Transcript Brain Paradox

Biopsychology
• The scientific study of the biology of
behavior.
• It is a research intensive field.
• New findings continually update our
current state of knowledge.
Pop Quiz: true/false
1. Everyone is born with all the neurons they
will have throughout life, what changes
are the connections between them.
2. When neurons of the CNS die they are
not replaced.
3. Glial cells provide the ‘glue’ that holds
neurons in place but do not directly
communicate with other cells.
4. Paralysis from stroke is permanent with
minimal functional restoration.
Karl Lashley (1890-1958)
• Coined the term “neuropsychology”
• Studied the effects of cortical lesions on learning
performance in rats with the goal of finding the
“engram” or locus of a memory trace.
• Principle of “equipotentiality”
• Principle of “mass action”
Phrenology
• Franz Joseph Gall (~1800)
• Personality traits can be
determined by measuring
protrusions or bumps on the skull.
• Although the methodology was discredited
as a pseudoscience, it did advance the
idea that certain functions may be
localized to specific brain regions.
Multiple memory systems
• Current research supports localization of
function…
• E.g., Different types of learning
– Behaviorism (S-R)
– Cognitivism (S-S)
• Neuropsychological evidence compellingly
demonstrates that different brain regions
mediate cognitive and associative
learning.
Can one localize ‘intelligence’
Once thought to be the complex function
of the prefrontal
cortex, until…
• Phineas Gage
Can we localize intelligence
within the brain?
…or put another way, is the brain of a ‘genius’ different?
Several publications have reported differences between
Einstein’s brain compared to ‘normal’ control brains,
which has led to some debate among scientists.
References:
1. Diamond, M.C., et al. (1985). On the brain of a scientist: Albert Einstein. Exp Neurol 88, 198204.
2. Kantha, S.S., (1992). Albert Einstein's dyslexia and the significance of Brodmann Area 39 of his
left cerebral cortex. Med Hypotheses 37, 119-122.
3. Anderson, B., Harvey, T. (1996). Alterations in cortical thickness and neuronal density in the
frontal cortex of Albert Einstein. Neurosci Lett 210, 161-164.
4. Galaburda, A.M. (1999). Albert Einstein's brain. Lancet 354, 1821; author reply 1822.
5. Hines, T. (1998). Further on Einstein's brain. Exp Neurol 150, 343-344.
6. Salvatori, R. (1999). Albert Einstein's brain. Lancet 354, 1821-1822.
7. Seitz, J.A. (1999). Albert Einstein's brain. Lancet 354, 1822-1823.
8. Colombo, J.A., et al. (2006). Cerebral cortex astroglia and the brain of a genius: a propos of A.
Einstein's. Brain Res Brain Res Rev 52, 257-263.
9. Falk, D. (2009). New information about Albert Einstein’s brain. Frontiers in Evolutionary
Neuroscience, 1, 1-6.
The brain’s brain
-
Princeton Hospital, Apr 17, 1955
The pathologist, Thomas Harvey is on call
Hans Albert’s retroactive approval
Harvey gets canned & moves to Kansas
Will publish soon, then 30 years later…
Looses license and wife but keeps the prize
Early 80’s, finally some research
The drive to CA, look what I have
Drives back to Princeton – here, you take it…
More research is done, 3 main pubs
One pub worth a million $
Apr 5, 2007 – the fun ends
Back home with Elliot Krauss
Opthalmologist, Henry Abrams
The End (or is it)
A strange journey
The brain-snatcher: Thomas Harvey
The driver:
Michael Paterniti
The passenger:
Einstein’s brain
“Anticlimactic endings are like
taking your dog for a walk
only to watch him urinate on
your rug when you come
back home. Not that the walk
itself wasn’t enjoyable, just
that the end result leaves a
lot to be desired.”
Review:
Horowitz, S. (2000). Driving Mr. Albert: A trip across America with Einstein’s brain, by
Michael Paterniti. Nature Medicine, 6, 1090.
Worth the read
Brian Burrell (2005)
Chapter 14: Einstein’s Brain
NPR interview with Burrell
http://www.npr.org/templates/story/story.php?storyId=4602913
The book includes an excellent critical
review of the scientific studies
performed with bits of the brain.
Some background
Mirian Diamond’s early studies on enriched environments
Neurons
&
Glia
Enriched environments increase the number of glia per neuron in rat cortex
http://www.youtube.com/watch?v=JNOKT-xv7Dw&feature=related
Diamond et al., 1985
“It was necessary to pool all glial cells counted to attain statistically
significant differences”
4 brain regions X 7 total measures = 28
1)neurons, 2)astrocytes, 3)oligodendrocytes, 4)pooled glia
5) neuron:astro, 6)neuron:oligo, 7)neuron:pooled glia
One out of 28 results were significant (p<.05 if you ignore previous tests): Einstein
had a smaller neuron-to-glial cell ratio in area 39 of the left hemisphere.
Concluded that, like rats exposed to an enriched environment, Einstein had more
glial cells to support neurons in a brain region mediating visuospatial and math
functions.
Many flaws with the study: unspecified control, questionable data selection,
transformation and statistical tests etc.
Neuron size and number not different.
