Flashcards in Chapter 56 (memory) Deck (22):
What is short term memory?
Includes memories that last for seconds or at most minutes unless they are converted into longer-term memories.
What is intermediate long-term memory?
Lasts days-weeks but then fade away
What is long-term memory?
Once stored they can be recalled for years to a lifetime
What is declarative memory?
Memories of various details of an integrated thought, such as memory of an important experience that include:
• Memory of the surroundings
• Memory of time relationships
• Memory of causes of the experience
• Memory of the meaning of the experience
• Memory of one’s deductions that were left in the persons mind.
I would say these memories are ones like your first break-up. You’ll remember all those things above in detail (at least I do... That bitch.)
What are skill memories?
These are motor activities of the person’s body, such as hitting a tennis ball:
• Sight of the ball
• Calculate the relationship and speed of the ball to the racquet
• Deduce rapidly the motions of the body, arms, and the racquet required to hit the ball as desired.
What is habituation?
the brains capability to ignore information that has no consequence by the inhibition of synaptic pathways.
What are memory traces?
new or facilitated pathways of synaptic transmission between neurons as a result of previous neural activity (memory).
What is sensitization?
the result of facilitation of the synaptic pathways for important stimuli to store as memories.
What are the 2 causes of short-term memories?
circuits of reverberating neurons and pre0synpatic facilitation/inhbiition
What are reverberating circuits?
Continual neural activity resulting from nerve signals that travel around and around a temporary memory trace.
What is pre-synaptic facilitiation or inhbiiton?
this is at synapses that lie on pre-synaptic terminal nerve fibrils. The neurotransmitter chemicals secreted at such terminals frequently cause facilitation or inhibition which lasts from seconds-minutes.
What are the causes of long term memories?
Results from temporary chemical or physical changes, or both, in either the synapse pre-synaptic terminals or the synapse postsynaptic membrane.
The changes in these terminals can persist for a few minutes up to several weeks.
What happens with habituation and sensory loss in memory processing?
o When the sensory terminal is stimulated repeatedly without simulation of the facilitator terminal, signal transmission is good at first but dissipates with repeated stimulation.
How does noxious stimuli from a facilitator neuron cause long term memory?
when a noxious stimulus excites the facilitator terminal at the same time that the sensory terminal is stimulated, instead of the transmitted signal becoming weak, the ease of transmission becomes stronger and stronger. This lasts for minutes-3 weeks.
What is the reason why habituation (densitization) happens?
o As talked about before, the effect in the sensory terminal results from progressive closure of the Ca++ channels through the terminal membrane. What causes the Ca++ channel closure? No one knows.
o Nonetheless, much smaller than normal amounts of Ca++ enter the habituated terminal and much less sensory terminal transmitter is therefore released.
Give me the 5 mechanism steps on how facilitation works to cause long term memories
1. Stimulation of the facilitator presynaptic terminal at the same time that the sensory terminal is simulated causes serotonin release at the facilitator synapse onto the sensory terminal.
2. Serotonin binds to serotonin R’s Gs activation cAMP
3. The increase in cAMP stimulates a protein kinase blocks the K+ channels K+ conductance decreases for several minutes-weeks
4. Lack of K+ causes a greatly prolonged AP in the synaptic terminal because K is necessary for rapid recovery from the AP.
5. Prolonged AP causes prolonged activation of Ca++ channels more Ca++ enters the sensory synaptic terminal more NT release more facilitation onto the subsequent neuron.
So when you think of long-term memory mechanisms, which NT should u be thinking about?
Real long term memory (like remembering events from your childhood) are a result of what change?
result from actual structural changes at the synapse instead of just chemical changes
What are the mechanisms to change the terminal structurally for long term memories?
increasing the vesicle release sites, # of transmitter vesicles released, # or presynpatic terminals, or just changes in structures of the dendrites to permit transmission of stronger signals.
What is the theory behind the # of neurons and long term memories?
When you’re developing from birth you make a crazy amount of neurons, but many fail to connect with appropriate subsequent neurons and dissolute within a few weeks.
Thus, the # of neuronal connections, and therefore memory, is determined by specific nerve growth factors released retrogradely from the stimulated cells.
Either you use it or lose it.
What is the mechanism ot cause anterograde amnesia (short term memory loss)?
o The hippocampus is the most medial portion of the temporal lobe Cx. Lesion here causes the inability to store verbal and symbolic types of long-term memories. They also can’t store immediate memory lasting longer than a few minutes.
The hippocampus is among the most important output pathways from the “reward” and “punishment” areas of the limbic system. Therefore, there is no drive in the brain to remember those painful or pleasurable experiences or thoughts that are either pleasant or unpleasant.