There is still a great deal that is unknown about various depressive conditions, though it is a very common affliction and cause of disability throughout the world. Not only do the underlying mechanisms of various types of depression remain uncertain, but the mystery of how different treatment options work and who will respond to them also persists. The aim of this study was to identify potential non-invasive biomarkers, to predict responsiveness to electroconvulsive therapy. Two hypotheses were investigated in this study. The first was that patient improvement from baseline on the neurocognitive, computer based pattern separation task prior to the third ECT treatment will correlate with a clinical antidepressant response. The second was that increased prefrontal slowing relative to baseline will correlate with a decrease in depressive symptoms. As a first step to validate this approach, a healthy control group performed both the pattern separation and EEG tasks once per week over the course of three weeks. Patient participants completed both tasks before their first ECT treatment, prior to their third treatment, and prior to their last treatment. A spectral analysis of EEG data was then conducted. Results indicated good test-retest reliability for the pattern separation task and EEG measurements across all three trials in the healthy control group. Results from patient data are inconclusive, but indicates that there is a change from baseline to subsequent trials for at least the EEG measurements. However, a larger sample size is needed to determine this. The limited results from this small patient sample suggest that these measurements may have clinical value in refining ECT treatment, and merit further study.

This project analyzed gender and color-specific differences in event-related potentials (ERPs). Previous studies have shown that males process color differently than females. In a recent study, sex differences were found in ERPs during a visual object recognition task. There were higher EEG amplitudes in females (especially P300) than males. Significant sex and color-specific differences have been found in diseases involving altered dopamine (DA) machinery. Thus, we analyzed differences between ERPs in males vs females during a color task. We also compared the color-specific differences in ERPs between males and females. Males and females participated in EEG recording sessions for 2 color studies during a color-go-no-go task, where two studies examined the gender and color-specific differences in ERPs, respectively. Data from 32 males and 24 females and 21 females and 31 males, respectively, in two color studies demonstrated significant sex-specific differences in ERPs during a color-go-no-go task. Males consistently showed higher EEG amplitudes (particularly P300) than females, which is contradictory to what we demonstrated previously in the object recognition task, indicating different color processing systems in males and females. Regarding color-specific differences, no significant differences were found in P300s between the three colors red, green and blue in males and females when each color was the relevant stimulus, suggesting that color is not a marker for inducing ERPs in normal subjects. These studies will provide the impetus to compare patients having altered DA mechanisms such as in attention-deficit hyperactivity disorder (ADHD), Parkinson's, or chemical addiction.

Emotional eating behavior is characterized by eating a large amount of calorie dense sweet and/or high fat foods in an attempt to control, cope with, or avoid negative emotions. Numerous factors are likely to contribute to emotional eating behavior, including attentional factors, such as rumination and avoidance coping. Rumination based emotional eating (attention focused on negative stimuli while mindlessly eating) is often utilized to improve mood while dwelling on problems. However, for those inclined to escape/avoid troublesome thoughts, another type of emotional-eating pattern may be used. By focusing attention on food, emotional eating is believed to distract individuals from negative emotions. However, along with avoiding distressing thoughts, a strong attentional focus on food may also lead to diminished attention resources and subsequently the missing of self-preserving thoughts (e.g. dietary restraint or satiety). While Denke & Lamm (2015) explored neural mechanisms underlying rumination based emotional eating, to the best of our knowledge, no one has investigated the neural correlates underlying avoidance based emotional eating. This study examined how attentional sub-processes contribute to emotional eating behavior among female participants in a task designed to explore escape type emotional-eating behavior. Dense-array EEG and a version of the canonical attentional blink task were used to ascertain the neural correlates underlying the attentional sub-processes and how attentional activation differs for emotional eaters vs. non-emotional eaters. Findings do not support the food fixation escape type emotional-eater hypothesis, but do indicate task validity.

