Methods of studying the brain: A brief Methods of studying the brain: A brief historyhistory

First…. a few basic facts about your brainFirst…. a few basic facts about your brain

Approximately 3 lbs.; slightly larger than size of Approximately 3 lbs.; slightly larger than size of an adult fistan adult fist

2% of total body weight; burns 70% of your bod2% of total body weight; burns 70% of your bodyy’’s glucoses glucose

100 billion+ neurons; trillions of synapses100 billion+ neurons; trillions of synapses Biochemical signals travel at 220 mphBiochemical signals travel at 220 mph Half of the 30,000 genes are dedicated to the Half of the 30,000 genes are dedicated to the

nervous systemnervous system The brain itself feels no pain, but registers it The brain itself feels no pain, but registers it

from everywhere elsefrom everywhere else

Early 1800sEarly 1800s Phrenology: measuring Phrenology: measuring

the bumps on peoplesthe bumps on peoples’’ headsheads

They were wrong about They were wrong about bumps; right about the bumps; right about the brain having localized brain having localized functions!functions!

http://www.bc.edu/http://www.bc.edu/bc_org/avp/cas/fnart/bc_org/avp/cas/fnart/phrenology/phrenology/phrenology_frames.htmlphrenology_frames.html

1848: Phineas Gage 1848: Phineas Gage (open up last night’s homework so we (open up last night’s homework so we can discuss; a video clip will also be shown: can discuss; a video clip will also be shown:

http://www.youtube.com/watch?v=9QXI_BxlY7M)http://www.youtube.com/watch?v=9QXI_BxlY7M)

1930s: Prefrontal lobotomies1930s: Prefrontal lobotomies

Dr. Walter Freeman: surgical disconnection of Dr. Walter Freeman: surgical disconnection of the frontal lobes from the thalamus with an the frontal lobes from the thalamus with an icepick icepick

Eliminated severe behavioral problems; also Eliminated severe behavioral problems; also took away emotions, problem solving, thinkingtook away emotions, problem solving, thinking

By 1949, 5,000 done annuallyBy 1949, 5,000 done annually http://www.youtube.com/watch?v=_0aNILW6ILkhttp://www.youtube.com/watch?v=_0aNILW6ILk http://www.pbs.org/wgbh/americanexperience/

films/lobotomist/

1950s: Electrical Stimulation of the Brain1950s: Electrical Stimulation of the Brain

  1954: James Olds and Peter Milner placed an electrode in 1954: James Olds and Peter Milner placed an electrode in the hypothalamus of the brains of rats by mistake and the hypothalamus of the brains of rats by mistake and discovered the pleasure center of the braindiscovered the pleasure center of the brain

When the rats learned that they could control the When the rats learned that they could control the electrical stimulation by pressing a lever, they pressed it electrical stimulation by pressing a lever, they pressed it 7,000 times an hour (endorphins).  7,000 times an hour (endorphins).  

http://accidentalmind.org/the_discovery_of_brain_plea.html

1969: Jose Delgado1969: Jose Delgado’’s s ““matadormatador”” experiment: stimoceiver experiment: stimoceiver http://wireheading.com/matador.html

Selective lesioningSelective lesioning

Selectively damaging Selectively damaging parts of the brain using parts of the brain using electrical instrumentelectrical instrument

Only used in animals… Only used in animals… obviously.obviously.

Rat hypothalamus studyRat hypothalamus study Accidents and brain Accidents and brain

damage are often studied damage are often studied in human beings.in human beings.

For modern technology!For modern technology!And now…And now…

Electroencephalogram (EEG)Electroencephalogram (EEG)

19241924

Computerized Axial Computerized Axial Tomography (CAT) Tomography (CAT)

X–rays taken along X–rays taken along an axis to reveal brain an axis to reveal brain structuresstructures

Positron Emission Positron Emission Tomography (PET)Tomography (PET)

Can view brain activity Can view brain activity while the subject is while the subject is engaged in mental engaged in mental activity. activity.

Injection of radioactive Injection of radioactive glucose is given.glucose is given.

Magnetic Resonance Imaging Magnetic Resonance Imaging (MRI)(MRI)

The machine aligns the The machine aligns the spinning atoms of brain spinning atoms of brain molecules; radio pulses molecules; radio pulses temporarily disorient the temporarily disorient the spinspin

fMRI ScansfMRI Scans

Used to determine which Used to determine which parts of the brain “light up” parts of the brain “light up” during different types of during different types of mental activity; blood mental activity; blood rushes to more active partsrushes to more active parts

What love looks like in an What love looks like in an fMRI Scan!fMRI Scan!