Category Archives: neuroscience

Why do we SLEEP?

We feel the urge to sleep when waves of tiredness fall upon us that has been accumulated along the day. After a good rest, we can feel the burden of physical and mental fatigue removed from our  body.

Through this, we can emit a question, “Do people sleep to relieve stress?”.

Although this is the significant answer to the question, there are other reasons why sleeping is crucial to our body.

1 Necessary Energy source; Sleep

One way to think about the function of sleep is to compare it to another of our life-sustaining activities: eating. Hunger is a protective mechanism that has evolved to ensure that we consume the nutrients our bodies require to grow, repair tissues, and function properly.

2 Sleep is crucial for LEARNING

Studying mice, scientists at Johns Hopkins have fortified evidence that a key purpose of sleep is to recalibrate the brain cells responsible for learning and memory so the animals can “solidify” lessons learned and use them when they awaken. Without at least 4~6 hours of sleep, more than 40% of the content one studied are not solid in the recollective systems in one’s brain. For young infants 11~13 hours of sleep is required for this ability to function correctly.

But still, the answer to the question cannot be satisfied with the pre-suggestions, for the question is asking for the fundamental reason why animals started the action, “sleeping”.There are several theories to clarify the reason to this action that existed to all living organisms from birth .

Inactivity Theory

Mimicking the Activies of Our barin

A mathematical model that successfully imitate the brain sequence related to memory consolidation during sleeping was built according to the study published in PLOS Computational Biology.

Recent studies have proposed that certain brain activities during sleeping might play important roles in memory consolidation. However, researches on those neuronal activity was hard to perform. Michael Schellenberger Costa, Arne Weigenand and their colleagues of the University of Lübeck, Germany, have successively mimicked the pattern of the neuronal activities.

There were some studies that modeled the activities of sleeping cortex. However, the activities related to memory consolidation occurs between cortex and the central brain system, thalamus. Distinct from the previous models, this new model have mimicked this thalamocortial coupling, which is related to the memory consolidation during sleeping.

The new model produces the sequence by predicting the activities of lager mass of neurons after looking at the activities of small groups of neurons, which is different from the past models that looks at the activities of individual neurons.

The researchers confirmed that the model was correct by comparing the neuronal activities recorded by electroencephalography (EEG) during the second and first level of N-REM sleeping with the sequence produced by the new model.

This new model, using the new algorithm for brain activity modeling, is relatively simple compared to the previous models and will be useful for the future studies on memory consolidation during sleeping and the diseases related to memory consolidation.