History Flashcards
Hippocrates
Believed the brain was the seat of intellect
Neolithic Humans
Cranial surgery, Trephinations;
4,000 year old trephinated skull, partially healed, suggests person survived and was alive for a while after the procedure
Aristotle
Heart for intellect; brain to cool blood
Claude Galen
Sensory vs. motor nerves; sensory and motor parts of brain
Leonard da Vinci
Drawings of brain, included ventricular system
Proposed center of sensory perception
Drew skull and brain with ventricles
Based drawings on wax mold of ox brain
Vesalius
Anatomy, including nervous system
Famous for conducting relatively advanced autopsies (against the church’s wishes)
Used pretty advanced tools for the 1500s
Picture of a man walking through the park with increasing layers peeled off (skin, muscles, bones, etc.)
De Humani Corporis Fabrica
Drawings of vascular system and peripheral nervous system
William Harvey
Physiology, including circulatory system
Rene Descartes
First mechanism by which brain produces movement
Thought muscles contracted because fluid came from brain to cause muscles to bulge and contract
Thought pineal gland, in response to willful attention, opened tubes to allow the fluid to flow
Correctly figured out that the eyes interpret images upside down
Albrecht von Haller
Disproved Descartes’ hypothesis
Tested Descartes’ hypothesis by measuring the volume of muscles when relaxed or contracted
Bell and Magendie
Bell-Magendie law
Published papers simultaneously in which they said sensory nerves exit on the dorsal (back) side and and motor nerves exit on the ventral (front) side
Argued nerves are anatomically separate
Johannes Peter Muller
Law of specific nerve energies; now labeled “Line Theory”
Nerves labeled by the type of information they carry
Proposed nerves labeled by sensation so that it wouldn’t depend on the type of stimulus, depends on the identity of the type of nerve being stimulated (ex: visual sensation, auditory sensation)
Franz Joseph Gall
Phrenology
Size of areas of the brain correlate with personality characteristics
Some people today consider imaging to be modern-day phrenology
Paul Broca
Localization of language in brain-damaged patient
Worked with “Tan” who could comprehend, but couldn’t generate speech
Broca identified a specific area of damage, and confirmed it with an autopsy after Tan’s death
Jean Pierre Flourens
First experimental brain damage; studied localization of function
Looked for specialization of brain function in animals
Produced specific damage in areas of dog brains to try (unsuccessfully) to link damage to function
Difficult to isolate damage because dog brains are less specialized
Karl Lashley
Localization of function; Law of Mass Action and Law of Equipotentiality
Did experiments similar to Flourens (but used rodents)
Law of Mass Action - greater the area of damage, the greater the impact on function
Law of Equipotentiality - All parts of the cortex have the same potential (no one part of the cortex is more important than any other)
Luigi Galvani
Animal electricity in frog legs
Galvanometer
Cut off frogs’ legs to try to elicit a muscle contractions in response to electrical stimulus
Alessandro Volta
Nerves respond to electrical stimulation
Reinterpreted Galvani’s experiment
Said electricity was reacting with brine soaked muscle, not the nerve
Emile duBois-Raymond
Recorded electric potential (voltage) in injured nerve
Recorded injury potentials (changes in voltage when nerve was injured)
Herman L. F. von Helmoltz
Speed of conduction
Father of physiological psychology
Measured speed of conduction of a nerve impulse
Used frog sciatic nerve, measured the time between stimulation and contraction of the leg
Charles Sherrington
Synapse, mechanism of reflex
Described all spinal reflexes that we know of today
Won a Nobel prize
Stimulated the skin and measured the time of the reflex–measured the time it should take, based on conduction velocity, and found it took longer than anticipated (something was happening with the spinal cord)
Deduced that there was a synapse–a space that causes the delay
Camillo Golgi
Golgi stain; reticular theory
Provided a good stain for human nervous tissues–stains cell bodies, axons, and neurons
Stains only 1-2% of neurons, allows a better view
Not selected for any particular type of neuron
Suggested that although cells initially are born separately, during the course of development, they grow together to form a continuous net (the Reticular Theory)
Santiago Ramon y Cajal
Neuron doctrine
Neuron doctrine–connections between neurons
Claude Bernard
Curare; suggested chemical messengers in blood
Ligated leg, injected curare–frog became paralyzed, except for the leg, suggesting that the poison was being carried by the blood; because the animal still responded to electrical stimuli
Bernard suspected something chemical in the communication between muscles and nerve (so there is electrical AND chemical)
Sir Henry Dale
Suggests acetylcholine acts as a neurotransmitter on a frog’s heart
Vagus nerve helps regulate heart beat
Suggested that the way the vagus nerve slows down the heart is by releasing acetylcholine
Otto Loewi
Showed the acetylcholine is in fact being released from nerve innervating frog’s heart
Expanded on Dale’s experiment by speeding up heart in one solution and slowing it down in another
Donald Hebb
Hebbian synapses, synaptic mechanism of learning
“Cells that fire together, wire together”
Contribution: The Organization of Behavior
If cell A activates cell B, the synapse between the two cells is strengthened
If B doesn’t fire, or if B fires in the absence of A, the synapse is weaker