#ccsn

by Rebecca Steinberg

“Same-Stuff” static is the electricity generated when two objects of the same material are rubbed against one another. We see it on a day-to-day basis in lightning, the generation of powders, and explosions. Despite its prevalence in our daily lives, the mechanisms behind these phenomena have been called into question.

In the traditional understanding of same-stuff static, two insulating materials hold onto electric charges of different strengths. If the objects of the same material are the exact same size, each object holds the same amount of charge. When the sizes of these objects differ, the possibility of the charges held transferring increases, thus generating static electricity. 

What was believed initially was that valence electrons in a higher energy perch at the surface of one object interlocked with lower energy levels on the surface of the other object. The difference in sizes of the objects is important when considering the number of electrons that can be transferred.

Physicist Heinrich Jaeger at the University of Chicago is calling this idea into question. Jaeger tested this theory with the static found among small zirconium dioxide-silicate beads. Smaller beads were negatively charged, while larger beads were positively charged. But the number of valence electrons available for transmission on each bead did not correlate exactly with the amount of static electricity generated, suggesting that there is some other mechanism at play. The beads possessed too few valence electrons to explain the static. 

Jaeger suggests that the extra electrons needed to generate static may be derived from hydroxide ions in a layer of water one molecule thick, or in the zirconium metal itself. Although more extensive research is required to pinpoint the exact source of extra electrons, the impact of this information could be useful for pharmaceutical initiatives in the future. 

References:

by Rebecca Steinberg

Nearly all studies using animal models can be impacted by an animal’s stress level. Jeffrey Mogil’s group at McGill University noticed an extraordinary connection between the gender of an experimenter and how it confounded with their study on pain measurement.

Mice showed fewer signs of physical pain when in the presence of male researchers when measuring the intensity of their grimace. This observation is not merely based on the sight of a male, but is even offset by the odor of the experimenter. Mogil, et al. placed male and female odor-ridden T-shirts within the lab room and found a similar effect.

This decrease in pain was not merely a masking of pain, but an actual physical decrease in pain, according to Mogil’s group. This was measured by the amount of stress hormone released, the amount of fecal matter deposited, and the animal’s body temperature, among other methods. Mogil believes that this natural painkiller is part of a primordial response, established for eons. It may be an instinctive attempt to not appear weak in front of a threatening presence.

Stress levels are critical to the establishment of animal behavior. In a stressful environment, any recorded responses may differ vastly from responses in a relaxed state of mind. This may be a cause for the inability for certain labs to replicate studies (Grimm, D). There may even be human applications for this information, in comparing the pain responses to treatment by a male or female physician.

Future studies should take this confounder into consideration. The findings by Mogil, et al. serve as an eye-opening reminder of the many detailed factors that can make or break the results of an experiment.

  References:

  Grimm, D. (2014). Male Scent May Compromise Biomedical Research. Science/AAAS 3 May 2014. < http://news.sciencemag.org/brain-behavior/2014/04/male-scent-may-compromise-biomedical-research>.

  Sorge, RE, Loren, JM, Isbester, KA, Sotocinal, SG, Rosen, S, Tuttle, AB, Wieskopf, JS, Acland, EL, Dokova, A, Kadoura, B, Leger, P, Mapplebeck, JCS, McPhail, M, Delaney, A, Wigerblad, G, Schumann, AP, Quinn, T, Frasnelli, J, Svensson, CI, Sternberg, WF, Mogil, JS. (2014)  Olfactory exposure to males, including men, causes stress and related analgesia in rodents. Nat Meth 2014/04/28 online. http://www.nature.com/nmeth/journal/vaop/ncurrent/full/nmeth.2935.html. 

by Rebecca Steinberg

Treatment of a stroke is generally centered on the immediate consequences of a stroke, namely the sensorimotor impacts and mechanics of speech. Less focus is placed on the lasting cognitive effects of a stroke. Deborah Levine, MD, MPH, et al. from the University of Michigan found that stroke victims lose global cognition and executive function at a faster rate than elderly individuals who hadn’t experienced a stroke.

Stroke has an apparent relationship to mental decline, according to the analysis by Levine. A drop in cognition unsurprisingly appeared at the time of stroke, but was followed by a steady and fast cognition decline in subsequent years. Executive function, or connecting the present with past experiences, did not show an immediate decline after stroke, but decreased subsequently.

Rehab focuses on correcting the obvious, mechanical consequences of stroke, but it has been found that potentially less recoverable functions of cognition should be an added application of treatment. Cognitive therapies appear to have only a modest effect on improving lost cognitive function, and the longevity of these treatments is in question. The findings in Levine’s study might be strengthened with increased follow-up for stroke patients. It is certainly easier to identify the immediate, obvious effects of stroke, but the greatest impacts of a disease dealing with cognitive function might not be as readily assessed.

Further studies might consider the factors that lead to stroke and their impact on cognitive decline. Is there a prior cause of stroke that is linked with other illnesses to generate mental decline? A greater focus on long-term effects of illness might be a concept applied to diseases beyond stroke.  Do other diseases exist that require more extensive follow-up methods in order to fully understand any accompanying loss of function?  Finally, what rehabilitation therapies are most effective for treating something as complex as cognitive dysfunction and its decline?

