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More on Synesthesia(fwd)
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From: Sandy P. Klein <spklein52@hotmail.com>
SUNDAY, FEBRUARY 2, 2003
THE TIMES OF INDIA
Scientists unravel the secrets of colour sense
VITHAL C. NADKARNI
MUMBAI: In his book An Anthropologist on Mars, Oliver Sacks, the renowned New
York-based neurologist, writes movingly about the curious case of the
colourblind painter: ‘‘He entered to find his entire studio, which was hung with
brilliantly coloured paintings, utterly grey and void of colour.
‘‘His canvases, the abstract colour paintings he was known for, were now greyish
or black or white. His paintings, once rich with associations and feelings,
looked unfamiliar and meaningless to him. At this point, the magnitude of his
loss overwhelmed him. He had spent his entire life as a painter, now even his
art was without meaning and he could no longer imagine how to go on.’’
Dr Sacks’s case of the colourblind painter is an example of acquired colour
deficiency —one that can be caused by brain trauma, disease, or the effects of
toxic agents. This can be distinguished from inborn or congenital deficiencies
such as red-green confusions linked the X female chromosome, that are more
prevalent among males than females.
The rest of us, blessed as we are with a perfect sense of colour, tend to take
it for granted. Sometimes, it is only when one has lost it that one begins
marvel at the ineffable mysteries of one’s sense of colour. Now, however, some
of that mystery has begun to recede, thanks to recent research pioneered at the
University of Texas-Houston Medical School. Researchers led by neurobiologist
Daniel J. Felleman claim to have discovered how the brain perceives colour a
finding that could one day help even those who have lost their sight.
By studying macaque monkeys, the scientists have shown how modules of cells—
called ‘thin stripes’ in a particular region of the brain—are arranged to
perceive colour, according to a Reuters report.
This finding provides the first physiological basis for the perception of the
full gamut of colour, says Dr Felleman. Dr Felleman and his colleagues showed a
series of coloured placards to rhesus monkeys while simultaneously mapping the
changes of blood flows in their brains with magnetic resonance imaging. While
the monkeys looked at different colours, the blood flow peaks in their brains
shifted systematically in specific portions of the stripes, the scientists
reported in the journal Nature.
Thus, an area with a peak flow for the colour red lay next to the portion that
peaked for orange which, in turn, was next to the portion for yellow, and so on.
“We believe that the brain uses a spatial code for colour such that the location
of the peak activity within these colour maps determines the colour that you
see,’’ Dr Felleman said in a press statement.
His laboratory specialises in research on primate brains for understanding the
functional organisation of local circuits involved in the perception of colour,
pattern and object discrimination. Although the research was done on rhesus
monkeys, the scientists believe that circuits in the human brain operate in a
similar way and that the knowledge could be used to develop visual aids for the
blind. The research also opens windows into other neurological mysteries such as
synesthesia. The word, which means ‘joined sensation’, shares a root with
anaesthesia, meaning ‘no sensation’. It denotes the rare capacity to hear
colours, taste shapes, or experience other equally startling sensory blendings
whose quality seems difficult for most of us to imagine.
For example, a synesthete might describe the colour, shape, and flavour of
someone’s voice, or music whose sound looks like ‘shards of glass’, a
scintillation of jagged, coloured triangles moving in the visual field. Or,
seeing the colour red, a synesthete might detect the ‘scent’ of red as well. The
experience is frequently projected outside the individual rather than being an
image in the mind’s eye.
In his classic book, The Man who tasted shapes, Richard Cytowic makes a
conservative estimate that one person in 25,000 individuals is born into a world
where one sensation involuntarily conjures up others, sometimes all five
clashing together. Curiously, like red-green confusions, synesthesia also has a
strong genetic component.
Indeed, the most famous family case of the clashing senses may be that of the
Russian novelist Valdimir Nabokov. When, as a toddler, he complained to his
mother that the letter colours on his wooden alphabet blocks were “all wrong’’,
she understood the conflict the child experienced between the colour of the
painted letters and his lexically-induced synesthetic colours. In addition to
perceiving letters and words in colour, as her son did, Ms Nabokov was also
affected by music.
