Midterm 4 - PSY 403

What are endogenous circadian rhythms?

internal mechanisms that operate on an approximately 24-hour cycle​

What are some things that the endogenous circadian rhythm control?

-sleep cycle

-frequency of eating and drinking

-body temperatures

-hormone secretion

-urination

-sensitivity to drugs

Zeitgeber

a stimulus that resets the circadian rhythm

What are some examples of zeitgeber?

-sunlight

-ocean tides

-exercise

-meals

-arousal of any kind

-temperature of environment​

What are some effects of using something other than sunlight as a zeitgeber​?

Depression, irritability, and impaired job performance

If you work irregular shifts is there anything you can do to minimize that impact?​

People adjust best to night work if they sleep in a very dark room during the day and work under very bright lights at night​

What is the superchiasmatic nucleus (SCN)?

The main control center of the circadian rhythms of sleep and temperature

Where is the SCN located?

above the optic chiasm and part of the hypothalamus ​

What are the effects of damage to the SCN?

Damage to the SCN results in less consistent body rhythms that are no longer synchronized to environmental patterns of light and dark​​

How is the SCN related to circadian rhythms?

-SCN generates circadian rhythms in a genetically controlled, unlearned manner​

-Single cells extracted from the SCN and raised in tissue culture continue to produce action potentials in a rhythmic pattern​

Where does the SCN get its input from?

the optic nerve

What is the retinohypothalamic path?

The retinohypothalamic path comes from a special population of ganglion cells that have their own photopigment called melanopsin​

How are the SCN and the retinohypothalamic path related?

Light resets the SCN via a small branch of the optic nerve (the retinohypothalamic path​)

-Travels directly from the retina to the SCN

What are some genes involved in generating the circadian rhythm? How do they do that?

PER and TIM produce proteins that accumulate during the day until they cause sleepiness​

What does melatonin do?

Melatonin is a hormone that increases sleepiness

How does melatonin work?

-The SCN regulates the pineal gland, an endocrine gland located posterior to the thalamus​

-The pineal gland secretes melatonin

How has the electroencephalogram (EEG) helped researchers to discover that there are various stages of sleep?

The EEG allows researchers to compare brain activity at different times during sleep​

What is a polysomnograph?

A combination of EEG and eye-movement records ​

Relaxation and Stage 1 Sleep

-Alpha waves are present when one begins a state of relaxation

-stage 1 sleep is when sleep has just begun

-The EEG is dominated by irregular, jagged, and low voltage waves​ and brain activity begins to decline​

Stage 2 sleep

Characterized by the presence of sleep spindles and K-complexes.

sleep spindles

12- to 14-Hz waves during a burst that lasts at least half a second​

K complex

a sharp wave associated with temporary inhibition of neuronal firing​

Slow Wave Sleep—Stage 3 and Stage 4​

Stage 3 and stage 4 together constitute slow wave sleep

-EEG recording of slow, large amplitude wave​

-Slowing of heart rate, breathing rate, and brain activity​

-Highly synchronized neuronal activity​

Paradoxical or REM Sleep​

REM sleep: characterized by rapid eye movements during sleep

Paradoxical sleep: deep sleep in some ways, but light sleep in other ways​

-EEG waves are irregular, low-voltage, and fast​

-Postural muscles of the body are more relaxed than other stages​

In what order do sleep cycles occur?

stages 1, 2, 3, and 4, then 4, 3, 2, and REM

How long does each sleep cycle usually last?

approximately 90 minutes

What stage of sleep is dreaming strongly associated with?

REM sleep is strongly associated with dreaming but people have reported dreaming throughout other stages as well.

what happens to the pons and limbic system during REM sleep?

The activity increases in the pons and limbic system

-Pons sends messages to the spinal cord, which inhibits motor neurons that control the body's large muscles

-Activity decreases in the primary visual cortex, the motor cortex, and the dorsolateral prefrontal cortex​

What are PGO waves?

Waves of neural activity in the pons, then lateral geniculate of the hypothalamus, then occipital cortex​

-high-amplitude electrical potentials

What stage of sleep is associated with PGO waves?

