Exam 4 (Final) Flashcards
What is typically measured in a sleep lab?
brain waves, muscle activity, eye movement
What is the rhythm for the waking state?
Beta, small-amplitude with a fast frequency (15-30Hz)
What is the rhythm for the relaxed state?
Alpha, large amplitude, slow frequency (7-11Hz)
What is the rhythm for the drowsy state?
Theta, slower frequency (4-7 Hz)
What is the rhythm for the sleeping state?
Delta, slow, large waves (1-3 Hz)
What type of rhythm is seen in REM sleep?
fast waves
What are the stages of sleep and how are they distributed?
Stages 1-4, predominantly non-REM sleep, alternate cycles roughly every 90 min
How does age affect sleep?
Waking increases and REM decreases
What happens during N-sleep?
Talking or grinding teeth, kicking a foot, temp decreases
What are some theories as to why we dream?
Freud: symbolic fulfillment of unconscious wishes
Jung: expressions of our “collective unconscious”
Why might sleep have evolved?
energy-conserving strategy, sleep during times they cannot travel as easily
How can you support an adaptational view of sleep?
Prey sleep less than predators
What is the basic rest-activity cycle?
recurring cycle of temporal packets, about 90 min periods in humans, during which an animal’s level of arousal waxes and wanes
Pros and cons of the theory of sleep being restorative?
Pros: chemical events that provide energy to cells are reduced during waking and are replenished during sleep; shown by semi-homeostatic regulation of sleep
Con: fatigue and alertness may simply be aspects of the circadian rhythms and have nothing to do with wear and tear on the body
What are the effects of sleep deprivation?
no marked physiological effects, at least in the periods studied (up to 18 days); does lead to decreased cognitive performance
What is the role of sleep and memory storage?
sleep plays a role in solidifying and organizing events in memory
What is consolidation?
process of stabilizing a memory trace after learning
What is reconsolidation?
process of restabilizing a memory trace after the memory is revisited
What are the theories of memory storage in sleep?
Multiple Process Theories: different kinds of memories are stored during different sleep states
Sequential Process Theory: memory is manipulated in different ways during different sleep states
Storage Process Theories: brain regions that handle different kinds of memory during waking continue to do so during sleep
What is the role of the reticular activating system?
stimulation produces a waking EEG; damage to it produces a slow-wave EEG and can result in a coma
What is the role of the basal forebrain in EEG changes?
contains cholinergic cells that secrete ACh onto neocortical neurons that stimulate a waking EEG when animal is still and alert
What is the role of the median raphe nucleus (midbrain) in EEG changes?
Contains serotonin neurons that project widely
throughout the neocortex; when stimulated,
neocortical cells produce a waking EEG when the
animal is moving
What is the role of the peribrachial area in REM sleep?
cholinergic nucleus in the dorsal brainstem has a role in R-sleep behaviors; projects to the medial pontine reticulum
What is the role of the medial pontine reticular formation (MPRF)?
nucleus in the pons participates in R-sleep; projects to several other brain areas that produce REM-related behaviors (atonia)
What happens if there is damage to the peribrachial area of the MPRF?
loss of REM sleep
What is insomnia?
disorder of slow-wave sleep resulting in prolonged inability to sleep
What is drug-dependency insomnia?
condition resulting from continuous use of “sleeping pills”; drug tolerance also results in deprivation of either REM or NREM sleep, leading the user to increase the dosage
What is narcolepsy?
slow-wave sleep disorder in which a person uncontrollably falls asleep at inappropriate times; may be due to mutations in the gene that produces hypocretin/orexin peptides
What is sleep apnea?
inability to breathe during sleep; person has to wake up to breathe
What is a conditioned stimulus?
cue the predicts an unconditioned stimulus
What is an unconditioned stimulus?
biologically important stimulus that elicits an unconditioned response
What is an unconditioned response?
innate response to something like food or pain
What is a conditioned response?
the learned response to a formerly neutral conditioned stimulus
What is the CS and US in the eyeblink conditioning test?