  References:

  Phend, C. (2014). Stroke Speeds Long-Term Brain Deficits. MedPage Today. http://www.medpagetoday.com/MeetingCoverage/ISCNeuroEdition/44342?xid=nl_mpt_AAN_confreporter_2014-02-18&utm_source=aan-confreporter&utm_medium=email&utm_content=mpt&utm_campaign=18%7C02%7C2014&userid=&eun=g5968703d8r&[email protected]&mu_id=5968703.

by Rebecca Steinberg

Epigenetics is the study of heritable genetic activity without alteration to the DNA sequence. It can also apply to stable, long term changes in transcriptional regions of a cell. Epigenetics is a term that has been liberally tossed around in the scientific community, but what exactly constitutes the phenomenon of epigenetics? Three traits of an epigenetic system must be present: the changes must be heritable, self-perpetuating, and reversible. Among commonly referenced phenomenon are prions, DNA methylation, nucleosome locations, histone modification, and noncoding RNA. But how can we accurately use the term epigenetics in a clinical context?

Epigenetic studies are of particular interest with regards to genetic variations not explained by differences in genome sequence. Epigenetic research has been sited in several genetic disorders, primarily with regards to imprinting, or the selective “on-off switching” of specific genes, chromosomes, or parts of chromosomes. For example, Prader-Willi syndrome occurs when certain genes on chromosome 15 of the paternal chromosome are unexpressed or silenced.

Recent studies are attempting to take advantage of the reversible trait of epigenetics in treating cancer patients. Already, certain patients suffering from liver cancer respond favorably to drugs that inhibit DNA methylation.

As evidence that individualized gene expression is, in fact, real, twin studies provide a basis for epigenetic claims. Identical twins carry all the same genes, but they are by no means exactly the same. Whether due environmental or epigenetic effects, twins might respond to the same stimuli in different ways. A study by King’s College London found that identical twins possessed differing pain tolerances. In addition to studying the epigenetic differences between the twins, researchers examined the epigenetic similarities among unrelated subjects. Further epigenetic studies in this realm might better target pain sensitivity with a focus on epigenetic modification.

Epigenetics is not only the basis for the fundamental differences that make us unique, but could be the answer to an effective treatment for common diseases and disorders.

References:

Raddihough, G., & Zahn, L.M. (2010). What is Epigenetics? Science 330(6004): 611.

King’s College London. “Pain sensitivity may be influenced by lifestyle, environment, twin study suggests.” ScienceDaily. ScienceDaily, 4 February 2014. <www.sciencedaily.com/releases/2014/02/140204112123.htm>.

by Rebecca Steinberg

If I told you that your brain is similar to a machine, your first thought might be about the electrical potentials that travel along axons or the chemical signals generated at synapses.  But what if I told you that your brain is like a machine—not because of the way it sends signals—but because it requires regular maintenance?

Emily Underwood considers the role of sleep based on a new study from the University of Rochester.  For years, researchers have been debating and proposing theories for the necessity of sleep.  Why would humans sacrifice constant alertness for a state of unconsciousness?  Maiken Nedergaard, Lulu Xie, and their colleagues may have justified the purpose of sleep.

According to the study, in sleep, the brain cleans itself.  Specifically, cells within the brain channel fluids in order to clear the brain of toxic metabolic byproducts.  The fluid, cerebrospinal fluid (CSF), acts as a scrub that washes away the “dirt” outside of cells.

Xie studied the activity of these channels in sleep for mice and found that the channels expanded to allow for more CSF to flow into the brain in sleep, but not when the subject was awake.  The theory behind this is simple: the brain cannot be “in use” and “in repair” at the same time.

Nedergaard et al. suggest that the “dirt” washed away includes byproducts from usage.  If these byproducts build up, Nedergaard predicts, this might be a cause of general brain damage and common neurological diseases through aggregation, such as Alzheimer’s disease.  This serves as a potential two-way street—these byproducts may signal to our brain that we need sleep, perhaps making us drowsy.

Other vying theories on sleep include memory consolidation, metabolism calibration, and fortification of the immune system.  Many researchers believe that these tasks work hand-in-hand during sleep, and that not just one mechanism is the primary function of sleep.  We already know that individuals who sleep alone are prone to a sleep fragmentation and fatigue during the day (see last month’s blog).  Now, we can predict that the cause of this fatigue is the buildup of metabolic byproducts, or the inability for the brain to give itself a good scrubbing.

Though there is still much to understand about sleep as a physiological requirement, the findings of Nedergaard et al. pave the way for further studies in the field.  Is this finding concerning CSF channels applicable to humans, or is this just observable in mice?  Can the activation of these channels be manipulated to remedy neurological diseases?  Do drugs, such as caffeine, that stimulate the brain to combat sleep have any effect on these channels?  Researchers have just scratched the surface of the common but mystifying phenomenon of sleep in humans.

