Sleeping and Waking
What receptor does caffeine block (or what neurochemical is involved)?
Adenosine receptors
True of false: only the pons is active during REM sleep
True
True or false: Classical and operant conditions are forms of associative learning
True
True or false: Associative memory includes habituation and sensitization
False
True or false: touching the mantle of the aplysia will trigger the gill-withdrawal reflex
False
- touching the siphon triggers the reflex
What stimuli interact with internal biological clocks to maintain circadian rhythms?
Zeitgebers
True or false: only the preoptic area is active during NREM
Describe the factors in Pavlov's experiment (US, UR, CS, CR)
US: food
UR: salivation elicited by food
CS: bell
CR: salivation elicited by bell
What is operant conditioning? How do reinforcement and punishment work?
- reinforcement: increases likelihood of behavior repeating
- punishment: reduces likelihood of behavior repeating
Fill in the blank
Input from the rhinal cortex travels via the __ to the dentate gyrus.
From the dentate gyrus, where does the info travel?
Perforant pathway
Mossy fibers of dentate gyrus synapse onto cells of CA3
The SCN communicates with what gland to regulate synthesis of what hormone?
Pineal gland, melatonin
Describe the sleep cycle
NREM: stages 1-4
- stages 1 and 2 are light sleep; stage 2 has sleep spindles and K complexes
- parasympathetic nervous activity
Cycle: stages 1-4, then stages 4-1, then REM sleep
- repeats 4-5 times per night, lasting 90-110 minutes
What are the three critical steps in memory processing?
Encoding: transformation of input into a form the brain can process further
Consolidation: organization of memory info into more long-term storage
Retrieval: recovery of stored info (which become vulnerable to modification and must be reconsolidated)
What are the differences between short-term, sensory, and long-term memory?
Sensory memory: holds large quantities of info for several seconds
Short-term memory: holds limited quantities of info for limited periods of time
- about 5-9 items for up to about 15 seconds
Long-term memory: holds unlimited amounts of info for unlimited periods of time
- retrieval from here to short-term memory
How do NMDA receptors facilitate LTP?
NMDA receptors facilitate associativity and cooperativity
- after AMPA receptors remove Mg2+ block and glutamate binds to NMDA receptor, Na+ and Ca2+
- Ca2+ stimulates biochemical cascades within the cell which initiates structural changes necessary to strengthen the synapse (and stabilize it)
What neurotransmitters and neurochemicals are involved in waking? Which ones are involved in sleep?
Waking: cortisol, acetylcholine, histamine, serotonin, hypocretin
Sleep: melatonin, adenosine
How does the raphe nuclei interact with the preoptic area?
During waking, raphe nuclei inhibits preoptic area from triggering sleep via serotonin release
Before falling asleep, the raphe nuclei no longer inhibits the preoptic area and now the preoptic area can inhibit waking areas to trigger sleep (NREM sleep specifically)
- the preoptic area is now disinhibited
Long-term memory includes what other forms of memory?
Declarative: explicit or unconscious, easy to discuss verbally
- semantic: basic knowledge of facts and language
- episodic: personal experiences
Non-declaractive: implicit or unconscious, hard to talk about verbally but easy to demonstrate
- procedural: stores info about motor skills and procedures
- also includes classical conditioning and priming
How does habituation occur in the aplysia?
Repeated stimulation to the siphon causes sensory neuron to release less transmitter onto the interneurons
Interneurons release less transmitter onto motor neuron
Motor neuron releases less transmitter onto gill, which now demonstrates weak withdrawal reflex
Describe the GluA1 and GluA2 receptors of working memory
GluaA1 receptors are inserted into postsynaptic cell during the initial, unstable phase following an LTP stimulus
GluA2 receptors become more important during the later, more stable phases
In genetically engineered mice lacking GluA1 receptors, memories are less stable
- rodents lacking GluA1 receptors made many errors in the radial arm maze, and so insertion of GluA1 receptors into postsynaptic membrane must be important for working memory
Waking: reticular formation in the midbrain, reticular formation in the medulla, basal forebrain, locus coeruleus, raphe nuclei; preoptic area is less active; reticular formation in pons is INactive
NREM: preoptic area is active; locus coeruleus and raphe nuclei are less active
REM: only pons is active
Describe each of the sleeping and waking disorders
Insomnia: issues falling asleep (most common disorder)
Narcolepsy: extreme levels of sleepiness while awake
Hypopnea: shallow breathing or low rate of breathing while asleep
Apnea: almost complete lack of breathing while asleep
Obstructive sleep apnea hypopnea: common in obese individuals
Central sleep apnea: deficits in brain activity that maintain breathing during sleep
SIDS: sleeping position has been implicated
Sleep talking and sleep walking
REM sleep behavior disorder: absence of normal REM paralysis so individuals can act out their dreams
Restless leg syndrome: tingling and interval movement of limbs
How does the aplysia demonstrate classical conditioning?
US: electrical shock to the tail
UR: gill-withdrawal reflex elicited by shock
CS: slight touch of the mantle shelf
- mantle shelf normally does not cause a withdrawal response
CR: gill-withdrawal reflex elicited by touch to mantle shelf
How does sensitization occur in the aplysia?
The tail of the aplysia is shocked. After this, sensory neuron in the tail releases transmitters onto interneuron
Interneurons release serotonin, causing siphon sensory neurons to release increased amounts of transmitter onto motor neuron
Motor neuron releases larger amounts of transmitter onto gill which demonstrates a stronger withdrawal reflex
Name and describe the four stages of LTP
1. generation (1 minute)
- Ca2+ enters the cell
- additional AMPA receptors are inserted into postsynaptic cell so glutamate can continue to bind
2. stabilization (15-20 minutes)
- Ca2+ levels continue to increase and more AMPA comes to surface
- spine is enlarged of postsynaptic cell (larger spines contain more glutamate receptors and are less vulnerable to pruning
3. consolidation (2-4 hours)
- BDNF produces sustained Ca2+ release
- protein synthesis contributes to stability
4. maintenance (indefinite)
- protein kinase M zeta prevents the (normal) removal of AMPA receptors from the synapse
- note: chemicals that inhibit protein kinase M zeta also prevent long term potentiation maintenance