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Development of Physiological Influences. The brain Nerve function Visual perception Brain localization Psychophysics. The Brain. Australopithecus africanus Trephining. Egyptians. Threw away brain when mummifying. Greek Doctors: Are there Animal Spirits in there?.
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Development of Physiological Influences • The brain • Nerve function • Visual perception • Brain localization • Psychophysics
The Brain • Australopithecus africanus • Trephining
Egyptians • Threw away brain when mummifying
Greek Doctors: Are there Animal Spirits in there? • Dissected brains and optic nerves; brain is organ of thought • The soul is in the fourth ventricle and the "animal spirits" (intellectual, motor system) are in the brain itself (cerebrum)
Galen’s Cell Doctrine • Galen localized the mind to the ventricular system of the brain • First cell: imaginativa and fantasia • Second cell: aestimativa, cognitativa, and ratio • Third cell: memorativa
Pre-Renaissance • “Animal Spirits”
Renaissance - da Vinci • da Vinci’s system: • Anterior ventricle: intelletto and imprensiva • Middle ventricle: volonta and sensocomune • Posterior ventricle: memoria
Renaissance - Descartes • Agreed with Galen about ventricles • Hydraulic theory of nerves
Whytt's (b. 1714) Reflex • Reflexive contraction of pupil to light • Reflexes were involuntary and depended on spinal cord
Luigi Galvani (b. 1737) claimed that he discovered animal electricity • Count Alessandro Volta (b. 1745) did not agree
Giovanni Aldini provided basis for a novel written by a famous writer…
du Bois-Reymond (b. 1818) • Discovered the action potential • He or Galvani the "Father of Electrophysiology“?
Sir Charles Bell (b. 1774) • Experiments with rabbits • Francois Magendie – experiments with puppies
Bell-Magendie Law • Dorsal roots of spinal nerves bring in sensory information • Ventral roots carry motor fibers down to the muscles
Johannes Muller (b. 1801) • Directly aware only of the activity in our nerves, not external reality • Doctrine of specific nerve energies
Hermann von Helmholtz (b. 1821) • Medicine, physics, math, psychology, music, philosophy • Metabolism • Determined wavelength of ultraviolet light • Optics • Theory of velocity of air in open tubes (acoustics) • Thermodynamics (Law of conservation of energy)
Contributions to Psychology • Measuring the speed of the nerve impulse (REACTION TIME) • Young-Helmholtz trichromatic color theory • Place theory of pitch perception
EwaldHering (b. 1834) • Opponent-process theory of color perception
Jan Purkinje (b. 1787) • Shift from cone to rod vision in twilight • The “Purkinje Effect” or “Red Shift”
Franz Gall (b. 1758); his pupil Spurzheim • The mysterious “Miss Leisler” • "Neither sin nor friends will ever leave me."
Gall’s Work on Nervous System • Nervous system is like a tree • Distinction between gray matter (neurons) and white matter (axons) • CNS fibers terminate in the cortex, not the medulla • Identified origins of cranial nerves I-VIII • Pyramidal tracts crossing brain hemispheres
Gall’s Claim • Mental activities localized in the cortex • Wanted to develop a functional anatomy and physiology of the brain, as well as a revised psychology of personality • Led to theories concerning localization and cranioscopy
The System of Organology • Brain is organ of the mind • Brain is a collection of organs representing various propensities, sentiments, faculties • Size of each organ indicates its power • Skull conforms to brain's shape • Mind's functions located in different places in the brain
How Many Faculties of Mind? • Gall sez 27 • Spurzheim sez 37
Phrenology taken over by Quacks • Employment • Marriage prospects • Children's prospects • 1920's - “The Psychograph” • Problems?
Contributions of Phrenology • Established brain as the source of mind • Mental functions localized in the brain
Pierre Flourens (b. 1794) • "An Examination of Phrenology" 1824 • Ablation technique- removal of one of six separate areas of brain
6 Different Brain Functions • Cerebral hemispheres - willing, judging, memory, seeing, hearing • Cerebellum - motor coordination • Medulla oblongata - mediation of sensory/motor functions • Corpora quadrigemina (inferior/superior colliculi) - vision • Spinal cord - conduction • Nerves - excitation
Flourens vs. Gall • Flourens’ approach reflected localization, but he stressed the common action of the various parts • Emphasis on the common unity of the entire system
Recovery of Function • Also observed recovery of mental function over time - forerunner of "neural plasticity"