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Fulltext Brain area-specific diurnal and photic regulation of val-opsinA and val-opsinB genes in the zebrafish

Hang CY, Kitahashi T, Parhar IS

J Neurochem, 2015 May;133(4):501-10.
PMID: 25727787 DOI: 10.1111/jnc.13084

Zebrafish possess two isoforms of vertebrate ancient long (VAL)-opsin, val-opsinA (valopa) and val-opsinB (valopb), which probably mediate non-visual responses to light. To understand the diurnal and light-sensitive regulation of the valop genes in different cell groups, the current study used real-time quantitative PCR to examine the diurnal changes of valopa and b mRNA levels in different brain areas of adult male zebrafish. Furthermore, effects of the extended exposure to light or dark condition, luminous levels and the treatment with a melatonin receptor agonist or antagonist on valop transcription were examined. In the thalamus, valop mRNA levels showed significant diurnal changes; valopa peaked in the evening, while valopb peaked in the morning. The diurnal change of valopa mRNA levels occurred independent of light conditions, whereas that of valopb mRNA levels were regulated by light. A melatonin receptor agonist or antagonist did not affect the changes of valop mRNA levels. In contrast, the midbrain and hindbrain showed arrhythmic valop mRNA levels under light and dark cycles. The differential diurnal regulation of the valopa and b genes in the thalamus and the arrhythmic expression in the midbrain and hindbrain suggest involvement of deep brain VAL-opsin in time- and light-dependent physiology. We show diurnal expression changes of vertebrate ancient long (VAL) opsin genes (valopa and valopb), depending on brain area, time of day and light condition, in the adult male zebrafish. Differential regulation of the valop genes in the thalamus and arrhythmic expression in the midbrain and hindbrain suggest their involvement in time- and light-dependent physiology to adjust to environmental changes.

Matched MeSH terms: Photic Stimulation*
Dexamphetamine increased speech and visual unimodal illusions in healthy participants without affecting temporal binding window

Voon FL, Loffman SJ, Lim MJH, Lee JWY, Iyyalol R, Martin-Iverson MT

Hum Psychopharmacol, 2024 May;39(3):e2896.
PMID: 38353526 DOI: 10.1002/hup.2896

OBJECTIVE: Stimuli received beyond a very short timeframe, known as temporal binding windows (TBWs), are perceived as separate events. In previous audio-visual multisensory integration (McGurk effect) studies, widening of TBWs has been observed in people with schizophrenia. The present study aimed to determine if dexamphetamine could increase TBWs in unimodal auditory and unimodal visual illusions that may have some validity as experimental models for auditory and visual hallucinations in psychotic disorders.
METHODS: A double-blind, placebo-controlled, counter-balanced crossover design with permuted block randomisation for drug order was followed. Dexamphetamine (0.45 mg/kg, PO, q.d.) was administered to healthy participants. Phantom word illusion (speech illusion) and visual-induced flash illusion/VIFI (visual illusion) tests were measured to determine if TBWs were altered as a function of delay between stimuli presentations. Word emotional content for phantom word illusions was also analysed.
RESULTS: Dexamphetamine significantly increased the total number of phantom words/speech illusions (p

Matched MeSH terms: Photic Stimulation/methods
Local spatial distortion caused by simple geometrical figures

Aksentijevic A, Elliott MA

Q J Exp Psychol (Hove), 2017 Aug;70(8):1535-1548.
PMID: 27244533 DOI: 10.1080/17470218.2016.1192657

Dynamic distortion of the visual field has been shown to affect perceptual judgment of visual dimensions such as size, length, and distance. Here, we report four experiments demonstrating that the different aspects of a triangle differently influence judgments of distance. Specifically, when the base of the triangle faces the centre of the display, participants consistently underestimate and overestimate the distance of a small dot from the unmarked centre of the display relative to conditions in which the vertex of the triangle faces the centre. When the dot is close to the figure, the distance of the dot to the centre is underestimated. Conversely, when the dot is close to the figure, the distance to the centre is overestimated. The effect is replicated when the internal distances are equalized and when ellipses are used instead of triangles. These results support a ripple model of spatial distortion in which local curvature acts to attract or repel objects. In conclusion, we suggest some implications of our findings for theories of perceptual organization.

