Core (rectal) body temperatures for young (average age 23 years ; open circles) and older (over age 65; solid circles) subjects. (Duffy JF et al 1998)


The older show their lowest temperature around 2-3 a.m., 3 hours earlier than the young


The lowest temperature (nadir) in the old: 36.45º C
The lowest temperature in the young: 36.25º C




Chronotypology:
“Morning people” i.e., people who are most alert and productive in the morning, tend to have approximately 0.5º C lower a.m. nadir temperatures that also occur earlier as compared to “night people” (Waterhouse J et al, 2001).

While people > 65 years show their lowest temperature at 2-3 a.m., younger people do so around 6 a.m.; the age difference in fluctuations can be abolished through use of melatonin, though melatonin may also shift temperatures slightly lower in the elderly (0.1-0.3º C; Gubin DG et al, 2006).

Fasting: Both fasting and substantial calorie restriction reduce temperatures, likely a survival mechanism in response to reduced food availability (Kelly GS, 2007).

Sleep deprivation: While acute sleep deprivation increases temperatures, chronic sleep deprivation exerts an effect similar to that of fasting, i.e., reduction in temperature, including reduction of early a.m. nadir (Kelly GS, 2007).

Fitness: Very physically fit people tend to have lower early a.m. temperatures by 0.2º C (oral) than unfit people (Atkinson G et al, 1993).
“Weekend effect”: Temperatures tend to be higher on Saturday and Sunday if you sleep later when not working. Kelly (2007) suggests that the temperature can be expected to increase 0.1º C for every hour later you awake from habitual sleep times.

Menstrual cycle: For women experiencing menses, temperatures (including a.m. nadir) are shifted higher 0.4º C starting 14 or so days after menstrual bleeding begins (the “luteal” phase, when progesterone levels are high)



Rectal temperatures in men and in healthy women by menstrual phase (Baker FC et al 2001). (http://jp.physoc.org/content/vol530/issue3/fulltext/565/Figures/565-F1.gif)

Normal temperature: 35.7 º C to 37.7 º C (Sund-Levander M et al 2002; Gomolin IH et al 2007; McGann KP et al 1993). This differs from the 37.0 º C often quoted as normal, a relic of the original 19th century observations on human temperatures in health and disease.

Internal organ temperatures best reflect body temperature. In research, temperatures from the pulmonary artery, gastrointestinal tract, bladder, urine, or rectum are used, though even rectal temperatures track slightly below that of true internal temperatures. However, for convenience, oral temperatures are often used, even though oral temperatures track approximately 0.5º C below that of internal temperature.

Of all the various ways to measure body temperature, axillary is the least reliable and the one most prone to inaccuracy. More so than other methods, axillary temperatures are subject to external ambient temperature, amount of clothing worn prior to temperature measurement, sweating, whether right or left arm is used (since there is variation of up to 2.0º F degrees from right to left), the amount of cutaneous (skin) dilation or constriction of blood vessels. Axillary temperatures track rectal temperature poorly, with wide variation in the day-to-day and minute-to-minute fluctuations of temperature, and especially marked divergence from rectal temperature in morning (temperature nadir) and evening (temperature peak) hours, with as much as 1.0-1.5º C variation within several minutes (Cattaneo CG et al 2000; Kelly G 2006). Axillary temperatures are therefore too variable and unreliable for use in assessing thermoregulation, whether for research or our purposes.

adapted from
http://www.trackyourplaque.com/library/fl_06-032thermoregulation.asp

Galacto, lacto, milky

Gr. Gala : Milk (genitive; galakta) -->Gr. galaktikos (milky)
.............................................-->L. galaxia (Milky way; Via Lactea)

L. Lac : Milk (genitive; lactis) (Fr Lait)



lactation : Suckling
lactose: Milk sugar; < Lact + ose (sugar suffix; hexose, pentose, triose, glucose...)
lactic acid: Milk acid; an acid obtained from sour milk
galactose: Brain sugar; a constituent of lactose
galactin: prolactin

Unconscious decision-making

Neuroscientists Daniel Kahneman and Amos Tversky received a 2002 Nobel Prize for their 1979 research that argued humans rarely make rational decisions.

