Can Portable EEG Headsets be Used to Determine if Students are Learning?

This study examined EEGs recorded from a single-channel, portable EEG headset (NeuroSky MindWave) during the study period of a paired-associate word paradigm which used Swahili words and their English meanings. It was hypothesized that there would be a significant difference in gamma, theta, and beta band powers for when students recalled words correctly vs. when they did not recall correctly on a subsequent test. There were 35 participants who consisted of students that volunteered at the University of Memphis (20 females and 15 males, 31 of which were right-handed and 4 which were left-handed). A paired-samples t-test suggested that there was a higher mean z-score for brainwave activity during the study period in the high gamma range (41-49.75Hz) for when participants did not recall words correctly on a test, which was opposite of what previous research has found regarding encoding. Based on the results of this study, the MindWave seems to capture muscle activity and/or saccadic behavior that is suggested by higher gamma maximums on average in the study period for word-pairs which resulted in failed recall. Exploratory results may lend insight to future work using portable EEG devices. This study\u27s main objective was to determine if portable EEG devices could be used to determine when students learn new information. Further testing, especially using other portable EEG devices is necessary to answer this question

Physically-Induced Cytoskeleton Remodeling of Cells in Three-Dimensional Culture

<div><p>Characterizing how cells in three-dimensional (3D) environments or natural tissues respond to biophysical stimuli is a longstanding challenge in biology and tissue engineering. We demonstrate a strategy to monitor morphological and mechanical responses of contractile fibroblasts in a 3D environment. Cells responded to stretch through specific, cell-wide mechanisms involving staged retraction and reinforcement. Retraction responses occurred for all orientations of stress fibers and cellular protrusions relative to the stretch direction, while reinforcement responses, including extension of cellular processes and stress fiber formation, occurred predominantly in the stretch direction. A previously unreported role of F-actin clumps was observed, with clumps possibly acting as F-actin reservoirs for retraction and reinforcement responses during stretch. Responses were consistent with a model of cellular sensitivity to local physical cues. These findings suggest mechanisms for global actin cytoskeleton remodeling in non-muscle cells and provide insight into cellular responses important in pathologies such as fibrosis and hypertension.</p> </div

Data supported a hypothesis that the global cellular phenomena observed were triggered by local physical cues.

<p>(A) A mathematical model was developed to test this on idealized cells, as described in detail in the supplemental methods section. Shown here are cartoons of idealized circular cells containing a population stress fibers that changes over time according to our model. Cells were divided into sectors, and stress fibers in each sector were assigned a level of pre-stretch. Sectors that were stretched or compressed outside of the allowable range depolymerized (white); those that did not depolymerize and that exerted sufficient stress on their adhesions became denser in stress fibers (darker). (B) All three types of temporal response were reproduced by the model. (C) Cells with lower variability in stress fiber pre-stretch levels tended to exhibit monotonic reinforcement and polarization, with sectors aligned with ETC stretch becoming denser with stress fibers. Those with higher variability tended to exhibit monotonic retraction or reinforcement following retraction.</p

Time series (frame rate: one confocal image stack every five minutes) showing partial fluidization followed by reinforcement and formation of actin stress fibers in response to mechanical stretch of 5%.

<p>(A) Following stretch, the actin cytoskeleton fluidized partially, but stress fibers reappeared or were reinforced over the 30 minutes of monitoring. The cell pictured contracted as reinforcement occurred, shortening in length along the stretch direction. (B) Formation and reinforcement of stress fibers is evident from subtraction images involving differences in image intensities of subsequent images (e.g. “2–1” represents the subtraction of image 1 from image 2). Images were aligned prior to subtraction using standard techniques in Matlab. Note that subtraction images contain effects of both cell shortening and stress fiber formation.</p

Three types of cytoskeletal response were observed following stretch (A, with two examples shown).

<p>The first time point imaged in each case was approximately two minutes after stretch, allowing sufficient time for stretch-induced cytoskeletal depolymerization to occur. The normalized fibrosity metric measures changes in the total length of features in an image that are within the thickness range of stress fibers (“fibrosity”). These three classes of response were significantly different relative to an unstretched control (B). Each curve represents the average of at least three cells that were imaged at both 5% and 10% stretch; error bars are standard error.</p

Model predictions of whether or not sectors of stress fibers in a circular cell would depolymerize following ETC stretch.

<p>Symbols represent the degree of stretch in stress fibers in individual sectors that would exist after the application of stretch to the ETC if depolymerization of stress fibers did not occur. Depolymerization does occur when stretch in a sector lies outside of a prescribed range, and the red symbols represent sectors that were predicted to depolymerize. For very low variation of stress fiber pre-stretch (top panel), only sectors nearly parallel (0°) to or perpendicular (90°) to the direction of ETC stretch were predicted to depolymerize. For higher variance in pre-stretch values (bottom two panels), the direction-dependence of depolymerization became weaker.</p