Final Flashcards
Sleep, Neuropsychological Assessment, Dementia and Multiple Sclerosis
What is chronobiology?
The study of biological rhythms
What are biological rhythms?
Inherent timing mechanisms that control various biological processes –> Circadian rhythm
What drives behaviour in biological rhythms?
External cues i.e. Sunlight, and internal cues i.e. melatonin
What are the 4 biological rhythms?
Circannual –> yearly, i.e., bird migration
Circadian –> daily, i.e., sleep-wake cycle
Ultradian –> less than a day, i.e., eating cycles
Infradian –> more than a day, i.e., menstrual cycle
What are free running rhythms?
Rhythm that the body devises in absence of all external cues, for example sleeping patterns when deprived of sunlight and darkness.
What are zietgerbers?
A cue from the environment that signals a “reset” in the biological rhythm, i.e., light and dark
What is suggested to be the neural basis of the biological clock?
The suprachiasmatic nucleus, located at the base of the hypothalamus.
What happens if the superchiasmatic nucleus is damaged or disrupted?
Damaged: Issues with timing of daily activities
Disrupted: Issues with length and timing of sleep
Where does the suprachiasmatic nucleus receive its information?
The retinohypothalamic tract –> light signals the release of excitatory neurotransmitters to entrain the rhythmic activity of the SCN
How does the Suprachiasmatic nucleus control our biological rhythms?
By giving input about the appropriate timing of behaviours through the circadian timing system
What is the circadian timing system?
The control of behaviours by slave oscillators that affect another behaviour.
How can we objectively measure sleep?
Recording equipments such as polysomnography through electroencephalogram, electromyogram and electrooculogram.
How do the three measures of polysomnography work?
Electronic equipment records readouts from electrodes attached to the sleeper. (A) EEG made from a point on the skull relative to a neutral point on the ear. (B) EMG made between two muscles, such as those on the chin and throat. (C) EOG made between the eye and a neutral point on the ear.
What are the 5 stages of sleep?
W – Waking
N1 - NREM stage 1
N2 - NREM stage 2
N3 - NREM stage 3
R-sleep – REM
What rhythm is active during the Waking state?
Beta rhythms, but may also produce alpha rhythms when relaxed
What occurs during non-rem sleep 1 (NREM1)?
Sleep onset–> Moves from beta activity to theta-wave activity
What occurs during non-rem sleep 2 (NREM2)?
Asleep –> Theta-waves, sleep spindles and k-complexes
What occurs during non-rem sleep 3 (NREM3)?
Deep sleep–> Difficult to arouse and groggy when woken up, delta rhythms
What occurs during r-sleep (REM sleep)?
Atonia, EEG pattersns are similar to the beta, alpha and theta-wave activity (possibly because they are dreaming)
What is characteristic of a typical night’s sleep?
Progressing through the sleeping stages in order, replacing the W-stage with REM as the cycle reverses.
What is a somnogram?
A sleep graph of an individual’s sleep cycling throuhgh their stages in the night.
What is true about sleep patterns as humans age?
Time asleep tends to decrease, REM sleep makes up less of that sleep too
What are some feats of NREM sleep (all stages)?
Maintain muscle tone – can sleep in various postures/positions
Body temperature and heart rate drop; growth hormone release increases
Can talk in our sleep, grind our teeth, flail our limbs – restless leg syndrome
Sleepwalking occurs
Dreaming can occur, though it is usually less vivid than during REM
Can have lucid dreaming during NREM, where we are aware of the dreams as we dream them.
What are some feats of REM sleep?
Our eyes move.
Our toes, fingers, and mouth will twitch.
Erections in males – regardless of whether accompanying dreams had sexual content in them or not
Mechanisms that regulate body temperature stop.
Body temperature moves toward whatever the room temperature is, so you might wake up extremely cold or extremely hot…
Experience paralysis and atonia.
What are two psychoanalytic theories of dreams?
Freud: Dreams are the symbolic fulfillment of unconscious desires and wishes; often emphasising sexual desires and wishes
Jung: Dreams allow us to relive the memories/history of the human race - our “collective unconscious”
What does recent research suggest about dreams?
Dreams are related to recent events and tend to concern ongoing problems in our lives
What is the activation-synthesis hypothesis of dreaming (as a means of meaningless brain activity)?
Cortex produces characteristic patterns of waking EEG during REM, which generates random meaningless dreams.
What does sleep accomplish?
Sleep serves as an energy-conserving strategy. The brain is a major user of the body’s energy supply, so decreasing brain activity by sleeping can help conserve this energy.
What is some evidence for the energy-conservation theory of sleep?
Animals sleep during non-optimal times
What is true about average sleep time in animals?