Neuron density is greater (with thinner cortex)
Area 9 in prefrontal cortex
Same number of neurons packed in a
thinner cortex, but why?
A possible interpretation
“…an increase in neuronal density
might be advantageous by
decreasing interneuronal conduction
time…[which] has been posited as a
limiting feature in the development
of brain size and cortical
connectivity.”
Hmm, any other possibilities?
Critical thinking
a) Two main cell types neurons and glia
b) Diamond et al. (1985) - Area 39 found
more glia per neuron – greater support
for neurons.
c) Anderson and Harvey (1996) – Area 9
found greater neuronal density without
any difference in neuron number or size.
d) Greater density + thinner cortex, what
might that tell you about glia cells?
Critical thinking
LESS GLIA PER NEURON!!!
They ignore the possibility that a decrease in
glial cells increased neuron density and
thinned the cortex.
Does that mean less support for neurons in
area 9 of the prefrontal cortex???
Area 39 is also associated with language…
Critical thinking
With respect to Area 39:
What are two ways to get a smaller
neuron:glia ratio?
1) decrease neurons
2) increase glia
Diamond et al. assumed the latter, but…
Maybe the glial cells were increased because of early
neuronal damage (or excessive pruning) related to
Einstein’s delayed language development
A picture is worth a million $
Figure 1
Photographs taken in
1995 of five views of
Einstein’s whole brain
(meninges removed)
A, superior; B, left lateral;
C, right lateral; D, inferior;
E, midsagittal view of the
left hemisphere. The arrow
in each hemisphere
indicates the posterior
ascending branch of the
Sylvian fissure as it runs
into (is confluent with) the
postcentral sulcus
(compare with figure 2).
Consequently, there is no
parietal operculum in either
hemisphere. Scale bar, 1
cm.
Figure 2:
Lateral photographs and tracings of
left (solid line) and right (dashed
line) superimposed hemispheres of a
typical control male brain (1, 2, 3)
and the brain of Einstein (4, 5, 6)
The photographs of the control brain
show the parietal operculum in the left
(stippled) and right (hatched)
hemisphere, situated between the
postcentral (PC) sulcus and the
posterior ascending branch of the
Sylvian fissure (SF), which originates at
the point of bifurcation () and terminates
at S. PC1 is the inferior end of PC at
SF. The tracing of the superimposed
hemispheres (3) shows the asymmetry
in position and size between the
parietal opercula. The tracing of
Einstein’s hemispheres (6) highlights
the confluence of PC and the posterior
ascending branch of SF in each
hemisphere, the absence of the parietal
opercula, and the symmetry of the
sulcal morphology between
hemispheres. Comparison of the
tracings shows the relatively anterior
position of the SF bifurcation in
Einstein, and the associated greater
posterior parietal expanse, particularly
in his left hemisphere compared with
the control brain.
“An extraordinarily large expanse of highly integrated cortex within a functional network”
Another look at the pics!
Falk, D. (2009). New information about Albert Einstein’s brain.
Frontiers in Evolutionary Neuroscience, 1, 1-6.
Pictures of Einstein’s brain were
compared to 58 control brains
Results
• Parietal lobes were larger
• Rare pattern of groves and ridges
• Pronounced knoblike structure in part
of the motor cortex that controls the
left hand (associated with musical
ability)
• Unusual primary somatosensory and
motor cortices
Conclusion
“It is possible that these atypical aspects
of Einstein’s cerebral cortex were
related to the difficulty with which he
acquired language, his preference for
thinking in sensory impressions
including visual images rather than
words, and his early training on the
violin”
“A. Einstein's astrocytic processes showed larger sizes and higher numbers of…bulbous
endings...of unknown significance and they have been described occurring in Alzheimer's disease.
These observations are placed in the context of the general discussion regarding the proposal –
by other authors – that structural, postmortem characteristics of the aged brain of Albert Einstein
may serve as markers of his cognitive performance, a proposal to which the authors of this paper
do not subscribe, and argue against.”
Lessons
Review research carefully, even studies
published in peer reviewed journals.
1) is the rationale sound?
2) are the methods used appropriate?
3) is the interpretation justified?
Healthy skepticism = good science
Einstein's Brain is a 1994 documentary by Kevin Hull following Japanese professor
Kenji Sugimoto in his search for Albert Einstein's brain. It is produced by BBC
Films,and is currently not available in any commercial format, but is on YouTube!
http://www.youtube.com/watch?v=y9ulxEGlw5w&feature=related
Localization of function
• Is still an open question
• As consumers of science, you should be a
discerning critic of research findings
• neo-phrenology or something more
• Brains and behavior are incredibly
complex…
The brain paradox
Flex your
mental
might…
It’s all in
how you
use it
Biopsychology in the news
•
•
•
•
•
http://www.npr.org/
http://www.biopsychology.com/
http://www.brainconnection.com/
http://www.sfn.org/
http://www.dana.org/braincenter.cfm
USE PRIMARY JOURNAL ARTICLES (NOT NEWS REPORTS) FOR
YOUR ARTICLE SUMMARY. THESE REPORTS MAY HELP TRACK
DOWN INTERESTING JOURNAL ARTICLES.