Chapter 8; Wakefulness and Sleep

The axons releasing ________ extend from the hypothalamus to the basal forebrain and many other areas, enhancing wakefulness.

orexin

Melatonin is released by the ________ .

pineal

The ________ , which contributes significantly to cortical arousal, has neurons that receive input from many sensory systems and generate spontaneous activity of their own.

pontomesencephalon

alpha waves

relaxation

The main driver of rhythms for sleep and body temperature is the ________ .

suprachiasmatic nucleus

What is an endogenous rhythm? Why are endogenous rhythms important for animals, including humans?

Animals readiness for a change in seasons comes partly from internal mechanisms. A self generated rhythm, generated from within.

Describe how humans progress through the stages of non-REM and REM sleep throughout the night. When is REM sleep predominant?

Over the course of about 90 minutes a sleeper goes through stages 1, 2, 3, and 4 and then returns to stages 3 and 2 to a stage called REM. REM is characterized by rapid eye movements, more brain activity than other sleep stages, complete relaxation of the trunk muscles, irregular breathing and heart rate, penile erection or vaginal lubrication, and increased probability of vivid dreams. To determine REM sleep: Examine EEG patterns, and eye movements. REM becomes more common towards the end of the night's sleep. Toward the morning REM occupies an increasing percentage of the time.

How long is the rhythm period generated by the human circadian clock when it has no external cue to set it?

People can adjust to a schedule off by a small amount of time pretty easily. Bodies generate rhythms of alertness and body chemistry that average about 23.4 to 24.4 hours, therefore a rhythm period of about 24 hours.

Why did psychologists in the early to mid-part of the 20th century resist the notion that wake and sleep cycles are generated from within the body?

When radical behaviorism dominated experimental psychology during the mid-1900s, many psychologists believed that every behavior could be traced to external stimuli.

Which perspective regards dreams as thinking that takes place under unusual conditions?

clinico-anatomical hypothesis

The ________ is usually inactive, especially during sleep, but it emits bursts of impulses in response to meaningful events.

locus coeruleus

Sleep spindles

12 to 14 Hz brain waves in bursts that last at least half a second. stage 2

Discuss the biological functions of REM sleep, including David Maurice's hypothesis related to eye movements.

David Maurice proposed that REM just shakes the eyeballs back and forth enough to get sufficient oxygen to the corneas of the eyes. The corneas, unlike the rest of the body, get oxygen directly from the surrounding air. During sleep, because they are shielded from the air, they deteriorate slightly. When eyes are motionless, that fluid becomes stagnant. According to this view; REM is a way of arousing a sleeper just enough to shake the eyes back and forth.

What is the relationship between REM sleep and dreaming?

Dreams begin with bursts of spontaneous activity in the pons, the PGO waves previously described- that activate parts of the cortex but not others. REM sleep (which accompanies most dreams), your motor cortex is inactive and your major postural muscles are virtually paralyzed. During REM sleep activity increased in the pons (which triggers the onset of REM sleep) and the limbic system ( which is important for emotional responses). REM sleep is associated with a distinctive pattern of high-amplitude electrical potentials known as PGO waves. a lot of dreaming happens during REM, but dreaming can occur during other sleep stages

What happens to human motor function during REM sleep?

During REM sleep your motor cortex is inactive and your major postural muscles are virtually paralyzed. That is, when you are dreaming (in REM cycle), you really cannot move.

What is paradoxical about paradoxical sleep?

Example: during certain periods of apparent sleep, the cat's brain activity was relatively high, but their neck muscles were completely relaxed. Paradoxical sleep is paradoxical ("apparently self-contradictory") because it is deep sleep in some ways(relaxed muscles) and light(high brain activity) in others. Researchers use the term REM sleep when referring to humans, but often prefer the term paradoxical sleep for non human species that lack eye movement.

Activation synthesis hypothesis:

Idea that a dream represents the brain's effort to make sense of sparse and distorted information.

Clinico-anatomical hypothesis:

Idea that considers dreams as a type of thinking that occurs under unusual conditions.

Discuss the relationship between sleep and memory, including REM sleep.

If people learn something and then go to sleep, or even take a nap, their memory often becomes better than it was before the sleep. Sleep also helps reanalyze their memories. Patterns that occurred during sleep resembled those that occurred during learning, except that they were more rapid during sleep. The amount of hippocampal activity during sleep correlated highly with the subsequent improvement in performance. REM is important for memory storage, especially for weakening the appropriate connections.

Name the five important functions of sleep listed by Kalat. What likely hypothesis is given by Kalat for the original function of sleep?

Rest our muscles Decrease metabolism Perform cellular maintenance in neurons Reorganize synapse Strengthen Memories Sleeps original function- and still an important one- is to SAVE ENERGY.

Endogenous (Circadian):

Self-generated rhythm that lasts about a day.

Endogenous (Circannual):

Self-generated rhythm that lasts for about a year.

Melanopsin

Surprising explanation is that the retinohypothalamic path to the SCN comes from a special population of retinal ganglion cells that have their own photopigment

Zeitgeber

The stimulus that resets the circadian rhythm. Meaning "time giver". Light is the dominant zeitgeber for land animals.

Dreamlike experiences, which an individual has trouble distinguishing from reality and often occur at the onset of sleep, are known as ________ .

hypnagogic hallucinations