Cellular and molecular LTD Flashcards
Where can we find long-term depression ?
LTD is most intensively studied
in the hippocampus and cerebellum
What is required for Hippocampal LTD ?
NMDA receptors
What prevents LTD induction?
Introducing inhibitors of calmodulin into the postsynaptic neuron
What is required for LTD ?
Protein Phosphatases
Hippocampal LTD
contributes to ?
Behavioural flexibility
Ca2+ ions entering through
NMDARs bind ?
To CaM
The Ca2+/CaM complex activates ?
Protein phosphatases
PP2B (a.k.a. Calcineurin) is directly activated by ?
Low nanomolar concentrations of Ca2+/calmodulin
PP2A is also required for LTD
although ?
It’s mechanism of activation is not so well understood
PP1 and PP2A sustain their
activity by ?
Autocatalysis
Activated PP1 dephosphorylates?
GluA1, TARP and PSD-95
What does activated PP1 also dephosphorylate ?
GSKβ
GSKβ regulates ?
The internalisation of AMPARs by endocytosis
Ca2+ flux through NMDA receptor channel determines ?
The sign of plasticity
Ca2+ flux through NMDA receptor channel determines?
- LFS is low frequency stimulation (e.g. 1 Hz)
- STDP is Spike Timing Dependent Plasticity
- DHPG is a mGluR agonist
Explain the Parallel fibres in the cerebellum ?
- Motor information input travels from the spinal
cord, cerebral cortex and vestibular system via
mossy fibers → major pathway of information flow - Granule cells relay signals to Purkinje cells.
- A single parallel fibre forms 1-5 excitatory synapses
onto a Purkinje cell dendrite - Many parallel fibres make synaptic contacts onto a
single Purkinje cell
Explain the Climbing fibres in the cerebellum ?
- A single climbing fibre forms > 300 excitatory
synapses onto a Purkinje cell - Arises from neurons in the inferior olivary nucleus.
- When motor information is associated with
failure, an ‘error’ signal conveyed by the climbing
fibre weakens the connection between parallel
fibers and the Purkinje cell that contributed to the
failed action → achieved by Long-term depression
What is the only output of the cerebellar cortex ?
Purkinje cells
It is a GABAergic neuron that forms ?
Inhibitory synapses on neurons in a cerebellar and
vestibular nucleus
What do Parallel fibre synapse (PFs) activate ?
AMPA and mGluR1 but not IP3 receptors
PF and CF synapses
together trigger ?
Activation of IP3R
In the PFs, what does Ca2+ activate ?
PKC and phosphorylates GluA2 with the help of PICK1
In the PFs, AMPARs with
phosphorylated GluA2
dissociate from ?
GRIP
AMPA receptors at the
PF synapse are
internalized by ?
Endocytosis
