mcdb 322 Exam 3 Questions And Answers Practice Questions with Solutions Newest | Already Graded A+

mcdb 322 Exam 3 Questions And Answers Practice Questions with Solutions Newest | Already Graded A+ Patient H.M. - Answer- Bilateral hippocampal lesions caused profound anterograde amnesia (inability to form new declarative memories) while retaining retrograde memories. Habituation (Aplysia) - Answer- Weakening of the gill withdrawal reflex after repeated gentle taps to the siphon. Sensitization (Aplysia) - Answer- A massive, exaggerated withdrawal response to a gentle tap after being paired with a noxious stimulus (tail shock); classical conditioning. Heterosynaptic Facilitation - Answer- Activating one pathway (e.g., tail shock) artificially strengthens the synaptic connection in a completely separate, intersecting pathway. Short - Answer- term Sensitization Mechanism - L29 neuron releases 5HT - activates adenylate cyclase - increases cAMP - activates PKA - closes K+ channels - prolongs action potential - more Ca2+ enters - increased neurotransmitter release. Long - Answer- term Sensitization Mechanism - PKA translocates to the nucleus and phosphorylates CREB, driving new gene transcription and structural changes. Induction vs. Maintenance - Answer- Induction is the short-term trigger (e.g., Ca2+ influx); Maintenance is the long-term stabilization requiring new protein synthesis. Hippocampal Circuitry - Answer- Entorhinal Cortex - Dentate Gyrus (via Perforant Path) - CA3 (via Mossy Fibers) - CA1 (via Schaffer Collaterals). Classic LTP (Location & Mechanism) - Answer- Occurs at Schaffer Collateral to CA1 synapses; strictly postsynaptic. NMDA Receptors (in Classic LTP) - Answer- Act as coincidence detectors requiring both Glutamate binding AND postsynaptic depolarization to remove the Mg2+ block, allowing Ca2+ influx. CaMKII (in Classic LTP) - Answer- Activated by Ca2+/Calmodulin; phosphorylates existing AMPA receptors and drives insertion of new AMPA receptors. Alternative LTP (Location & Mechanism) - Answer- Occurs at Mossy Fiber to CA3 synapses; strictly presynaptic and NMDA-independent. Alternative LTP (Signaling) - Answer- Relies on presynaptic Ca2+ influx - activates adenylate cyclase - increases cAMP - PKA activation - long-term increase in glutamate release. mEPSP Frequency vs. Amplitude - Answer- Increased frequency = presynaptic change (more vesicles); Increased amplitude = postsynaptic change (more/better receptors). Occlusion - Answer- When a synapse is already maximally potentiated, applying a stimulus produces no further LTP. Silent Synapses - Answer- Synapses with only NMDA receptors (no AMPA); "unsilenced" during LTP by the insertion of AMPA receptors. Dendritic Spines - Answer- Remodel constantly (CA1 spines last 1-2 weeks); LTP enlarges/forms them, LTD shrinks/eliminates them; requires transcription/translation. Morris Water Maze - Answer- Tests hippocampus-dependent spatial memory by having a rodent find a hidden, submerged platform using room cues. Place Cells vs. Grid Cells - Answer- Place cells (Hippocampus/CA1) fire in specific locations; Grid cells (Entorhinal Cortex) fire in a hexagonal pattern to map space. Engram Neurons - Answer- The specific ensemble of neurons activated during learning; can be tagged using a c-fos promoter and optogenetics (like ChR2). Creating False Memories - Answer- Done by tagging engram neurons in a safe context and optogenetically reactivating them with light while the animal is shocked in a different context. Multiple Trace Theory - Answer- Suggests the hippocampus is still capable of participating in remote memory recall because the engram expands over time, opposing the Standard Model. Three Tests for Sleep - Answer- 1) Homeostatic rebound, 2) Increased arousal threshold, 3) Circadian timing. Two - Answer- Process Model - Process S is the homeostatic drive (slow-wave activity); Process C is the circadian drive governed by the SCN. Brainstem Arousal Pathways - Answer- Ascending pathways that keep the brain awake; cutting above the brainstem causes a permanent coma.