Module B-08 Flashcards
Define: Synaptic Plasticity
- Lingering event-related changes in synaptic efficacy
- variable postsynaptic responses to specific synaptic inputs
Molecular /physiological (cellular changes) representation of a memory is called_______
Engram
Role of Hippocampus in memory
Consolidating factual information throughout cerebral cortex
What parts of brain are involved in acquisition of motor skills?
cerebellum and basal ganglia work in concert with the frontal lobes
How are short term memories encoded?
Transient changes in synaptic function through altered metabolism
How are long term memories encoded?
permanent alteration of cellular function, with protein expression and even cellular structure being altered
3 types of memories to encode
- Factual
- Sensory
- Motor
Acquired pathological deficits of memory are called _______
Amnesias
Acquired pathological deficits in memory are caused by either
– Losses of engrams (deficit in initial storage)
– Failures in accessing engrams
Region of brain involved in formation and maintenance of long-term memory for FACTS.
The hippocampus and surrounding parahippocampal structures
Describe structure of Hippocampus
contains a collection of transversely oriented parallel processing units (lamellae).
Describe pathway of Hippocampal neurons
- Efferents of the entorhinal region of the parahippocampal gyrus relay information into the granule cells forming the dentate gyrus.
- The dentate gyrus then projects to pyramidal cells of CA3, which then project to the pyramidal cells of CA1.
- CA1 then projects through the subiculum and back to the entorhinal cortex.
- This largely excitatory feedback system is thus well suited to reverberatory processing of information.
- CA1 also projects through the fimbria and fornix to the mammillary bodies of the hypothalamus, which communicate with the cerebral cortex via the thalamus
the hippocampus demonstrate synaptic
plasticity in response to electrical stimulation of _______
Afferents
2 types of synaptic responses in Hippocampus due to synpatic plasticity
1) Long-term potentiation (LTP) - With high-frequency
stimulation
2) Long-term depression (LTD)- following low-frequency electrical stimulation
How do High frequency stimulation of CA1 cause Long term potentiation?
1) substantial increase in intracellular [Ca2+]
2) activate kinases that alter the phosphorylation of key proteins for LTP
How do LOW frequency stimulation of CA1 cause Long term depression?
1) smaller rise in intracellular [Ca2+].
2) different enzymes, protein phosphatases, are activated
3) dephosphorylation of proteins, including those forming AMPA receptors. LTD results
Which are the receptors in the hippocampus and cortex that mediate Calcium influx?
NMDA
Activation of which receptors mediate plasticity in NMDA receptor independent regions?
metabotropic glutamate receptors