RE: virus: Fwd: Mind's Eye Re-Creates Visual Memories

Sodom (
Fri, 16 Apr 1999 10:24:37 -0400

Wow Wade, thanks a lot for the Mind's Eye article. Very informative and worth reading for people of this interest.

Bill Roh

> -----Original Message-----
> From:
> []On Behalf
> Of Wade T.Smith
> Sent: Friday, April 16, 1999 9:36 AM
> To: Church of Virus;
> Subject: virus: Fwd: Mind's Eye Re-Creates Visual Memories
> Mind's Eye Re-Creates Visual Memories
> By William J. Cromie
> Gazette Staff
> Using magnetic fields that disrupt brain activity, researchers have
> proved that visual memories are re-created in the brain as mental
> pictures. Stored images are played, like videotapes, on a screenlike
> sheet of tissue at the back of the head.
> Brain scans previously revealed intense activity in this area of the
> brain when people recall a familiar object, scene, or letter.
> However,
> scientists debated whether the area actually plays a role in handling
> information. It's possible, some argued, that such activity is only a
> by-product of processing that occurs elsewhere in the brain. Now, by
> using magnetic currents to blur the "mind's-eye" screen, Harvard
> researchers have found they can delay visual imagination,
> strong evidence
> that memories of what the eye once saw are replayed in this little
> theater of the brain.
> "Scenes that register on the retina of the eye are faithfully
> projected
> by patterns of nerve signals activated in the visual area of
> the brain,"
> explains Stephen Kosslyn, professor of psychology. "The
> images are then
> stored in the temporal lobes (under the temples) in a
> compressed form not
> unlike magnetic pulses on a videotape.
> "To recall things like the number of windows in a house, information
> about the geometry of the house is unpacked from memory and
> sent back to
> the visual area," continues Kosslyn. "Unpacking memories is what
> visualization is all about."
> The area where visual images are recalled or first imagined can be
> pinpointed by a brain scanning technique known as positron emission
> tomography, or PET. If experimenters send pulses of magnetic
> energy to
> this same area, the visualization is delayed, which would not
> happen if
> activity in this area played no role in recall or imagination.
> "This is a new use of a technique called repetitive
> transcranial magnetic
> stimulation (rTMS) whereby magnetic fields are used to both map and
> change brain activity," notes Alvaro Pascual-Leone, a Harvard Medical
> School researcher who worked with Kosslyn on these
> experiments. He has
> used rTMS to treat depression, Parkinson's disease, schizophrenia,
> obsessive- compulsive behavior, and to help blind people
> learn Braille.
> Magnetic Effects
> In 1993, Kosslyn and his colleagues showed that two small
> areas at the
> middle of the back of the brain become active when you close
> your eyes
> and visualize letters of the alphabet. A few years later, he
> found that
> smaller objects activate areas farther back in the visual cortex than
> larger ones. Much the same thing happens when we first view
> objects of
> different sizes.
> "It's a peculiar feature of how this part of the cortex is folded,"
> Kosslyn notes.
> PET scans measure brain activity by how much blood flows to different
> sites. Kosslyn and his colleagues found that people with the weakest
> flows took the longest to use mental pictures. Once flow exceeds a
> certain level, however, subjects respond relatively rapidly.
> "It's not
> clear whether the latter group sees more vivid images, but they do
> classify parts of visualized objects quicker."
> In their latest experiments, Kosslyn and colleagues at Harvard-
> affiliated Massachusetts General Hospital in Boston had eight people
> remember patterns of stripes located in four different boxes
> presented
> together on a single screen. Afterward, the researchers asked them
> questions such as whether the stripes in box number one were
> shorter or
> longer than those in box number four. Other questions dealt
> with whether
> stripes were vertical or horizontal, thicker or thinner, tilted or
> straight.
> Later, people did the same test after Pascual-Leone waved a
> magnetic wand
> over their mind's eye. An electric current running through the wand
> rapidly turns on and off, generating a magnetic field that
> penetrates the
> scalp. In some sessions, the coil was positioned so the
> magnetism missed
> the key areas where visual images are replayed. Investigators then
> compared results with and without magnetic stimulation of the
> key visual
> area.
> "Every one of the people who received magnetic stimulation of
> that area
> took more time to visualize and perceive the patterns of
> stripes," notes
> Kosslyn. "The magnetic fields were directed at the small area
> where the
> PET scans had registered activity during visualization."
> The memory delay, no doubt, stems from disruption of the brain cells.
> Other studies have shown that intense magnetic fields can impair
> short-term memory for words and for previously learned
> movement responses.
> Magnetic Therapy
> Would it be possible to wipe out memories - say, recurring traumatic
> images of abuse or assault - with magnetism?
> "Possibly," Kosslyn answers. "But I think you'd need to do it
> within a
> year, before the memory becomes consolidated."
> Electroshock therapy is used for both memory obliteration and
> treating
> major depression, and physicians are starting to use magnetic
> stimulation
> for the same purposes. Magnetism has the advantage of not
> shocking people
> into convulsions.
> In experiments at Beth Israel Deaconess Medical Center in Boston,
> Pascual-Leone improved the moods of 11 of 17 badly depressed
> people who
> had not been helped by electroshock treatment or drugs.
> "If we prolong stimulation for five to ten days, we can
> sometimes extend
> the benefit up to several months," Pascual- Leone notes. "I
> hope that it
> will eventually work well enough so that individual treatments can be
> custom-designed for patients."
> Kosslyn notes that images created by pure imagination share the same
> projection equipment as actual memories. That makes it easy
> to confuse
> real and implanted memories of abuse, or of witnessing a crime.
> There is, however, evidence that false and true memories can
> be separated
> by the amount and pattern of brain activity they produce.
> "Real memories
> contain more information, more detail, and thus activate the brain
> differently," Kosslyn points out. "It's only speculation at
> this point,
> but we may be able to exploit these differences to verify the
> truth of a
> memory."
> Copyright 1999 President and Fellows of Harvard College
> *******************************************
> Wade T. Smith
> ** **