9.2.1 Stages Of Sleep And Brain Mechanisms 2 Flashcards
People who are awakened during OEM reported ____ 80% to 90% of the time. Later research, however, found that people also sometimes report dreams when awakened from NREM sleep.
dreams
REM dreams are more likely than NREM dreams to include striking ____ ____ and ____ ____, but not always. REM and dreams usually overlap, but they are not the same thing.
visual imagery and complicated plots
A cut through the midbrain decreases arousal by damaging the ____ ____, a structure that extends from the medulla into the forebrain.
reticular formation
Some neurons of the reticular formation have axons ascending into the brain, and some have axons descending into the spinal-cord. Those with axons descending into the spinal-cord form part of the ____ ____ of ____ ____.
medial tract of motor control
One part of the reticular formation that contributes to cortical arousal is known as the ____.
pontomesencephalon
The term ____ describes the widespread connections among neurons in this system.
reticular
These neurons in the reticular formation receive input from many ____ ____ and generate spontaneous activity of your own.
sensory systems
The axons of the neurons of the reticular formation extend into the forebrain, releasing ____ and ____, which excites cells in the hypothalamus, thalamus, and basal forebrain.
acetylcholine and glutamate
The pontomesencephalon maintains ____ during wakefulness and increases it in response to new or challenging tasks. Stimulation of the pontomesencephalon awakens a sleeping individual or increases alertness in one already awake.
arousal
The ____ ____, a small structure in the pons, is usually inactive, especially during sleep, but it emits burst of impulses in response to meaningful events, especially those that produce emotional arousal.
locus coeruleus
Axons from the locus coeruleus release ____ widely throughout the cortex, so this tiny area has a huge influence. Anything that stimulates the locus coeruleus strengthens the storage of recent memories and increases wakefulness.
norepinephrine
The hypothalamus has several axon pathways that influence arousal. One pathway releases the neurotransmitter ____, which produces excitatory effects throughout the brain. Cells releasing histamines are active during arousal and alertness.
histamine
_____ drugs, often used for allergies, counteract the transmitter histamine and produce drowsiness. Antihistamines that do not cross the blood-brain barrier avoid that side-effect.
Antihistamine
Another pathway from the hypothalamus, mainly from the lateral and posterior nuclei of the hypothalamus, releases a peptide transmitter called either ____ or ____.
orexin or hypocretin
The axons releasing orexin extend to the basal forebrain and other areas, where they stimulate neurons responsible for wakefulness. Orexin is not necessarily for waking up, but it is for ____ ____.
staying awake
Drugs that block orexin receptors increase sleep, and procedures that increase orexin lead to increased ____ and ____.
wakefulness and alertness
Other pathways from the lateral hypothalamus regulate cells in the ____ ____ (an area just anterior and dorsal to the hypothalamus). Basal forebrain cells provide axons that extend throughout the thalamus and the cerebral cortex.
basal forebrain
Some of the axons from the basal forebrain release ____, which is excitatory and tends to increase arousal. Acetylcholine is released during wakefulness and REM sleep, but not during slow-wave sleep.
acetylcholine
During wakefulness, the release of acetylcholine sharpens _____ – that is, it increases the accurate, reliable detection of sensory stimuli.
attention
GABA is the brains of main _____ transmitter.
inhibitory
____ is responsible for sleep. During sleep, body temperature and metabolic rate decrease slightly, as does the activity of neurons, but by less than we might expect.
GABA
Spontaneously active neurons continue to fire at close to the usual rate, and neurons in the brains sensory areas continue to respond to sounds and other stimuli. Nevertheless, we are unconscious. The reason is that GABA inhibits ____ ____.
synaptic activity
When a neuron is active, the increased GABA levels cut the activity short and prevent axons from spreading stimulation to other areas. When stimulation doesn’t spread, you don’t become ____ of it.
conscious
Because sleep depends on ____ ____, it can be local within the brain. That is, you might have substantial inhibition in one brain area and not so much in another. Ordinarily, different brain areas wake up and go to sleep at almost the same time, but not necessary.
GABA-mediated inhibition
Thinking of sleep as a local phenomenon helps make sense of some otherwise puzzling phenomena. Take, for instance, ____. Almost by definition, a sleepwalker is awake in one part of the brain and sleep another.
sleepwalking
REM sleep is associated with a distinctive pattern of high-amplitude electrical potentials known as ____ ____, for pons-geniculate-occipital.
PGO waves
Most adults need about ________ of sleep per night, but some have been known to get by with a little three hours per night.
7 1/2 to 8 hours
Ambg people who ordinarily get more than the typical 7 1/2 to 8 hours of sleep, some are better than others at withstanding a temporary lack of sleep. People who tolerate ____ ____ relatively well are usually “evening people”, who like to awaken late and stay up late.
sleep deprivation
The best gauge of ____ – inadequate sleep – is how someone feels the following day. If you feel tired during the day, you’re not sleeping enough at night.
insomnia
Causes of insomnia include noise, uncomfortable temperatures, stress, pain, diet, and medications. Insomnia can also be the result of epilepsy, Parkinson’s disease, brain tumours, depression, anxiety, or other ____ or ____ conditions.
neurological or psychiatric
