Synaptic Transmission 1
What is the resting membrane potential?
-70mV
What is the threshold of excitation?
The membrane potential needed at the axon hillock for an AP to be generated
True or False: Neurotransmitters can freely float in the terminal buttons
False, free floating neurotransmitter are destroyed by enzymes
What is the Opponent Process Theory?
Hering: The belief there is three classes of color vision cells: red/green, blue/yellow, bright/dark
What are the three dimensions of light?
Hue: wavelength of light
Brightness: intensity of light
Saturation: relative purity of light
What is the distribution of these ions: Na+, A-, K+, Cl-
Intraceullular: A-, K+
Extracellular: Cl-, Na+
What's the difference between temporal and spatial summation?
Temporal Summation:the integration of signals that occur at different times at the same synapses
Spatial Summation: the integration of signals that originate at different synapses on the neuron's membrane
What are the five types of neurotransmitters?
Amino Acids, Monoamines, Acetylcholine, Unconventional, Neuropeptides
What is blindsight?
The ability to respond to visual stimuli in a scotoma without conscious awareness of the stimuli
What are scotomas?
An area of blindness in corresponding areas of visual field, produced by damage to the primary visual cortex
What four mechanisms keep the unequal ionic distribution of neuronal membranes?
Ion channels, electrostatic pressure, diffusion pressure, sodium-potassium pump
Describe how neurotransmitter bind to ionotropic receptors and metabotropic receptors
Ionotropic receptor: neurotransmitter binds to the receptor and opens the associated ion channels, the ions then flow in or out of the postsynaptic neuron
Metabotropic receptor: neurotransmitter binds to a signal protein, causes a subunit of the G protein to break off. The G protein will either bind to an ion channel (allowing ions to flow in or out of postsynaptic neuron) or stimulate the synthesis of a second messenger
What are the subtypes of Amino Acid neurotransmitters?
Glutamate, GABA, Glycine, Aspartate
What are the Magnoecellular and Parvocellular layers in the LGN?
Magnocellular: bottom 2 layers, large cells, responsive to rods/movement
Parvocellular: top 4 layers, small cells, response to color/fine detail/slow-stationary
What is the Component Process Theory?
Young and Helmholtz: three different cones (red,blue,green)
The ratio of cones activated creates different color
Define the following: EPSP and IPSP
EPSP: excitatory postsynaptic potential, increases the likelihood that an action potential will be generated
IPSP: inhibitory postsynaptic potential, decrease the likelihood that an action potential will be generated
What is the process of exocytosis?
AP arrives at terminal button
Opens Ca2+ voltage-gated ion channels
Ca2+ rushes in
Synaptic vesicles to fuse to membrane and neurotransmitter flow out into synaptic cleft
Which neurotransmitter is the most prevalent inhibitory neurotransmitter in the CNS?
GABA
Which six layers of the LGN are contralateral vs ispilateral?
Layers 1,4,6= contralteral (opposite)
Layers 2,3,5= ispilateral (same)
What are the five layers of the retina? From front to back of eyeball
Rentinal ganglion cells, amacrine cells, bipolar cells, horizontal cells, and photoreceptors
What is the difference between absolute and relative refractory period?
Absolute refractory period: brief period in which it is impossible for an AP to be generated in the same neuron
Relative refractory period: period after absolute refractory period in which it takes more stimulation for an AP to be generated