Matched MeSH terms: Photic Stimulation
Fulltext Comparative study on interaction of form and motion processing streams by applying two different classifiers in mechanism for recognition of biological movement

Yousefi B, Loo CK

ScientificWorldJournal, 2014;2014:723213.
PMID: 25276860 DOI: 10.1155/2014/723213

Research on psychophysics, neurophysiology, and functional imaging shows particular representation of biological movements which contains two pathways. The visual perception of biological movements formed through the visual system called dorsal and ventral processing streams. Ventral processing stream is associated with the form information extraction; on the other hand, dorsal processing stream provides motion information. Active basic model (ABM) as hierarchical representation of the human object had revealed novelty in form pathway due to applying Gabor based supervised object recognition method. It creates more biological plausibility along with similarity with original model. Fuzzy inference system is used for motion pattern information in motion pathway creating more robustness in recognition process. Besides, interaction of these paths is intriguing and many studies in various fields considered it. Here, the interaction of the pathways to get more appropriated results has been investigated. Extreme learning machine (ELM) has been implied for classification unit of this model, due to having the main properties of artificial neural networks, but crosses from the difficulty of training time substantially diminished in it. Here, there will be a comparison between two different configurations, interactions using synergetic neural network and ELM, in terms of accuracy and compatibility.

Matched MeSH terms: Photic Stimulation
Effects of action observation on corticospinal excitability: Muscle specificity, direction, and timing of the mirror response

Naish KR, Houston-Price C, Bremner AJ, Holmes NP

Neuropsychologia, 2014 11;64:331-48.
PMID: 25281883 DOI: 10.1016/j.neuropsychologia.2014.09.034

Many human behaviours and pathologies have been attributed to the putative mirror neuron system, a neural system that is active during both the observation and execution of actions. While there are now a very large number of papers on the mirror neuron system, variations in the methods and analyses employed by researchers mean that the basic characteristics of the mirror response are not clear. This review focuses on three important aspects of the mirror response, as measured by modulations in corticospinal excitability: (1) muscle specificity; (2) direction; and (3) timing of modulation. We focus mainly on electromyographic (EMG) data gathered following single-pulse transcranial magnetic stimulation (TMS), because this method provides precise information regarding these three aspects of the response. Data from paired-pulse TMS paradigms and peripheral nerve stimulation (PNS) are also considered when we discuss the possible mechanisms underlying the mirror response. In this systematic review of the literature, we examine the findings of 85 TMS and PNS studies of the human mirror response, and consider the limitations and advantages of the different methodological approaches these have adopted in relation to discrepancies between their findings. We conclude by proposing a testable model of how action observation modulates corticospinal excitability in humans. Specifically, we propose that action observation elicits an early, non-specific facilitation of corticospinal excitability (at around 90ms from action onset), followed by a later modulation of activity specific to the muscles involved in the observed action (from around 200ms). Testing this model will greatly advance our understanding of the mirror mechanism and provide a more stable grounding on which to base inferences about its role in human behaviour.

Matched MeSH terms: Photic Stimulation
Inter-hemispheric EEG coherence analysis in Parkinson's disease: assessing brain activity during emotion processing

Yuvaraj R, Murugappan M, Ibrahim NM, Sundaraj K, Omar MI, Mohamad K, et al.

J Neural Transm (Vienna), 2015 Feb;122(2):237-52.
PMID: 24894699 DOI: 10.1007/s00702-014-1249-4

Parkinson's disease (PD) is not only characterized by its prominent motor symptoms but also associated with disturbances in cognitive and emotional functioning. The objective of the present study was to investigate the influence of emotion processing on inter-hemispheric electroencephalography (EEG) coherence in PD. Multimodal emotional stimuli (happiness, sadness, fear, anger, surprise, and disgust) were presented to 20 PD patients and 30 age-, education level-, and gender-matched healthy controls (HC) while EEG was recorded. Inter-hemispheric coherence was computed from seven homologous EEG electrode pairs (AF3-AF4, F7-F8, F3-F4, FC5-FC6, T7-T8, P7-P8, and O1-O2) for delta, theta, alpha, beta, and gamma frequency bands. In addition, subjective ratings were obtained for a representative of emotional stimuli. Interhemispherically, PD patients showed significantly lower coherence in theta, alpha, beta, and gamma frequency bands than HC during emotion processing. No significant changes were found in the delta frequency band coherence. We also found that PD patients were more impaired in recognizing negative emotions (sadness, fear, anger, and disgust) than relatively positive emotions (happiness and surprise). Behaviorally, PD patients did not show impairment in emotion recognition as measured by subjective ratings. These findings suggest that PD patients may have an impairment of inter-hemispheric functional connectivity (i.e., a decline in cortical connectivity) during emotion processing. This study may increase the awareness of EEG emotional response studies in clinical practice to uncover potential neurophysiologic abnormalities.

