https://www.youtube.com/watch?v=FFwA0QFmpQ4&list=PLPNW_gerXa4Pc8S2qoUQc5e8Ir97RLuVW&index=155&pp=iAQB

Goal

Dreaming, learning and unlearning (of troubling emotional events) during dreaming

Cycling Sleep

• As we get sleepy, we tend to shut our eyes (as there are some autonomic centres of our brain, some neurons that control the closing of the eyelids when we are sleepy) and we transition into sleep.
• Regardless of how long we sleep, it is broken down into a series of 90-minute cycles: ultradian cycles.
• Early in the night: these cycles are comprised of more shallow sleep and slow-wave sleep (stage 1 and 2) and we tend to have less REM (Rapid Eye Movement) sleep,
• For every 90-min cycle, we start having more and more REM sleep, less of the slow-wave sleep. This is regardless of whether our sleep is broken. The more sleep we get throughout the night, we more REM sleep we’ll have.
• REM and non-REM sleep have distinctly different roles in learning and unlearning and of different types of information. This has huge implications for learning of motor skills, unlearning of traumatic events, processing of emotionally pleasing events.
• One can leverage day-time activities to access more REM or non-REM sleep depending on our physical or emotional needs.

Non-REM sleep (slow-wave sleep, SWS)

• It is characterised by a particular pattern of brain activity in which the brain is metabolically active but there are big sweeping waves of activity that include a lot of the brain.
• Interesting thing: the neuromodulators (NMs) that tend to be associated with it, that are most and least active during this phase (ref to Lecture 1 for a primer on neuromodulators of various kinds)
  • There is no acetylcholine (its production, release and action from the 2 major sites of the brain stem or from the forebrain), almost to 0. This NM is associated with focus - the big sweeping waves of activity through the brain and a distortion of space and time so that we aren’t really focused on any one thing.
  • Norepinephrine - this is surprising as in the waking state it is associated with alertness and a desire to move. Not a lot of it is released. Thus, something related to the movement circuitry is going on.
  • Lot of serotonin (associated with the sensation of bliss, well-being but not a lot of movement). And we tend not to move during sleep.
• During this phase, we can move. We aren’t paralysed. We can roll over. Sleep walking happens during this phase.
• Motor learning generally occurs in this phase (coordinated movements at the level of fingers or at the level of the whole body and large limb movements), in the early part of the night.
• It is also shown to be important for the learning of detailed information about specific events. Not always cognitive information, but like very specific rules of how certain words are spelled, etc. Thus, if people are tested on these types of exams that require the learning of very detailed information and they’re denied slow wave sleep, they tend to perform poorly.