Women Have a Better Sense of Touch
December 28, 2009
People who have smaller fingers have a finer sense of touch, according to new research in the Dec. 16 issue of The Journal of Neuroscience. This finding explains why women tend to have better tactile acuity than men, because women on average have smaller fingers.
“Neuroscientists have long known that some people have a better sense of touch than others, but the reasons for this difference have been mysterious,” said Daniel Goldreich, PhD, of McMaster University in Ontario, one of the study’s authors. “Our discovery reveals that one important factor in the sense of touch is finger size.”
To learn why the sexes have different finger sensitivity, the authors first measured index fingertip size in 100 university students. Each student’s tactile acuity was then tested by pressing progressively narrower parallel grooves against a stationary fingertip — the tactile equivalent of the optometrist’s eye chart. The authors found that people with smaller fingers could discern tighter grooves.
“The difference between the sexes appears to be entirely due to the relative size of the person’s fingertips,” said Ethan Lerner, MD, PhD, of Massachusetts General Hospital, who is unaffiliated with the study. “So, a man with fingertips that are smaller than a woman’s will be more sensitive to touch than the woman.”
The authors also explored why more petite fingers are more acute. Tinier digits likely have more closely spaced sensory receptors, the authors concluded. Several types of sensory receptors line the skin’s interior and each detect a specific kind of outside stimulation. Some receptors, named Merkel cells, respond to static indentations (like pressing parallel grooves), while others capture vibrations or movement.
When the skin is stimulated, activated receptors signal the central nervous system, where the brain processes the information and generates a picture of what a surface “feels” like. Much like pixels in a photograph, each skin receptor sends an aspect of the tactile image to the brain — more receptors per inch supply a clearer image.
To find out whether receptors are more densely packed in smaller fingers, the authors measured the distance between sweat pores in some of the students, because Merkel cells cluster around the bases of sweat pores. People with smaller fingers had greater sweat pore density, which means their receptors are probably more closely spaced.
“Previous studies from other laboratories suggested that individuals of the same age have about the same number of vibration receptors in their fingertips. Smaller fingers would then have more closely spaced vibration receptors,” Goldreich said. “Our results suggest that this same relationship between finger size and receptor spacing occurs for the Merkel cells.”
Whether the total number of Merkel cell clusters remains fixed in adults and how the sense of touch fluctuates in children as they age is still unknown. Goldreich and his colleagues plan to determine how tactile acuity changes as a finger grows and receptors grow farther apart.
The research was supported by the National Eye Institute and the Natural Sciences and Engineering Research Council in Canada.
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Source: Society for Neuroscience
Photo: nesharm / iStockphoto
New Inherited Eye Disease Discovered
December 12, 2009
University of Iowa researchers have found the existence of a new, rare inherited retinal disease. Now the search is on to find the genetic cause, which investigators hope will increase understanding of more common retinal diseases.
The findings appeared in the Nov. 9 issue of the Archives of Ophthalmology.
The macula, located within the retina, is an area of high-resolution central vision that is needed to read or drive, for example. This area is damaged in more common retinal conditions such as macular degeneration and can be damaged by diabetes.
Antioxidants Could Be H1N1 Influenza’s Achilles Heel
December 8, 2009
A recent article from the FASEB Journal shows that antioxidants, largely found in plant-based foods, just may be H1N1 influenza’s Achilles heel. In laboratory testing they demonstrate the ability to prevent the H1N1 virus from invading and colonizing our lungs. The research, conducted by Sadis Matalon and his colleagues, also suggests that antioxidants can help in the treatment of H1N1 influenza.
The team of researchers discovered that influenza virus’ contain a protein called M2, which destroys or damages the epithelial cells of our lungs by removing liquid from inside, promoting the early stages of pneumonia as well as other lung problems.
Brain Stimulation with Infrared Light
December 2, 2009
Researchers have recently found that infrared light has the capability of stimulating brain cells. Infrared light causes the excitation of neurons thus altering their activity. This new type of brain stimulation method is referred to as infrared nerve stimulation (INS). INS has a variety of applications for altering the functioning of central nervous system disorders. For many brain disorders, brain activity is altered in comparison to more normal states. Infrared light has a very high selectivity and can target very small sub-populations of brain cells. This type of stimulation could potentially reduce many of the side effects of current brain stimulation.
Are Right-Handed People Right-Eared As Well?
November 27, 2009
It never occurred to many of us that there is a difference between our left and right ears as far as hearing capabilities are concerned. We always thought that the ears have equal distribution of hearing capabilities but results of studies show that there is indeed a difference. So, which ear can people hear best with? In the results of most studies, they indicate that if a person is right handed, the ear that can hear best is the right one too. Same theory of course applies for left-handed people. Interesting, don’t we think?
Where Do Those Cold-blooded Animals Go in Winter?
February 13, 2009
I love a New England winter. With snow falling and wind raging outside, I’m inside with hot chocolate in hand, curled up in my puffy chair, and snug-as-a-bug-in-a-rug. What’s that? Is a bug actually snug in a rug? Better not be in my rugs! Bugs and other creatures are outside in the elements, not in my rugs I hope.
