PSYC 3513
Cognitive Neuroscience
Instructor: Andrew B. Leber
Assistant: Lisa Heisterberg
Cognitive Neuroscience
What is Cognitive Neuroscience?
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Cognition – variety of higher mental processes
(thinking, perceiving, imagining, speaking, acting,
planning, etc.)
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Neuroscience – biological investigations of the brain
Cognitive Science
Cognitive Psychology
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Cognitive Neuroscience
Biology
Neuroscience
What is Cognitive Neuroscience?
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QUESTION:
How does the brain enable mind?
• relations between brain and behavior
• better understanding of how complex cognitive and
affective behavior is mediated by the brain.
What do YOU know about the brain?
How did we get here?
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History of human thought
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History of biology, psychology and medicine
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Central issues:
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How do biological systems work?
Undifferentiated whole blob or smaller subcomponents?
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localization vs. antilocalization (mass action/equipotentiality)
And can function be altered in any way?
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Dedicated?
Plastic?
How did we get here?
Philosophers
1800 –
1820 –
1840 –
1860 –
Phrenologists, localizationist manifesto
Broca’s (1861) paper on language localization
Fritsch & Hitzig (1870) stimulation of dog’s cortex and movement
Electroencephalography (EEG) developed as a research tool
(Berger, 1929)
1920 –
1940 –
1960 –
1980 –
2000 –
Discovery of action potentials (Hodgkin & Huxley, 1938),
enables single cell recordings
Structural imaging: Computerized Tomography (CT) (Hounsfield, 1973),
Magnetic Resonance Imaging (MRI)(Lauterbur, 1973)
in vivo blood flow measure in humans:
Positron Emission Tomography (PET) (Reivich, 1979)
Transcranial Magnetic Stimulation (TMS) (Barker et al., 1985)
Blood Oxygen Level Dependent (BOLD) à fMRI (Ogawa et al., 1990)
Early conceptualizations
The mind-body problem
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How do the mind and the body causally
interact?
Is the mind physical or non-physical?
Where do mind and brain meet?
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Liver
Heart
Pineal gland
Early conceptualizations
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Aristotle (384-322 BC)
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Rene Descartes (1620s) - dualism
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pineal gland (mind immortal, body physical and mortal)
Influences spirits flowing through ventricles
Baruch Spinoza (1650s) - dual-aspect theory
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Heart is seat of intelligence, brain cools blood
Mental and physical are part of the same substance
Each comprises an “aspect”
Others
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to fill skull
Vesalius, 1543
Vesalius:
promoted
dissection as a
teaching tool
De Viessens (1685)
Gall & Spurzheim (1810)
Phrenologists (1810)
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Franz Joseph Gall and Johann Spurzheim
(early 19th century)
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35 areas (different functions)
Brain grows to accommodate functions
Anatomical personology
Localizationist
Phrenology then:
Phrenology now:
Anti-localizationist (1824)
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Jean Pierre Flourens
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Removed localized portions of cortex and noted their
effects on bird behaviors.
“ All sensations, all perceptions, and all volitions occupy the
same seat in these cerebral organs. The faculty of
sensation, percept and volition is then essentially one
faculty”
Aggregate field (mass action)
Big debate:
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localization versus equipotentiality
(skull palpators versus bird-brain ablators)
Modern neuropsychology
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Hughlings Jackson
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Characteristic progression of seizures
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(Now called “Jacksonian seizures,” originate in motor cortex)
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Some topography in epilepsy (body map)
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Less extreme type of localization:
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Localization of symptoms, not function
Based on interconnectedness of brain areas
Similar point as above from Claude Bernard (1855):
“If it is possible to dissect all the parts of the body, to isolate them in order to study
them in their structure, form and connections it is not the same in life, where all parts
cooperate at the same time in a common aim. An organ does not live on its own, one
could often say it did not exist anatomically, as the boundary established is
sometimes purely arbitrary. What lives, what exists, is the whole, and if one studies
all the parts of any mechanisms separately, one does not know the way they work. In
the same way, anatomically, we take the organism apart, but we cannot grasp the
whole. This whole can only be seen when the organs are in motion.”
Modern neuropsychology
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Paul Broca 1861:
l Language comprehension,
but failure of speech production
l “Tam, tam, tam, tam…”
l Aphemie (Aphasia)
Modern neuropsychology
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Paul Broca 1861:
l Language comprehension,
but failure of speech production
l “Tam, tam, tam, tam…”
I called my mother on the television and
did not understand the door. It was too
l Aphemie (Aphasia)
breakfast, but they came from far to
Karl Wernicke (1876)
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Production without comprehension
near. My mother is not too old for me to
be young.
Electrical stimulation
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Frisch and Hitzig (1870)
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Electric stimulation in dog to produce movement
Neuron Doctrine and Cytoarchitectonics
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German neuroanatomists (early
1900s)
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Camillo Golgi
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And others
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Santiago Ramon y Cajal
Brodmann, Nissl, Von Bonin and Bailey,
Von Economo
Golgi, Cajal, Purkinje, Freud, von
Helmholtz
Neuron doctrine
At least some form of localization
agreed upon
Neuron Doctrine and Cytoarchitectonics
What is the neuron doctrine?
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Camillo Golgi
Neurons are the basic functional units
of the brain
These basic building blocks can be
studied to understand how the mind
works
By the early 1900s, the neuron
doctrine began to gain acceptance,
and some form of localizationalism
was broadly accepted.
Santiago Ramon y Cajal
Brodmann’s cytoarchitectonic maps (1909)
Consistent with
localizationists
(different
cytoarchitecture
corresponds to
different function)
A word about the enterprise of Cognitive Neuroscience
What does learning about the brain (localizing function,
etc.) tell us about the mind?
l Does it help us describe behavior?
l Does it help predict behavior?
l What can be gained, from a psychological standpoint?
Levels of Analysis
Marr (1982):
1.
Computational level, the goal
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2.
Algorithmic level, the method
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3.
What’s is the purpose of the behavior
In computers: what does this program do?
What are the processes, steps, etc.
Implementation level, the substrate
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What runs the algorithm? Neural structures, silicon, etc.
Questions:
A.
If you are only interested in how the mind works, which
level of analysis is most important to you?
B.
If you are focused on completely understanding one
level, can knowledge of the other levels provide any
insights in this pursuit?
Levels of Analysis: Examples
Phineas Gage
Levels of Analysis: Examples
Phineas Gage
Railroad Foreman
September 13, 1848:
Spike through part of frontal
lobe.
(Have we been taught the
real story? Read here:
http://slate.me/1fUqE8K)
Does knowledge of the substrate tell us about the algorithm?
Levels of Analysis: Examples
Henry Molaison (1926 – 2008)
• Better known as “HM”
• Epileptic in 20s in 1953
• Seizures from age 10, uncontrollable
• Despite absence of epileptogenic activity,
bilateral medial temporal lobectomy
Levels of Analysis: Examples
Henry Molaison (1926 – 2008)
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About half hippocampus removed (MRI in 1995)
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In contrast to W. Scoville’s report but rest atrophied
Levels of Analysis: Examples
Henry Molaison (1926 – 2008)
• After surgery
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No seizures
Normal intelligence (IQ 112)
Cooperative and motivated
Normal perceptual and reasoning skills
• BUT
• Unable to form new long-term memories
For HM, Does knowledge of the substrate tell us about the algorithm?