f**d
发帖数: 768 | 1 来自Caltech的研究
Christof Koch 算是计算神经科学领域响铛铛的牛人, 也做很多实验研究
他最近几年的研究多少有点‘离奇’
几年前他和DNA结构的发现者克拉克合作的一篇文章，发表在NATURE NEUROSCIENCE上
指出单个皮层神经元具有intelligence，曾引发学术界不小的震荡
现在又来一篇。。。结果好像不意外，但还是很神奇
Neuroscience research involving epileptic patients with brain electrodes
surgically implanted in their medial temporal lobes shows that patients
learned to consciously control individual neurons deep in the brain
with thoughts.
Subjects learned to control mouse cursors, play video games and alter
focus of digital images with their thoughts. The patients were each
using brain computer interfaces, deep brain electrodes and software
designed for the research.
The article below offers more detail.
Controlling Individual Cortical Nerve Cells by Human Thought
Five years ago, neuroscientist Christof Koch of the California Institute
of Technology (Caltech), neurosurgeon Itzhak Fried of UCLA, and their
colleagues discovered that a single neuron in the human brain can
function much like a sophisticated computer and recognize people,
landmarks, and objects, suggesting that a consistent and explicit code
may help transform complex visual representations into long-term and
more abstract memories.
Now Koch and Fried, along with former Caltech graduate student and
current postdoctoral fellow Moran Cerf, have found that individuals
can exert conscious control over the firing of these single neurons—
despite the neurons’ location in an area of the brain previously
thought inaccessible to conscious control—and, in doing so,
manipulate the behavior of an image on a computer screen.
The work, which appears in a paper in the October 28 issue of the
journal Nature, shows that “individuals can rapidly, consciously, and
voluntarily control neurons deep inside their head,” says Koch, the
Lois and Victor Troendle Professor of Cognitive and Behavioral Biology
and professor of computation and neural systems at Caltech.
The study was conducted on 12 epilepsy patients at the David Geffen
School of Medicine at UCLA, where Fried directs the Epilepsy Surgery
Program. All of the patients suffered from seizures that could not be
controlled by medication. To help localize where their seizures were
originating in preparation for possible later surgery, the patients were
surgically implanted with electrodes deep within the centers of their
brains. Cerf used these electrodes to record the activity, as
indicated by spikes on a computer screen, of individual neurons in parts
of the medial temporal lobe—a brain region that plays a major role
in human memory and emotion.
Prior to recording the activity of the neurons, Cerf interviewed each of
the patients to learn about their interests. “I wanted to see what
they like—say, the band Guns N’ Roses, the TV show House, and the
Red Sox,” he says. Using that information, he created for each
patient a data set of around 100 images reflecting the things he or
she cares about. The patients then viewed those images, one after
another, as Cerf monitored their brain activity to look for the targeted
firing of single neurons. “Of 100 pictures, maybe 10 will have a
strong correlation to a neuron,” he says. “Those images might
represent cached memories—things the patient has recently seen.”
The four most strongly responding neurons, representing four different
images, were selected for further investigation. “The goal was to get
patients to control things with their minds,” Cerf says. By thinking
about the individual images—a picture of Marilyn Monroe, for example—
the patients triggered the activity of their corresponding neurons,
which was translated first into the movement of a cursor on a computer
screen. In this way, patients trained themselves to move that cursor
up and down, or even play a computer game.
But, says Cerf, “we wanted to take it one step further than just brain
–machine interfaces and tap into the competition for attention
between thoughts that race through our mind.”
To do that, the team arranged for a situation in which two concepts
competed for dominance in the mind of the patient. “We had patients sit
in front of a blank screen and asked them to think of one of the target
images,” Cerf explains. As they thought of the image, and the
related neuron fired, “we made the image appear on the screen,” he
says. That image is the “target.” Then one of the other three images
is introduced, to serve as the “distractor.”
“The patient starts with a 50/50 image, a hybrid, representing the ‘
marriage’ of the two images,” Cerf says, and then has to make the
target image fade in—just using his or her mind—and the distractor
fade out. During the tests, the patients came up with their own personal
strategies for making the right images appear; some simply thought of
the picture, while others repeated the name of the image out loud or
focused their gaze on a particular aspect of the image. Regardless of
their tactics, the subjects quickly got the hang of the task, and they
were successful in around 70 percent of trials.
“The patients clearly found this task to be incredibly fun as they
started to feel that they control things in the environment purely
with their thought,” says Cerf. “They were highly enthusiastic to
try new things and see the boundaries of ‘thoughts’ that still allow
them to activate things in the environment.”
Notably, even in cases where the patients were on the verge of failure—
with, say, the distractor image representing 90 percent of the composite
picture, so that it was essentially all the patients saw—”they were
able to pull it back,” Cerf says. Imagine, for example, that the target
image is Bill Clinton and the distractor George Bush. When the
patient is “failing” the task, the George Bush image will dominate. “
The patient will see George Bush, but they’re supposed to be thinking
about Bill Clinton. So they shut off Bush—somehow figuring out how to
control the flow of that information in their brain—and make other
information appear. The imagery in their brain,” he says, “is stronger
than the hybrid image on the screen.”
According to Koch, what is most exciting “is the discovery that the
part of the brain that stores the instruction ‘think of Clinton’
reaches into the medial temporal lobe and excites the set of neurons
responding to Clinton, simultaneously suppressing the population of
neurons representing Bush, while leaving the vast majority of cells
representing other concepts or familiar person untouched.”
The work in the paper, “On-line voluntary control of human temporal
lobe neurons,” is part of a decade-long collaboration between the Fried
and Koch groups, funded by the National Institute of Neurological
Disorders and Stroke, the National Institute of Mental Health, the G.
Harold & Leila Y. Mathers Charitable Foundation, and Korea’s World
Class University program.
Contact: Kathy Svitil
Source: California Institute of Technology (Caltech) | m********a
发帖数: 239 | 2 Since every single thought is created by neuronal activity, this work
basically shows neuronal activity in certain parts of the brain affects
activity in another part. The subject may feel that they have a control of
their brain activity, it is essential "their brains" control their brains. |
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