Lecture 24 Flashcards
How do drugs affect our brain?
Typically drugs are drugs because they cause a ‘high’, this high varies based on the drug but is normally caused by the drug impacting neuron signals, whether that is by blocking certain receptors or triggering the release of lots of chemicals.
What are some common examples of neurotransmitters?
Acetylcholine (EPSP), glutamate (EPSP), gamma-Aminobutyric acid (GABA, IPSP), norepinephrine, dopamine, serotonin.
What are the two main types of neurotransmitter with regards to membrane potential?
Excitatory: the neurotransmitter excites the neuron’s membrane, causing a local depolarisation, can be done by activating Na+ or Ca2+ channels
Inhibitory: The neurotransmitter inhibits the neuron’s membrane, causing a local hyperpolarisation, can be done by activating Cl- or K+ channels.
How does summation of membrane potentials work?
Excitatory and inhibitory synapses will add together to form the total synaptic potential, EPSPs adding will create a larger EPSP, IPSPs adding will create a larger IPSP, adding an EPSP and an IPSP will cancel.
What are the two summation types?
Summation over a short time period from the same synaptic knob is temporal summation, summation of inputs from different synaptic knobs is spacial summation.
What role does the axon hillock play in allowing or declining an action potential?
The action potential is the point where all the synaptic potentials will reach, if they summate to be at or below the threshold potential at the axon hillock an action potential will travel down the axon, if not below the threshold potential then no action potential will occur.
How does temporal summation work?
If the signals are rapid enough the local membrane potential of the post synaptic neuron will not be able to return to RMP before the next signal comes, hence the signals will add to each other.
What are the two types of brain networks?
divergence: information from a single neuron diverges to multiple neurons or body parts.
Convergence: Information from multiple neurons converging on one neuron.
What is the benefit of divergent brain networks?
Allows the opportunity to amplify signals (multiple reactions for one signal), allows for control points e.g to precisely coordinate control of muscle.
What is the benefit of convergent brain networks?
Provides redundancy, if one neuron fails others can send the signal.
