Author Archives: jdfloyd

May
02
2013

Autobiographical Memory and the Brain

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Do you have a highly superior autobiographical memory? Meaning, can you tell your life’s story from childhood to present with effortless ease? Let me give you a quick quiz. Describe your day on March 14, 2002. Unless this day was your birthday or of special significance to you, the likelihood of you succeeding to fulfill my request is rare. However, if you were successful, your brain may be different, not only in your experiences and knowledge but even in functioning and composition.

This unique ability to recall information has been studied by the University of California, Irvine (UCI) Center for Neurobiology of Learning and Memory. A study of eleven people with highly superior autobiographical memory has showed a distinction in nine structures of the brain. More white matter was located between the frontal lobe and the parietal region. Most other differences were in parts of the brain known to have a link to autobiographical memory.  The memories have 99% accuracy beyond around ten years old. Other correlations were found between the study’s subjects. Obsessive-compulsive tendencies, which may or may not be associated with their memory capabilities, were prevalent among the group. Also, a common hobby of the subjects was having incredibly organized collections of a wide range of objects.

Another unusual aspect of these findings is that these people with highly superior autobiographical memory did not have extraordinary memory capabilities in other categories of memory such as mass amounts of facts or intellectual material. This gives a refining to the area of autobiographical memory. The separation of one type of memory from another may lead to a better understanding of the memory processes and how they develop variation from possibly genetics or in linkage and cooperation between brain structures. An exciting alternative explanation is that experiences and training can lead to these changes in the brain.

 

References:

Cleary, Anne, Ph.D.. “People with Extraordinary Autobiographical Memory | Quirks of     Memory.” Psychology Today: Health, Help, Happiness + Find a Therapist. Sussex   Publishers, LLC, 9 Jan. 2013. Web. 19 Apr. 2013.

University of California – Irvine. “Brains are different in people with highly superior autobiographical memory.” ScienceDaily, 30 Jul. 2012. Web. 19 Apr. 2013.

 

 

May
02
2013

Toads’ Leaping Legs

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Toads are generally known for their warts. However, the toad’s impressive attribute is its strong, powerful leg musculature. While the jumping distance is noteworthy, the landing ability is what is interesting to biologist Emanuel Azizi. The studies he performed involved the toad’s ability to protect its leg muscles by bracing for specific impact intensities.

When jumping, toads’ leg muscles contract. When landing, these muscles stretch. The body comes to a complete stop after moving at a fairly high speed due to the muscles acting as brakes. To disperse the energy and force of impact, the muscles of the legs take the risk of overstretching and possible injuries. A neuromuscular response to shorten the leg muscles that are involved in landing protects the muscles during larger impacts from jumping longer distances. How much the muscles shorten depends on the distance of the jump. The nervous system adapts the motor control patterns with each individual jump.

These findings can be applied to rehabilitation programs in the future. Neuromuscular deficiencies may be better understood by the looking at the strength and precision of the nervous system adaptations in toads. With further study into the sensory information being reported to the nervous system which enables the quick defensive measures to prevent injury, improvements can be made to the way we treat strains and overstretching injuries of muscles in humans.

References:

Nogrady, Bianca. “Toads Tweak Muscle Length to Soften Impact › News in Science (ABC Science).” Toads             Tweak Muscle Length to Soften Impact › News in Science (ABC Science). Australia’s Broadcasting              Company, 19 Dec. 2012. Web. 03 Apr. 2013.

University of California – Irvine. “Leaping toads reveal muscle-protecting mechanism.” ScienceDaily, 19  Dec. 2012. Web. 2 Apr. 2013.

Apr
25
2013

The Star-nosed Mole and Sensory Receptors

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The most sensitive area to touch in a human is located at the fingertips. Touch receptors are densely packed with about one hundred per square centimeter. Pain receptors (nocireceptors) occur at lower ratio. The neurons can respond to these two possible stimuli at the same time. What keeps these signals from mixing?

A look at the star-nosed mole (which is not only the fastest eating mammal, but also the animal with the most touch and pain sensitive organ of any mammal) may help. The most sensitive area is not in its fingers (because it has claws) but on its nose. The star shaped portion of its nose has the highest density of nerve endings with over one hundred thousand fibers per square centimeter of skin. Neurons are packed into these nerve endings. More of these neurons respond to touch rather than pain. This translates into several other mammals as well.

This news is important new research because these same types of receptors have been found in the sensory receptors of humans and mice. The sense of touch and pain are closely related, but knowing how these are sensed simultaneously and differentiated in the cells is still being researched. The goal of these studies is to pinpoint certain genes that distinguish which sensation should reported, touch or pain. Further findings in this field may lead to treatments of chronic pain through new medications or types of therapy.

 

References:

Kimball, John W. “Mechanoreceptors.” Mechanoreceptors. Kimball’s Biology Pages, 19 Feb. 2011. Web. 28 Feb. 2013.     http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mechanoreceptors.html

Public Library of Science. “Leading by the nose: Star-nosed mole reveals how mammals perceive touch, pain.” ScienceDaily, 30 Jan. 2013. Web. 28 Feb. 2013.             http://www.sciencedaily.com/releases/2013/01/130130184156.htm

 

Feb
13
2013

Stress Can Shrink the Brain

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In light of upcoming exams, stress may be on the rise among students. However, students should take extra precautions against falling prey to stress. The physical tolls that stress takes on the body affects homeostasis in the brain and can actually cause the prefrontal cortex to shrink. This portion of the brain controls metabolism, emotions, self control, and the ability to adapt.

Studies have pinpointed which types of stress affect which part of the brain. Stress from a life trauma (more of a prolonged circumstance) can shrink the mood centers of the brain and cause depression and anxiety disorders. Stress from single life events affect emotions and can cause inappropriate emotions or a lack of emotions. Chronic stress from day to day activities does not pose an immediate threat to the size of the brain, but may gradually shrink the prefrontal cortex. This could lead to a person having an unusually difficult time when faced with adversity or life trauma because his or her brain has already eroded from former stressors.

While these are alarming studies in adults, the results are even more of concern for children. Stress and traumas experienced by children can shrink their brains in the area associated with fear and threat. Because the brain is still forming at this time, the damage may be more definitive. Social, emotional, cognitive, and behavioral aspects of children can be affected. If already affected by stressors in life, maintaining current brain health and even reversing some of the effects of stress may be possible through exercise, meditation, and positive social relationships.

 

Park, Alice. “Study: Stress Shrinks the Brain and Lowers Our Ability to Cope with Adversity | TIME.com.” Time. Time, 09 Jan. 2012. Web. 31 Jan. 2013.

Perry, Bruce D. and Pollard, Ronnie. “Homeostasis, stress, trauma, and adaptation: A neurodevelopmental view of childhood trauma.” Database: PsychINFO. Child and Adolescent Psychiatric Clinics of North America,  Vol 7(1), Jan   1998, 33-51.