L7 Sleep, Decision-Making

Question 1

Circadian cycle

Answer 1

evolved to maintain appropriate daily rhythms and hmeostatic functions with variable daylight in variable seasons

Question 2

Cells of Circadian Cycle

Answer 2

Photosensitive ganglion cells that detect the cues for the clock

contain photopigment called melanopsin and are depolarized by light

help to encode illumination, allow for reset of circadian clock

project to the suprachiasmatic nucleus (SCN), which controls the circadian cycle

Question 3

Melatonin

Answer 3

produced by the pineal gland
modulates neural activity by activating melatonin receptors on neurons in SCN

Question 4

Orexin

Answer 4

promotes wakefulness, from the hypothalamus

Question 5

Suprachiasmatic nucleus

Answer 5

governs physiologic responses associated with sleep wake cycle including BP, hormone secretion, body temp, urine output

Question 6

Even with light cues removed…

Answer 6

individuals present with a 24 hour clock

Question 7

Sleep

Answer 7

defined behaviorally by the normal suspension of consciousness and electrophysiologically by specific wave critera

Question 8

Sleep deprivation

Answer 8

can be deleterious and even fatal
can also call mood swings, hallucinations

Question 9

Sleep is not just a downregulation of brain activity…

Answer 9

series of precisely controlled physiological states governed by brainstem nuclei

high levels of brain activity occurs

Question 10

Amount of sleep required

Answer 10

Adults: 7-8
Teens: 9
Babies: more

Question 11

Sleep debt

Answer 11

getting too little sleep that has to be made up

judgement, reaction time, memory, cognitive, other functions are impaired

Question 12

What are the purposes of sleep?

Answer 12

1. Energy conservation
2. Memory Consolidation
3. Metabolic wastes cleared from brain
4. We are dependent on visual info to find food, need to avoid predators

Question 13

Energy conservation and sleep

Answer 13

sleep replenishes brain glycogen levels
minimize heat loss by dropping body temp
metabolism is decreased during slep

Question 14

Fatal Familial Insomnia

Answer 14

Genetic disorder that causes death within several years of onset, unable to enter REM sleep

Question 15

Stage 2 Sleep

Answer 15

further decrease in frequency of EEG waves and increase in the amplitude, also has high frequency spike clusters called sleep spindles

Question 15

Stages of Sleep

Answer 15

defined by the amount of electroencephalographic energy recorded

Question 15

Stage 1 Sleep

Answer 15

Drowsy period
decrease in EEG frequency, increased amplitude

Question 15

Sleep Spindles

Answer 15

periodic bursts of activity at about 10 to 12 Hz that generally last 1 to 2 seconds and arise as a result of interactions between thalamic and cortical neurons

Question 16

Stage 3 Sleep

Answer 16

moderate to deep sleep
number of sleep spindles decreases
amplitude of EEG increases, frequency decreases

Question 16

Stage 4 Sleep

Answer 16

deepest level of sleep
low level of EEG frequency, high amplitude fluctuations (delta waves)
takes about an hour to reach this stage

Question 16

Slow wave cycle

Answer 16

Stage 3 and Stage 4

Question 17

Non-REM sleep

Answer 17

Stages 1-4

Question 18

REM Sleep

Answer 18

EEG recordings are similar to as when you are awake
after about 10 minutes in REM, the brain cycles to the other 4 stages
about 4 periods of REM sleep occur

Question 19

Stage 1 Physiological Changes

Answer 19

slow, rolling eye movements
decrease in muscle tone, body movements, heart rate, breathing, BP, metabolic rate, temperature

(reach their lowest values in stage 4)

Question 20

REM Sleep Physiological Changes

Answer 20

increases in BP, HR, metabolism
rapid ballistic eye movements, pupillary constriction, paralysis, twitching of smaller muscles
Dreams occur during REM

sleep walking and sleep talking do not occur in REM, are not motivated by dreams

Question 21

Prefrontal Cortex of Frontal Lobe

Answer 21

helps with decision-making/thinking/planning
difficult to identify the flow of information through the PFC

Question 22

Rough Path of input to output in prefrontal cortex

Answer 22

1. Info about sensory stimuli is conveyed to orbitofrontal cortex
2. This info flows rostrally and laterally to other lateral and medial PFC
3. Then the resulting signals flow to other PFC regions that use info to plan possible responses
4. Signals are sent to premotor and parietal cortexes, then other cortical regions that help with behavior, which are influenced by dopamine, serotonin

Question 23

Orbitofrontal Cortex

Answer 23

-OFC receives input from all major modalities, has few motor connections
-Receives input from hippocampus and m. temporal lobe (memory storage and retrieval)
-Input from reward related dopamine neurons in midbrain

Question 24

OFC output

Answer 24

-OFC provides output to systems that help with selection and execution of behaviors

Question 25

OFC Purpose

Answer 25

-helps us to perform estimation of the value of an option based on past and present information
-helps shape associations among objects, actions, consequences
-integrates info about prior experiences to help determine value of different choices
-subjective value: value can change with other sensory inputs, like fullness

Question 26

Common currency theory

Answer 26

the OFC and the ventromedial prefrontal cortex make use of a universal value that allows comparison of any decision

Question 27

Actually making a choice

Answer 27

occurs after evaluation and requires values of each of the options
the vmPFC and the OFC show systematic changes when the values of multiple options are maintained

Question 28

Lesions of the vmPFC

Answer 28

deficits in comparing values of different options
buying a car–the individual wouldn’t be able to figure out between price, styling, mileage, etc

Question 29

Dorsolateral Prefrontal Cortex

Answer 29

1. Communicates with reward related regions like the OFC and anterior cingulate cortex, premotor cortex, parietal areas
2. Changes in firing rate are matched with changes in rules that govern effective behavior

Damage: when the rule is changed, individuals continue with the one that they learned. Impairments of short term memory

Question 30

Cingulate Cortex

Answer 30

1. Might be the source of error-related negativity
2. Concerned with consequences of choosing an option than by the nature of the option or its value
3. Helps us to learn from our consequences
4. Generation of feedback signals that help to update goals and adapt new rules
5. Detects the need to change
6. Helps with conflicting action plans that are activated at the same time

Question 31

Error-related negativity

Answer 31

observed in standard lab tasks immediately after an individual commits an error, changes in levels of dopamine when an error is committed

Question 32

Cingulate Cortex lesions

Answer 32

lead to impairments in learning from consequences of actions

Question 33

OCD

Answer 33

associated with atypical levels of activity in the anterior cingulate cortex
overly sensitive to stimuli
self-doubt
Illogical acts

Question 34

Ventrolateral Prefrontal Cortex

Answer 34

1. Self-control
2. Damage to this area causes impulsivity. Tourettes, OCD, depression are examples

Question 35

Anterior Insula

Answer 35

1. Uses body stats to regulate behavior
2. Associated with emotional awareness and expression. Attention, love, time perception, music
3. Can play a role in gambling and drug addiction

Question 36

Posterior Cingulate Cortex

Answer 36

1. Self-Awareness
2. Has slow long lasting fluctuations with reduced activity during performance of tasks, high activity between trials
3. Not exactly clear as to what the role is, possibly involved in default mode network
4. Active during daydreaming, distracted
5. Info about self, like autobiographical memory, thinking about your future, considering others in relatin to yourself

Damage: Alzheimer’s disease