how the brain got its folds: learning about function by looking at structure professor sam wang...

How the Brain Got its Folds:How the Brain Got its Folds:Learning about Function by Looking at StructureLearning about Function by Looking at Structure

Professor Sam WangPrinceton University

Sam WangDamonClark

A small brain

ProfessorPatrick

Hof(160

pounds)

A killerwhalebrain(20pounds)

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?Whose brain is most like ours?

ChimpChimp HumanHuman

What makes the brain folded?

Jennifer Shultz

Hofman (1989)

Jerison (1987)

Allometry in the neocortex

A ~ V0.91

P. Rakic

Jenny Shultz and Sam Wang

W. Rushton

What makes the brain folded?

…lots of neurons with fat wires.

In some cases, caused bycocaine use during pregnancy.

Fewer neurons?

Normal brain Pachygyric brain

Let’s see someLet’s see somereal brains!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/brainwww.pbs.org/wgbh/aso/tryit/brain

Hemineglect

ModelModel Patient’s copyPatient’s copy

Memory loss

Memory loss: The patient H.M. can’t remember anything…

...but he can still learn!

Brenda Milner

Aphasia

Broca’s AphasiaBroca’s Aphasia

““Girl...wants to...flowers...flowers Girl...wants to...flowers...flowers and wants to...The woman...wants and wants to...The woman...wants to...The girl wants...the flowers and to...The girl wants...the flowers and the woman.”the woman.”(Describing a picture of a girl giving (Describing a picture of a girl giving flowers to a woman).flowers to a woman).

““The kiss...the lady kissed...the lady The kiss...the lady kissed...the lady is...the lady and the man and the is...the lady and the man and the lady...kissing.”lady...kissing.”(Describing a picture of a woman (Describing a picture of a woman kissing a man). kissing a man).

• Motor aphasiaMotor aphasia• Non-fluent, slow labored speechNon-fluent, slow labored speech• Comprehension largely intactComprehension largely intact• Patient aware of deficitPatient aware of deficit

Wernicke’s AphasiaWernicke’s Aphasia

Q: “How are you feeling today?”Q: “How are you feeling today?”A: “Well, it has been suggested that A: “Well, it has been suggested that there were certain oddities and there were certain oddities and restrictions, technically the activities restrictions, technically the activities of the student body, so to speak.”of the student body, so to speak.”

Q: “This is a beautiful day.”Q: “This is a beautiful day.”A: The only reason I say it is a nice A: The only reason I say it is a nice day I see all the girls working behind day I see all the girls working behind the floor and believe me when I the floor and believe me when I worked for people on Broadway they worked for people on Broadway they were glad to work because it is nice to were glad to work because it is nice to do it in the afternoon.”do it in the afternoon.”

• Sensory aphasiaSensory aphasia• Fluent, meaningless speechFluent, meaningless speech• Comprehension impairedComprehension impaired• Patient Patient notnot aware of deficitaware of deficit

Agnosia

Agnosias

These symptoms can all occur as a resultThese symptoms can all occur as a resultof a of a strokestroke, which is a , which is a brain attackbrain attack..

If you experience a If you experience a sudden loss of feeling,sudden loss of feeling,movement, speech, or recognitionmovement, speech, or recognition, , get to an emergency room get to an emergency room immediatelyimmediately..

Ambiguous figures

Synaesthesia

In the next picture, In the next picture, do you see rows? or do you see rows? or

columns?columns?

Synaesthesia

What the patient “E.R.” sees!What the patient “E.R.” sees!

Ramachandran and Hubbard (2001)

Rickard et al. (2000)

Brain regions that communicate in synaesthesia?

ColorsDigit recognition

samwang@princeton.edsamwang@princeton.ed

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