Tack vare framsteg inom portabel elektroencefalografiteknologi (PEEGT) har det blivit lättare och billigare att studera hjärnans aktivitet i form av hjärnvågor. Syftet med det här arbetet var att studera skillnaden i hjärnaktivitet mellan musikaliska aktiviteter, genom att använda sig av PEEGT. Verktyget som användes till ändamålet är utvecklat av företaget EMOTIV och heter ”Insight”. Att använda sig av PEEGT för att uppskatta känslor och sinnestillstånd är ett relativt nytt forskningsområde med en lovande framtid. Det här arbetet motiveras av möjligheten att använda sig av sådan hjärnforskning för att leta efter svar på frågor kring undervisning och musicerande. Till studien valdes de två musikaliska aktiviteterna improvisation och avistaläsning. EMOTIVs Insight användes sedan till att samla data vid 10 olika tillfällen, som därefter analyserades med ett Wilcoxon signed rank test. Den kvantitativa datan triangulerades med anteckningar från en loggbok om subjektiva upplevelser vid de 10 mättillfällena. Resultatet visade ingen statistiskt signifikant skillnad mellan de musikaliska aktiviteterna. Som varandes ett självexperiment visade det sig ändå vara lärorikt för forskningssubjektet, framförallt vad gäller insikter om förhållandet mellan anteckningarna i loggboken och datan från EEG:en. Förhoppningsvis kan arbetet tjäna som inspiration till att göra liknande arbeten i framtiden. / Thanks to recent advances in the development of portable electroencephalografy technology (PEEGT), doing research on brain activity has become both cheaper and more convenient to do. The purpose of this study was to investigate the difference of the brain activity between musical activities, using the commercially available PEEGT “Insight”, developed by the tech company EMOTIV. The use of these PEEGT to estimate states of mind and emotions is a relatively new area of research, with a promising future. The study is motivated by the possibility to use research like this to address questions about education and musicmaking. Two musical activities were chosen for the study, improvisation and sight-reading. EMOTIVs Insight was used to collect data on 10 separate occasions, which later was analyzed with the Wilcoxon Signed Rank Test. The quantitative data was triangulated with notes from a logbook about the subjective experiences during the 10 occasions. No statistically significant difference was found between the activities. On the other hand, the study proved useful for the subject. Especially regarding insights on the relationship between the notes in the logbook, and the reported data from the EEG. Hopefully the work can also serve as an inspiration for future studies.

Atypical sensory reactivity to visual and/or auditory stimuli is prevalent among individuals with autism spectrum disorders (ASD). Data from cognitive neuroscience research suggests that changes in attention can alter sensory processing at several levels of analysis, and thus could be contributing to changes in sensory reactivity. Furthermore, attentional pathways are modulated by the individual difference variable of working memory capacity (WMC). This study examined the relationship between sensory reactivity, individual difference, and auditory attention in ASD by using electroencephalography technique. Participants (n=25, 12 with ASD and 13 age- and IQ-matched controls) completed a sensory profile, complex operation span task for working memory capacity (WMC), and performed a modified 3-stimulus (target, non-target, and distractor) oddball task under varying perceptual load (high or low). Event-related potential (ERP) analysis assessed early sensory processing (P50, ~50ms latency; N100, ~100ms latency), cognitive control (N200, ~200ms latency), and attentional processing (P3a and P3b, ~300ms latency). Behavioral data demonstrates participants with ASD and neurotypical performed similarly on WMC and auditory target detection, but diverged in sensory profiles. In target processing under high perceptual load did not enhance P3b latency in those with ASD suggesting increased perceptual capacity compared to neurotypicals. No neurophysiological difference between groups in target data suggests intact top-down control in people with and without ASD. Early and late orienting ERPs (P50, N100, P3a) in non-target processing were unaffected by perceptual load. Robust differences in distractor processing were observed between groups in both early (N100) and late (N200) neural correlates of auditory attention. N100 responses in participants with ASD were strongly attenuated by increasing perceptual load compared to neurotypical controls. Decreased distractor interference at high loads in participants with ASD contrasted attenuation of enhanced late, perceptual processes indexed by the N200 in neurotypical controls. Increased perceptual capacity and decreased distractor processing suggest enhanced bottom-up attention in participant with ASD and has a direct relationship to atypical sensory reactivity in ASD. Collectively, data describes intact top-down control, behaviorally and neurophysiologically, while demonstrating benefits of atypical sensory reactivity on bottom-up attention in people with ASD. / acase@tulane.edu