Matched MeSH terms: Photic Stimulation
Influence of education level on design-induced N170 and P300 components of event related potentials in the human brain

Begum T, Reza F, Ahmed I, Abdullah JM

J Integr Neurosci, 2014 Mar;13(1):71-88.
PMID: 24738540 DOI: 10.1142/S0219635214500058

Simple geometric and organic shapes and their arrangement are being used in different neuropsychology tests for the assessment of cognitive function, special memory and also for the therapy purpose in different patient groups. Until now there is no electrophysiological evidence of cognitive function determination for simple geometric, organic shapes and their arrangement. Then the main objective of this study is to know the cortical processing and amplitude, latency of visual induced N170 and P300 event related potential components on different geometric, organic shapes and their arrangement and different educational influence on it, which is worthwhile to know for the early and better treatment for those patient groups. While education influenced on cognitive function by using auditory oddball task, little is known about the influence of education on cognitive function induced by visual attention task in case of the choice of geometric, organic shapes and their arrangements. Using a 128-electrode sensor net, we studied the responses of the choice of the different geometric and organic shapes randomly in experiment 1 and their arrangements in experiment 2 in the high, medium and low education groups. In both experiments, subjects push the button "1" or "2" if like or dislike, respectively. Total 45 healthy subjects (15 in each group) were recruited. ERPs were measured from 11 electrode sites and analyzed to see the evoked N170/N240 and P300 ERP components. There were no differences between like and dislike in amplitudes even in latencies in every stimulus in both experiments. We fixed geometric shapes and organic shapes stimuli only, not like and dislike. Upon the stimulus types, N170 ERP component was found instead of N240, in occipito-temporal (T5, T6, O1 and O2) locations where the amplitude is the highest at O2 location and P300 was distributed in the central (Cz and Pz) locations in both experiments in all groups. In experiment 1, significant low amplitude and non-significant larger latency of the N170 component are found out at O1 location for both stimuli in low education group comparing medium education groups, but in experiment 2, there is no significant difference between stimuli among groups in amplitude and latency. In both experiments, P300 component was found in Cz and Pz locations though the amplitudes are higher at Cz than Pz areas. In experiment 1, medium education group evoked significantly (geometric shape stimuli, P = 0.05; organic shape stimuli, P = 0.02) higher amplitude of P300 component comparing low education group at Cz location. Whereas, there is no significant difference of amplitudes among groups across stimuli in Cz and Pz locations in experiment 2. Latencies have no significant differences in both experiments among groups also, but longer latency are found in low education group at Cz location comparing medium education group, though not significant. We conclude that simple geometric shapes, organic shapes and their arrangements evoked visual N170 component at temporo-occipital areas with right lateralization and P300 ERP component at centro-parietal areas. Significant low amplitude of N170 and P300 ERP components and longer latencies during different shape stimuli in low education group prove that, low education significantly influence on visual cognitive functions in low education group.

Matched MeSH terms: Photic Stimulation
Fulltext Photopic and scotopic multifocal pupillographic responses in age-related macular degeneration

Rosli Y, Bedford SM, James AC, Maddess T

Vision Res, 2012 Sep 15;69:42-8.
PMID: 22898702 DOI: 10.1016/j.visres.2012.07.019

We compared photopic and scotopic multifocal pupillographic stimuli in age-related macular degeneration (AMD). Both eyes of 18 normal and 14 AMD subjects were tested with four stimulus variants presented at photopic and 126 times lower luminances. The multifocal stimuli presented 24 test regions/eye to the central 60°. The stimulus variants had two different check sizes, and when presented either flickered (15 Hz) for 266 ms, or were steady for 133 ms. Mean differences from normal of 5 to 7 dB were observed in the central visual field for both photopic and scotopic stimuli (all p < 0.00002). The best areas under receiver operating characteristic plots for exudative AMD in the photopic and scotopic conditions were 92.9 ± 8.0 and 90.3 ± 5.7% respectively, and in less severely affected eyes 83.8 ± 9.7% and 76.9 ± 8.2%. Damage recorded at photopic levels was possibly more diffusely distributed across the visual field. Sensitivity and specificity was similar at photopic and scotopic levels.

