Psychobiology - Chapter 1

Trepanation

Prehistoric brain surgery that involved drilling holes in the skull

Excerebration

Removal of the brain, primarily during ancient Egyptian mummification process

Hippocrates

Greek philosopher

View → brain is responsible for sensation and intelligence

Aristotle

Greek philosopher

View → heart = center of intelligence, brain acts as a cooling agent for blood and heart

Galen

Ancient Roman physician

Through sheep dissection discovered: cerebrum, cerebellum, ventricular system and theory

Galen’s Cerebrum

Largest part of the brain

2 hemispheres

Galen’s hypothesis (proven right):

Process and receive sensations

Galen’s Cerebellum

Galen’s hypothesis (proven right):

Part of brain responsible for commanding movement

Ventricular System

Holds cerebrospinal fluid (cushions and nourishes CNS)

Ventricular Theory

Galen’s hypothesis (proven wrong):

The brain communicates via cerebrospinal fluid

Leonardo da Vinci

Scientist who studied human anatomy

Found nerves do not converge on ventricles → debunked Ventricular Theory

Fluid-mechanical Theory of Brain Function

Theory:

Liquid in the pineal gland is connected to the mind and soul

The pineal gland is the seat of the soul, bc its at center of brain

Rene Descartes

Philosopher who proposed the Fluid-mechanical Theory of Brain Function

Pineal Gland

Brain part that receives info on the light-dark cycle & produces and secretes melatonin

Melatonin

Natural hormone and antioxidant that helps regulate sleep

Suprachiasmatic Nucleus

Master clock of the brain and body that helps regulate sleep/wake cycles by relaying information to the pineal gland

Gray matter

Brain tissue containing most of the brain’s neuronal cell bodies

Performs most of brain’s functions

White matter

Brain tissue containing most of the brain’s neuronal axons

Transmits signals between different regions

Gyri

Bumps on the surface of the brain

Help increase surface area for more neurons

Help compartmentalize tissue

Sulci

Grooves on the surface of the brain

Help increase surface area for more neurons

Help compartmentalize tissue

Galvani and du Bois-Reymond

Discovered the brain can generate electricity and communicates with the body via electrical signals

Nerves

Cord-like bundles of nerve fibers (axons) that act as electrical cables → transmitting signals between brain/spine and rest of the body

Bell-Magendie Law

Dorsal roots - carry sensory info TO spinal cord

Ventral roots - carry motor commands AWAY from spinal cord

Dorsal roots

Incoming (afferent) sensory fibers of the spinal cord that enter toward back of spine

Carry sensory info from body to spine

Ventral root

Outgoing (efferent) motor fibers of the spinal cord that enter toward front of spine

Carry motor commands from spine to body

Pseudoscience

Claims presented as science but lack scientific basis and are therefore false

Franz Gall

Anatomist

Established phrenology

Phrenology

Pseudoscience

Each gyri on brain are responsible for one’s personality traits

Broca’s Area

Left frontal lobe area

Speech production

Broca’s Aphasia

Speech Production impaired

Speech Comprehension intact

Wernicke’s Aphasia

Speech Production intact; however with word salad

Speech Comprehension impaired

Wernicke’s Area

Left temporal lobe area

Speech comprehension