by cecylia witkowski. synesthesia occurs when one sensory modality triggers another a common...
TRANSCRIPT
SynesthesiaFunctional and Magnetic Resonance
Imaging: Activation of V4/V8
J.A. Nunn, L.J. Gregory, M. Brammer, S.C.R. Williams, D.M. Parslow, M.J. Morgan, R.G. Morris,
E.T. Bullmore, S. Baron-Cohen, & J.A. Gray
By Cecylia Witkowski
What is Synesthesia?
Synesthesia occurs when one sensory modality triggers another
A common synonym for Synesthesia is “Coloured Hearing”
Picture the number two in your mind
2how most people see
the number 2
2how people with
synesthesia see it
The Experiments
Three experiments conducted Experiment 1
› 30 blocks of single spoken words (abstract and concrete) were alternated with single pure tones over a course of 5 min
› Synesthetes were asked to describe the colour they experienced after each word This data was used for experiment 3
The Experiments Experiment 2
› This was a control to see whether the presentation of words along with images of colour (Mondrians) would activate the same brain areas as synesthetes
The Experiments
Experiment 3 Non-synesthetes would learn the word-
colour combinations that synesthetes described
They were required to predict and imagine the colours associated with the words
Also required to re-test to obtain 100% accuracy
The Results
Both the synesthetes and non-synesthetes displayed activation in all brain regions EXCEPT for the V4/V8 region› V4/V8 regions are gathered to be
responsible for coloured vision Even in Experiment 3, V4/V8 regions in
non-synesthetes were not activated
fMRI Results
Discussion
V4/V8 regions are still under much investigation for their absolute function and their relation to synesthesia
Despite training non-synesthetes, there was still no activation of V4/V8 regions› V4/V8 regions specific only to synesthetes?
Discussion
Due to activation, synesthetic colour experience is that of colour perception rather than imagery
There was no left V4/V8 activation in response to colours› Competition between normal colour
perception and synesthetic perception
Thoughts
Very well laid out Had methodical approach to riddle out
whether just association can procure ‘synesthesia-like’ effects
Interesting results› Synesthetes had regions activated that
don’t in normal people Usage of fMRI and PET scans to obtain
accurate results
Strengths & Limitations
Effectively used controls to determine synesthete and non-synesthete activations
Limited number of participants› 13 synesthetes › 27 controls› All female
Further Research
More participants› Variation in gender (not just females)
Vary in testing such that controls would see a word in colour, then repeated again without colour and test to see whether association will occur
Questions