development of physiological influences the brain nerve function visual perception brain...
Post on 17-Jan-2016
236 Views
Preview:
TRANSCRIPT
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 senso comune
• Posterior ventricle: memoria
Renaissance - Descartes
• Agreed with Galen about ventricles
• Hydraulic theory of nerves
Nerve Function (electricity view)
Whytt's (b. 1714) Reflex
• Reflexive contraction of pupil to light• Reflexes were involuntary and depended on
spinal cord
Galvani-Volta Debate
• Luigi Galvani (b. 1737) claimed that he discovered animal electricity
• Count Alessandro Volta (b. 1745) did not agree
• Galvani will become known for…?
• Volta will become known for…?
Giovanni Aldini provided basis for a novel written by a famous writer…
HINT:
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
Research on Visual Perception
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
Ewald Hering (b. 1834)
• Opponent-process theory of color perception
Hering Illusions
Hering bow
Jan Purkinje (b. 1787)
• Shift from cone to rod vision in twilight
• The “Purkinje Effect” or “Red Shift”
Brain Localization
Phrenology
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
Napoleon’s & Descartes’ Heads
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"
Brain Localization: The Story of Phineas Gage
• Sept. 13, 1848 - Vermont - a deadly day for Phineas
• Iron rod entered under left cheek, exited through top of head, landed 30 yards away.
• Dr. John Harlow• MRI analysis by Damasio shows damage in
ventromedial region on left side of brain
• Off Off Off Theatre• Boo Hoo Ramblers
Language Localization in Brain
Paul Broca (b. 1824)
• Patient named Mr. Leborgne
• Autopsy showed lesion to 3rd convolution of left frontal lobe
• Concluded this area important for speech articulation
Broca’s Brain!
Karl Wernicke (b. 1848)
• Damage in top left temporal lobe causes poor language comprehension (Receptive aphasia)
Psychophysics – the Beginning of Psychology?
Ernst Weber (b. 1795)
• Investigated 2-point thresholds for touch
• Jnd's investigated for various stimuli
• Jnd's vary by a constant ratio called “Weber Fraction”
• First to quantitatively measure the mind?
Gustav Fechner (b. 1801)
• "Elements of Psychophysics" 1860
• The term “Psychophysics” coined
• Fechner's Law• Developed method of
limits, method of constant stimuli, method of average error (adjustment)
top related