Split brains Flashcards
Sperry (1964)
Monkeys: each hand learned independently, no transfer. Could learn separate tasks.
Gazzaniga 1962
Alien hand - pick up newspaper etc
Lateralisation of language
Word to JW’s RH = could not name (after full callosotomy). Could only point etc.
Although with only partial callosotomy: could describe, and then LH could guess.
Baynes 1998
Left-handed patient, could write with LH
Gazzaniga 2000
JW’s RH learned to speak after 13 years
Turk 2002
LH = self-recognition
Weschler blocks
RH better at visuospatial task
Shinohara 2012
Split brain rats better spatial learning and memory if using right HC
Ortigue 2009
LH better at MIT, RH better at IIT.
monkey mirror neurons = F5
Iacoboni 2001
fMRI found neurons in right STC concerned with imitation of action.
Luck 1989
Visual attention can be done in both hemispheres = visual search task faster than controls
Holtzman 1984
Two independent orientating systems
Arguin 2000
Cued to divide attention to both hemifields at same time = could do this, faster RTs than controls.
Simultaneously direct attention to both HFs.
But differences in type of info used for search: LH higher-level, could use top-down info to guide search, RH couldn’t (Gazzaniga 2015)
Lausberg 2003
LH worse at using whole of personal space to make motor gestures. So specific deficits, not just visual attention as a whole.
Kingstone & Gazzaniga 1995
Full callosotomy = sky and scraper separate
Funnell 2000
Partial callosotomy / spared anterior and splenial fibres = could draw “breakfast”
Risse 1989
Spared splenium = could transfer visual info but not sensorimotor.
Opposite if more anterior fibres spared.
= topography / regional specialisation of CC
Uddin 2008
MRI revealed intact subcortical connections - may allow transfer of visual info, or become active as result of damaged CC fibres.
But only resting state! Not functional
Sergent 1991
Interhemispheric subcortical transfer of simple information allowed size discrimination judgements (but not same/different).
Corballis 1994
Only 3 sizes of circle!
Alternative methods used.
Also cross-cueing? e.g. transfer of binary gaze shift info.
Good methodological design and careful interpretation is crucial
Gazzaniga 2005
DTI: investigate callosal function specifically.
e.g. rates/routes of interhemispheric recruitment during difficult task.
Funnell
LH = false memories.
“Rational” brain e.g. chicken and shovel experiment
Miller
Left PFC activated when recalling false memories.
Wolford
LH tries to work out sequence / pattern of flashing stimuli, so ends up less accurate. Tries to develop logical strategy.
RH doesn’t try to do this.
Gazzaniga 2015 (consciousness)
RH = literal/truthful.
LH = inventive, seeks explanations. Has consciousness that far surpasses RH.
Although brain is a collection of specialised modules, LH integrates information and rationalises it so we have subjective, unified feeling of consciousness.
