2. Hemispheres Flashcards

1
Q

Corpus callosum

A

A large collection of axons which serve as a bridge for the two hemispheres to communicate

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2
Q

Contralateral organisation

A

Controlling the opposite side

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3
Q

Left visual field

A

The right halves of each eye

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4
Q

Right visual field

A

The left halves of each eye

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5
Q

Left hemisphere

A

Language
Production of speech
Reading, writing
Verbal memory

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6
Q

Right hemisphere

A

Emotional perception
Spacial awareness
Faces
Understands speech, cannot produce it

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7
Q

Cerebral lateralization

A

Hemispheres/different areas of the brain developing different, specialised skills

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8
Q

Cause of lefthandedness

A

Either the right or left hemisphere will be dominant, resulting in left or right handedness

Unclear why left-handedness is rare as it does not cause any severe disadvantages

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9
Q

Possible causes of lefthandedness

A
  • Fetus predisposition
    • Which hand you lay on more
  • Genetics
  • Slower development of RH
  • Prenatal stress (infections, increased testosterone)
  • Vitamin D levels
  • Testosterone levels
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10
Q

Right-sided world hypothesis

A

World is designed for right-handed people so left-handed people have more accidents

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11
Q

Survival of the unexpected

A

Gives left-handed people certain advantages like in sports and music

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12
Q

Lateralization

A

Division of responsibilities between the hemispheres

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13
Q

Split brain patients

A

Severing of the corpus callosum to treat severe epilepsy

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14
Q

Effects of split brain on epilepsy

A
  • Prevents the seizure crossing over to the other side of the brain
    Seizures occur on only one side of the body
  • Less frequent
  • Shorter
    • Normally epileptic activity bounces between the hemispheres
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15
Q

Behaviour changes in split brain patients

A
  • They can use their hands independently in ways that we can’t
    • Drawing two different shapes simultaneously or the same shape at different speeds

Behavioural effects when stimuli is presented to only one side of the body
- Information cannot cross to the other hemisphere
- Can only point to what each hemisphere saw
- Cannot verbally describe what the right hemisphere saw but is able to point it out

  • Initially, patients experience conflicts between the two sides of their body as they don’t communicate and do separate, opposing things
    • e.g. right hand picks up groceries, left hand puts them back
    • This usually passes with time
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16
Q

Unchanged behaviour in split brain patients

A
  • There is no effect on familiar tasks like tying shoes
  • Intellect, motivation, speech are all the same
17
Q

Interpreter

A

the tendency of the left hemisphere to explain and defend its actions when the cause is unclear

18
Q

Split brain & Children

A
  • Behaviours of split-brain patients are comparable to those in young children as the corpus callosum develops from 3-5 years old
  • Sometimes, children are born without the corpus callosum - both hemispheres will be active during speech
    • Ordinarily, both hemispheres are in charge of language but the left will eventually block the right, this doesn’t happen without a corpus callosum
19
Q

Planum temporale

A
  • Comprehension of language
  • Damage - aphasia (trouble with language)
  • Bigger in the left hemisphere
20
Q

Heschl’s Gyrus

A
  • Located in the later fissure
  • Primary auditory cortex
  • Asymmetrical - right one is bigger than the left - might have an impact on split brained patients
  • Bigger in the left hemisphere
21
Q

3 Theories about Cerebral Lateralization

A

Analytic (LH) and Synthetic (RH) Theory
Motor Theory
Linguistic Theory

22
Q

Analytic (LH) and Synthetic (RH) Theory

A

2 basic modes of thinking, one for each hemisphere
Analytic (LH) - logical, computer-like thinking
Synthetic (RH) - organizes & processes information as a whole, not the sum of its parts

23
Q

Frontal operculum AKA Broca’s Area

A

Speech production; more pronounced in LH

24
Q

Motor Theory

A

LH is specialised to the control of fine movements, with speech falling under this category

25
Linguistic Theory
The primary role of the LH is language Opposes prior two theories which see language as a secondary role of the LH Evidence: damage leads to disruption of sign language, but not pantomime gestures
26
Sodium Amytal Test
Sodium amytal is injected into the carotid artery on one side of the neck to numb certain parts of the corresponding hemisphere for a short time Purpose: to study lateralization
27
Dichotic Listening Test
Headphones play different numbers in each ear, see which one the participant heard to show which hemisphere was more dominant
28
What type of matter are axons?
White matter
29
What type of matter are neuron bodies
Grey matter
30
Functional brain imaging
fMRI, PET - brain activity; LH - language
31
Visual completion
being unaware of a scotoma (blind spots) -> brain filling them in by using information from the surrounding areas of the visual field
32
Helping-hand phenomenon
one hand grabbing the other hand and redirecting it toward the stimuli thought to be right by that certain hemisphere
33
Cross-cueing
hemispheres communicating with each other by an external route