People do indeed make optimal decisions—but only when their unconscious brain makes the choice.

You don't consciously decide to stop at a red light or steer around an obstacle in the road. Once we started looking at the decisions our brains make without our knowledge, we found that they almost always reach the right decision, given the information they had to work with

A very simple unconscious-decision test.

A series of dots appears on a computer screen, most of which are moving in random directions. A controlled number of these dots are purposely moving uniformly in the same direction, and the test subject simply has to say whether he believes those dots are moving to the left or right. The longer the subject watches the dots, the more evidence he accumulates and the more sure he becomes of the dots' motion.

Subjects in this test performed exactly as if their brains were subconsciously gathering information before reaching a confidence threshold, which was then reported to the conscious mind as a definite, sure answer.

The subjects, however, were never aware of the complex computations going on, instead they simply "realized" suddenly that the dots were moving in one direction or another. Human brain is wired naturally to perform calculations of this kind.

A probabilistic decision-making system has several advantages. The most important is that it allows us to reach a reasonable decision in a reasonable amount of time. If we had to wait until we're 99 percent sure before we make a decision, then we would waste time accumulating data unnecessarily. If we only required a 51 percent certainty, then we might reach a decision before enough data has been collected.

Another main advantage is that when we finally reach a decision, we have a sense of how certain we are of it—say, 60 percent or 90 percent—depending on where the triggering threshold has been set.

The findings are published in the Dec 26 2008 issue of the journal "Neuron"

http://www.sciencedaily.com/releases/2008/12/081224215542.htm

Delusions and right hemisphere

Delusions associated with consistent pattern of brain injury

How delusions arise and why they persist.

Patients with certain delusions and brain disorders reveals an injury to the frontal lobe and right hemisphere of the human brain. The cognitive deficits caused by these injuries to the right hemisphere, leads to the over-compensation by the left hemisphere, resulting in delusions.

The article entitled "Delusional misidentifications and duplications: Right brain lesions, left brain delusions" will appear in the latest issue of the journal of Neurology.

Problems caused by these right brain injuries include

~ impairment in monitoring of self

~ impairment in awareness of errors

~ incorrectly identifying what is familiar and what is a work of fiction

However, delusions result from the loss of these functions as well as the over activation of the left hemisphere and its language structures, that 'create a story', a story which cannot be edited and modified to account for reality.

Delusions result from right hemisphere lesions, but it is the left hemisphere that is deluded.

Often bizarre in content and held with absolute certainty, delusions are pathologic beliefs that remain fixed despite clear evidence that they are incorrect.

Most neurologic patients with delusions usually have lesions in the right hemisphere and/or bifrontal areas. For example, the neurological disorders of

~ Confabulation (incorrect or distorted statements made without conscious effort to deceive),

~ Capgras (the ability to consciously recognize familiar faces but not emotionally connect with them) and

~ Prosopagnosia (patients who may fail to recognize spouses or their own face but generate an unconscious response to familiar faces) result from right sided lesions.

The right hemisphere of the brain dominates

~ self recognition,

~ emotional familiarity and

~ ego boundaries.

After injury, the left hemisphere tends to have a creative narrator leading to excessive, false explanations. The resistance of delusions to change despite clear evidence that they are wrong likely reflects frontal dysfunction of the brain, which impairs the ability to monitor self and to recognize and correct inaccurate memories and familiarity assessments. Thus, right hemisphere lesions may cause delusions by disrupting the relation between and the monitoring of psychic, emotional and physical self to people, places, and even body parts. This explains why content specific delusions involve people, places or things of personal significance and distort ones relation to oneself.

In one study, nine patients with right hemisphere infarctions at a stroke rehabilitation unit had frequent delusion. While size of the stroke did not correlate when compared to the control group, the presence of brain atrophy was a significant predictor of delusions. When delusions occurred, it was usually caused by a right hemisphere lesion. Also, one study pointed out that delusional patients with Alzheimer's disease usually have significantly more right frontal lobe damage.

