BIO 132 Neurophysiology

Lecture Goals: Course overview - syllabus & tentative schedule Course overview - syllabus & tentative schedule How to succeed in Bio 132 How to succeed in Bio 132 Historical perspective of Neuroscience Historical perspective of Neuroscience

Course Overview

Where in the body are memories stored; do commands to move come from; is sensory information processed; do consciousness, logic and emotion stem from? What evidence do you have to support your answer? History of Neuroscience: A Perspective

The Ancient Egyptians Greatly interested in physiology and how the body and mind worked. Greatly interested in physiology and how the body and mind worked. Thought the heart was seat of consciousness, and the brain did nothing important. Thought the heart was seat of consciousness, and the brain did nothing important. When embalming the dead they would take great care to preserve the heart but the brain was pulled out through the nose and thrown out. When embalming the dead they would take great care to preserve the heart but the brain was pulled out through the nose and thrown out

The Ancient Greeks (~400b.c.)  Hippocrates claims that the brain is the center of sensation and movement. Why would he come to this conclusion? He had no scientific tools like microscopes or MRI machines.  Aristotle claimed that the heart “seethed” with emotion and that the brain was just a radiator to cool the body. Aristotle’s view one out over Hippocrates’ view, which was held for about 500 years. Aristotle’s view one out over Hippocrates’ view, which was held for about 500 years

Ancient Romans (~150 ad.) Galen was a writer and physician to the gladiators. Galen was a writer and physician to the 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 soft and back was hard, and concluded that the front dealt with memories and back dealt with movement. By poking on the brain he noticed that the front was soft and back was hard, and concluded that the front dealt with memories and back dealt with movement. He dissected sheep brains and noted they had hollow cavities filled with fluid. He dissected sheep brains and noted they had hollow cavities filled with fluid. He proposed that information was sent via the fluid traveling through nerves, which he considered just hollow tubes. He proposed that information was sent via the fluid traveling through nerves, which he considered just hollow tubes. This view was held for about 1,500 years. This view was held for about 1,500 years

Renaissance ( ) Galen’s views were strengthened by invention of hydraulics. Galen’s views were strengthened by invention of hydraulics. Philosopher Rene Descartes ("I think therefore I am.“) developed a dualistic view of the human mind: soul and body were separate entities Philosopher Rene Descartes ("I think therefore I am.“) developed a dualistic view of the human mind: soul and body were separate entities Claimed the soul communicated with the body through the pineal gland in the brain. Claimed the soul communicated with the body through the pineal gland in the brain

Scientists took a closer look at the brain doing careful dissections. Scientists took a closer look at the brain doing careful dissections. Grey and white matter found. Grey and white matter found. White matter continuous with nerves of the body so assumed that it carried information. White matter continuous with nerves of the body so assumed that it carried information. Found that there was a central nervous system and peripheral nervous system. Found that there was a central nervous system and peripheral nervous system. Found that bumps (gyri) and fissures (sulci) on the brain are universal among people. Found that bumps (gyri) and fissures (sulci) on the brain are universal among people

Bump (gyrus) Fissure (sulcus) Peripheral NS Central NS

1751 Ben Franklin publishes paper on electricity which gives scientist a new tool. Ben Franklin publishes paper on electricity which gives scientist a new tool. Others found that shocking muscle causes twitches. Others found that shocking muscle causes twitches. Shocking limbs elicits sensation. Shocking limbs elicits sensation. Galen’s “fluid theory” replaced with one stating nerves use electrical pulses to carry info. Galen’s “fluid theory” replaced with one stating nerves use electrical pulses to carry info. It wasn’t known if the same nerve carried both sensory and motor information. It wasn’t known if the same nerve carried both sensory and motor information

1810 Two scientist in different labs showed that neurons carry sensory or motor information, but not both. Two scientist in different labs showed that neurons carry sensory or motor information, but not both. Nerves branch at the spinal cord, connecting with the front and back. Nerves branch at the spinal cord, connecting with the front and back. If front branch is cut, movement is lost; if back branch is cut, sensation is lost. If front branch is cut, movement is lost; if back branch is cut, sensation is lost

