Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
L&M: Neurobiology
Neurobiology ch. 25
| Question | Answer |
|---|---|
| Procedural memories are more amenable to investigation than declarative memories. Why? | they are robust memories that can be formed along simple reflex pathways that link sensations to movements |
| procedural learning involved learning a motor response (procedure) in reaction to a sensory input, and is typically broken down into 2 categories: | nonassociative learning and associative learning |
| nonassociative learning describes what? | the change in the behavioral response that occurs over time in response to a single type of stimulus |
| What are two types of nonassociative learning? | habituation and sensitization |
| habituation | learning to ignore a stimulus that lacks meaning. |
| sensitization | learning to intensify your response to all stimuli, even the ones that previously evoked little or no reaction |
| associative learning | form associations between events |
| What are two types of associative learning? | classical conditioning and instrumental conditioning |
| classical conditioning | associating a stimulus that evokes a measurable response with a second stimulus that normally does not evoke this response |
| classical conditioning: unconditional stimulus (US) | no training (conditioning) is required to yield a response (Pavlov's meat) |
| classical conditioning: conditional stimulus (CS) | requires training (conditioning) before it yields a response (Pavlov's bell) |
| instrumental conditioning | an individual learns to associate a response, a motor act, with a meaningful stimulus, typically a reward such as food |
| Which invertebrate has been particularly important in the study of the neurobiology of learning? | Aplysia californica, the sea slug |
| nonassociative learning was studied in the aplysia using the ____-_____ reflex | gill-withdrawal reflex |
| How many neurons mediate the gill withdrawal reflex in Aplysia? | Two, the siphon sensory neuron and the motor neuron L7 |
| What causes habituation in the gill withdrawal reflex in Aplysia? | The presynaptic terminal of the sensory neuron releases fewer quanta each time it is repeatedly activated |
| what is the underlying mechanism for habituation of the gill withdrawal reflex in Aplysia | Adaptation of the voltage-gated calcium channels in the synaptic terminal, resulting in fewer quanta being released |
| How many neurons are involved in the sensitization of the gill withdrawal reflex in Aplysia? | More than three, but the synaptic interconnections of the siphon sensory neuron, L29, and L7 are where the sensitization occurs |
| How is the interneuron L29 wired into the gill withdrawal reflex circuit in Aplysia? | It is presynaptic to the gill muscle, in parallel with the siphon sensory neuron |
| What neurotransmitter is released by the interneuron L29 to sensitize the gill withdrawal reflex in Aplysia? | serotonin (5-HT) |
| What is the mechanism for serotonin to cause sensitization of the gill withdrawal reflex in Aplysia? | Serotonin activates the adenylyl cyclase cascade that phosphorylates a potassium channel and prolongs the action potential |
| What pharmacological agents might you expect to block sensitization of the gill withdrawal reflex in Aplysia? | A serotonin release blocker |
| When Aplysia is subjected to a gentle water jet to the siphon and a strong shock to the tail, the result is what? | classical conditioning |
| Classical conditioning of the gill withdrawal gives a greater response with paired stimuli because why? | when both neurons were stimulated, adenylyl cyclase increases which generates cAMP which means more activation |
| In classical conditioning of the gill withdrawal response in Aplysia, what constitutes learning? | presynaptic calcium pulse coincides with G-protein-coupled activation of adenylyl cyclase |
| In classical conditioning of the gill withdrawal response in Aplysia, what constitutes memory? | potassium channels are phosphorlyated and neurotransmitter release is enhanced |
| Summarize what was learned from invertebrate studies of the neural basis of memory | L&M can result from modifications of synaptic transmission, synaptic modifications can be triggered by the conersion of neural activity into intracellular 2nd messengers, and memories can result from alterations in existing snynaptic proteins |
| Who discovered long-term potentiation (LTP) in the hippocampus? | Bliss and Lømo |
| LTP | high-frequency stimulation of an excitatory pathway to the hippocampus produces long lasting enhancement in the strength of the stimulated synapses. |
| information flow through hippocampus | 1. entorhinal cortex via the perforant path --> dentate gyrus 2. dentate gyrus granule cells emit mossy fibers that synapse of pyramidal neurons in CA3. 3. CA3 axons, called Schaffer collaterals, synapse on pyramidal neurons in CA1 |
| How would you characterize LTP in pyramidal cells of CA1 of the hippocampus? | A burst of activity from any input fibers to the cell makes the cell more responsive to any subsequent input |
| How long does the LTP in neurons of CA1 in the hippocampus last? | weeks or longer |
| What is the excitatory neurotransmitter used in the hippocampus? | Glutamate |
| BMC Theory (named after its 3 authors) | snyapses that are active when the postsynaptic cell is only weakly depolarized by other inputs will undergo LTD instead of LTP |
| What did BMC theory inspire? | search for LTD in CA1 |
| LTD and LTP are both triggered by what? | postsynaptic Ca2+ entry through the NMDA receptor |
| phosphorylation as a LTM mechanism is problematic for two reasons: | phosphorylation of protein is not permanent and protein molecules themselves are not permanent (lifespan) |
| phosphorylation of synaptic proteins, and memory, could be maintained if what? | the kinases were made to stay "on" all the time (normally they are only "on" in the presence of 2nd messengers) |
| Ca2+ entry into the postsynaptic cell and activation of ______ are required for the induction on LTP in CA1 | CaMKII |
| the hinge-like subunit of CaMKII is normally off when what? | the catalytic region is covered by the regulatory region |
| the hinge opens on activation of the molecule by Ca2+ bound ________, freeing the catalytic region to phosphorylize proteins | calmodulin |
| a large elevation of Ca2+ can cause what? | phosphorylation of one subunit by another, enabling the catalytic region to stay on permanently (autophosphorylating protein kinase) |
| What happens when a "knock out" mouse is missing the gene for the alpha subunit of CaMKII? | There are deficits in LTP in the hippocampus and corresponding memory deficits |
| What happens if mice are genetically modified so that they have more NMDA receptors than normal mice have? | They have enhanced learning and memory capabilities at many tasks |
| What do transcription factors do? | Regulate gene expression |
| one transcription factor is called cyclic AMP response element binding protein (CREB). CREB is a protein that does what? | binds to specific segments of DNA (CREs) and functions to regulate the expression of neighboring genes |
| two forms of CREB: what does CREB-2 do? | represses gene expression |
| two forms of CREB: what does CREB-1 do? | activates transcription, but only when it is phosphorylated by protein kinase A |
| Tully and Yin showed that CREB regulates the gene expression required for ________ ____________ in the fruit fly drosophila | memory consolidation |
| What molecular mechanism might control the strength of a memory? | How much CREB is produced |
| What is the clearest correlate of long-term memory in Aplysia? | increased number of synapses |
| Which cAMP response element-binding protein activates gene expression? | CREB-1 after it is phosphorylated |
| What is the effect on the number of synapses made by the sensory neuron in the Aplysia gill withdrawal reflex when long-term sensitization occurs? | The number of synapses is doubled |
Created by:
cmccartney2