1 Neurons and Potentials Flashcards
What is a Golgi stain, and who developed it?
developed by Italian Golgi, improved by Ramon y Cajal ; silver staining technique visually revealing the neurites and cell body structures of neurons
The Neuron Doctrine
The neuron is the structural and functional unit of brain activity (Ramon y Cajal)
The law of dynamic polarization
The flow of information in a neuron (generally speaking) is one directional, starting at the aggregation of information based on information inputs (at dendrites) decides whether to fire an action potential (at axon hillock), which subsequently travels down an axon(s) into a synapse with the release of neurotransmitter(s)
What is the relationship between STRUCTURE and FUNCTION in the brain? (examples)
Structure constrains / determines the possible electrical dynamics of the brain Function in turn can influence the emerging structures of the brain, as seen in neuromodulatory systems which can determine whether a synapse response to a particular neurotransmitter
What are nuclei? (example)
Nuclei are collections of neurons with specificconnectivity for functionality
I what does EEG measure?
measure collective activity of nuclei with local field potentials/ EEG
What are the two primary functions of the hippocampus?
(CA1, CA3) determinism where you are memory
What are the different levels of analysis in neuroscience, and the mechanisms for measuring each?
synapse : the electrical potential of a single synapse - single cell recording neuron : electrical potential of a single neuron - single cell recording nuclei : temporal resolution of a population of synapses - EEG/field potentials regions : temporal resolution of oxygenated blood flow in brain regions - fMRI
Label the parts of the neuron
Syanptic potentials are ________ while action potentials are __________
snaptic : continuous
action: all or nothing
What part of the brain? What is its primary function
hippocampus: orientation & memory
What kind of neuron? Where are these founds?
Pyramidal cells are found in the cerebral cortex, amydgala and hippocampus
What kind of neuron?
Stellate neuron; found many places in the body; can be spinous or aspinous
What are some of the parameters on which you can classify neurons?
1) Shape/Number of axons; 2) Location; 3) Spinous or Aspinous dendrites; 4) Which neurotransmitters they handle
Equilibrium potential
The membrane potential at which the net change of ions across the membrane is zero, given the overall concentration of ions on either side of the membrane
What are the different types of electrical potentials in the brain?
membrane potential
equilibrium potential
synaptic potential
action potential
membrane potential
the voltage difference between the intracelluar and extracellular spaces [includes resting, synaptic and action potential]
snaptic potential
a change in the membrane potential to a positive or negative value (excitatory and inhibitory) brought about by the influx of ions through the ion channels of the synapse
excitatory and inhibitory inputs from one neuron (at axon terminal button) onto another neuron (at dendrite or soma)
ions move from areas of ______ concentration to ______ concentration
high to low
typical ion charges … Na / K / Cl … and where they are typically found
Na + //extracellular
K + //intracellular
Cl- //intracellular
What are the properties of Ion Channels?
ion selectivity: (e.g. Na+, Ca++, K+, Cl-)
gating: (e.g. by voltage, ligand)
kinetics (e.g. amount of time the channels remain open)
state (e.g. activated, inactive, deinactivated, persistent)
distribution (e.g. location on the neuron)
What does a neurotransmitter do?
A neurotransmitter mediates information exchange between neurons, through the generation of synaptic potentials
What are the three types of neurotransmitters?
Excitatory
Inhibitory
Neuromodulatory
excitatory neurotransmitters
increase likelihood a neuron will fire an action potential by influencing the ion flow through the cell membrane; usually located on the dendrites
glutamate, ACh
Inhibitory neurotransmitters
decrease the likelihood the neuron will reach threshold for action potential, by influencing the ion flow through cell membrane; usually found on the cell body
GABA, glycine
Neuromodulatory neurotransmitters
NE, 5-HT, DA, HA, Ach
What factors influence the speed of conduction of an action potential?
the axon length and myelination
action potentials
all or non electrical events in a neuron, reflecting the spatial/temporal integration of synaptic potentials of the neuron, and the intrinsic excitability of the neuron. The neuron fires an action potential when the integration reaches its threshold
What is the average resting potential for a neuron?
ranges from -40 to -90 milivolts; with the intracellular space being more negatively charged than the extracellular space
What ions are generally found inside/outside the cell, at resting potential?
inside: K+ and negatively charged proteins;
outside: Na+ Cl-
In an unstimuluated neuron, _____ ions pass from ______ to ______ the cell, through _____
K+ pass from inside to outside through potassium channels
As more K+ ions leave the cell, the inside becomes more - charged, which then causes some K+ to be pulled back in; which then balances to a resting potential
TRUE