Matched MeSH terms: Photic Stimulation
Variations in prestimulus neural activity predict the emotion-enhanced memory effect

Yick YY, Buratto LG, Schaefer A

Neuroreport, 2016 08 03;27(11):864-8.
PMID: 27295027 DOI: 10.1097/WNR.0000000000000628

Here, we report evidence that electrophysiological neural activity preceding the onset of emotional pictures can predict whether they will be remembered or forgotten 24 h later, whereas the same effect was not observed for neutral pictures. In contrast to previous research, we observed this effect using a paradigm in which participants could not predict the emotional or the neutral content of the pictures before their onset. These effects were obtained alongside significant behavioural effects of superior recognition memory for emotional compared with neutral items. These findings suggest that the preferential encoding of emotional events in memory is determined by fluctuations in the availability of processing resources just before event onset. This explanation argues in favour of mediational models of emotional memory, which contend that emotional information is preferentially encoded because it mobilizes a greater amount of processing resources than neutral information.

Matched MeSH terms: Photic Stimulation
Fulltext Fractional Diffusion Based Modelling and Prediction of Human Brain Response to External Stimuli

Namazi H, Kulish VV

Comput Math Methods Med, 2015;2015:148534.
PMID: 26089955 DOI: 10.1155/2015/148534

Human brain response is the result of the overall ability of the brain in analyzing different internal and external stimuli and thus making the proper decisions. During the last decades scientists have discovered more about this phenomenon and proposed some models based on computational, biological, or neuropsychological methods. Despite some advances in studies related to this area of the brain research, there were fewer efforts which have been done on the mathematical modeling of the human brain response to external stimuli. This research is devoted to the modeling and prediction of the human EEG signal, as an alert state of overall human brain activity monitoring, upon receiving external stimuli, based on fractional diffusion equations. The results of this modeling show very good agreement with the real human EEG signal and thus this model can be used for many types of applications such as prediction of seizure onset in patient with epilepsy.

Matched MeSH terms: Photic Stimulation
The effects of negative emotion on encoding-related neural activity predicting item and source recognition

Yick YY, Buratto LG, Schaefer A

Neuropsychologia, 2015 Jul;73:48-59.
PMID: 25936685 DOI: 10.1016/j.neuropsychologia.2015.04.030

We report here a study that obtained reliable effects of emotional modulation of a well-known index of memory encoding--the electrophysiological "Dm" effect--using a recognition memory paradigm followed by a source memory task. In this study, participants performed an old-new recognition test of emotionally negative and neutral pictures encoded 1 day before the test, and a source memory task involving the retrieval of the temporal context in which pictures had been encoded. Our results showed that Dm activity was enhanced for all emotional items on a late positivity starting at ~400 ms post-stimulus onset, although Dm activity for high arousal items was also enhanced at an earlier stage (200-400 ms). Our results also showed that emotion enhanced Dm activity for items that were both recognised with or without correct source information. Further, when only high arousal items were considered, larger Dm amplitudes were observed if source memory was accurate. Three main conclusions are drawn from these findings. First, negative emotion can enhance encoding processes predicting the subsequent recognition of central item information. Second, if emotion reaches high levels of arousal, the encoding of contextual details can also be enhanced over and above the effects of emotion on central item encoding. Third, the morphology of our ERPs is consistent with a hybrid model of the role of attention in emotion-enhanced memory (Pottage and Schaefer, 2012).

