Posted on by johanne_marais

Sleeping more and moving less? Thank the suprachiasmatic nucleus!

The winter solstice rolls us into the second half of the solar year. Trees surrender their fiery leaves to frozen dewdrops on bare branches. Shorter periods of daylight and longer portions of night lure thick socks and hot water bottles out from a deep drawer of winter clothes. Hearty stews simmer and fires frequently flicker as the season shifts. Animals seek warmth and reprieve from the cold by “… migration, hibernation and resistance (tolerance)”. For many humans, winter may burgeon these types of adaptations too, encouraging changes to our appetite, our exercise patterns, even our sleep and wakeful behaviours! Unpacking the physiology of this can help us be kinder to our bodies and minds for embracing our inner polar bears during winter months. So, allow me another moment of sleep science nerdery…

An intrinsic, 24-hour, regulatory system is present in each of our bodies. The system is called the circadian rhythm; internal oscillations that cycle around a biological clock. Some molecular mechanisms of the biological clock are retained across plant and animal kingdoms – from the most primitive single-cell organisms like cyanobacteria to human beings. In mammals, the circadian rhythmicity is observed in fluctuations of hormones, sleep-wake cycles and even periods of optimal cognitive functioning. Genetic variables of circadian rhythms are by no means conserved across species, and especially not within the same species.

Your 24-hour structure may differ from your housemate, sibling, or colleague by up to eight hours. This depends on microenvironments within and macroenvironments around the body. For example, your sibling, a shift worker who drives shipment trucks across the country, might wake up at two o’clock in the morning to arrive at their destination by four o’clock that afternoon. Their bedtime may be 6pm. At this time, a night nurse who clocked in at Rahima Moosa moments earlier may be enjoying his equivalent of a “morning coffee” and prepares to work through the night. How can this vary so vastly (and manageably) from person to person?

In brief, the answer is light and chemistry!

The circadian rhythm’s master-regulatory site is called the suprachiasmatic nucleus – a cluster of thousands of neuronal cells in the brain, situated on top of the optic chiasm. The suprachiasmatic nucleus (SCN) is receptive to photic stimulation (think: packages of light called photons sent via the visual system) and chemical (or, neurotransmitter) stimulation. The SCN’s sensitivity to light means that timely exposure to or limitation of daylight can shift the phase of our circadian rhythms; we can feel a desire to sleep earlier and wake up later, like with shift workers.

This is happening across the world as seasons change: a phase shift of circadian rhythm aligning with Earth’s orbital cycles and environmental cues. During winter, the sun sets about 90 minutes earlier than it would in warmer months – it may be a challenge to stay awake until your 11pm summer-bedtime. Similarly, the 5am Club may lose a few committed members (not mentioning any names erhuurhm @me) between May and August. Frankly, if the Sun can go to sleep earlier, so can I! This is an expected adaptation; a sign of your body adjusting well to its circumstance. No big deal!

It is also common for emotional affect to change in winter. Ever heard of Seasonal Affective Disorder? It’s basically the SADs that often come with less sunlight exposure. Our mental health is a huge determinant of our sleep-wake behaviours, too. People who live with a psychiatric illness (or even symptoms of one) are considerably more likely to experience coincident insomnia – up to 90% coincidence! This relationship, though, is no coincidence. Several molecular messengers involved in sleep, wakefulness, appetite control, and mood regulation are in the same class of neurotransmitters called monoaminergic neurotransmitters.

Just as animals do, humans may migrate smaller distances in winter: like, no further than to the snack stash and back. So, maybe we gather a little more belly fat. We don’t have that spring (haha, get it?) in our step. We want to sleep in… Guess what? Colder times of the year welcome a series of natural and protective evolutionary traits to be expressed and experienced. Sometimes that feels like seven extra centimetres between your skin and your belt buckle or admitting you simply must rest for 12 hours every day. Just as we do not look up at leafless trees nor look down at frost on the grass with judgement, there should be no shame around the physical, psychological, or physiological changes that come from seasons changing. If you’re sleeping more and moving less, give thanks to the suprachiasmatic nucleus!

Posted on by johanne_marais

Study tips and self-guided learning techniques by praxis

What do your moods, behaviours, motivation, memories, and emotions have in common?

These are processed in the same brain region called the limbic system! The word limbic means on the border, here describing the border of the cerebral cortex; the characteristically ‘iconic’ portion of the brain.

Part of the limbic system which is specifically important for learning and memory is called the hippocampus.

On the topic of learning and memory…

I took two gap years after matric. By the time I began my undergraduate degree (after being situated in the role of an active worker and a passive student) I had completely lost touch with how I preferred to consume knowledge. If I travelled back in time (and I absolutely can time-travel, of course. I simply choose not to), I would begin by prompting my younger self with three reflective questions:

  • What kind of learner am I?

I now know that I learn best through a multi-modal approach – combining note taking; watching videos; listening to lectures; reading books; drawing images; touching structures; practicing techniques; using colourful pens… Understanding the mode in which you best absorb specific information is a very important first step.

  • Where do my interests lie?

Interest-based learning is a tactic that appreciates how easily our minds take in information that feels relevant to us, and relatable to our lives. Studying is about more than simply remembering information for a test. It’s about gaining understanding and feeling excited about what you can learn! Curiosity and intrigue will encourage you to get through your coursework effortlessly.

  • How do I want to engage with what I learn?

Perhaps it’s a consequence of studying the microscopic world of proteins and ion exchange and cellular interaction, but keeping the bigger picture in mind can be a flaw in my learning process. I combat this using mind-maps. The brain often harnesses association and imagery to improve memory retention and recall. By drawing a mind-map, I connect specific concepts to areas on an A3 page and can emphasize this with drawings or bold mnemonics that remind me of the central theme.

The RSVP to active learnership promises a perpetual feast on an intellectual snack platter; a byte-size buffet of your selection.

However, if the intention is not only to absorb and regurgitate knowledge, but to take a bite; taste it; experience the textures… flavours… and say “I don’t like this” or “Oooh, yummy, I would eat that again”, then the takeaway tips to all students everywhere are these:

  1. Become that ‘first row’ student.

Dissolve the idea that you need to maintain a coolness factor by not participating in your own acquisition of knowledge. There is no shame in asking questions. It’s cool to pay attention.

2. Learn by both listening and teaching.

Good learning techniques start with acute listening skills. By explaining to someone what you have learned, and allowing them the chance to ask questions, you will see knowledge gaps in your description or think about how you could better understand the information you are sharing. Do not harbour knowledge for yourself.

3. Think critically about the source of your information.

There are both implicit and explicit bias in every bit of knowledge you gain and share. Are you learning about the history of South Africa through a book written by a privileged, older man with high socio-economic status? Are you being told that homosexuality is a sin by a theology lecturer? Are you checking multiple sources before you decide “Yes! This is objectively true!”?

4. Have a plan and plan to take breaks!

Consistency is my key to maximizing memorability and motivation, while avoiding overwhelm and burnout. Detailing a study plan helps me hold myself accountable to realistic daily targets. My plan often includes studying across topics, like a study trifle, so that I can keep my interest up and my “information-saturation” down. I cannot emphasize enough how necessary it is to plan for rest, too.

5. Repeat steps one to four.

Repetition helps to consolidate short term memory to long term memory.

Since you’ve come to the end of this blog, I wonder if you could teach someone else the answers to these questions:

  • What is the role of the hippocampus?
  • Where in the brain is it situated?
  • What do your moods, behaviours, motivation, memories and emotions have in common?