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Phrenology and Localization

Gall’s method: Correlating variations in character with variations in craniological signs.

Moral and intellectual faculties depend on the physical structure of an individual brain. Relative development (usage) results in differential growth. Brain is an “collective” of many faculties and their physical counterparts.

Franz Joseph Gall (1758-1828)

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Phrenology and Localization

A summary of Gall’s view of the brain:

1. The brain is the organ of the mind.2. The mind is composed of multiple distinct, innate faculties.3. Because they are distinct, each faculty must have a separate seat or "organ" in the brain.4. The size of an organ, other things being equal, is a measure of its power.5. The shape of the brain is determined by the development of the various organs.6. As the skull takes its shape from the brain, the surface of the skull can be read as an accurate index of psychological aptitudes and tendencies.

1. impulse to propagation (Zeugungstrieb, Fortpflanzung; Instinct de la génération, de la reproduction, de la propagation); 15. faculty of language (Sprachsinn, Sprach-Forschungs-sinn; sens de langage, Talent de la philologie); 2. Tenderness for the offspring, or parental love (Jungenliebe, Kinderliebe; Amour de la progéniture); 16. disposition for colouring, and the delighting in colours (Farbensinn; sens des rapports de couleurs); 3. friendly attachment or fidelity (Anhänglichkeit, Freundschaftsinn; Attachement, amitié); 17. sense for sounds, musical talent (Tonsinn, Musiktalent; Talent de la musique, sens des rapport des tons); 4. valour, self-defense (Mut, Raufsinn, Selbstverteidigungsinstinkt; Instinct de la défense de soi-même et de sa propriété); 18. arithmetic, counting, time (Zahlensinn, Zeitsinn; Sens des rapports des nombres); 5. murder, carnivorousness (Mord/Würgsinn; Instinct carnassier); 19. mechanical skill (Kunstsinn, Bausinn; Sens de mécanique, de construction, Talent de l'architecture); 6. sense of cunning (Schlauheitssinn, List; ruse); 20. comparative perspicuity, sagacity (vergleichender Scharfsinnorgan; Sagacité comparative); 7. larceny, sense of property (Diebessinn, Eigenthumsinn; Sentiment de la propriété); 21. metaphysical perspicuity (Metaphysischer-Tiefsinn; Esprit métaphysique, profondeur d'esprit); 8. pride, arrogance, love of authority (Stolz, Hochmut, Herrschsucht; Orgueil, fierté, hauteur); 22. wit, causality, sense of inference (Witz, Causalität, Folgerungsvermögen; Esprit caustique); 9. ambition and vanity (Eitelkeit, Ruhmsucht, Ehrgeiz; Vanité, ambition, amour de la gloire); 23. poetic talent (Dichtergeist; Talent poétique); 10. circumspection (Behutsamkeit, Vorsicht, Vorsichtigkeit; Circonspection); 24. Good-nature, compassion, moral sense (Gutmüthigkeit, Mitleiden, moralischer Sinn; Bonté, compassion, douceur); 11. aptness to receive an education, or the memoria realis (Erziehungs-Fähigkeit, Sachsinn, Sachgedächtnis; mémoire des choses et des faits, perfectibilité); 25. Mimic (Nachahmungssinn; Faculté d'imiter, mimique) 12. sense of locality (Ortsinn, Raumsinn; Sens des localités); 26. Theosophy, sense of God and religion (Organ der Theosophie, Sinn für Gott und die Religion; Sentiment religieux); 13. recollection of persons (Personensinn; mémoire des personnes); 27. Perseverance, firmness (Organ der Festigkeit, Beständigkeit; Fermeté, constance, persévérance). 14. faculty for words, verbal memory (Wortsinn, Wort-Gedächniss; sens des mots, mémoire verbale);  

Gall’s original 27 faculties:

http://pages.britishlibrary.net/phrenology/

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The extreme localizationist view.

How do we test this?In-class project.

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Broca’s Brain

Pierre Paul Broca (1824-1880)

B = Broca’s area of motor speech; A = sensory speech center of Wernicke; Pc = area concerned with language (after Wernicke)

Patient Tan’s brain

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Patient Tan“When the patient was admitted to Bicêtre, at the age of 21, he had lost, for a some time, the use of speech; he could no longer pronounce more than a single syllable, which he ordinarily repeated twice at a time; whenever a question was asked of him, he [p. 236] would always reply tan, tan, in conjunction with quite varied expressive gestures. For this reason, throughout the hospital, he was known only by the name of Tan. […] The state of intelligence could not be exactly determined, but there is evidence that Tan understood almost everything that was said to him. Not able to express his ideas or his desires other than by the movement of his left hand, he often made incomprehensible gestures. The numerical responses were the ones he made best, by opening or closing his fingers. He would indicate, without error, the time on a watch to the second. He knew exactly how many years he had been in Bicêtre, etc. [p. 237] However, many questions to which a man of normal intelligence would have found the means to respond by gesture, remained without intelligible response; other time the response was clear, but did not answer the question. Undoubtedly, then, the intelligence of the patient had been affected to a great degree [atteinte profonde], but he maintained certainly more of it than was needed for talking.”

Paul Broca (1861) Loss of Speech, Chronic Softening and Partial Destruction of the Anterior Left Lobe of the Brain. Bulletin de la Société Anthropologique, 2, 235-238

http://psychclassics.yorku.ca/Broca/perte-e.htm

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Broca on Localizationism

There are in the human mind a group of faculties and in the brain groups of convolutions, and the facts assembled by science so far allow to state […] that the great regions of the mind correspond to the great regions of the brain.