REM sleep is associated with a distinctive pattern of PGO waves

What might result from deprivation of REM sleep?

REM deprivation results in a high density of PGO waves during uninterrupted sleep​

What is insomnia?

A sleep disorder associated with inadequate sleep​

What causes insomnia?

-Caused by a number of factors, including noise, stress, pain, diet, and medication​

-Can also be the result of disorders such as epilepsy, Parkinson's disease, depression, anxiety or other conditions​

-Dependence on sleeping pills or alcohol and shifts in the circadian rhythms can also result in insomnia​

What is sleep apnea?

A sleep disorder characterized by the inability to breathe while sleeping for a prolonged period of time​

What are the causes and effects of sleep apnea?

Causes: genetics, hormones, old age, obesity and deterioration of the brain mechanisms that control breathing ​

Effects: sleepiness during the day, impaired attention, depression, and sometimes heart problems​, cognitive impairment may also result​

What is narcolepsy?

A sleep disorder characterized by frequent periods of sleepiness​

-Attacks of sleepiness during the day​

-Occasional cataplexy: muscle weakness triggered by strong emotions​

-Sleep paralysis: inability to move while falling asleep or waking up​

What causes narcolepsy?

Caused by lack of hypothalamic cells that produce and release orexin​

-Orexin regulates arousal, wakefulness, and appetite​

What are some possible treatments of narcolepsy?

Primary treatment is with stimulant drugs (i.e., Ritalin), which increase wakefulness by enhancing dopamine and norepinephrine activity​

What is parasomnia?

A sleep disorder that may involve abnormal movements, behaviors, emotions, perceptions and dreams​

What causes parasomnia?

-Can be triggered by anxiety, fatigue, fever, medications​

-Usually occurs after quick, incomplete arousal from NREM sleep in the first third of sleep period​

-Engage in automatic behaviors and lack conscious awareness or memory​

-Cerebellum, posterior cingulate, and brainstem are awake, while cortex, anterior cingulate, and cerebrum are asleep​

what are some functions of sleep?

-Resting muscles​

-Decreasing metabolism​

-Performing cellular maintenance in neurons ​

-Reorganizing synapses​

-Strengthening memories​

how is energy conservation accomplished?

-Decrease in body temperature of about 1-2 Celsius degrees in mammals​

-Decrease in muscle activity​

Why shouldn't you stay up all night studying during finals?​

Performance on a newly learned task is often better the next day if adequate sleep is achieved during the night​

What does the the Activation-Synthesis Hypothesis suggest?

it suggests that dreams begin with spontaneous activity in the pons, which activates many parts of the cortex​

-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​

What does the Neurocognitive Hypothesis​ suggest?

-Places less emphasis on the pons, PGO waves, or even REM sleep​

-Suggests that dreams are similar to thinking, just under unusual circumstances​

-Also says dreams begin with stimuli that are generated within the brain​

-Stimulation is combined with recent memories and information from the senses​

-Because the brain is getting little information from the sense organs, images are generated without constraints or interference​

-Lack of sensory input from V1 and no criticism from the prefrontal cortex creates the hallucinatory perceptions​

-Activity in the prefrontal cortex is suppressed, which impairs working memory during dreaming​

Unresponsive wakefulness syndrome (formerly known as vegetative state)

eyes are open, but only reflexive behavior​

Minimally conscious state

nonreflexive movements, visual fixation and pursuit, follow commands​

Locked-in syndrome

unable to move any muscles, but fully conscious with normal sleep-wake-cycles​

What does the James-Lange theory of emotion suggest?

-Suggests that autonomic arousal and skeletal action occurs first in an emotion​

-The emotion felt is the label we give the arousal of the organs and muscles​

Event occurs -> we interpret the event -> we respond to the event -> we feel the emotion ->

What is an example of the James-Lange theory of emotion?

You encounter a scary snake and realize that it poses a threat to you, you decide to run away and then feel fear.

What is the evidence against the James-Lange theory of emotion?

Research findings - people who have been paralyzed report feeling the same degree of emotion as before being paralyzed

Pure autonomic failure: Output from autonomic nervous system to body fails​, people with this condition report feeling same emotions, but less intensely​. This also suggests other factors are involved in the perception of emotion​

What is the evidence in favor of the James-Lange theory of emotion?