Matched MeSH terms: Photic Stimulation
Investigation of brain electrophysiological properties among heroin addicts: Quantitative EEG and event-related potentials

Motlagh F, Ibrahim F, Rashid R, Seghatoleslam T, Habil H

J Neurosci Res, 2017 08;95(8):1633-1646.
PMID: 27862172 DOI: 10.1002/jnr.23988

This study aims to introduce a new approach of a comprehensive paradigm to evaluate brain electrophysiological properties among addicts. Electroencephalographic spectral power as well as amplitudes and latencies of mismatch negativity (MMN), P300, and P600 components were evaluated among 19 male heroin addicts and 19 healthy nonsmoker subjects using a paradigm consisting of three subparadigms, namely (1) digit span Wechsler test, (2) auditory oddball, and (3) visual cue-reactivity oddball paradigms. Task 1 provided auditory P300 and P600 in association with working memory. Task 2 provided auditory P300 as well as small and large deviant MMN event-related potential (ERPs). Finally, task 3 provided visual cue-reactivity P300. Results show that beta power was higher among heroin addicts while delta, theta, and alpha powers were decreased compared with healthy subjects. ERP analysis confirmed the decline of brain-evoked potential amplitudes when compared with healthy subjects, thus indicating a broad neurobiological vulnerability of preattentive and attentional processing including attentional deficits and compromise of discrimination abilities. The prolonged latency of ERPs reflects poor cognitive capacity in the engagement of attention and memory resources. On the other hand, an increase of attention towards the heroin-related stimuli could be concluded from the increase of P300 in the cue-reactivity condition among heroin addicts. Findings suggest that applying this paradigm in addiction studies benefits comprehensive evaluation of neuroelectrophysiological activity among addicts, which can promote a better understanding of drugs' effects on the brain as well as define new neuroelectrophysiological characteristics of addiction properties. © 2016 Wiley Periodicals, Inc.

Matched MeSH terms: Photic Stimulation
Presence of a predator image in potential breeding sites and oviposition responses of a dengue vector

Dieng H, Satho T, Suradi NFB, Hakim H, Abang F, Aliasan NE, et al.

Acta Trop, 2017 Dec;176:446-454.
PMID: 28865898 DOI: 10.1016/j.actatropica.2017.08.033

In dengue vector control, attempts to minimize or replace the use of pesticides have mostly involved use of predators, but success has been severely impeded by difficulties associated with financial and environmental costs, predator mass production, and persistence in target habitats. Visual deterrents have been used successfully to control animal pests, in some cases in an effort to replace pesticide use. Despite evidence that visual signals are crucial in site choice for egg deposition by dengue vectors, and that female mosquitoes respond to artificial predation, the role of predator intimidation as it affects the oviposition behavior of dengue vectors remains largely unexplored. Here, we examined the oviposition responses of Aedes aegypti exposed to various mosquito predator pictures. Gravid females were presented with equal opportunities to oviposit in two cups with predator images [Toxorhynchites splendens-TXI, Goldfish (Carassius auratus)-small (SFI) and large (LFI) and Tx. splendens+Goldfish-TXFI] and two others without pictures. Differences in egg deposition were examined between sites with and without these images. When given a chance to oviposit in cups with and without TXI, Ae. aegypti females were similarly attracted to both sites. When provided an opportunity to oviposit in cups displaying pictures of fish (SFI or LFI) and blank cups, egg deposition rates were much lower in the fish picture sites. Females showed a preference for blank cups over TXFI for egg deposition. They also equally avoided cups with pictures of fish, regardless of the size of the picture. Our results indicate that the presence of images of goldfish and their association with Tx. larvae significantly reduced egg deposition by Ae. aegypti, and this was not the case with the predatory larvae alone. The observations that the images of natural predators can repel gravid females of a dengue vector provide novel possibilities to develop effective and inexpensive alternative tools to harmful insecticides.

Matched MeSH terms: Photic Stimulation
Fulltext A novel language-neutral Visual Cognitive Assessment Test (VCAT): validation in four Southeast Asian countries

Lim L, Ng TP, Ong AP, Tan MP, Cenina AR, Gao Q, et al.

Alzheimers Res Ther, 2018 01 22;10(1):6.
PMID: 29370825 DOI: 10.1186/s13195-017-0333-z

