College 2 Synaptic transmission and memory Flashcards
Serotenergic system
Regulates wakefullness, is important for mood regulation Related to - anxiety - depression - OCD - tics - schizofrenia - sleep apnea - SIDS
Raphé nuclei
plaatje met de paarse pijlen
Cholinergic system (acetylcholine)
- regulates normal waking behavior
- attention and memory
related to Alzheimers
Midbrain nuclei - forebrain
- frontal cortex
- corpus callosum
Plaatje met de rode pijlen
Norepinephrine system (noradrenergic)
Has a role in learning by stimulating neurons to fire faster or even change their structure
Regulates arousal, alertness and emotion
Linked to ADHD
Thalamus, cerebellum, forebrain & cortex
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Dopaminergic system
Basal ganglia Two different pathways Nigrostratial path (orange) - coordinating movement - Parkinsons Mesolimbic path (purple) - involved in reward, learninng and addicition - enhances response to environmental stimuli, motivation and focussing attention
Action Potential
- short lastin event
travels down the axon - the electrical membrane of a cell rapidly rises and falls
resting potential is -70Mv - the force stays the same but frequency and speed can change
- functions on a YES/NO principle –> there is or is not an action potential
Depolarise, Repolarise and Hyperpolarise
Depolarisation
Positive change in the resting potential
-70Mv –> -65Mv
Repolarisation
Negative change in the potential
-65 –> -70Mv
Hyperpolarisation
Brings it back to the resting potential
back to -70Mv
Electrical signals
-70Mv
Excitatory signal –> less negative -70 to -65
Inhibitory signal –> more negative -65 to -70
Chemical synaps
Juction where messenger molecules (neurotransmitter) are released from one neuron to the excite or inhibit an other neuron
Neurotransmitter
Messenger molecule
Chemical released by a neuron onto a target with an electrical excitatory or inhibatory effect
outside of CNS in the bloodstream –> hormone
Hormones
Have distant targets
- their actions are much slower than neurotransmitters
Nodes of Ranvier
Tiny gaps in Myelin sheets
serves to facilitate the rapid conduction of nerve impulses
Myelin
White matter produced by GLIAL CELLS (swam cells)
- speeds up the neural impuls
Summation of inputs
EPSP (EXCITATORY POSTSYNAPTIC POTENTIAL) & IPSP are summed ( they can cancel each other out )
two different kinds of summation
TEMPORAL SUMMATION:
pulses that occur at approximately the same time are summed
SPATIAL SUMMATION:
pulses that occur at approximately the same location on a membrane are summed
Microtubule
Transport structure that carries substances to the axon terminal
Storage granule
Large compartment that holds synaptic cesicle
Synaptic cleft
Small space separating presynaptic terminal and postsynaptic dendretic spine
Post synaptic membrane
Contains receptor molecules that receive chemical messages
Pre synaptic membrane
Encloses molecules that transmit chemicle messages
Synaptic vesicle
Round granule that contains neurotransmitter
Fixed number of neurotransmitters inside (quotum)
Postsynaptic receptor
Site to which a neurotransmitter molecule binds
Mitochondrion
Organelle that provides the cell with energy
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4 steps of neurotransmission
- SYNTHESIZED and stored in the axon terminal
- Transported to the presynaptic membrane and RELEASED in response to an action potential (exocytosis)
- Able to ACTIVATE receptors on the target-cell located on the postsynaptic membrane
- INCTIVATION reuptake back into terminal OR inactivated by enzymes in sybaptic cleft
Inhibitory neurotransmitter
Hyperpolarise the postsynaptic membrane and thereby DECREASING the likelihood of an action potential in the postsynaptic neuron
Excitatory neurotranmission
Depolarise (make less negative) the postsynaptic membrane and thereby INCREASING the likelyhood of an action potential in the postsynaptic neuron
GABA
Main INHIBITATORY transmitter
relieves anxiety and pain
ALCOHOL is GABA agonist
Glutamate
Main EXCITATORY transmitter involved in many processes
including learning
Aminoacid neurotransmitters
Devided into two GLUTAMATE & GABA - quick acting - work horses of the brain - only active in the brain - interact with each other to obtain balance
Amine neurotransmitter
DOPAMINE, NOREPINEPHRINE, SEROTONINE, ACETYLCHOLINE
- common function: slowing down or speeding up transmission
- produced in brainstem, CNS and brain (cortex, limbic system and basal ganglia)
- influenced by diet
Neurotransmitters ANS
Cholinergic –> acetylcholine
Sympathetic excitation, fight or flight
Parasympathetic inhibition, rest and digest
Nerepinephrine –> fight or flight
Neurotransmitters SNS
Motorneurons: cholinergic
Neurons: acetylcholine
Peptides
Larger, slower action, active throughout body compared to aminoacid neurotransmitters (GABA and Glutamate)
OPIODS, INSULIN, OXYTOCIN
- stress - birth, lactation and grooming
- mother infant bond - attachment
- pleasure, pain - decrease anxiety
Learning
Relatively permanent change in behavior that results from experience
Hebbs law
experience and repitition of cell A and B axciting
WHAT FIRES TOGETHER WIRES TOGETHER
efficiency = increased
Habituation
Response to stimulus weakens with repeated presentation of the stimulus
Less calcium –> less neurotransmitters –> less depolarisation
Sensitization
Hyper responsiveness to a stimulus
antidepressants
Classes of neurotransmitters
small molecule
- peptide transmitters
- lipid transmitters
- gaseaous transmitters
- ion transmitters
Renshaw loop
feedback circuit enables motor neuron to inhibit itself from over excitation
Parkinsons
Disorder of the motor system
Substantia nigra: degenerates
Level of dopamine: less than 10% of normal in basal ganglia
Vagus Nerve
Cranial nerve from the brain to the heart
Epinephrine (epi)
Adrenaline
chemical, neurotransmitter, CNS
mobalize body for fight or flight
produced by adrenal glands, located on top of the kidneys
Metobotropic receptor
Indirect
Slow changein the neuron through a chain of actions from the stimulation of the receptor
Ionotropic receptor
Direct
Open gate, involved in action potential as ions can change the charge of the neuron