Botox: people with botox injections report weaker than usual emotional responses after watching short videos​. This Implies body change is important part of feeling an emotion​.

Pencil smiling thing: people report feeling happier after putting a pencil between their teeth (it forces a smile)

What are the functions of emotion?

-Emotions help communicate needs to others​ and understand others' needs​

-Aid in quick decision making​

-Emotion has adaptive value (fear leads to escape, anger leads to attack)

How do genes impact aggressive behavior?

-Twin studies indicate significant amount of heritability although there is some debate about experimental design​

-MAOa gene—low activity form shows a link to aggression​

(MAOa breaks down serotonin, norepinephrine and dopamine)​

How does environment impact aggressive behavior?

-Witness or victim of violence in childhood​

-Living in a violent neighborhood​

-Abused children are more likely to express violent behavior​

-Exposure to lead can harm developing brains​

What is the interaction between genes and the environment in regards to violent behavior?

Men who experienced childhood maltreatment were more likely to engage in antisocial behaviors and have lower MAOa levels.

What is the evidence that testosterone is related to aggressive behavior"?

-Giving women doses of testosterone resulted in more arguing during collaborative tasks

-Male prisoners convicted for violent crimes (rape, murder, etc) tended to have higher testosterone levels

What is the evidence that serotonin is related to aggressive behavior?

Low serotonin turnover found in people with history of violent behavior ​

-Relationship between serotonin and aggression is small​

What is the relationship between testosterone, serotonin, and aggression?

Aggressive behavior does not correlate strongly with any one chemical because it depends on a combination​. Aggressive behavior depends on ratio of testosterone to cortisol​

-Testosterone facilitates aggressive, assertive, dominant behavior​

-Serotonin tends to inhibit impulsive behaviors​

-Cortisol inhibits aggression​

What is the startle reflex?

Auditory information stimulates an area of the pons that commands tensing of neck and other muscles​

-Information reaches the pons within 3-8 milliseconds ​

-Startle response occurs within two-tenths of a second​

-Startle reflex is more vigorous if already tense​

-Startle reflex can be used as a behavioral measure of anxiety​

How does the human amygdala respond to visual stimuli?

fMRI studies show the amygdala responds strongly to photos that arouse fear or photos of faces showing fear​

-Response is stronger when the meaning is unclear and requires some processing​

-Responds more strongly to an angry face directed toward the viewer and frightened faces directed elsewhere​

What are the effects of damage to the amygdala?

In humans, amygdala damage does not result in the loss of emotion​

-Individuals can classify emotional pictures without difficulty​

-Individuals experience little arousal from viewing unpleasant photos​

What is Urbach-Wiethe Disease​

A rare genetic condition that causes calcium to accumulate in the amygdala until it wastes away​

What are the effects of Urbach-Wiethe Disease?

Case study of person called SM​ showed that she:

-Experiences fearlessness​

-Correctly drew faces with various emotions but had trouble drawing a fearful face​

-Did not generally look at people's eyes​

-Lack of fear is dangerous to her​

What is panic disorder?

-Frequent periods of anxiety and occasional attacks of rapid breathing, increased heart rate, sweating, and trembling​

-More common in women than men, and in adolescents and young adults​

-Possible genetic component​

-Linked to hypothalamus abnormalities​

-Decreased GABA, increased orexin​

What is PTSD?

-Frequent distressing recollections and nightmares about traumatic event​

-Vigorous reactions to noises and other stimuli​

-Not all people who endure trauma get PTSD​

-Smaller hippocampus may predispose people to PTSD​

What are benzodiazepines?

-The most commonly used anti-anxiety drugs​

-Examples: diazepam (Valium), alprazolam (Xanax)​

-Bind to the GABAa receptor, and facilitate the effects of GABA​

-Exert their effects in the amygdala, hypothalamus, midbrain, and other areas​

-Alcohol effects on GABA receptors responsible for the anti-anxiety and intoxicating effects​

What is the HPA axis comprised of?

Hypothalamus, pituitary gland, and the adrenal cortex

How does the HPA axis react in stress?