This thesis aims to determine whether RF pulsed exposures from mobile phones can influence nervous function within the human brain and heart. In order to address this objective, a robust double-blind study to investigate mobile phone exposures on nervous response has been undertaken by means of analysis of electrophysiological test measures of brain wave activity and heart responses. Generally, test measurements of the electroencephalogram (EEG), the electrocardiogram (ECG), and the pulse plethysmogram (PPG) (for indications of blood pressure response) have been undertaken whilst participants are exposed and sham exposed to various GSM mobile phone radiofrequency and low-frequency protocols. In initial work, both standby and full-power mode GSM exposures have been investigated (Chapter 3 - EEG investigated only), while pulsed 900 MHz and 1800 MHz continuous wave exposures have been investigated in the final experimental work involving 100 test participants (Ch apter 8 - EEG, ECG, and PPG measures are investigated). Four predominant outcomes are determined from the final experimental work conducted. These main outcomes specifically include: 1. A new 'characteristic' finding in the EEG alpha band (8-13 Hz) as due to 900 MHz exposures is observed from almost all recording sites, over both brain hemispheres. Notably, this response only appears at 900 MHz, though is not observable for the 1800 MHz exposure; 2. An EEG effect due to both pulsed 900 MHz and 1800 MHz exposures notably appearing at 16 Hz is a new critical finding and is observed across both hemispheres. Most importantly, at this beta rhythm only a decreasing tendency in EEG power can be noted for the 900 MHz exposure tested but only an increasing tendency in EEG power may be noted at 1800 MHz, suggesting that the direction of the effect in EEG power may be dependent on the RF component; 3. Effects at 900 MHz on the contralateral side to exposure at central, temporal, and parietal sites appear to indicate a common median difference response between sham and exposure EEG spectral power density, which does not appear on the ipsilateral side to exposure; 4. As consistent with most previously published research, 900 MHz or 1800 MHz exposures pulsed at 217 Hz do not appear to alter heart rate, heart rate variability (HRV), or blood pressure variability (BPV). To reduce confounding factors and errors in experimental results, several novel approaches were developed as described (Chapters 4 - 8). These approaches include the development and testing of an experimental handset to support multiple mobile phone signals, a comparative analysis of 900 MHz and 1800 MHz exposures (near the health protection limits) on the same group of participants in simultaneous experiments, development of a statistical analysis approach to EEG that addresses both type 1 and type 11 errors at high resolution, and quantification of potential effects of EEG recording leads on SAR and electric field distribution (at both 900 MHz and 1800 MHz) inside a SAM phantom and realistic computational head model. Outcomes of this research address forefront international health concerns regarding almost 2-billion mobile phone users worldwide.

