hi bruce
on 19 july 1997 bruce warr wrote:
>>...in my label memory bank would be one called "triangle"
>>but the association between the object and its label was missing
on 20 july 1997 janet paterson wrote:
>it seems to me that in one of the many news articles about brain research
>that i posted in the last year or so
>one discussed the idea that very specific areas of the brain
>are responsible for very specific memory functions
i did some digging and found the two articles
[which i have included below]
which i had posted last year about the connections
between recognising an object and remembering its name
it was the concept of very specific 'brokers' that amazed me at the time
e.g. there is a broker specifically for helping
to remember the names of animals
i said it before
and i'll say it again:
"we are the miraculous, the true wonders of this world ~ maya angelou"
janet
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'Broker' in brain puts names, faces together, researcher says
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Copyright 1996 Nando.net Copyright 1996 The Boston Globe
(Apr 11, 1996 5:30 p.m. EDT) -- If, like many people, you never forget a
face but are terrible with names, it's the "broker" in your brain you
should blame.
"Broker" is what scientists are calling a newly discovered brain function
that, most of the time, enables us to dip into our enormous store of words
and dredge up the correct one for a face or object.
Neuroscientists had long believed that retrieving known words was just a
two-step process: One part of your brain recognized the concept (it's an
eating utensil, or a musical instrument) and then triggered a separate
speech center that would in turn produce the specific word ("spoon" or
"clarinet").
But Drs. Hanna and Antonio Damasio, renowned neuroscientists at the
University of Iowa, say they've found there's a previously unsuspected
middleman.
"We find evidence that you don't go from concepts to words nonstop," said
Dr. Antonio Damasio in a telephone interview Wednesday. "There's an
intermediary structure that helps you go from one to the other, like a
diplomatic broker that is talking to both sides at the same time."
Moreoever, he said, there may be as many brokers as there are categories of
words. In experiments being reported today in the journal Nature, the
Damasios and their colleagues found at least three brokers: one that helps
retrieve names of familiar people, another for names of tools, and another
for animals.
Surprisingly, the areas of the brain that act as brokers, in effect as the
brain's dictionary or thesaurus, aren't part of structures long considered
the primary speech and language areas -- Broca's and Wernicke's areas.
Instead, they are scattered about the temporal lobe of the left hemisphere,
said Damasio.
The experiments that revealed the existence of the brokers were done in two
groups of people: 127 patients who had had strokes or other forms of brain
damage, and 7 normal volunteers.
The researchers asked the brain-damaged subjects to name objects in
pictures in a standard test and found that some of them made errors
indicating a word-broker wasn't working.
Shown a skunk, for example, one said: "Oh, that animal makes a terrible
smell if you get close to it; it is black and white and gets squashed on
the road by cars sometimes."
His brain produced the right concept, but the brokering step failed, and he
couldn't recall the word. The researchers noted what part of the brain was
damaged in that patient and concluded that's where the "mental dictionary"
for animals was located.
The normal volunteers underwent PET scans, which revealed what parts of the
brain were especially active when they took various word-retrieval tests.
The "hot spots" turned out to be the same areas that were damaged and
inactive in the stroke patients who couldn't recall certain kinds of words.
The fact that there are many brokers may explain bizarre cases of people
with brain damage who can no longer name certain categories of words, like
tools or animals, but have no trouble naming others. Damasio said the
findings might someday help people who have difficulty thinking of certain
words.
In a commentary, neuropsychologist Alfonso Caramazza of Harvard University
praised the Damasios' work and called for studies to determine what other
brokers exist. "Are abstract concepts -- justice, evidence and ambition,
for example -- also represented categorically?" he asked.
It's not surprising that people's names are hard to dig up, Damasio added,
because "different brokers handle different levels of complexity, and the
names of specific people involve the highest levels of complexity. When
you're distracted or tired, those may be hard to retrieve, while you'd have
less trouble coming up with the name of a tool or an animal."
The Damasios' co-authors are Thomas J. Grabowski, Daniel Tranel and Richard
D. Hichwa.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Clues To How The Brain Processes Words And Pictures Uncovered
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
WESTPORT, Sep 19 1996 (Reuters)
Some brain-damaged patients can name objects from pictures but not from
verbal descriptions. Other patients have the reverse deficit. Now, British
researchers have identified the structures in the brain that are activated
when people make semantic judgments based on words or pictures.
In today's issue of Nature, Dr. Cathy Price and colleagues at the Institute
of Neurology in London report, "We contrasted activity during two semantic
tasks... and a baseline task... performed either with words or with pictures."
According to Dr. Price, positron emission tomography studies showed that,
"...semantic tasks activate a distributed semantic processing system shared
by both words and pictures, with a few specific areas differentially active
for either words or pictures."
She adds, "The anatomy and function of the common semantic processing
stream we describe suggests that... when primates acquired language, a
preexisting object-recognition system could have been adapted to attribute
meaning to nouns."
In an accompanying News and Views article, Dr. Alfonso Caramazza of the
Cognitive Neuropsychology Laboratory at Harvard University points out that,
in the study by Dr. Price's group, "...the areas that showed selective
activation for type of stimulus (picture or word) did so for both visual
and functional/associative judgments.
This result shows that the areas selectively activated for pictures and for
words are not modality-specific semantic systems but neural mechanisms
involved in the recognition of pictures and words, respectively."
Dr. Caramazza concludes that "...it is clear that we are entering an
exciting new phase in the study of the human brain; functional neuroimaging
studies ..promise to answer increasingly finer-grained questions about the
organization of language processes in the brain."
Nature 1996;383:254-256,216-217.
Westport Newsroom 203 221 7648
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[log in to unmask]
