Brain Structure Slides Flashcards
Thomas Willis
- coined term neurology
- known for circle of willis
- first anatomist to link brain structure with behaviour
- started the field of cog neuro
Franz Gall
- known for phrenology
- localization of function
- not a scientist
marie jean pierre flourens
- best known for whole brain theory
- first to show localization of function through animal brain lesion studies
- no area responsible for higher functions
- coined “aggregate field theory” - faculties of perception and volition are one faculty
john hughlings jackson
- best known for human neuropsychology
- observed behaviour of patients with brain damage
- noticed that seizure progressed in a stereotypical manner form one body part to another
- led to the idea of topographic organization
paul broca
- best known for broca’s area
- patient tan - large left hemisphere lesion
- speech production
carl wernicke
- best known for Wernicke’s area
- speech comprehension
- damage to posterior left hemisphere at temporal-parietal junction
wilder penfield
- best known for mapping humonculus
- how biology shapes behaviour
- used electrical stimulation to map sensorimotor cortices
Donald hebb
- psych and bio cannot be separated
- best known for hebbian synapse
- “cells that fire together wire together”
- brain is always active even without external input
- beginnings of neural networks
cajal’s neuron doctrine
refer to connectional specificity and dynamic polarization
connectional specificity
cells are separate and connections among neurons are not random. circuits pass information through specific pathways
dynamic polarization
portions of neurons are for different purposes: some for gathering information, some for outputting information
difference between dendrites and axons
dendrites receive - axons send information
in between is the synapse
glial cells make up how much of the brain’s volume
half
astrocytes
- surround neurons and connect to blood vessels
- transport substances from blood to neuron
- gating - lets in some substances, keeps out others
- barrier is called Blood Brain Barrier (BBB) which protects the CNS from dangerous agents in blood
microglial cells
remove damaged cells
oligodendrocytes
form myelin to wrap around axons in the CNS: can cover several axons
Schwann cells
form myelin to surround axons in PNS, can only cover one axon
multiple sclerosis
damage to myelin sheath in PNS or CNS or both
- cause unknown, probably auto-immune
- symptoms depend on which neurons are being de-myelinated
first stage of neuronal signaling
neurons receive information through chemicals (neurotransmitters, environmental, or physical)
second stage of neuronal signaling
signals from chemicals initiate changes in the membrane of the neuron that allow electrical current to flow
third stage of neuronal signaling
electrical currents, if strong enough, spike during transmission and create an action potential
4th stage of neuronal signaling
action potentials transmit signal down axon to terminal buttons
5th stage of neuronal signaling
terminal buttons release neurotransmitters to next neuron
depolarization
makes the neuron LESS negatively charged - this gain can reach threshold for an action potential.
action potential
rapid depolarization and repolarization of membrane
hyperpolarization leads to..
refractory period
saltatory conduction
nodes between myelin sheath allows the action potential to travel down the axon more quickly
large diameter axons conduct signals slower or faster? why?
faster due to decreased axon resistance
what can cause an action potential signal to flow faster?
increase in membrane resistance or decrease of axon resistance
nodes
breaks among the myelin sheath where action potentials can occur
first step of chemical transmission
action potential arrives at axon terminals which leads to depolarization
second step of chemical transmission
vesicles containing neurotransmitters fuse with membrane and release into synaptic cleft