BIO 132BIO 132NeurophysiologyNeurophysiology

Lecture Goals:Lecture Goals: Course overview - syllabus & tentative scheduleCourse overview - syllabus & tentative schedule

How to succeed in Bio 132How to succeed in Bio 132

Historical perspective of NeuroscienceHistorical perspective of Neuroscience

Course OverviewCourse Overview

Where in the body are memories Where in the body are memories stored; do commands to move come stored; do commands to move come from; is sensory information from; is sensory information processed; do consciousness, logic processed; do consciousness, logic and emotion stem from?and emotion stem from?

What evidence do you have to support What evidence do you have to support your answer?your answer?

History of Neuroscience: A History of Neuroscience: A PerspectivePerspective

The Ancient EgyptiansThe Ancient Egyptians Greatly interested in physiology and how the Greatly interested in physiology and how the

body and mind worked.body and mind worked. Thought the heart was seat of consciousness, Thought the heart was seat of consciousness,

and the brain did nothing important.and the brain did nothing important. When embalming the dead they would take great When embalming the dead they would take great

care to preserve the heart but the brain was pulled care to preserve the heart but the brain was pulled out through the nose and thrown out.out through the nose and thrown out.

20000 1000500-500 1500

The Ancient Greeks (~400b.c.)The Ancient Greeks (~400b.c.) Hippocrates claims that the brain is the Hippocrates claims that the brain is the

center of sensation and movement.center of sensation and movement.Why would he come to this conclusion? Why would he come to this conclusion?

He had no scientific tools like microscopes or He had no scientific tools like microscopes or MRI machines.MRI machines.

Aristotle claimed that the heart “seethed” Aristotle claimed that the heart “seethed” with emotion and that the brain was just a with emotion and that the brain was just a radiator to cool the body.radiator to cool the body.

Aristotle’s view one out over Hippocrates’ Aristotle’s view one out over Hippocrates’ view, which was held for about 500 years.view, which was held for about 500 years.

20000 1000500-500 1500

Ancient Romans (~150 ad.)Ancient Romans (~150 ad.) Galen was a writer and physician to the Galen was a writer and physician to the

gladiators.gladiators. He saw the effects of brain and spinal injuries.He saw the effects of brain and spinal injuries. By poking on the brain he noticed that the front was By poking on the brain he noticed that the front was

soft and back was hard, and concluded that the front soft and back was hard, and concluded that the front dealt with memories and back dealt with movement.dealt with memories and back dealt with movement.

He dissected sheep brains and noted they had He dissected sheep brains and noted they had hollow cavities filled with fluid.hollow cavities filled with fluid.

He proposed that information was sent via the fluid He proposed that information was sent via the fluid traveling through nerves, which he considered just traveling through nerves, which he considered just hollow tubes.hollow tubes.

This view was held for about 1,500 years.This view was held for about 1,500 years.

20000 1000500-500 1500

Renaissance (1500-1600)Renaissance (1500-1600) Galen’s views were strengthened by Galen’s views were strengthened by

invention of hydraulics.invention of hydraulics. Philosopher Rene Descartes ("I think Philosopher Rene Descartes ("I think

therefore I am.“) developed a dualistic therefore I am.“) developed a dualistic view of the human mind: soul and body view of the human mind: soul and body were separate entitieswere separate entities Claimed the soul communicated with the body Claimed the soul communicated with the body

through the pineal gland in the brain.through the pineal gland in the brain.

20000 1000500-500 1500

1700-17501700-1750 Scientists took a closer look at the brain Scientists took a closer look at the brain

doing careful dissections.doing careful dissections. Grey and white matter found.Grey and white matter found. White matter continuous with nerves of the White matter continuous with nerves of the

body so assumed that it carried information.body so assumed that it carried information. Found that there was a central nervous system Found that there was a central nervous system

and peripheral nervous system.and peripheral nervous system. Found that bumps (gyri) and fissures (sulci) on Found that bumps (gyri) and fissures (sulci) on

the brain are universal among people.the brain are universal among people.

20000 1000500-500 1500 1750

Bump(gyrus)

Fissure(sulcus)

Peripheral NS

Central NS

17511751 Ben Franklin publishes paper on electricity Ben Franklin publishes paper on electricity

which gives scientist a new tool.which gives scientist a new tool. Others found that shocking muscle causes Others found that shocking muscle causes

twitches.twitches. Shocking limbs elicits sensation.Shocking limbs elicits sensation. Galen’s “fluid theory” replaced with one stating Galen’s “fluid theory” replaced with one stating

nerves use electrical pulses to carry info.nerves use electrical pulses to carry info. It wasn’t known if the same nerve carried both It wasn’t known if the same nerve carried both

sensory and motor information.sensory and motor information.

