Neural mechanisms of pavlovian conditioning

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what is necessary for LTP?

1. it requires burst of pulses (slow pulse train wont affect)

2. depolarise the cell, send stimulus down axon and then specifically the synapse will get strengthened and LTP/bigger response

3. activity of NMDA receptors necessary as it controls the calcium channels

4. influx of Ca2+ into the cell

5. activity of NP synthase

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explain engineering memories (Nabavi, 2014)

why?can maniuplate genes so if you shine on these neurons you can activate them and provide footshock as US

how?insert genes into rat and put optic fibres into certain place and have lights with certain frequency to activate the neurons - fear conditoning was observed as a reduction in previously trained lever pressing (US = footshock)

what did they find? an increase in AMPA mediated the responses in the amygdala from those recieving paired training - indicating LTP - the change in behaviour is a result of an increase in AMPA receptor activity

NMDA antagnost (MK801) impaired optogenetic conditioning - this leaning is mediated by NMDA receptors

implications/conclusions? could induce LTP in these animals by flashing lazer light on/off - there is no difference in using a real/evoked tone - LTP is mediated by NMDA receptors

effect of protocols? 2 protocols (fast vs. slow):

1. LTP - give trains of 100 2ms bursts of light at 100hz           2. LTD - give 900 2ms pulses of light at 1hz

found: LTD protocol inactivates fear behaviour - LTP protocol activates fear behaviour - shown by reduction in lever pressing in LTP protocol - effect of LTP protocol was only effective if they had been previously trained (isnt LTP itself inducing fear behav) - LTD effective on both tone and optogenetic conditioning (real world and induced) - more dramatic reduction in just tone - LTP cannot bring back a fear that has become extinct

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