Class Notes (806,849)
Canada (492,483)
York University (33,494)
Biology (2,145)
BIOL 4370 (20)

Nov. 14th.docx

3 Pages
Unlock Document

York University
BIOL 4370

Nov 14 th • Synapitic platicicity in aplysia: sea slug - 1 foot across, live in ponds - gill withdrawal reflex: aplysia withdraws when given shock or pinch. Have mechanoreceptors which synapse onto motor neuron which synapse onto gill (causing gill to contract) - gill withdrawal reflex habituates: sensory neuron releases less glutamate with each pinch (learning) - sensitization occurs when you give a shock after pinching over many trials - the more time goes by sensitization lasts longer (learns to be more afraid of normal to what it was habituated to) • When tail is shocked, sensory neuron release glutamate onto interneturon (modulatory interneuron) which releases serotonin onto axon terminal of sernsory neuron from syphon (axoaxonic synapse) - this axoaxonic synapse causes more glutamate to be released every time there was AP in sensory neuron from syphon - after sensitization AP in terminal of Sensory neuron from syphon AP is broader and more Ca coming in - serotonin from interneuron bind to serotonin receptor on sensory neuron which activates enzyme (adenylyl cyclase) which breaks down ATP into cAMP which activates protein kinase A (phosphorylates voltage gated K channel) . this phosphorylation of K channel reduces probability that K channel will open (causes prolonged falling phase in AP) leading to more glutmate causing sensitization • Rat hippocampus: important in memory - different regions have excitatory projection that play an important role in memory (increase in synaptic strength) - CA3 pyramidal neurons go to CA1 pyramidal neuron (neurons are called Shaffer collaterals) - delivering a tetanus stimuliation in pathway 1 before single shock causes a higher magnitude EPSP in single shock in path way 1 - if delivering a tetanus to pathway 1, and single shock to pathway 2 single shock causes normal EPSP (this is caused LTP specificity) - associativity: when giving tetanus to pathway 1, if you give weak stimulation to pathway 2 then both pathways will strengthen - cooperativity: if pathway 1 and pathway 2 are weakly stimulated repeatedly, over the course of time both pathways will become strengthened - when postsynaptic neuron Is stimulated at same time as pre synaptic neuron LTP occurs - dendritic spine of post synaptic pyramidal cell receives glutamate - spines have 2 types of glutamate receptors: AMPA and NMDA. NMDA binds glutamate and is blocked by magnesium ion - for magnesium ion to unblock NMDA, glutamate must be binded to NMDA receptor and the dendrite must be depolarized to cause the Mg to be repelled and it pops out of channel - Sodium, Potassium, and Calcium can flow through NMDA. Calcium creates LTP - in specificity: a lot of glutamate is released (by pathway 1) and whole neuron is deporlarized (pathway 2 is not strengthened because no glutamate at pathway 2) - in associativity: whole synaptic cell is depolarized (
More Less

Related notes for BIOL 4370

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.