20000 1000500-500 1500 1751

18101810 Two scientist in different labs showed that Two scientist in different labs showed that

neurons carry sensory neurons carry sensory oror motor motor information, but not both.information, but not both. Nerves branch at the spinal cord, connecting Nerves branch at the spinal cord, connecting

with the front and back.with the front and back. If front branch is cut, movement is lost; if back If front branch is cut, movement is lost; if back

branch is cut, sensation is lost.branch is cut, sensation is lost.

20000 1000500-500 1500 1810

18101810 Gall, an Austrian, Gall, an Austrian,

developed “phrenology” developed “phrenology” which correlates skull which correlates skull bumps with personality bumps with personality traits.traits. Scientists didn’t believe Scientists didn’t believe

Gall’s theory since skull Gall’s theory since skull bumps don’t follow brain bumps don’t follow brain bumps (gyri).bumps (gyri).

Mainstream public bought Mainstream public bought 100,000 copies of Gall’s 100,000 copies of Gall’s book.book.

20000 1000500-500 1500 1810

18201820 Scientists look to see if different brain areas have Scientists look to see if different brain areas have

specific functions using “experimental ablation specific functions using “experimental ablation method” which destroys a brain area to see what method” which destroys a brain area to see what function is lost.function is lost. Only large crude destruction was possible.Only large crude destruction was possible. Found that cerebrum is for sensation and perception, Found that cerebrum is for sensation and perception,

cerebellum is for movement coordination.cerebellum is for movement coordination. Johannes Muller realizes that sensory systems Johannes Muller realizes that sensory systems

and not the stimuli themselves produce and not the stimuli themselves produce sensations.sensations. Recognized that perceived sensations depend on the Recognized that perceived sensations depend on the

sensory organ type.sensory organ type.

20000 1000500-500 1500 1820

18591859 Charles Darwin publishes Charles Darwin publishes On the Origin On the Origin

of Speciesof Species Darwin includes behavior among heritable Darwin includes behavior among heritable

traits.traits. He observed that many mammals show He observed that many mammals show

similar behavior when frightened.similar behavior when frightened. Concluded animal nervous system probably Concluded animal nervous system probably

share common wiring and underlying share common wiring and underlying mechanisms.mechanisms.

20000 1000500-500 1500 1859

1860s1860s Broca, a neurologist, had a patient who Broca, a neurologist, had a patient who

could understand speech but couldn’t could understand speech but couldn’t speak.speak. The patient’s words were jumbled together The patient’s words were jumbled together

and didn’t make sense.and didn’t make sense. After patient died, Broca examined his After patient died, Broca examined his

brain and saw a lesion in a brain area.brain and saw a lesion in a brain area. Today the area is called Broca’s area and it Today the area is called Broca’s area and it

is responsible for communication.is responsible for communication. This was the first evidence that a specific This was the first evidence that a specific

brain area had a specific function.brain area had a specific function.

20000 1000500-500 1500 1860

1870s1870s Scientists could apply a small shock to Scientists could apply a small shock to

the brain and elicit movement.the brain and elicit movement. Destruction of the same brain area Destruction of the same brain area

caused paralysis.caused paralysis. Mapping of the brain’s functions Mapping of the brain’s functions

begins.begins.

20000 1000500-500 1500 1870

1870s1870s Nissl invents the Nissl stain and is able to Nissl invents the Nissl stain and is able to

see cell bodies under the microscope.see cell bodies under the microscope. Golgi invents the Golgi stain which shows Golgi invents the Golgi stain which shows

the outline of neurons.the outline of neurons. He proposes the "Reticular Theory" - all He proposes the "Reticular Theory" - all

neurons are one big net.neurons are one big net. Cajal uses Golgi stain to advance histology of Cajal uses Golgi stain to advance histology of

brain to unprecedented heights and proposes brain to unprecedented heights and proposes "Neuron Doctrine" - each neuron is separate."Neuron Doctrine" - each neuron is separate.

Golgi and Cajal, bitter rivals, must share the Golgi and Cajal, bitter rivals, must share the Nobel Prize (1st time ever) in 1906.Nobel Prize (1st time ever) in 1906.

20000 1000500-500 1500 1870

1950s1950s Electron microscope invented and shows Electron microscope invented and shows

that Cajal was correct (*usually).that Cajal was correct (*usually). Hodgkin and Huxley use giant squid Hodgkin and Huxley use giant squid

axon to test action and membrane axon to test action and membrane potentials.potentials. They pioneered the use of the voltage clamp They pioneered the use of the voltage clamp

technique to change and measure the technique to change and measure the potential (charge) inside a neuron.potential (charge) inside a neuron.

They developed a model for activation and They developed a model for activation and threshold energies.threshold energies.

They shared the Nobel Prize in 1952.They shared the Nobel Prize in 1952.

20000 1000500-500 1500 1950