Cerebral Asymmetries I'

1
Lecture 8 Cerebral asymmetries I. 1. What is
lateralisation? 2. Aphasia, apraxia,
neglect 3. T-scope studies 4. Dichotic
listening studies 5. Anatomical asymmetries?
2
"that vast repertoire of symbolism associated
with right and left, which permeates so much of
our daily lives, from the political left and
right wing, through dexterity and
cack-handedness, to left-handed marriages. If
we do have such symbolisms, why do we have them?
Is it perhaps because our hands are so
asymmetrical, or because our hearts are
asymmetric, or even because the universe in which
we live is asymmetric? McManus (2002)
3
cerebral lateralisation - the tendency for one
of the two hemispheres to excel at a particular
skill or function
4
Lateralisation does not mean that people are
left hemisphere types (rational, mathematical,
analytic, serial processors, masculine) or right
hemisphere types (emotional, artistic, holistic,
parallel processors, feminine)
5
Human Information Process Survey (Taggart
Torrance, 1994) Cognitive Style and Hemispheric
Dominance (Christensen, 1991) The Hemispheric
Mode Indicator Edwards' 44-item hemisphericity
scale (1986)
6
(No Transcript)
7
(No Transcript)
8
Aphasia and apraxia When they occur, almost
always a consequence of LEFT hemisphere damage
9
Hemispatial neglect and prosopagnosia? When they
occur, almost always follows RIGHT hemisphere
damage
10
tachistiscopic studies - involve
presenting visual stimuli to the left or the
right visual field so briefly that the
subjects do not have the time to move their eyes
towards the stimulus
11
(No Transcript)
12

13
cake
14

15
took
16
.

17
. . . . . . . . . . . . . . .

18
The LEFT VISUAL FIELD (not eye!) is processed in
the RIGHT HEMISPHERE Left visual field
advantages in t-scope studies include Dot
localization, number of dots Faces Depth (??)
19
The RIGHT VISUAL FIELD (not eye!) is processed
in the LEFT HEMISPHERE Right visual field
advantages in t-scope studies include Words S
ingle letters
20
dichotic listening studies- present two
different sounds to each ear simultaneously
21
(No Transcript)
22
The right ear projects primarily to the LEFT
hemisphere Right ear advantages in dichotic
tasks Digits Words Nonsense syllables
23
The left ear projects primarily to the RIGHT
hemisphere Left ear advantages in dichotic
tasks Musical sounds (e.g. chords or melodies)
24
Anatomical asymmetries?

• planum temporale - region which contains
  Wernickes area is larger in the left hemisphere
  in 65 of people

25
(No Transcript)
26
(No Transcript)
27
Next week Lecture 9 Cerebral asymmetries II
The split brain