Paul Broca

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Carl Sagan on Broca

Scientists infer the development of Broca's area from the inside of hominid skulls…

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The Nissl Stain stains cell bodies throughout the brain

Nissl stain of the six layers of cerebral cortex

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Brodmann’s Brain Maps

Korbinian Brodmann

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Brodmann’s Map of the Human Cortex

Brodmann’s cytoarchitectural map of human cortex (1909)

BA17BA18

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Brodmann’s Maps

Brodmann, K., Vergleichende Lokalisationslehre der Grosshirnrinde in ihren Prinzipien dargestellt auf Grund des Zellenbaues. Leipzig: J.A. Barth, 1909.

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Brodmann’s View of Localization

Brodmann on the connection between cytoarchitechtonics and regional functional specialization:

"The specific histological differentiation of the cortical areas proves irrefutably their specific functional differentiation--for it rests as we have seen on the division of labor--the large number of specially built structural regions points to a spatial separation of many functions and from the sharp delineation of some fields there follows finally the sharply delimited localization of the physiological processes which correspond to it“

K. Brodmann, in “Some Papers on the Cerebral Cortex”, 1909

13Camillo Golgi (1843-1929)

Santiago Ramon y Cajal (1852-1934)

Golgi and Cajal

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The Golgi Stain

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Cajal’s Neuroanatomy

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The “Neuron Doctrine”

Theodor Schwann (1839): “Cell Theory” (all tissues of the body are composed of cells)

Wilhelm Waldeyer (1891): “The nerve cell is the anatomical, physiological, metabolic and genetic unit of the nervous system”. Coined the term “Neuron” -> “neuron theory”.

Cajal’s studies using Golgi stain: neurons are discrete entities that interact by “contact”

Golgi’s view was different: Nervous tissue forms a syncytium, nerve cells are not bounded (“reticular theory”)

Cajal also proposed the “Law of Dynamic Polarization” (neurons as directed structures with dendrite, soma, axon)

Sir Charles Sherrington: coins the term “synapse” in 1906.

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Lashley and Mass Action

Mass action: reduction in learning is proportional to the amount of tissue destroyed, and the more complex the learning task, the more disruptive lesions are.

Equipotentiality: all cortical areas can substitute in supporting learning.Lashley picked the wrong task (maze learning). Its complexity allowed for multiple areas to become involved and therefore compenstate.

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Stephen Kosslyn on localizationists vs holists:

The mistake of early localizationists is that they tried to map behaviors and perceptions into single locations in the cortex. Any particular behavior or perception is produced by many areas, located in various parts of the brain. Thus, the key to resolving the debate is to realize that complex functions such as perception, memory, reasoning, and movement are accomplished by a host of underlying processes that are carried out in a single region of the brain. Indeed, the abilities themselves typically can be acccomplished in numerous different ways, which involved different combinations of processes…. Any given complex ability, then is not accomplished by a single part of the brain. So in this sense, the globalists were right. The kinds of functions posited by the phrenologists are not localized to a single brain region. However, simple processes that are recruited to exercise such abilities are localized. So in this sense, the localizationists were right.

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Gestalt Phenomena

Proximity

Continuity

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Gestaltism or Behaviorism?

“I found, somewhat to my amusement, that there were two schools in

this field [animal psychology], of whom the most important

representatives were Thorndike in America, and Köhler in Germany. It

seemed that animals always behave in a manner showing the

rightness of the philosophy entertained by the man who observes

them. […] Animals observed by Americans rush about frantically until

they hit upon the solution by chance. Animals observed by Germans

sit still and scratch their heads until they evolve the solution out of

their inner consciousness.''

Bertrand Russell (An Outline of Philosophy, 1927, page 241)

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Overview of Unit 1

Cellular structure, membrane potential, AP, synaptic transmission

Integration of synaptic inputs, synaptic and cellular plasticity

Methods of cognitive neuroscience, functional neuroimaging, EEG, TMS, MEG

Data analysis methods, neural coding, computational neuroscience

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What is the goal of learning about neurons?

Neurons are small and stupid.The brain is large and smart.

Neuronal activity is simple.Behavior is complex.

How does knowledge about neurons help us understand complex behavior? Discuss.

Related questions: Why should we care that our models are biologically plausible? Isn't it enough that they predict behavior and are testable?

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Cellular Components of the Brain

Total Volume 1035 mlTotal Surface Area 165,800 mm2

Total Number of Neurons 8.3 x 109

Total Number of Connections 6.6 x 1013

Total Wiring Length 107,600,000 m

Some Data on the Cerebral Cortex

Neurons form densely connected networks and communicate via spikes.Glia provide trophic and structural support.

Source: Murre and Sturdy, Biol. Cybern. 73, 529, 1995.

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Can we know a Grain of Salt?In a grain of salt (1 microgram), which is just visibleto the naked eye, there are:

1016 sodium and chlorine atoms (10,000,000,000,000,000)10 million billion atoms

Source: Carl Sagan, Broca's Brain

Connections in the brain: 6.6 x 1013

Could store about 1 percent of the information in agrain of salt.But an absolutely pure crystal of salt is regular: Sodium, chlorine, sodium, chlorineDescribe with 10 bits of information.Structure is critical. How do neurons represent it?

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Brain States

There are:

Connections in the brain: 1014

Assume each brain connection is either active (1)or inactive (0). The number of possible states of the brain is:

States of the brain 21014

In matlab:»2^(10^14)

ans =

Inf

Particles in the Universe: 1080

Many more brain states than particles in the universe. But we'd need a brain at least as big as the universe to code all the relations between all the particles.

Bad french movie translation (Amile):More neurons in the brain than atoms in the universe.

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The Neuron

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Dendrites

Dendrites of a single neuron = dendritic tree.

Dendrites are covered with thousands of synapses (see previous picture).

Postsynaptic membrane (part of dendrite) contains receptors.

Many (not all) dendrites are covered in spines.

3D reconstruction of dendritic spines