The use of mobile phones is continually increasing throughout the world, with recent figures showing that there are currently more than 2 billion mobile phone users worldwide. However, despite the recognised benefits of the introduction and widespread use of mobile phone technologies, concerns regarding the potential health effects of exposure to the radiofrequency electromagnetic fields emitted by mobile phone handsets have similarly increased, leading to an increase in demand for scientific research to investigate the possibility of health effects related to the use of mobile phones. An increasing amount of radiofrequency bioeffects research related to mobile phone use has focussed on the possible effects of mobile phone exposure on human brain activity and function, particularly as the absorption of energy in the head and brain region is much higher than in other body regions, which is a direct result from the close proximity of the mobile phone to the head when in normal use. In particular, the use of sleep research has become a more widely used technique for assessing the possible effects of mobile phones on human health and wellbeing, and is particularly useful for providing important information in the establishment of possible radiofrequency bioeffects, especially in the investigation of potential changes in sleep architecture resulting from mobile phone use. A review of the previous literature showed that a number of studies have reported an increase in the electroencephalogram spectral power within the 8 � 14 Hz frequency range in both awake and sleep states following radiofrequency electromagnetic field exposure. In regards to sleep, the enhancements reported have not been entirely consistent, with some early studies failing to find an effect, while more recent studies have reported that the effect differs in terms of particular frequency range. However, in general the previous literature suggests that there is an effect of mobile phone emissions on the sleep electroencephalogram, particularly in the frequency range of sleep spindle activity. In addition to changes in spectral power, changes in other conventional sleep parameters and the production and secretion of melatonin have also been investigated, however, there has been little or no consistency in the findings of previous studies, with the majority of recent studies concluding that there is no influence of mobile phone radiofrequency fields on these parameters of sleep or melatonin. Following a detailed review of the previous research, the current study was developed with the aim to improve on previous methodological and statistical limitations, whilst also being the largest study to investigate mobile phone radiofrequency bioeffects on human sleep. The principle aims were thus to test for the immediate effects of mobile phone radiofrequency electromagnetic fields on human sleep architecture and the secretion of the pineal hormone, melatonin. The experiment included 50 participants who were randomly exposed to active and sham mobile phone exposure conditions (one week apart) for 30 minutes prior to a full night-time sleep episode. The experimental nights employed a randomised exposure schedule using a double-blind crossover design. Standard polysomnography was used to measure subsequent sleep, and in addition, participants were required to provide urine samples immediately following exposure and upon waking in the morning. A full dosimetric assessment of the exposure system was also performed in order to provide sufficient details of the exposure set-up used in the current thesis and to account for the lack of detailed dosimetric data provided in the majority of previous studies. The results of the current study suggest that acute exposure to a mobile phone prior to sleep significantly enhances electroencephalogram spectral power in the sleep spindle frequency range compared to the sham exposure condition. The current results also suggest that this mobile phone-induced enhancement in spectral power is largely transitory and does not linger throughout the night. Furthermore, a reduction in rapid eye movement sleep latency following mobile phone exposure was also found compared to the sham exposure, although interestingly, neither this change in rapid eye movement sleep latency or the enhancement in spectral power following mobile phone exposure, led to changes in the overall quality of sleep. Finally, the results regarding melatonin suggested that, overall, overnight melatonin secretion is unaffected by acute exposure to a mobile phone prior to sleep. In conclusion, the current study has confirmed that a short exposure to the radiofrequency electromagnetic fields emitted by a mobile phone handset immediately prior to sleep is sufficient to induce changes in brain activity in the initial part of sleep. The consequences or functional significance of this effect are currently unknown and it would be premature to draw conclusions about possible health consequences based on the findings of the current study.

Segmentational grouping in music listening refers to the organisation of individual tones into tone groups that tend to be processed and subsequently recalled as perceptual units or chunks. Grouping of tones via this process tends to occur at natural breaks in structure of a tone sequence, so that relatively larger changes in pitch, amplitude or timing are perceived as boundaries which cue the segmentational grouping process. Segmentational grouping processes have been examined using behavioural research techniques; yet neurophysiological processes underlying the grouping process have received little attention, and are poorly understood. This study aimed to identify brain regions involved in the segmentational grouping process as cued by rhythmic information. Participants performed two auditory tasks while brain electrical activity responses were monitored using Steady-State Probe Topography (SSPT). Behavioural responses evoked in a task probing individuals' use of lengthened-duration tones to organise memory for pitch sequences indicated that longer-duration tones were used as cues to organise working memory representations of the musical patterns. Examination of dynamic SSPT responses during the encoding phase of a probe recognition task indicated that greater use of rhythmic cues to organise working memory representations was associated with activation of a network of left hemisphere frontal, temporal and parietal regions. During the lengthened tone, activation of left central and vertex regions and progressive activation of left temporal and temporoparietal regions were linked with use of the deviant status of the lengthened tone to update temporal expectations for the sequence. Excitatory responses observed in left posterior frontal and temporal regions to a tone following the lengthened tone were proposed to reflect temporal allocation of attention to this point in time, whereas sustained excitatory activation of left temporal, and temporoparietal regions reflected the role of these regions in supporting representations of the tone events in working memory. Finally, late inhibitory responses to the tone following the lengthened tone in left frontal, temporal, temporoparietal, and parietal regions were linked with the manipulation and closure of the working memory trace in association with the grouping process. Together, these findings support the activation of a network of left frontal, temporal and parietal regions underlying rhythmic grouping of pitch sequences.

