Neuro

• Functions of sleep?

  • Energy conservation
  • Thermoregulation
  • Somatic and Neural growth regulation
  • Immune regulation
  • Memory consolidation
  • Regulation of affect
• The circadian rhythm is controlled by the suprachiasmatic nucleus (SCN) within the anterior hypothalamus
• The pineal gland secretes melatonin which rises at night
• type of sleep disroders?

  • Insomnia
  • Obstructive sleep apnoea
  • Parasomnia
  • Restless leg syndrome
  • narcolepsy
• The Epworth sleepiness scale can be used to measure whether you are experiencing excessive sleepiness that needs medical attention. Each activity on the scale eg. watching telly is scored from 0 to 3 on how likely you are to fall asleep
• There is a dual centre for sleep and wakefulness in the brainstem called the ascending arousal system (ARAS). The wake centre is in the upper brainstem and posterior hypothalamus and the sleep center is in the preoptic area and the adjacent anterior hypothalamus
• Sleep can be separated into 3 phases on an EEG:

  1. Wake
  2. NREM - N1, N2, N3
  3. REM
• Sleep disorders can be diagnosed using polysomnography which produces a hypnogram
• Features of REM sleep?

  • Muscle atonia - descending inhibitory signal from the pons to the spinal motoneurons leads to reduction of skeletal muscle tone
  • Elevated Heart rate
  • Increased brain activity
• Orexin also known as hypocretin is a hypothalamic neuropeptide that stabilises the circuit between asleep and awake.
• Which neurotransmitters are active in wake time?

  • Dopamine
  • Noradrenaline
  • Histamine
  • Orexin (hypocretin)
  • Acetylcholine
  • Glutamate
• Which neurotransmitters are highest in NREM sleep?

  • Galanin
  • GABA
• Which neurotransmitters are highest in REM?

  • Acetylcholine
  • GABA
  • Glycine
  • Dopamine
• Which neurological pathway is responsible for light detection and therefore circadian rhythm?

  • The retinohypothalmic tract
• Normal range of sleep for teenagers?

  8 to 10 hours
• Normal range of sleep for adults?


  7 to 9 hours or 6 to 10 normal for some. As you get older you need less sleep
• How does sleep affect age?

  • Homeostatic regulation of sleep declines with age
  • Decreased slow wave sleep
  • Increased wakening's
  • Decreased melatonin production from children to adults
• The psychomotor vigilance test can measure defecits in reaction speed which correlated well to sleep debt
• Half life of caffeine is 3.5 to 7 hours
• How does alcohol impact sleep?

  • Fall asleep quicker (decreases sleep latency)
  • Less REM sleep in second half of the night once alcohol metabolised
• Obstructive sleep apnoea is snoring with partial or complete collapse of the upper airway leading to complete or partial reduction in airflow. The cycle repeats throughout sleep leading to a fragmented night, daytime sleepiness, sore throat
• Risk factors for obstructive sleep apnoea?

  • Age
  • Male gender
  • Obesity
  • Sedative drugs eg. opiods, alcohol
  • Treatment resistant HTN
  • Treatment resistant atrial fibrillation
  • High dose opiods
• Central sleep apnoea is characterised by transient cessation of the respiratory rhythm generator located in pontomedullary region of the brain. Instead of being caused by upper airway obstruction like in obstructive sleep apnoea, it can be caused by high dose opioids or stroke
• Narcolepsy is a sleep disorder characterised by the inability to regulate sleep-wake cycles. Symptoms include inability to stay asleep or awake and crazy vivid dreams. Average age of onset is in teenage years
• Canin narcolepsy is caused by a mutation in the hypocretin receptor 3 gene
• Human narcolepsy is an auto-immune condition due to the loss of hypocretinergic neurons in the hypothalamus
• Sleep walking is called NREM parasomnia
• REM sleep behaviour disorder is a neurodegenerative problem causing loss of normal REM muscle atonia (muscles remain active) where dream re-enactment occurs, often with injury and dream recall.

  • Strongly linked with parkinsons
• Insomnia is the difficulty falling asleep or staying asleep, with daytime impact, at least 3 months, > 3 days a week
• Treatment for insomnia disorder?

  • CBT specific for insomnia
  • Advice regarding sleeping habits
• Topographic map of S1 can be found on the post-central gyrus
• The intention of motor activity is controlled in the supplementary motor cortex
• The frontal eye field is responsible for conscious control of where we look. It is found in the prefrontal cortex
• Language understanding = Wernike's area

  Language production = brocca's area
• Visual world --> Retina --> Thalamus --> V1 in occipital lobe --> processed in association cortex
• What makes up the limbic system?

  • Amygdala
  • Hippocampus
  • Hypothalamus
  • Basal ganglia
  • Cingulate gyrus
• The hippocampus is associated with declarative memory (events and facts). It has widespread connections to every other area of cortex )
• Balint's syndrome is where the ability to perceive multiple objects is lost. It is caused by bilateral damage to the posterior parietal and lateral occipital cortex.
• Genes implicated in autism are generally genes that affect synaptic development and genes that control chromatin and transcriptional regulation
• Delerium is a state of mental confusion that starts suddenly and is caused by a physical condition of some sort. It is temporary and acute.