Synaesthesia Flashcards
The brain perceives the world based on what three things?
- Information from each sense
- Information from different senses
- Stored knowledge of the world
The ears, eyes, nose, mouth and skin have receptors that convert physical signals to what?
Neural signals
Define multi-sensory perception
The process by which information from different senses is brought together
What are three advantages of multi-sensory perception?
- More efficient and accurate than processing each sense separately
- Enables us to establish a single coherent perspective of the world
- Enables us to act on world
Briefly describe the McGurk illusion
“BA” is presented to the ears
“GA” is presented to the eyes
Subject perceives “DA”
fMRI shows silently looking at moving lips activates the auditory part of the brain
Brain is getting something “wrong” but in a sophisticated way - no one can move mouth in “GA” way and say “BA” but brain combines two to try and make sense of clash it is receiving
What is synaesthesia?
Concrete perceptual experiences elicited by stimuli in the external environment or by internal thoughts.
Automatic and can’t be suppressed
Subjective -two people with condition don’t see same thing
What is developmental synaesthesia?
Runs in families and has a genetic component - but this doesn’t tell us which type people will have, just means more likely to get synaesthesia
Equally as common in males and females, present throughout lifespan, triggered by linguistic stimuli, colours for letters and numbers about 1-2% of population
May be atypical connectivity between colour perception region and letter recognition region
Exuberant connectivity across whole brain, not just in regions related to synaesthesia
How do the connections in synaesthesiacs brains compare to control brains?
Many more connections in brain of synaesthesiacs
Connections either grow or develop overtime that just aren’t there in controls
How do people develop acquired synaesthesia?
Sensory deprivation or pharmacologically triggered
Effects are temporary not permanent
How does LSD lead to acquired synaesthesia?
Switches on pathways that are normally hidden, or switches some normal ones off (Doesn’t create new brain pathways)
Explain the link between vision and touch in people with mirror synaesthesia
Mirror synaesthesia is where people can feel touch when seeing others being touched
Watching someone else being touched activates our own somatosensory cortex - done in much more hyper activated way with people with MS
What is number-space synaesthesia?
Seeing numbers in spatial arrays
small numbers on left and large numbers on right
(We are all faster at responding to small numbers with left hand and large numbers with right hand as if we have a mental number line, can swap hands over and small still in left and large still in right)