SUNDAY, FEBRUARY 2, 2003
THE TIMES OF INDIA
Scientists unravel the secrets of colour sense
VITHAL C. NADKARNI
MUMBAI: In his book An Anthropologist on Mars, Oliver Sacks, the renowned New
York-based neurologist, writes movingly about the curious case of the
colourblind painter: ‘‘He entered to find his entire studio, which was hung with
brilliantly coloured paintings, utterly grey and void of colour.
‘‘His canvases, the abstract colour paintings he was known for, were now greyish
or black or white. His paintings, once rich with associations and feelings,
looked unfamiliar and meaningless to him. At this point, the magnitude of his
loss overwhelmed him. He had spent his entire life as a painter, now even his
art was without meaning and he could no longer imagine how to go on.’’
Dr Sacks’s case of the colourblind painter is an example of acquired colour
deficiency —one that can be caused by brain trauma, disease, or the effects of
toxic agents. This can be distinguished from inborn or congenital deficiencies
such as red-green confusions linked the X female chromosome, that are more
prevalent among males than females.
The rest of us, blessed as we are with a perfect sense of colour, tend to take
it for granted. Sometimes, it is only when one has lost it that one begins
marvel at the ineffable mysteries of one’s sense of colour. Now, however, some
of that mystery has begun to recede, thanks to recent research pioneered at the
University of Texas-Houston Medical School. Researchers led by neurobiologist
Daniel J. Felleman claim to have discovered how the brain perceives colour a
finding that could one day help even those who have lost their sight.
By studying macaque monkeys, the scientists have shown how modules of cells—
called ‘thin stripes’ in a particular region of the brain—are arranged to
perceive colour, according to a Reuters report.
This finding provides the first physiological basis for the perception of the
full gamut of colour, says Dr Felleman. Dr Felleman and his colleagues showed a
series of coloured placards to rhesus monkeys while simultaneously mapping the
changes of blood flows in their brains with magnetic resonance imaging. While
the monkeys looked at different colours, the blood flow peaks in their brains
shifted systematically in specific portions of the stripes, the scientists
reported in the journal Nature.
Thus, an area with a peak flow for the colour red lay next to the portion that
peaked for orange which, in turn, was next to the portion for yellow, and so on.
“We believe that the brain uses a spatial code for colour such that the location
of the peak activity within these colour maps determines the colour that you
see,’’ Dr Felleman said in a press statement.
His laboratory specialises in research on primate brains for understanding the
functional organisation of local circuits involved in the perception of colour,
pattern and object discrimination. Although the research was done on rhesus
monkeys, the scientists believe that circuits in the human brain operate in a
similar way and that the knowledge could be used to develop visual aids for the
blind. The research also opens windows into other neurological mysteries such as
synesthesia. The word, which means ‘joined sensation’, shares a root with
anaesthesia, meaning ‘no sensation’. It denotes the rare capacity to hear
colours, taste shapes, or experience other equally startling sensory blendings
whose quality seems difficult for most of us to imagine.
For example, a synesthete might describe the colour, shape, and flavour of
someone’s voice, or music whose sound looks like ‘shards of glass’, a
scintillation of jagged, coloured triangles moving in the visual field. Or,
seeing the colour red, a synesthete might detect the ‘scent’ of red as well. The
experience is frequently projected outside the individual rather than being an
image in the mind’s eye.
In his classic book, The Man who tasted shapes, Richard Cytowic makes a
conservative estimate that one person in 25,000 individuals is born into a world
where one sensation involuntarily conjures up others, sometimes all five
clashing together. Curiously, like red-green confusions, synesthesia also has a
strong genetic component.
Indeed, the most famous family case of the clashing senses may be that of the
Russian novelist Valdimir Nabokov. When, as a toddler, he complained to his
mother that the letter colours on his wooden alphabet blocks were “all wrong’’,
she understood the conflict the child experienced between the colour of the
painted letters and his lexically-induced synesthetic colours. In addition to
perceiving letters and words in colour, as her son did, Ms Nabokov was also
affected by music.