Neurobiology of Sleep | Understanding the Brain The Neurobiology of Everyday Life | Final peer graded assignment

This is the slides that I submitted for the final project of the course Understanding the Brain : The Neurobiology of Everyday Life.

Feel free to use this as a reference.

1. Understanding
the Brain: The
Neurobiology of
Everyday Life
Final Peer-graded Assignment
Title: The Neurobiology of Sleep
By Aaditya Jha

2. Personal Experience
•During my college years, I often
struggled with sleep deprivation. I was
managing full-time studies during the
day and a part-time job at night.
Because of this, I usually got only 3-4
hours of sleep after work and another
3-4 hours after returning from college.
This lack of sleep affected my daily
life, but it also helped me understand
more about how sleep works in the
brain.

3. The Sleep Cycle
Photo Source: https://www.sleepfoundation.org/stages-of-sleep
•Sleep is not a homogeneous state
but rather a dynamic process
comprising different stages.
•It is broadly categorized into non-
rapid eye movement (NREM) sleep,
which constitutes approximately
80% of total sleep time, and rapid
eye movement (REM) sleep,
accounting for the remaining 20%.
•NREM sleep is further divided into
three stages: N1, N2, and N3, with
N3 (also known as slow-wave sleep)
considered the most restorative.

4. Sleep Pattern
•A typical night's sleep follows a characteristic
pattern, visualized through a hypnogram.
•Sleep begins in NREM, progressing through
stages N1 to N3, before transitioning to REM
sleep.
•This cycle repeats throughout the night, with
REM episodes generally becoming longer
towards morning.
•These steps are not merely descriptive but
functionally significant, with each stage
serving distinct physiological purposes
Photo Source: https://en.wikipedia.org/wiki/Hypnogram

5. •Sleep is regulated by two interacting processes: the circadian
rhythm (Process C) and the homeostatic sleep drive (Process S).
•This two-process model provides a framework for understanding the
timing and propensity for sleep.
Photo Source: https://makesleepyourfriend.com/?page_id=53

6. •Process C, driven by the suprachiasmatic nucleus (SCN)
in the hypothalamus, generates a roughly 24-hour rhythm
in alertness and sleep propensity.
•The SCN, often referred to as the body's "master clock,"
receives light input via the retinohypothalamic tract.
•This photic information suppresses melatonin secretion
from the pineal gland during daylight hours, promoting
wakefulness. As darkness falls, this suppression is lifted,
allowing melatonin levels to rise and facilitate sleep
onset.
•At the molecular level, circadian rhythms are generated
by a transcriptional-translational feedback loop involving
clock genes such as CLOCK, BMAL1, PER, and CRY.
•This molecular machinery is present not only in the SCN
but in cells throughout the body, highlighting the
pervasive influence of circadian rhythms on physiological
functions.
Photo Source: Pathways through which light might influence mood and reward systems in... | Download Scientific Diagram (researchgate.net)
Retinohypothalamic tract
Process C

7. •Process S, on the other hand, represents the
homeostatic drive for sleep that accumulates
during wakefulness.
•This process is thought to be mediated by the
buildup of sleep-promoting substances, such as
adenosine, in the brain.
•The interplay between Process C and Process S
explains why we feel increasingly sleepy the
longer we stay awake, yet our alertness can vary
at different times of day even with equal
durations of prior wakefulness.
•Normally, a substance called adenosine builds
up in the brain during wakefulness, making us
feel more tired (this is called Process S).
However, I often fought against this natural urge
to sleep because of my busy schedule, which
made things even harder.
Process S
Photo Source: https://makesleepyourfriend.com/?page_id=53

8. The Sleep-Wake Cycle: A
Delicate Balance Disrupted
•My irregular sleep schedule disrupted my
body's natural circadian rhythm, which is
controlled by the suprachiasmatic
nucleus (SCN) in the hypothalamus.
•Because I was exposed to light at odd
times and didn't have a regular sleep
pattern, my SCN likely became confused,
making it harder for my body to know
when to sleep and when to be awake.
Photo source: Know Your Brain: Suprachiasmatic Nucleus (neuroscientificallychallenged.com)

9. The Neurological Impact
of Sleep Deprivation
As the semester went on, I noticed several changes that I now
know were related to how sleep deprivation affects the brain:
•Cognitive Impairment: I found it hard to focus in class and
remember information. This was probably because my brain
wasn't getting enough time to process and store memories
during sleep, especially during the deep sleep stage called
slow-wave sleep (Stage N3).
•Mood Changes: I became more irritable and had mood swings.
This was likely due to sleep deprivation affecting the amygdala,
a part of the brain involved in emotions.
•Microsleeps: Sometimes, I would briefly fall asleep without
meaning to, especially during lectures or while studying. These
"microsleeps" happened because my brain was so tired that the
sleep-promoting neurons in the ventrolateral preoptic nucleus
(VLPO) took over, even when I was trying to stay awake

10. The Body's Attempt to
Compensate
Despite trying to keep up with my schedule, my
body tried to make up for the lack of sleep in a
few ways:
•REM Rebound: On the rare occasions when I
could sleep longer, I had vivid and intense
dreams. This is known as REM rebound, where
the brain tries to catch up on lost REM sleep.
•Increased Sleep Efficiency: I noticed that I
could fall asleep very quickly whenever I had
the chance. This was my brain's way of making
the most of the limited sleep time I had.

11. Long-term Consequences and Lessons
Learned
Recent research shows that sleep is important for the brain's glymphatic system,
which helps clear out waste products. By not getting enough sleep, especially slow-
wave sleep, I might have been interfering with this important process.
Also, the constant stress of sleep deprivation could have affected my overall
nervous system, possibly impacting my immune system and heart health.
Looking back, I realize that the lack of sleep could have long-term effects.

12. Conclusion: The Value
of Sleep Hygiene
•This experience taught me how important sleep is
and how it affects the brain.
•The course "Understanding the Brain: The
Neurobiology of Everyday Life" helped me
understand the neurobiologybehind sleep . It made
me realize that sleep isn't just a luxury but a basic
need for good health.
•Since then, I've made a conscious effort to
maintain a regular sleep schedule, recognizing how
crucial sleep is for my cognitive function and
overall well-being.
•This personal journey has given me a deeper
appreciation for the complex processes that
regulate our sleep-wake cycles.

13. References
•https://www.youtube.com/watch?v=97XCm_Js8Ro
•https://www.coursera.org/learn/neurobiology
•https://makesleepyourfriend.com/?page_id=53
•Brain Basics: Understanding Sleep | National Institute of Neurological Disorders and Stroke (nih.gov)
•How Does Lack of Sleep Affect Cognitive Impairment? | Sleep Foundation
•Mental Health and Sleep (sleepfoundation.org)

14. Thankyou !