Behavioral Neuroscience Chapter 8.3

Functions of sleep

1) some of the many functions of sleep include:
- resting m……
- decreasing met…….
- performing cellular maintenance in neu….
- reorganizing syn…..
- strengthening memor…

Why sleep? Why REM? Why dreams?

1) we’ve evolved mechanisms to force us to s….
2) inhibitory processes in our brains force us to become less a…… And less alert, and thus to sl…

Sleep and energy conservation

1) the original function of sleep was probably to conserve e…..
2) conservation of energy is accomplished via:
- decrease in body temperature about ?-? Celsius degrees in mammals
- decrease in mus… Activity

Hibernation is analogous to sleep

1) decrease in body t………. to only slightly above that of the environment
2) heart rate and brain activity drop to almost n……
3) neuron cell bodies shrink, and dendrites lose almost a f….. Of their branches
- replace later when body temperature in…….

Some facts about hibernation

1) Bear “hibernation” is not as extreme as that of smaller hibernators such as bats and ground squirrels
2) hibernating animals come out of hibernation for a few h…. Every few d…
3) hibernation retards the a…. Process
4) hibernation is also a period of relative invulnerability to inf…… And trauma

Species differences in sleep

1) animals sleep habits are influenced by particular aspects of their life including:
- whether they are pre….. Or pr..
- how many hours they spend each day devoted to looking for f…

-safety from predators while they sleep
Sleep patterns of Dolphins, migratory birds, and swifts

Sleep and memory
Sleep=critical to memory!!!

1) sleep also plays an important role in enhancing L……. and s………… Memory
- performance on a newly learned task is often better the next day if adequate sleep is achieved during the night
2) increased. Rain activity occurs in the area of the brain activated by a newly learned ta.. While one is as….

Sleep and memory

1) patterns of activity in the hippocampus during learning were similar to those shown during s….
- suggests that the brain replays its daily experiences during sleep
2) the brain strengthens some syn….. And weakens others during sleep
3) sleep spindles increase in number after new L…….: correlated with nonverbal IQ

Amounts of REM Sleep

1) humans spend one-t…. Of their life asleep; about one-f…. Is spent in REM
2) species vary in amount of sleep time spent in REM
- most common in bi… And mam….
- percentage of REM sleep is positively correlated with the total amount of sleep in most animals
- among humans, those who get the most sleep have the highest percentage of REM

Functions of REM Sleep

1) research is inconclusive regarding the exact functions of REM
2) during REM:
- the brain may discard useless conn…….
- learned motor skills may be consolidated
3) Maurice (1998) suggests the function of REM is simply to shake the eyeballs back and forth to provide sufficient oxy… To the corneas

Biological perspectives on dreaming

1) biological research on dreaming is complicated by the fact that subjects cannot often accurately remember what was dreamt
2) two biological theories of dreaming include:
- the activation synthesis hy……..
- the clinico-anatomical hypothesis

The activation-synthesis hypothesis

1) suggests that dreams begin with spontaneous activity in the PO.., which activates many parts of the cor…
- the cortex synthesizes a story from the pattern of activation
- normal sensory information is sometimes integrated, but usually is not
- when dreaming, you really can’t move, this is also a common dream

The clinico-anatomical hypothesis

1) places less emphasis on the p…, PGO waves, or even REM Sleep
2) suggests that dreams are similar to thi….., just under unusual circumstances

3) similar to the activation synthesis hypothesis is that dreams begin with arousing stimuli that are generated within the b….
- stimulation is combined with recent memories and information from the senses

The clinico-anatomical hypothesis

1) because the brain is getting little information from the sense organs, images are generated without const…… Or inter…….
2) arousal cannot lead to actions as the primary motor cortex and the motor neurons of the spinal cord are supp……
3) activity in the prefrontal cortex is suppressed, which impairs working memory during dre…..

The clinico-anatomical hypothesis conditions

1) activity is high:
-in the inferior part of the parietal cortex, an area important for visual-spatial perception
Patients with damage report problems in binding body sensations with vision and have no dr….

• in areas outside of V1, accounting for the visual imagery of dr….

• in the hypothalamus and amygdala,which accounts for the emoti…. And moti…….. Content of dreams

The clinico-anatomical hypothesis summary

1) either internal or external stim……. Activates parts of the parietal, occipital, and temporal cortex
2) lack of sensory input from V1 and no criticism from the prefrontal cortex creates the hallucinatory perceptions