Since its first use in human in 1929, the electroencephalogram (EEG) has become one of the most important diagnostic tool in clinical neurophysiology. However, their use in clinical studies is limited because the huge quantity of collected information is complicated to treat. Indeed, it is very difficult to have an overall picture of this multivariate problem. In addition to the impressive quantity of data to be treated, an intrinsic problem with electroencephalograms is that the signals are "contaminated" by body signals not directly related to cerebral activity. However, these signals do not interest us directly to evaluate treatment effect on the brain. Removing these signals known as "parasitic noise" from electroencephalograms is a difficult task. We use clinical data kindly made available by the pharmaceutical company Eli Lilly (Lilly Clinical Operations S.A., Louvain-la-Neuve, Belgium). Particular types of analyses were already carried out on these data, most based on frequency bands. They mainly confirmed the enormous potential of EEG in clinical studies without much insight in the understanding of treatment effect on the brain. The aim of this thesis is to propose and evaluate a panel of statistical techniques to clean and to analyze electroencephalograms. The first presented tool enables to align curves such as selected parts of EEGs before any further statistical treatment. Indeed, when monitoring some continuous process on similar units (like patients in a clinical study), one often notices a typical pattern common to all curves but with variation both in amplitude and dynamics across curves. In particular, typical peaks could be shifted from unit to unit. This complicates the statistical analysis of sample of curves. For example, the cross-sectional average usually does not reflect a typical curve pattern: due to shifts, the signal structure is smeared or might even disappear. Another of the presented tools is based on the preliminary linear decomposition of EEGs into statistically independent signals. This decomposition provides on the one hand an effective cleaning method and on the other hand a considerable reduction of the quantity of data to be analyzed. The technique of decomposition of our signals in statistically independent signals is a well-known technique in physics primarily used to unmix sound signals. This technique is named Independent Component Analysis or ICA. The last studied tool is functional ANOVA. The analysis of longitudinal curve data is a methodological and computational challenge for statisticians. Such data are often generated in biomedical studies. Most of the time, the statistical analysis focuses on simple summary measures, thereby discarding potentially important information. We propose to model these curves using non parametric regression techniques based on splines.

This study examined the moderating role of motivational tendencies for social approach and avoidance behavior, as measured by anterior EEG asymmetry, on symptom expression. In particular, this study aimed to replicate and extend previous findings that measures of anterior EEG asymmetry provide an important marker of subgroups of HFA children that significantly differ from each other, and controls, on measures of social communication impairment. EEG data were collected across two occasions on 51 HFA and 44 non-HFA children. EEG asymmetry was computed for homologous electrode pairs (e.g., lnF4-lnF3). More positive scores were indicative of relative left frontal asymmetry. Data on social and behavioral functioning were collected via parent- and self-report. Results of this short-term longitudinal study revealed moderate test-retest reliability for midfrontal asymmetry, r (65) = .39, p < .01. Results supported previous research demonstrating the differential relation of EEG asymmetry to symptom impairment among HFA children, such that parents of LFA-HFA children reported lower levels of impairment than RFA-HFA children on the SCQ Total Score, F (3, 47) = 3.58, p = .065, and Social Interaction Domain, F (3, 47) = 4.59, p < .05. Results also indicated that parents of LFA-HFA children reported higher levels of general communicative competence on the CCC-2, GCC, F (3, 47) = 6.83, p = .01, but greater impairment in pragmatic communication when compared to RFA-HFA children, SIDC, F (3, 47) = 4.41, p < .05. Additional analyses indicated that RFA was associated with early and more confident recognition of atypical (and stereotypically autistic) development based on retrospective parent-report (ADI-R #86), while LFA was associated with early, but less unambiguously autistic impairment, X2 (51) = 3.75, p = .05. This study demonstrates that anterior EEG asymmetry subgroups are reliable and useful markers of phenotypic variability that are meaningfully related to the experience and expression of symptoms of core autism impairment.