Category Archives: WHY CORNER

Why Do Some People Sleepwalk?

Sleepwalking or somnambulism runs in families, indicating a genetic component. Studies show that it is also associated with sleep deprivation, fever, stress and intake of drugs, especially sedatives, hypnotics, antipsychotics, stimulants and antihistamines. Somnambulism occurs because normal physiological systems are active even at inappropriate times. Why the brain issues commands to the muscles during certain phases of sleep is not known, but these commands are usually suppressed by other neurological mechanisms. At times this suppression can be incomplete and actions that normally occur during wakefulness emerge in sleep.

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In children, it is believed to be related to fatigue, prior sleep loss or anxiety. Children, mostly aged six to 12 years, are afflicted, perhaps because they spend more time in the “deep sleep” phase of slumber.

Physical activity happens only during the non-rapid eye movement (NREM) cycle of deep sleep, which precedes the dreaming state of rapid eye movement (REM) sleep. During this phase, the body releases a chemical that paralyses the body. However, sleepwalkers do not have this chemical trigger, hence the behaviour. With several cycles of non-REM and REM sleep in a night, sleepwalking occurs mostly during deep non-REM sleep early in the night or near morning.

In adults, sleepwalking is associated with a disorder of the mind but may also be seen with reactions to drugs and/or medications and alcohol, and medical conditions like partial complex seizures. In the elderly, it may be indicative of an organic brain syndrome, REM behaviour disorders or a personality disturbance.

Sources: The Telegraph (Kolkata, India)

Why Do Parts of Our Body ‘Fall Asleep’?

The weird “separate” sensations we experience when a particular limb “falls asleep” are the result of nerves under pressure.

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For example, if an arm has fallen asleep, it is most likely that the person had slept on the arm. The sleeping position squeezed and exerted pressure on the nerves, which were as a result unable to carry messages to the brain as well as other parts of the body. And if the position also squeezed the blood vessels, it would mean that oxygen carried by them did not reach the nerves.

When one removes the pressure on the nerves and on the blood vessels, in this case by a change in the position, the nerve fibres awaken in order of their thickness and of the thickness of their myelin sheaths (protective covering). Hence, the thickest and most protected ones awaken last. This gradual awakening process causes the different sensations we experience as the affected body part returns to normalcy.

The first sensation we experience is a tingling sensation, followed by a burning sensation, as the fibres that control pain and temperature now function and are again able to transmit these messages to the brain. Not until later, does the numbness we feel disappear, simply because the fibres that control touch and position are thicker fibres with thicker myelin sheaths.

Similar fibres, known as motor neurons, travel in the same nerves, but take direct orders from the brain to the spinal cord to the muscles, and awaken shortly after those controlling touch and position. For this reason, after the numbness disappears, we regain our ability to move the affected body part, and life is finally back to normal.

Sources: The Telegraph (Kolkata, India)

Why Do Our Eyelids Sometimes Twitch?

This irritating phenomenon, affecting millions of people, is not a serious condition for most. It is an involuntary muscle spasm around the eyelid, associated with an abnormal function of the “basal ganglion”, the brain area responsible for controlling the muscles.

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Eye twitching may be nothing more than a sign that you need to take it easy, as much as it may be a sign that something is very wrong. Some also believe that eye twitching is hereditary, running in families.

Why only the eyelid? Our bodies are remarkable machines, at times capable of doing unusual things. Muscle spasms can occur in other places as well including the facial area. Hemifacial spasm is a muscle spasm of a side of a face including the eyelids. Myokymia is not a twitch but more of a slow muscle contraction. Essential Blepharospasm is more of the quick muscle contractions, or twitching of the eyelid area.

Normal eye twitching will usually go away, but taking a few steps often helps reduce the eye twitches altogether. First, if you are seriously stressed, invest in some stress management techniques. The next key tip is to prevent over-fatigue and lack of sleep. Those toss-and-turn nights make us extra tired. Thus trying to get to bed early or taking a nap after a long night can help. To prevent fatigue, just don’t overdo it. Minimising caffeine intake can also help reducing the restless nights and extra tiring days. Some people find eye twitching a result of nothing more than anxiety. So, keep anxiety at bay.

If these don’t help, you should see a doctor as the condition could lead to other serious problems. There are treatment options like surgery and botox injections but coping with it the natural way is preferable.

You may click to see :-> Eye Twitching or Blepharospasm

Blepharospasm

Sources: The Telegraph (Kolkata, India)

Why Does the Body Temperature Rise During Fever?

Normal body temperature fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). When our body temperature rises above 98.6°F, we call it fever. Our normal body temperature is maintained by a certain part of the brain called the “anterior hypothalamus”. This region functions like a thermostat, registering the body temperature. The nervous system constantly relays information about the body’s temperature to the thermostat, which in turn activates different physical responses, designed to cool or warm the body, depending on the circumstances, in order to maintain the body temperature at a normal set point.

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Fevers are primarily caused by viral or bacterial infections. So, when an infection occurs, fever-inducing agents called pyrogens are released in the bloodstream, either by the body’s immune system or by the invading cells. The pyrogens trigger the resetting of the thermostat at a higher level and we thus register a higher body temperature during fever.

To reach a higher temperature from the normal body temperature, the body moves blood to the warmer interior, increasing the metabolic rate, and inducing shivering — that often accompanies a fever and is caused by these movements of blood to the body’s core, leaving the surface and the extremities cold. Once the higher temperature is achieved, the shivering and chills stop. Again, when the infection is overcome or drugs such as aspirin or acetaminophen are taken, the thermostat resets to normal (98.6°F) and the body’s cooling mechanisms send the blood back to the surface and sweating occurs.

We often panic when we have high temperature or fever. However, fever is an important component of our immune system. Actually, the immune system chemicals, that react with the fever-inducing agent and trigger the resetting of the thermostat, increase the production of cells that fight off the invading bacteria or viruses. Higher temperatures also inhibit the growth of some bacteria, accelerating the chemical reactions that help the body cells to repair themselves. In addition, the increased heart rate that may accompany the changes in blood circulation also speeds up the arrival of white blood cells to the site of infection to fight with the invaders.

Sources: The Telewgraph (Kolkata, India)

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Why Drunk People Take Risks

New brain imaging research shows that social drinkers have decreased sensitivity in brain regions involved in detecting threats, and increased activity in brain regions involved in reward.

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After alcohol exposure, threat-detecting brain circuits can’t tell the difference between a threatening and a non-threatening social situation.

Working with 12 healthy participants who drink socially, researchers used functional magnetic resonance imaging (fMRI) to study activity in emotion-processing brain regions during alcohol exposure. When participants received a placebo instead of alcohol, they showed greater activity in the amygdala, insula, and parahippocampal gyrus — brain regions involved in fear and avoidance — when shown a picture of a fearful facial expression.

Alcohol, meanwhile, activated striatal areas of the brain that are important components of the reward system, but did not increase brain activity in areas involved in fear.

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Sources:

* Science Daily April 30, 2008

* The Journal of Neuroscience April 30, 2008