Total sleep times differ between species, and largely reflects the amount of time required to obtain food and by their risk of predation.
Why is sleep a restorative process?
Chemical processes in our bodies that provide energy to cells are depleted during waking periods and are replenished during sleep.
What is REM sleep deprivation and its effects?
Subjects take less time than usual to get back to REM sleep
The “need/pressure/desire” for the brain to enter REM sleep increases – “REM rebound”
What is REM rebound?
When finally given the chance to enter REM sleep subjects spend almost double the amount of time in REM than normal.
Why is sleep a factor in memory storage?
Sleep helps solidify and organize our memories and allows for better memory retention.
Place cells (hippocampal neurons for spatial memory) fire during sleep as a “remembering and replaying” event.
What is the role of melatonin on the neural basis of sleep?
Hormone secreted from the pineal gland of the brain in response to darkness that causes sleepiness
What is the role of the Reticular Activating System on the neural basis of sleep?
Associated with both sleeping behavior and our ability to wake up from sleep
RAS stimulation by sensory information causes us to wake up
Damage to the RAS
Produces a slow-wave EEG (sleep-like)
Can result in a coma – a prolonged state of deep unconsciousness that resembles deep sleep.
What are two brainstem nuclei in the ascending pathway of the RAS that influence waking EEG?
Basal forebrain nucleus and the median raphe nucleus.
What is the role of the Peribrachial area on the neural basis of sleep?
Part of RAS; cholinergic nucleus in the dorsal brainstem that projects to the medial pontine reticular formation.
Initiates REM sleep and REM-related behaviors.
What is the role of the Medial pontine reticular formation on the neural basis of sleep?
Nucleus in the pons participating in REM sleep and REM-related behaviors
Connections with the spinal motor neurons and inhibits them = produces the atonia/paralysis characteristic of REM sleep
What are some disorders of sleep
Insomnia
Sleep-paralysis
Narcolepsy
Cataplexy
What is insomnia?
The most common sleep disorder, resulting in a prolonged inability to fall asleep due to dysfunction of slow waves (Delta-waves)
What is sleep-paralysis?
A REM-sleep disorder
Atonia and dreaming when a person is still “awake”, usually after just falling asleep or more commonly right before waking up
What is narcolepsy?
Slow-wave sleep disorder in which a person uncontrollably falls asleep at inappropriate times
Can be a secondary symptom of sleep apnea
What is cataplexy?
Form of narcolepsy; animal suddenly experiences atonia, as if they are in REM, while still awake
Often tied to an emotional event (ex. overexcitement)
What is the applied science that is concerned with the behavioural expression of brain dysfunction?
Clinical psychology
What are some of the origins of neuropsychological assessments?
Screening, diagnosis, monitoring and rehabilitation of people in the wars
What are dynamic imaging techniques?
Electroencephalography, Positron Emission Tomography and functional MRIs
What are static imaging techniques?
X-rays, CT scans and MRIs
What are 5 reasons neuropsychological assessments are used in clinical examinations?
Diagnosis
Patient Care and Planning
Treatment
Research
Forensic Questions
What are some ways a diagnosis can be useful?
Neurological symptoms vs psychiatric
Distinguishing between similar conditions
Early detection and prediction
Behavioural data
What are some ways a neuropsychological assessments can be useful in patient care and planning?
Can help provide information on cognitive functioning and capacity –> provides factual information
What are some ways a neuropsychological assessments can be useful in treatment?
A diagnosis can help determine the most appropriate type of treatment by determining an individual’s strengths and weaknesses
What are some ways a neuropsychological assessments can be useful in research?
They can evaluate specific questions in research
What are some ways a neuropsychological assessments can be useful in forensic neuropsychology?
Assessments can be undertaken for legal purposes to determine whether an individual is deemed at fault for a crime, or whether they have a disability from an accident.
What are some components of a neuropsychological assessment?
Collateral information, clinical interviews
What are some examples of collateral information?
Previous neuropsychological assessments, chart review, family questioning, imaging, psychiatric history and diagnoses, etc.
What is collected during a clinical interview for a neuropsychological assessment?
Basic orientation information to time and place, medications, languages of origin, subjective complaints, emotional issues, developmental history, etc.
What are 3 dimensions of behaviour?
Cognitive, emotion and executive functioning
Why is cognition most important in a neuropsy assessment?
For most patients these tend to be their most prominent symptoms/complaints.
What are two approaches to neuropsychological assessments and measurement?
Quantitative data and qualitative data
What would be an example of quantitative data from a neuropsychological assessment?
Drawing conclusions based on the scores obtained using standardized tests
Each test has cut-off scores for impaired or not impaired
A set battery of tests is used.
Drawback: Doesn’t consider how the individual performed the task