Tone - CS
Air puff - US
Describe implicit memory?
unconscious memory; subjects can demonstrate knowledge but cannot explicitly retrieve the information
Describe explicit memory?
conscious memory; subjects can retrieve an item and indicate that they know that the retrieved item is the correct item
What is the difference in encoding for implicit and explicit memory?
Implicit is processed “bottom-up”
Explicit is processed “top-down”
What is involved in short-term memory?
information held only briefly then discarded; involves frontal lobes
What is involved in long-term memory?
held indefinitely; involves the temporal lobe
How are memories stored?
information from each sensory modality is processed and stored in different neural areas
What is episodic memory?
autobiographical memory for events pegged to specific place and time contexts
What is episodic amnesia?
inability to recall any personally experienced events; associated with frontal lobe injuries or reduced blood flow to the frontal lobes
What happened to patient H.M.?
had no explicit memory after surgery; could still recall memories from childhood; implicit memory was unaffected
What brain areas are thought to have been affected in H.M.?
entorhinal cortex, hippocampus, amygdala
What happened to patient J.K.?
developed Parkinson’s (damage to basal ganglia) resulting in impaired implicit memory
What are the prime structures for explicit learning?
Medial temporal region (hippocampus, amygdala, entorhinal cortex, parahippocampal cortex, perirhinal cortex)
Frontal cortex
What is the role of the hippocampus in spatial memory?
serves as the basis for visuospatial memory; lesions to this area cause difficulty locating objects
How does hippocampal size vary in animals?
those with good spatial memory (animals who store food) have larger hippocampi than those who don’t
What is the reciprocal neural circuit for explicit memory?
the neocortex projects to the entorhinal cortex which projects back to the neocortex
Benefits: keep the sensory experience “alive” in the brain
What is the role of the frontal lobe in short-term memory?
all sensory systems project to the frontal lobes; involved in working memory
What is Korsakoff’s Syndrome?
permanent loss of the ability to learn new information (anterograde) and to retrieve old information (retrograde) (although unusual to cause both); caused by diencephalic damage from chronic alcoholism or malnutrition that produces a vitamin B1 deficiency
What is the role of the hippocampus in explicit memory?
consolidates new memories; once consolidate, no longer needed
What is the neural circuit for implicit memory?
basal ganglia, ventral thalamus, substantia nigra, premotor cortex
Is the implicit memory neural circuit unidirectional or bidirectional? What does this mean?
Unidirectional; you do not know what you know until you do it
What is the pathway of the implicit memory neural circuit?
basal ganglia receive input from the entire neocortex and send projections first to the ventral thalamus and then to the premotor cortex
What is emotional memory and what structure is the most important?
memory for the affective properties of stimuli or events; can be implicit or explicit; amygdala is critical
Describe Long-term Potentiation (LTP).
in response to stimulation at a synapse, changed amplitude of an excitatory postsynaptic potential that lasts for hours to days or longer; plays a part in associative learning
How do you measure LTP?
stimulating electrode; field potential recording electrode
Describe long-term depression (LTD).
decrease in EPSP size; could be a mechanism for clearing out old memories; neuron becomes less active in response to repeated stimulation; requires Calcium entry
What two types of receptors act on the postsynaptic membrane?
AMPA - normally responds to glutamate
NMDA - double gated channels, normally blocked by Mg ions
What must happen for NMDA receptors to open?
- Depolarization of postsynaptic membrane, displaces Mg from pore (strong electrical stimulus)
- Activation by glutamate from the presynaptic neuron (weak electrical stimulus)
- Strong and weak stimuli have been paired
What happens after NMDA receptors are open?
Ca enters the postsynaptic neuron, altering it
Increased responsiveness of AMPA receptors to glutamate; formation of new AMPA receptors; retrograde messengers that trigger more glutamate release from presynaptic neuron
What is the evidence for neurogenesis in adult brains?
olfactory bulbs, hippocampal formation, and possibly the neocortex
How do you show neurogenesis?
done with stain Brdu, which can only be taken up when cells are dividing; use NeuN stain for neuronal tissue; when the two stains show on the same neuron that means a new neuron was created
What are the effects of enriched environments on the brain?
increased brain weight, more dendrites, more astrocytes, more capillaries, increased mitochondrial volume; NOT an increase in neuron number