Other research showed that Reduplicative Paramnesia and Capgras syndrome cases with unilateral brain lesions strongly implicate the right hemisphere, usually the frontal lobe of the brain. Among 69 patients with Reduplicative Paramnesia, lesions were primarily in the right hemisphere in 36 cases (52%), bilateral in 28 (41%) and left hemisphere in 5 (7%) -- a sevenfold increase of right over left-sided lesions. Similarly in 26 Capras patients, lesions were primarily in the right hemisphere in 8 (32 %), bilateral in 16 (62 %) and left sided in 2 (7%)- a four-fold increase of right - over left-sided lesions. For both delusional syndromes, many bilaterial cases had maximal damage in the right hemisphere.

Among another study of 29 cases of delusional misidentification syndromes, all patients had right hemisphere pathology, while 15 (52 %) had left hemisphere damage. Fourteen had exclusively right hemisphere damage but none had isolated left hemisphere damage. When lateralized lesions are found, right hemisphere lesions are more common in other delusional misidentification and content specific delusions. Frontal lesions are strongly implicated in misidentification syndromes. Exclusively frontal lesions were associated with delusions in 10 of 29 (34.5) cases- four with right frontal and six with bifrontal lesions. None had lesions sparing the frontal lobes.

Source:
New York University School of Medicine
January 13th, 2009


adapted from
http://www.physorg.com/news151069576.html

Cultural Neuroscience

Experiences can alter "hard-wired" brain structures. Through rehab, stroke patients can coax a region of the motor cortex on the opposite side of the damaged region to pinch-hit, restoring lost mobility; volunteers who are blindfolded for just five days can reprogram their visual cortex to process sound and touch.

The medial prefrontal cortex supposedly represents the self: it is active when we think of our own identity and traits. But with Chinese volunteers, the results were strikingly different. The "me" circuit hummed not only when they thought whether a particular adjective described themselves, but also when they considered whether it described their mother. The Westerners showed no such overlap between self and mom.

Depending whether one lives in a culture that views the self as autonomous and unique or as connected to and part of a larger whole, this neural circuit takes on quite different functions.

Westerners focus on individual objects while East Asians pay attention to context and background (another manifestation of the individualism- collectivism split). Sure enough, when shown complex, busy scenes, Asian-Americans and non-Asian--Americans recruited different brain regions. The Asians showed more activity in areas that process figure-ground relations—holistic context—while the Americans showed more activity in regions that recognize objects.

Drawings of people in a submissive pose (head down, shoulders hunched) or a dominant one (arms crossed, face forward) was shown to Japanese and Americans. The brain's dopamine-fueled reward circuit became most active at the sight of the stance—dominant for Americans, submissive for Japanese—that each volunteer's culture most values.

Chinese speakers use a different region of the brain to do simple arithmetic (3 + 4) or decide which number is larger than native English speakers do, even though both use Arabic numerals. The Chinese use the circuits that process visual and spatial information and plan movements (the latter may be related to the use of the abacus). But English speakers use language circuits. It is as if the West conceives numbers as just words, but the East imbues them with symbolic, spatial freight. (consider about Asian math geniuses.) Neural processes involving basic mathematical computations seem to be culture-specific.

from
Sharon Begley
West Brain, East Brain: What a difference culture makes.

Newsweek
Mar 1, 2010
http://www.newsweek.com/id/233778

Coma should be redefined

A man with a severe traumatic brain injury remained physically unresponsive, and hence, was presumed to be in a vegetative state for six years. Now, it is understood that he is conscious and he can communicate yes and no via his thought patterns.

Using functional magnetic resonance imaging (fMRI), the patient's brain activity was mapped while he was asked to answer yes and no questions such as "Is your father's name Thomas?".

The researchers were astonished when they saw the results of the patient's scan. He
was able to correctly answer the questions that were asked by simply changing his thoughts, which they then decoded using our fMRI technique

The new technique can decode the brain's answers to such questions in healthy, non-vegetative, participants with 100 per cent accuracy.

But it has never before been tried in a patient who is in coma, hence, cannot move or speak.

