It is still rough and ready, but we are mapping brain changes
underway that relate to memory. What we are mapping though are the
neural pathways to the memories. It still says nothing about how it
may be recorded if it is recorded at all. As plausibly, these
memories are been re-experienced with no actual recording taking
place. Because they are not been reinforced except through the media
itself it is prone to continuing enhancements. Thus our experience
with the real malleability of human memory.
As I have posted before, it would be marvelously efficient to recover
memories by merely returning directly to the time and revisiting
them. It is not that I think this happens, but I do think we need to
think outside our comfort zone on this one.
Meanwhile we will soon have a higher resolution of memory inducing
activities in gthe brain.
Making Memories:
Drexel Researchers Explore the Anatomy of Recollection
by Staff Writers
Philadelphia, PA (SPX) Nov 15, 2012
What was your high
school mascot? Where did you put your keys last night? Who was the
first president of the United States? Groups of neurons in your brain
are currently sending electromagnetic rhythms through established
pathways in order for you to recall the answers to each of these
questions.
Researchers in
Drexel's School of Biomedical Engineering, Science and Health Systems
are now getting a rare look inside the brain to discover the exact
pattern of activity that produces a memory.
Dr. Joshua Jacobs, a
professor in Drexel's School of Biomedical Engineering, Science and
Health Systems, is analyzing data accumulated from 60 epilepsy
patients who have had electrodes implanted on their brains in order
to determine the causes of their epileptic episodes.
"When performing
seizure mapping, surgeons implant electrodes in manybrain areas,
while searching for seizure activity," Jacobs said. "Thus,
there many electrodes end up being in normal brain tissue, and they
measure neuronal activity that reflects normal brain function - this
is the function that we're studying to learn about the nature of
working memory."
A Hi-Res Look at the
Brain
This type of study is unique because researchers are essentially looking at a more detailed picture of the brain than those generated from the more common electroencephalogram (EEG) and magnetic resonance imaging(MRI).
"Because the
electrodes are implanted directly on the brain surface, inside of the
skull, they measure brain activity more precisely than noninvasive
technique, such as EEG or MRI," Jacobs said. "This reveals
more detailed brain patterns than can be observed with external
recording technology."
Jacobs equates his
research technique to using a set of microphones to record an
orchestra. If each microphone is positioned right next to an
individual instrument, it gives a better recording than if the
microphones are outside of the building.
The Mental Time
Machine
Jacobs and his research assistants are monitoring patients' memory-relatedbrain activity in two ways.
First, for some
subjects, they record brain activity near the electrodes while asking
the patients a series of questions designed to make them use their
active memory. The prompts include exercises such as reciting a
sequence of letters or numbers or remembering information about sets
that are presented to them. The process of coming up with these
answers activates the parts of the brain responsible for working, or
short-term, memory.
For other subjects,
the researchers add electric stimulus to various sets of electrodes
while questioning the patient and recording the effects of the
administered stimuli on the patients' responses.
In a recent study, a
rare opportunity presented itself to combine the two types of brain
monitoring and data collection. This testing that has yielded one of
Jacobs' most interesting discoveries thus far.
"We explored the
rare but fascinating phenomenon of how applying electrical current to
a patient's brain surface causes them to remember old
memories," Jacobs said.
During a series of
testing sessions with a single patient, the researchers stimulated an
area of the patient's brain that triggered his high school memories.
In a follow-up a week
later, Jacobs asked the patient a series of questions, including some
about high school experiences and people from high school, while
monitoring the brain activity. What he found was that the areas of
the brain that he stimulated to cause the patient to have memories
about high school, were the same areas that responded when the
patient was asked to recall information about high school on his own.
"By conducting
this unique experiment that combined brain stimulation and
normal recordings without stimulation, our findings suggest that
stimulation causes memory retrieval when it puts the brain back in
the old brain state that corresponds to a memory," Jacobs said.
"Thus, stimulation causes a sort of neural time travel."
Moving Forward on
Thinking Back
Jacobs is in his third year of research in conjunction with The University of Pennsylvania, Jefferson Hospital and UCLA's medical center. Thus far he's examined 60 subjects, but the research has already yielded some intriguing results, including the high school memory discovery, which Jacobs recently published in the Journal of Cognitive Neuroscience and presented at the Society for Neuroscience.
One of the ways that
Jacobs' work could prove valuable in mental health studies is by
helping to answer questions about the nature of schizophrenia. A
recent grant from the Brain and Behavior Research Foundation
Scientific Council has charged Jacobs to examine the link between
disruptions in working-memory pathways and schizophrenia.
"Going forward, I
am interested in characterizing how the human brain represents a
range of different memories and, in particular, distinguishing the
extent to which separate memories are stored in individual,
specialized brain regions or whether memories are
represented throughout the entire brain," Jacobs said.
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