Roman F. Loonis表示，神經特徵可幫助我們透過學習策略的變化，及早發現阿茲海默患者、或強化其學習的方式，以期患者能與疾病和平相處。
科學家曾將所有的「學習」等同視之。1953年，曾透過手術移除部分腦組織的癲癇患者──Henry Molaison ，在術後無法記得幾分鐘才吃過早餐、動作技巧學習與能力保存卻正常；且Miller也發現：與Henry一樣的健忘患者雖無法記得自己做過的事，但在技巧的學習上都與他人無異。自此，科學家們對學習開始有了不同的看法。
有關大腦的學習與記憶可粗分為「顯性」與「隱性」兩類。在顯性學習（Explicit Learninig）中，我們能清楚知道自己在做什麼，並能解釋詳細的活動內容，無論是文章段落的記憶、或解開複雜棋局的策略……等都屬於顯性學習；而隱性學習（Implicit Learning）較為內化、無意識，多為動作技巧學習或肌肉記憶，如學會騎腳踏車或雜耍技巧……等。「當然，也有如音樂與樂器演奏等特殊內容，必須同時仰賴兩種不同屬性的學習方式。」Miller強調。
新聞來源：Brain waves reflect different types of learning, Science Daily.
Brain Waves Reflect Different Types of Learning
Figuring out how to pedal a
bike and memorizing the rules of chess require two different types of learning,
and now for the first time, researchers have been able to distinguish each type
of learning by the brain-wave patterns it produces.
These distinct neural signatures could guide scientists as they
study the underlying neurobiology of how we both learn motor skills and work
through complex cognitive tasks, says Earl K. Miller, the Picower Professor of
Neuroscience at the Picower Institute for Learning and Memory and the
Department of Brain and Cognitive Sciences, and senior author of a paper
describing the findings in the Oct. 11 edition of Neuron.
When neurons fire, they produce electrical signals that combine
to form brain waves that oscillate at different frequencies. "Our ultimate
goal is to help people with learning and memory deficits," notes Miller.
"We might find a way to stimulate the human brain or optimize training
techniques to mitigate those deficits."
The neural signatures could help identify changes in learning
strategies that occur in diseases such as Alzheimer's, with an eye to
diagnosing these diseases earlier or enhancing certain types of learning to
help patients cope with the disorder, says Roman F. Loonis, a graduate student
in the Miller Lab and first author of the paper. Picower Institute research
scientist Scott L. Brincat and former MIT postdoc Evan G. Antzoulatos, now at
the University of California at Davis, are co-authors.
versus implicit learning
Scientists used to think all learning was the same, Miller
explains, until they learned about patients such as the famous Henry Molaison
or "H.M.," who developed severe amnesia in 1953 after having part of
his brain removed in an operation to control his epileptic seizures. Molaison
couldn't remember eating breakfast a few minutes after the meal, but he was
able to learn and retain motor skills that he learned, such as tracing objects
like a five-pointed star in a mirror.
"H.M. and other amnesiacs got better at these skills over
time, even though they had no memory of doing these things before," Miller
The divide revealed that the brain engages in two types of
learning and memory -- explicit and implicit.
Explicit learning "is learning that you have conscious
awareness of, when you think about what you're learning and you can articulate
what you've learned, like memorizing a long passage in a book or learning the
steps of a complex game like chess," Miller explains.
"Implicit learning is the opposite. You might call it motor
skill learning or muscle memory, the kind of learning that you don't have
conscious access to, like learning to ride a bike or to juggle," he adds. "By
doing it you get better and better at it, but you can't really articulate what
Many tasks, like learning to play a new piece of music, require
both kinds of learning, he notes.
waves from earlier studies
When the MIT researchers studied the behavior of animals
learning different tasks, they found signs that different tasks might require
either explicit or implicit learning. In tasks that required comparing and
matching two things, for instance, the animals appeared to use both correct and
incorrect answers to improve their next matches, indicating an explicit form of
learning. But in a task where the animals learned to move their gaze one
direction or another in response to different visual patterns, they only
improved their performance in response to correct answers, suggesting implicit
What's more, the researchers found, these different types of
behavior are accompanied by different patterns of brain waves.
During explicit learning tasks, there was an increase in alpha2-beta
brain waves (oscillating at 10-30 hertz) following a correct choice, and an
increase delta-theta waves (3-7 hertz) after an incorrect choice. The
alpha2-beta waves increased with learning during explicit tasks, then decreased
as learning progressed. The researchers also saw signs of a neural spike in
activity that occurs in response to behavioral errors, called event-related
negativity, only in the tasks that were thought to require explicit learning.
The increase in alpha-2-beta brain waves during explicit
learning "could reflect the building of a model of the task," Miller
explains. "And then after the animal learns the task, the alpha-beta
rhythms then drop off, because the model is already built."
By contrast, delta-theta rhythms only increased with correct
answers during an implicit learning task, and they decreased during learning.
Miller says this pattern could reflect neural "rewiring" that encodes
the motor skill during learning.
"This showed us that there are different mechanisms at play
during explicit versus implicit learning," he notes.
Boost to Learning
Loonis says the brain wave signatures might be especially useful
in shaping how we teach or train a person as they learn a specific task.
"If we can detect the kind of learning that's going on, then we may be
able to enhance or provide better feedback for that individual," he says.
"For instance, if they are using implicit learning more, that means
they're more likely relying on positive feedback, and we could modify their learning
to take advantage of that."
The neural signatures could also help detect disorders such as
Alzheimer's disease at an earlier stage, Loonis says. "In Alzheimer's, a
kind of explicit fact learning disappears with dementia, and there can be a
reversion to a different kind of implicit learning," he explains.
"Because the one learning system is down, you have to rely on another
Earlier studies have shown that certain parts of the brain such
as the hippocampus are more closely related to explicit learning, while areas
such as the basal ganglia are more involved in implicit learning. But Miller
says that the brain wave study indicates "a lot of overlap in these two
systems. They share a lot of the same neural networks."
Scott L. Brincat, Evan G. Antzoulatos, Earl K. Miller. A Meta-Analysis Suggests Different
Neural Correlates for Implicit and Explicit Learning Roman F. Loonis
, October 2017