In a three-year study, 23 patients diagnosed as vegetative were scanned. The new technique was able to detect signs of awareness in four of these cases.

However the researchers only managed to communicate, in the yes, no fashion, with one of the patients.

It's early days, but in future we hope to develop this technique to allow some patients to express their feelings and thoughts, control their environment and increase their quality of life

For example, patients who are aware, but cannot move or speak, could be asked if they are feeling any pain, allowing doctors to decide when painkillers should be administered

Recently, a Belgian man named Rom Houben who was wrongly diagnosed as comatose for 23years, is now planning to write a book about his extraordinary story. Since 2006, when his true condition was correctly diagnosed, Houben has regained enough coordination to allow him to use a finger, when aided, to tap out messages on a special computer keyboard.

Published in
New England Journal of Medicine

http://www.news.com.au/breaking-news/world/vegetative-man-communicates-via-scan/story-e6frfkui-1225826619059?from=news+newsletter_rss


**

Belgian man named Rom Houben was thought to have been in a coma (vegetative state) for 23 years (from 23 years of age to 46), however he was simply paralysed and unable to communicate. Finally doctors realised he was, in fact, conscious.

Cut off from the world, he passed his time in thought for years. He could hear what was being said around him throughout but was unable to respond.

"Doctors and nurses tried to speak to me and eventually gave up" The worst moment came when his mother and sister told him of the death of his father and though he wanted to weep, his body remained motionless.

After the correction of the diagnosis, he has regained enough coordination to allow him to use a finger, when aided, to use a special computer keyboard. Using a specially-adapted computer to type messages, Houben has been able to describe the ordeal he endured for more than two decades. He told that he meditated to pass the long years trapped in his own body. "I would scream, but no sound would come out," he said, "I will never forget the day they finally discovered what was wrong -- it was my second birth."

Houben is still unable to move, but he can read thanks to a device set up over his bed, and he communicates through a keyboard. "I want to read, to talk to my friends with the computer and to live life now people know I'm not dead," he said

There are too many cases inaccurately diagnosed coma -- more than 40 per cent in certain categories of sufferers. It is vital, with any coma patient, to discover whether they have plunged into a vegetative state or if there is some minimal consciousness

http://www.news.com.au/breaking-news/world/man-in-false-coma-plans-memoirs/story-e6frfkui-1225803497327

http://www.heraldsun.com.au/news/rom-houben-spent-more-than-twenty-years-in-what-doctors-thought-was-a-coma-but-he-was-actually-awake-and-paralysed/story-e6frf7jo-1225803146317

http://www.news.com.au/world/man-misdiagnosed-as-being-in-coma-for-23-years/story-e6frfkyi-1225803256170

Brain On A Chip?

How does the human brain run itself without any software?

They are building a ‘neural’ computer that will work just like the brain but on a much smaller scale in order to search this.

The human brain is often likened to a computer, but it differs from everyday computers in three important ways:

1- it consumes very little power,
2- it works well even if components fail,
3- it seems to work without any software.

The goal is to to build a ‘neural computer’ which emulates the brain. The first effort is a network of 300 neurons and half a million synapses on a single chip. The team used analogue electronics to represent the neurons and digital electronics to represent communications between them. It’s a unique combination.

Since the neurons are so small, the system runs 100,000 times faster than the biological equivalent and 10 million times faster than a software simulation. They can simulate a day in one second

The network is already being used by FACETS researchers to do experiments over the internet without needing to travel to Heidelberg.

New type of computing

Now the team are working on stage 2, a network of 200,000 neurons and 50 million synapses.

Beyond the brain?

Practical neural computers could be only five years away. Applications for neural computers are wherever there are complex and difficult decisions to be made. Companies could use them, for example, to explore the consequences of critical business decisions before they are taken.

The FACETS project, supported by the EU’s Sixth Framework Programme, is due to end in August 2009

Where could this go?

It is pointed out that neural computing, with its low-power demands and tolerance of faults, may make it possible to reduce components to molecular size publications


http://facets.kip.uni-heidelberg.de
http://www.sciencedaily.com/releases/2009/03/090318090142.htm