So how do cold-blooded creatures cope with this season, anyway? First of all, let’s be clear on what, “cold-blooded” means. This is actually an inaccurate and outdated word. We’re talking about animals that get their heat from their environment, like amphibians, reptiles, insects and other arthropods, and fish. We call them “ectothermic”, meaning literally, “outside heat”. These creatures seek out warm places or cooler places in order to stay just the right temperature. The benefit of being ectothermic is food. They don’t need to eat nearly as much as mammals and birds who need to fuel that fire within. Going without eating for a few months therefore works for them; winter’s cold though is a challenge.
Definitions and Dangers Of Genetically Modified Organisms
September 2, 2008
Can genetically modified organisms be defined? Biologists classify every living thing into four basic categories (Plantae, Animalia, Protista and Fungi). Yet, Genetically Modified Organisms could fall under several of those categories and therefore are in a category all their own.
Since Genetically Modified Organisms often contain genes from different kingdoms, they do not fall into any of these categories and cannot technically be considered an animal, a plant, a protist or a fungi. Nor can they simply an animal, vegetable or mineral. They are not even natural (as nature has never combined the DNA of two different Kingdoms, in the history of the planet).
Even when GMOs consist of two species of the plant kingdom or animal kingdom, they are technically a new plant or animal. So, really, what are they?
The Jewel of the Sea
September 1, 2008
Diatoms, microscopic algae that encase themselves in ornate, exquisitely patterned glass shells, are found in prolific numbers in every ocean on earth. They have fascinated scientists for centuries—in fact, ever since the microscope was first invented and men could sketch their beauty. Justifiably, the diatom is called the jewel of the sea.
Electromagnetism for Brain Disorders
July 29, 2008
Transcranial magnetic stimulation (TMS) has helped to improve a variety of different brain disorders including schizophrenia, migraines and major depression. The general idea behind this technology is using an electromagnetic pulse that passes through a person’s skull and this then generates an electric current inside their brain. By changing the frequency of the pulse, researchers can either increase or decrease activity selectively in many brain areas.
The main problem with current TMS is that it can penetrate only around 1-2 cm into the brain. So it is basically limited to activating and deactivating brain regions in close proximity to the skull (the neocortex). Researchers have created a new deep transcranial magnetic stimulation device that is able to reach further into the brain. This device can inhibit or excite more areas that were previously out of reach. It has the ability to reach almost any brain area. Many brain disorders often have areas that are either overactive or underactive when compared to a normal brain. So this technology may eventually allow scientists to normalize acitivty in disturbed brain regions by non-invasive stimulation. TMS can be performed on a person while they are wide awake and fully conscious. So the ease of use for this device is extremely good.
Researchers are testing the device to treat people who are overweight or obese. To do this they are stimulating the hypothalamus which is a deeper brain structure. The hypothalamus is involved in the body’s metabolic processes. So stimulating this area may allow a person to lose weight. This would be a non-invasive way of shedding the pounds without actually having to do any work.
Researchers are using deep tms to reduce the auditory hallucinations that accompany schizophrenia. About 50 to 70 percent of schizophrenic patients can hear voices that aren’t real. These voices can be very frightening and distressing as they can make disparaging comments to the person. Researchers have discovered that an area of the brain named the left temporoparietal cortex is activated when auditory hallucinations are occuring. Deep TMS will be able to decrease activity in this specific brain areas and this may lead to a reduction in auditory hallucinations.
Researchers are also using this device to treat many of the symptoms of depression. They are directly targeting brain areas that are involved in a person’s ability to experience pleasure. Electrical stimulation of the nucleus accumbens has been shown to be rewarding. However until recently, stimulating this area required patients to undergo brain surgery to get an implant. Now, scientists are able non-invasively stimulate this area of the brain without the need for surgery. Depressed patients often experience anhedonia (the inability to experience pleasure). This is due to altered functioning of the reward circuits of the brain. So stimulating specific brain areas associated with reward using deep tms may be able to alleviate chronic anhedonia and apathy in depressed patients.
The researchers have already done studies on upwards of 100 depressed patients and have found the deep tms can relieve anhedonia in over 50% of them. So this treatment may enable depressed patients to get more enjoyment from life than they would normally. In a study performed on bipolar depressed patients, researchers found that 80% of the patients responded to the treatment, while 50% of them experienced a significant improvement in their symptoms. The scientists have even tested the deep TMS on normal healthy volunteers and have claimed that it improved their mood. So this treatment may even allow a healthy person to get more enjoyment from life.
This new deep TMS technology shows a lot of promise for many different brain disorders. It may allow a person to shed the pounds, experience more pleasure in life and increase overall mood. If this technology even does half what the company says it can, it will definitely be a revolution in the treatment of brain disorders.
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About the Author:
Michael Webb blogs about transcranial direct current stimulation, Deep transcranial magnetic stimulation and deep brain stimulation.
Cocktails, Neurons and Nanos: Super-cognition?
April 9, 2008
Improving overall cognitive capability is becoming as simple as consuming a pill…
An interesting paradox has been the axis of much attention in the fields of pharmacy, brain research and ethics in the last few years. The advent of new technologies, particularly in the field of brain research, has induced scientists to improve the treatment of several conditions, such as Alzheimer’s disease, sleep disorders and dementia. However, what was primarily intentioned to provide solutions for patients with cognitive deficits has also proven functional for healthy people – not only functional, but quite efficient.
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