-The HPA axis becomes the dominant response to prolonged stressors​

-Activation of the hypothalamus induces the pituitary gland to secrete adrenocorticotropic hormone (ACTH)​

-Stimulates the adrenal cortex to secrete cortisol​

-Cortisol helps to mobilize energies to fight a difficult situation​

What are the effects of prolonged stress?

-Produces symptoms similar to depression​

-Weakens the immune system​

-Can harm the hippocampus​

-Toxins or overstimulation more likely to damage or kill neurons in the hippocampus​

What is classical conditioning?

Pairing two stimuli creates new response to one of the stimuli​

Equipotentiality

-proposed by Lashley

-All parts of the cortex contribute equally to complex functioning behaviors (learning)

Mass action

-proposed by Lashley

-The cortex works as a whole, and more cortex is better

What is an engram?

A physical representation of what has been learned

-Lashley worked to search for an engram

What area of the brain did Lashley focus on?

The cortex

-He cut lesions into rats' cortexes but no cut impaired their learning, but making lots of cuts did impair their performance

Where did Richard Thompson suggest classical conditioning occur?

Thompson suggested that classical conditioning is located in the cerebellum

Describe Richard Thompson's study for engram searches

He focused on eyelid response in rabbits by pairing a puff of air with a bell tone. The rabbits learned to blink when they heard a bell tone.

What were the two relevant brain regions for classical conditioning?

Lateral interpositous nucleus and the red nucleus

What is the red nucleus?

The red nucleus is responsible for the output of learning (physical response), it is part of the midbrain, gets input from cerebellum

What happened when Thompson inactivated the red nucleus after training

When the red nucleus was inactivated (by cooling or with drugs) there was no behavioral response to the training BUT once the area recovered from cooling/drugs, the rabbit immediately shows learned response

What is the Lateral interpositus nucleus?

The area responsible for learning, it is part of the cerebellum, cells show little response to tone before training, response increased with training

What happened when Thompson inactivated the lateral interpositus nucleus after training?

When the Lateral interpositus nucleus was inactivated (by cooling or with drugs), there was no behavioral response to training BUT when the area recovered from cooling/drugs there was no indication the rabbit had learned

What is short term memory?

memory of events that have just occurred

What is long term memory?

memory of events that occurred further back in time

How do short- and long-term memory differ?

Short term memory has a limited capacity while long term does not, short term memory fades quickly without rehearsal while long term persists, memories from long term memory can be stimulated with a cue/hint while the retrieval of short term memory do not benefit from the presence of the cue

What is consolidation?

to strengthen a memory or make it more long-lasting

What was the original idea behind consolidation?

The original idea was that information enters short term storage, then was consolidated to become long term

What are some cautions of consolidation?

Many short term memories are not on their way to becoming long term memories, memory influenced by emotion (emotional memories form quickly), memories that are consolidated can still change

What areas of the brain are involved in consolidation?

The hippocampus is important for consolidation and memories are then stored in cortex

What is some evidence behind the brain regions involved in consolidation?

fMRI studies showed that after 15 minutes, the hippocampus was activated but after 24 hours, the cerebral cortex

What did fMRI studies show of progressively older events?

Older events produced more activity in cortex and less in hippocampus/amygdala

What is explicit memory?

A type of long term memory, deliberate recall of information that you recognize as a memory

-episodic and semantic memory

What is episodic memory?

memories of single personal events

What is semantic memory?

memories of facts independent of context

What is Implicit memory

A type of long term memory, influence of experiences on behavior even if you don't recognize that influence

-procedural memory

What is procedural memory?

Development of motor skills and habits

In simple terms, what is amnesia?

memory loss

What is anterograde amnesia?

the inability to form new memories of events that occur AFTER the brain damage

What is retrograde amnesia?

the loss of memory for events that occurred BEFORE the brain damage

What did H.M experience after having had his hippocampus removed?

H.M's intellect and language ability were still intact and his personality was largely the same, he had anterograde amnesia for declarative memories, still had few but weak new semantic memories and severe impairment for new episodic memories (he could not describe any experience after his surgery. His short term memory was still intact and his procedural memory was nearly intact