the hemispheres Flashcards
which side connects to which eye
LH sees only R half of the world and the RH sees only the L
each H is connected to half of each eye
R half of visual field - L half of each retina - LH
L half of visual field - R half of each retina - RH
half of the axons from each eye cross to the opposite side of brain at the optic chiasm
which side connects to which ear
both H get auditory info from both ears, but slightly stronger info from the contralateral ear
which side controls taste and smell
taste & smell are uncrossed
each H gets taste info from both sides of tongue
each H gets smell info from its own nostril
analytic-synthetic theory
states there are 2 ways of thinking: analytic vs synthetic
LH = logical & analytical
RH = thinks synthetically (processes & organizes info as a whole
criticism: difficult to test & hard to say if task requires analytical or synthetic processing
motor theory
states the LH is responsible for controlling fine motor movements & RH is about gross motor skills
criticism: does not explain why lateralization occurs
linguistic theory
states the main purpose of LH is language
criticism: diametrically opposes the other 2 theories
what is the corpus callosum & function
a bundle of axons that connects the 2 H
L & R use it (+ the anterior & hippocampal commissures) to exchange info
allows H to receive info from both sides - without it they would only react to opposite side of the body
what is a split brain person
people who have has the CC cut (usually to treat epilepsy)
- maintain intellect, motivation, ability to talk & walk
- can use hand together on familiar tasks but struggle on unfamiliar tasks
- can use hand independently in ways others cant
the H can communicate neurally via indirect pathways through the brain stem = cross cuing
lateralization
for many functions there is no huge diff between L & R - when they exists it is usually a slight preference
language is the most lateralized cog abilities (to the L)
superiority of LH in controlling ipsilateral movement
when there is complex movement in 1 hand most of the activation is seen in the contralateral H
but sometimes can be seen in the ipsilateral H - more so in the LH
superiority of RH in spatial ability
an exp found the RH was better in a spatial task
performance of L hand/RH was rapid & silent
performance of R hand/LH was hesitant and accompanied by a running verbal commentary
superiority of RH for emotion
RH has been found to be better at some tests of emotions - e.g. accurately identifying facial expressions of emotion
RH more responsive to emotional stimuli - e.g. perceiving emotion in gestures and tone of voice
damage to RH usually causes failure in understanding humor & sarcasm
however there is not unambiguous support for this
differences in memory of the H
both H have similar abilities that tend to be expressed in diff ways
both have ability to perform on mem tests but LH is better at some and RH at others
2 approaches to studying lateralization of mem:
1. link mem processes with a H - e.g. LH is specialized for episodic memory
2. link mem processes of each H to materials - e.g. LH better for verbal material
anatomical differences in the H
planum temporale (Wernicke’s area): located in the posterior region of the lateral fissure - involved in comprehension of lang - bigger in the LH
heschl’s gyrus: located in the lateral fissure, anterior to the PT - location of primary auditory complex
