptic Sunday

1) Real-life Avatar: The first mind-controlled robot surrogate

Tirosh Shapira, an Israeli student, controlled the movements of a small robot over a thousand miles away using only his thoughts.

The fMRI (functional magnetic resonance imaging) reads his thoughts, a computer translates those thoughts into commands, and then those commands are sent across the internet to the robot in France. The system requires training: On its own, an fMRI can simply see the real-time blood flow in your brain (pictured below right). Training teaches the system that a particular “thought” (blood flow pattern) equates to a certain command.

Some of the future uses for such technology are medical (for people who have suffered paralysis for example) and military.

Shapira mentions in the article that he “became one with the robot.” How would we come to feel about these robotic extensions of ourselves? If they get damaged or destroyed, would we feel as if a part of us had been killed, or after some disappointment would we settle for any replacement?

2) Mind-controlled robot arms show promise

Using implants to record neuronal activity in parts of the brain associated with the intention to move, researchers were able to help two people with tetraplegia manipulate a robotic arm by thinking about certain actions (e.g. lifting up a cup).

The challenge lies in decoding the neural signals picked up by the participant’s neural interface implant — and then converting those signals to digital commands that the robotic device can follow to execute the exact intended movement. The more complex the movement, the more difficult the decoding task.

This is amazing work.

Synaptic Sunday #6 – The Dog’s Mind and fMRI Edition

by hkatz, posted in Neuroscience, Research, Synaptic Sunday

1) How do you train a dog to get into an fMRI scanner and stay there without resorting to restraints and drugs?

2) More importantly, why would you want to get a dog into an fMRI scanner?

Scientists Use Brain Scans to Peek at What Dogs Are Thinking

From the link:

The researchers aim to decode the mental processes of dogs by recording which areas of their brains are activated by various stimuli. Ultimately, they hope to get at questions like: Do dogs have empathy? Do they know when their owners are happy or sad? How much language do they really understand?

An fMRI scan doesn’t give us mind-reading abilities; it shows blood-flow to different areas of the brain (oxygen-rich as compared to deoxygenated blood), and researchers infer brain activity from that. When the dogs were given a signal for “treat,” for instance, there appeared to be increased activity in a part of the brain that in people is associated with rewards. But can we get a real understanding of what the dog is experiencing? If you look at questions of empathy, what is empathy to a dog? Maybe we’d see increased activity in certain parts of the brain that in humans is associated with empathy, which could be interesting, but what does that tell us more deeply about the dog’s mind and subjective experiences? If they know when their owners are happy or sad, what kind of knowledge is this: a reading of facial and behavioral cues, or something deeper than that? This is a limitation of fMRI when it’s used on people as well, though with people we can try to supplement the fMRI scan findings with other measures – various cognitive tasks, including those that ask for verbal input (“woof, woof”).

3) Overall, fMRI studies can be quite problematic, for dogs or humans (or dead salmon) – as detailed in this recent article: Controversial science of brain imaging.