1810 Gall, an Austrian, developed “phrenology” which correlates skull bumps with personality traits. Gall, an Austrian, developed “phrenology” which correlates skull bumps with personality traits. Scientists didn’t believe Gall’s theory since skull bumps don’t follow brain bumps (gyri). Scientists didn’t believe Gall’s theory since skull bumps don’t follow brain bumps (gyri). Mainstream public bought 100,000 copies of Gall’s book. Mainstream public bought 100,000 copies of Gall’s book

1820 Scientists look to see if different brain areas have specific functions using “experimental ablation method” which destroys a brain area to see what function is lost. Scientists look to see if different brain areas have specific functions using “experimental ablation method” which destroys a brain area to see what function is lost. Only large crude destruction was possible. Only large crude destruction was possible. Found that cerebrum is for sensation and perception, cerebellum is for movement coordination. Found that cerebrum is for sensation and perception, cerebellum is for movement coordination. Johannes Muller realizes that sensory systems and not the stimuli themselves produce sensations. Johannes Muller realizes that sensory systems and not the stimuli themselves produce sensations. Recognized that perceived sensations depend on the sensory organ type. Recognized that perceived sensations depend on the sensory organ type

1859 Charles Darwin publishes On the Origin of Species Charles Darwin publishes On the Origin of Species Darwin includes behavior among heritable traits. Darwin includes behavior among heritable traits. He observed that many mammals show similar behavior when frightened. He observed that many mammals show similar behavior when frightened. Concluded animal nervous system probably share common wiring and underlying mechanisms. Concluded animal nervous system probably share common wiring and underlying mechanisms

1860s Broca, a neurologist, had a patient who could understand speech but couldn’t speak. Broca, a neurologist, had a patient who could understand speech but couldn’t speak. The patient’s words were jumbled together and didn’t make sense. The patient’s words were jumbled together and didn’t make sense. After patient died, Broca examined his brain and saw a lesion in a brain area. After patient died, Broca examined his brain and saw a lesion in a brain area. Today the area is called Broca’s area and it is responsible for communication. Today the area is called Broca’s area and it is responsible for communication. This was the first evidence that a specific brain area had a specific function. This was the first evidence that a specific brain area had a specific function

1870s Scientists could apply a small shock to the brain and elicit movement. Scientists could apply a small shock to the brain and elicit movement. Destruction of the same brain area caused paralysis. Destruction of the same brain area caused paralysis. Mapping of the brain’s functions begins. Mapping of the brain’s functions begins

1870s Nissl invents the Nissl stain and is able to see cell bodies under the microscope. Nissl invents the Nissl stain and is able to see cell bodies under the microscope. Golgi invents the Golgi stain which shows the outline of neurons. Golgi invents the Golgi stain which shows the outline of neurons. He proposes the "Reticular Theory" - all neurons are one big net. He proposes the "Reticular Theory" - all neurons are one big net. Cajal uses Golgi stain to advance histology of brain to unprecedented heights and proposes "Neuron Doctrine" - each neuron is separate. Cajal uses Golgi stain to advance histology of brain to unprecedented heights and proposes "Neuron Doctrine" - each neuron is separate. Golgi and Cajal, bitter rivals, must share the Nobel Prize (1st time ever) in Golgi and Cajal, bitter rivals, must share the Nobel Prize (1st time ever) in

1950s Electron microscope invented and shows that Cajal was correct (*usually). Electron microscope invented and shows that Cajal was correct (*usually). Hodgkin and Huxley use giant squid axon to test action and membrane potentials. Hodgkin and Huxley use giant squid axon to test action and membrane potentials. They pioneered the use of the voltage clamp technique to change and measure the potential (charge) inside a neuron. They pioneered the use of the voltage clamp technique to change and measure the potential (charge) inside a neuron. They developed a model for activation and threshold energies. They developed a model for activation and threshold energies. They shared the Nobel Prize in They shared the Nobel Prize in