  References:

  Underwood, E. (October 17, 2013). Sleep: The Ultimate Brainwasher? Science/AAAS, 342(6156), 301. http://news.sciencemag.org/brain-behavior/2013/10/sleep-ultimate-brainwasher

by Rebecca Steinberg

Being ostracized can cause a person great anxiety.  We often describe feelings of social and romantic rejection in parallel with physical pain, hence the term “heartbreak.”  But are these pangs of pain in response to distress directly associated with rejection, or do these perceived physical responses operate on a much deeper neurological level?

Several studies with small number of subjects highlight the activation of the pain matrix in the brain in response to social rejection. Qualitative reviews of Cyberball neuroimaging studies in particular emphasize the pain matrix activated by ostracism in a three-person game of catch with strangers.  These studies argue that activity of this region directly corresponds to the manifestation of social pain in the body.

However, a recent, quantitative meta-analysis of the Cyberball neuroimaging studies challenge this view by arguing that depending on the type of rejection, different regions of the brain may be stimulated, and that even with the stimulation of the pain matrix, there may be no physical connection between emotional rejection and literal pain.

Director of the CCSN HPEN laboratory, Stephanie Cacioppo et al. investigated this question through a quantitative meta-analysis of fMRI studies of social rejection including more than 300 participants.  Their findings indicate insufficient evidence exists that social rejection manifests itself in a literal, physical form.  Even with the manipulation of individuals involved in rejection, from friends to romantic partners, deficient neurological imaging data was available to comfortably conclude the connection of literal pain with rejection.

This work leaves open a number of important questions.  How heavily activated are certain regions of the brain when an individual is more or less concerned with the rejection at hand?  Could other types of rejection, such as from programs, institutions, or friendships, activate different brain regions than the rejections of strangers or romantic partners?  And finally, if the pain centers of the brain are activated and indeed incite physical pain in an individual, what motivates a person to keep moving forward emotionally in their attempts for approval, despite the natural human tendency to avoid painful stimuli?  The study by Cacioppo et al. reveals that there is much to be understood in the connection of emotional events and their accompanying physical response.

References:

Cacioppo, S., Frum, C., Asp, E., Weiss, R. M., Lewis, J. W., & Cacioppo, J. T. (2013). A Quantitative Meta-Analysis of Functional Imaging Studies of Social Rejection. Sci. Rep. 3, 2027; DOI:10.1038/srep02027.

by Rebecca Steinberg

The “high-school sweetheart” image of dating that America is known for is undergoing rapid technological upgrades.  With the emergence of on-line dating, meeting other singles is a convenient click away.  On-line dating has become an innovative socializing resource, particularly for those with full work weeks and little time.  Though the means of online dating has become diverse and expansive, the outcome of marriages founded through dating sites has not been as extensively investigated.  John Cacioppo, director of the CCSN, et al. reveal the effect of spouse meeting venue, on-line or otherwise, on overall marital satisfaction.

The data suggests that marriages generated from an on-line venue are more likely to result in marital satisfaction than off-line venues.  What might cause the effectiveness of on-line dating?  Cacioppo et al.’s study didn’t specifically address this question. Further scientific studies need to be done to explore the causal relationship between meeting venues and long-term marital satisfaction. In the meantime, one might draw a few hypotheses.

Three factors of dating spring to mind that might account for this trend.  The first and most obvious reason for the success of on-line dating is the ability to be selective for traits.  When an individual knows the type of partner right for them, easily selecting those traits and narrowing available options proves to be more time-efficient by leaving less room for unexpected, incompatible qualities.  While traditional daters might have to engage in scores of incompatible matches, on-line dating provides more guaranteed matches by emphasizing personality before physical attraction.

The second reason might be the lack of face-to-face confrontation.  As observed in myriad social media sites, such as Facebook, Tumblr, and Twitter, the ability to converse with others is made easier through a computer, rather than a personal interaction.  On-line dating draws away the pressure of being “interesting” on the spot by generating user confidence.  By lowering social pressure, dating sites appear to generate more fluid conversation in which each partner is eager and interested in what the other is typing.  This greater “on-line self-disclosure” may take away the tension and uncertainty that typical dating methods might possess. 

The third reason for the success of on-line dating may be the personality type of site users.  Users may be more impulsive or willing to take risks on-line rather than off-line, because the consequences of “putting oneself out there” appear less severe.  In addition, users may be specifically looking for marriage partners, rather than casual dating, and so might take on-line dating more seriously than off-line couples.  Motivation, willingness, and overall lifestyle may be driving forces behind the success of on-line founded marriages.

Despite the apparent success of online dating, on-line venues may still be improved to accommodate even more searching singles.  By examining which off-line venues appear the most successful for marriage (schools, places of worship, and social gatherings) in contrast with the least successful (bars, work, and blind dates), dating sites may be restructured to provide an even more satisfactory dating experience for those too busy to fit dating into their schedule. 

References:

Cacioppo, J. T., Cacioppo, S., Gonzaga, G. C., Ogburn, E. L., & VanderWeele, T. J. (2013). Marital satisfaction and break-ups differ across on-line and off-line meeting venues. PNAS, 110 (25), 10135-10140.