PSYC1002 Lecture Notes - Lecture 6: Thiamine, Anterograde Amnesia, Degenerative Disease
28 Aug 2018
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PSYC1002- Neuroscience
Lecture 6- Lateralisation & Memory
Hemispheric Lateralisation
• Body and sensory world split between two cerebral hemispheres
• Right hemisphere receives sensory input from left and controls motor
response on left side of body
• Left receives sensory input from right
Hemispheric “Dominance”
• Several higher functions are lateralised; one side is more
important/dominant
• All cognitive or behaviour functions, language is the most lateralised
• For most of us, left hemispheres controls speech and is better at
comprehension
Lateralisation of Language
• Stroke in left brain often causes aphasia (problems with speech)
• Brain imaging: left hemisphere is more active when person speaks or
listens to speech
• Dichotic listening task: people understand a word faster if presented in
right ear
Speech Areas
• Broca’s Area: lower posterior region of left frontal lobe
• Damage to Broca’s area causes difficulty in speaking but can understand
• Wernicke’s Area: posterior region on left temporal lobe
• Damage causes comprehension of speech, meaningless speech and cannot
read
The Split Brain
• Lateralisation of function not normally evident because information
shared between hemispheres by corpus callosum
• But patients with intractable epilepsy had surgery to cut the corpus
callosum
• Split brain patients can still walk talk, but report different between what
left and right hands did
Functions in Right Hemisphere
• Right was submissive to left
• Contributes more than left to adding and interpreting emotional content
in speech (sarcasm)
