Transcript Science on Saturday talk by Sam Wang

How the Brain Got its Folds:
Learning about Function by Looking at Structure
Professor Sam Wang
Princeton University
Sam Wang
Damon
Clark
A small brain
Professor
Patrick
Hof
(160
pounds)
A killer
whale
brain
(20
pounds)
How can brains of different sizes be compared?
Cerebrotypes
Damon Clark,
Partha Mitra,
and Sam Wang
Whose brain is most like ours?
Chimp
Human
Gorilla
Noel Rowe, Pictorial Guide to the Living Primates
Whose brain is most like ours?
Chimp
Human
What makes the brain folded?
Jennifer Shultz
Allometry in the neocortex
A ~ V0.91
Jerison (1987)
Hofman (1989)
P. Rakic
Jenny Shultz and
Sam Wang
W. Rushton
What makes the brain folded?
…lots of neurons with fat wires.
Normal brain
Pachygyric brain
In some cases, caused by
cocaine use during pregnancy.
Fewer neurons?
Let’s see some
real brains!
The brain has specialized parts
Penfield’s Homunculus
Mapping of the body surface depends
on an animal’s needs
J. Kaas
www.pbs.org/wgbh/aso/tryit/brain
Model
Patient’s copy
Hemineglect
Memory loss
Memory loss:
The patient H.M. can’t remember anything…
...but he can still learn!
Brenda Milner
Aphasia
Broca’s Aphasia
“Girl...wants to...flowers...flowers
and wants to...The woman...wants
to...The girl wants...the flowers and
the woman.”
(Describing a picture of a girl giving
flowers to a woman).
“The kiss...the lady kissed...the lady
is...the lady and the man and the
lady...kissing.”
(Describing a picture of a woman
kissing a man).
• Motor aphasia
• Non-fluent, slow labored speech
• Comprehension largely intact
• Patient aware of deficit
Wernicke’s Aphasia
Q: “How are you feeling today?”
A: “Well, it has been suggested that
there were certain oddities and
restrictions, technically the activities
of the student body, so to speak.”
Q: “This is a beautiful day.”
A: The only reason I say it is a nice
day I see all the girls working behind
the floor and believe me when I
worked for people on Broadway they
were glad to work because it is nice to
do it in the afternoon.”
• Sensory aphasia
• Fluent, meaningless speech
• Comprehension impaired
• Patient not aware of deficit
Agnosia
Agnosias
These symptoms can all occur as a result
of a stroke, which is a brain attack.
If you experience a sudden loss of feeling,
movement, speech, or recognition,
get to an emergency room immediately.
Ambiguous figures
Synaesthesia
In the next picture,
do you see rows? or columns?
Synaesthesia
What the patient “E.R.” sees!
Brain regions that communicate in synaesthesia?
Digit recognition
Colors
Ramachandran and Hubbard (2001)
Rickard et al. (2000)
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