Learning and Memory Flashcards
Explain the different components of the California sea slug!
Siphon - expel water and waste products.
Mantle shelf (together with siphon = tactile stimuli)
Respiratory organ - gill.
What is the habituation of the gill withdrawal.
Repeated stimulation of the siphon causes habituation (a decreased response or contraction for the stimuli presented).
What physiological changes take place to allow the habituation of gill withdrawal to occur?
It is due to presynaptic changes - there are fewever presynaptic VOCC, reduced quantal release of glutamate and reduced active release zones.
The motor neurone is unaffected - doesn’t have input and therefore doesn’t respond.
Space training is more effective - decrease 30% connectivity.
What is the sensitisation of the gill withdrawal
It is due to harmful stimuli or shock - it is a bigger presynaptic response for the same stimuli.
What physiological changes take place to allow the sensitisation of gill withdrawal to occur?
Facilitatory neurones (5HT) act on the presynaptic terminal. Via A Gs coupled G protein - causes increase cAMP, increase PKA…this causes phosphorylation of K+ channels, blocking them and causing increased excitability. It also causes enhanced vesicular release. Also it causes L type Ca++ channels to open.
Via Go linked…PLC…DAG…increase PKC…cause l-type Ca++ channels to open and enhanced vesicular release.
What is classical conditioning?
Pairing a conditioned stimuli with an unconditioned one.
Eg...conditioned = brushed siphon. unconditioned = electrical shock to tail.
Explain the presynaptic effects of a conditioned stimuli.
Ca++ entry,
Ca++ binds to calmodulin,
Ca++:calmodulin binds to adenylate cyclase…increase cAMP.
Explain the presynaptic effects of an unconditioned stimlui.
5HT binds to receptor (Gs) and increase adenylated cyclase activity…increasing cAMP.
What are the CS and the US coupled by?
They are coupled by co-incidence detection of adenylate cyclase.
What effect doe co-incidence detection of Adenylate cyclase causes int he post synaptic motor neurone?
Causes a massive depolarisation of the motor neurone which activates NMDA receptors (Mg++ block is released) which increases calcium entry and releases retrograde signal from motor neurone to the pre synaptic terminal to the presynaptic terminal.
What short term effects does co-incidence have?
Phosphorylate K channels. Reduced potassium current. Larger AP. Greater Ca++ entry. More transmitter is released.
What long term effects foes co-incidence detection have?
Persistant activation of PKA and recutrits MAPK (mitogen activated kinase).
PKA and MAPK to the nucleus.
PKA phosphorylates CREB (cAMP response element binding protein).
CREB - TF that binds CRE (camp response elements) on DNA to regulated gene expression of c-fos, BDNF, neuropeptide and structural proteins.