BACKGROUND: Cognitive screeners are imperative for early diagnosis of dementia. The Visual Cognitive Assessment Test (VCAT) is a language-neutral, visual-based test which has proven useful for a multilingual population in a single-center study. However, its performance utility is unknown in a wider and more diverse Southeast Asian cohort.
METHODS: We recruited 164 healthy controls (HC) and 120 cognitively impaired (CI) subjects- 47 mild cognitive impairment (MCI) and 73 mild Alzheimer's disease (AD) dementia participants, from four countries between January 2015 and August 2016 to determine the usefulness of a single version of the VCAT, without translation or adaptation, in a multinational, multilingual population. The VCAT was administered along with established cognitive evaluation.
RESULTS: The VCAT, without local translation or adaptation, was effective in discriminating between HC and CI subjects (MCI and mild AD dementia). Mean (SD) VCAT scores for HC and CI subjects were 22.48 (3.50) and 14.17 (5.05) respectively. Areas under the curve for Montreal Cognitive Assessment (0.916, 95% CI 0.884-0.948) and the VCAT (0.905, 95% CI 0.870-0.940) in discriminating between HCs and CIs were comparable. The multiple languages used to administer VCAT in four countries did not significantly influence test scores.
CONCLUSIONS: The VCAT without the need for language translation or cultural adaptation showed satisfactory discriminative ability and was effective in a multinational, multilingual Southeast Asian population.

Matched MeSH terms: Photic Stimulation
Fulltext Repetition Is the Feature Behind the Attentional Bias for Recognizing Threatening Patterns

Shabbir M, Zon AMY, Thuppil V

Evol Psychol, 2018;16(1):1474704918754782.
PMID: 29455569 DOI: 10.1177/1474704918754782

Animals attend to what is relevant in order to behave in an effective manner and succeed in their environments. In several nonhuman species, there is an evolved bias for attending to patterns indicative of threats in the natural environment such as dangerous animals. Because skins of many dangerous animals are typically repetitive, we propose that repetition is the key feature enabling recognition of evolutionarily important threats. The current study consists of two experiments where we measured participants' reactions to pictures of male and female models wearing clothing of various repeating (leopard skin, snakeskin, and floral print) and nonrepeating (camouflage, shiny, and plain) patterns. In Experiment 1, when models wearing patterns were presented side by side with total fixation duration as the measure, the repeating floral pattern was the most provocative, with total fixation duration significantly longer than all other patterns. Leopard and snakeskin patterns had total fixation durations that were significantly longer than the plain pattern. In Experiment 2, we employed a visual-search task where participants were required to find models wearing the various patterns in a setting of a crowded airport terminal. Participants detected leopard skin pattern and repetitive floral pattern significantly faster than two of the nonpatterned clothing styles. Our experimental findings support the hypothesis that repetition of specific visual features might facilitate target detection, especially those characterizing evolutionary important threats. Our findings that intricate, but nonthreatening repeating patterns can have similar attention-grabbing properties to animal skin patterns have important implications for the fashion industry and wildlife trade.

Matched MeSH terms: Photic Stimulation
Emotion classification in Parkinson's disease by higher-order spectra and power spectrum features using EEG signals: a comparative study

Yuvaraj R, Murugappan M, Ibrahim NM, Omar MI, Sundaraj K, Mohamad K, et al.

J Integr Neurosci, 2014 Mar;13(1):89-120.
PMID: 24738541 DOI: 10.1142/S021963521450006X

Deficits in the ability to process emotions characterize several neuropsychiatric disorders and are traits of Parkinson's disease (PD), and there is need for a method of quantifying emotion, which is currently performed by clinical diagnosis. Electroencephalogram (EEG) signals, being an activity of central nervous system (CNS), can reflect the underlying true emotional state of a person. This study applied machine-learning algorithms to categorize EEG emotional states in PD patients that would classify six basic emotions (happiness and sadness, fear, anger, surprise and disgust) in comparison with healthy controls (HC). Emotional EEG data were recorded from 20 PD patients and 20 healthy age-, education level- and sex-matched controls using multimodal (audio-visual) stimuli. The use of nonlinear features motivated by the higher-order spectra (HOS) has been reported to be a promising approach to classify the emotional states. In this work, we made the comparative study of the performance of k-nearest neighbor (kNN) and support vector machine (SVM) classifiers using the features derived from HOS and from the power spectrum. Analysis of variance (ANOVA) showed that power spectrum and HOS based features were statistically significant among the six emotional states (p < 0.0001). Classification results shows that using the selected HOS based features instead of power spectrum based features provided comparatively better accuracy for all the six classes with an overall accuracy of 70.10% ± 2.83% and 77.29% ± 1.73% for PD patients and HC in beta (13-30 Hz) band using SVM classifier. Besides, PD patients achieved less accuracy in the processing of negative emotions (sadness, fear, anger and disgust) than in processing of positive emotions (happiness, surprise) compared with HC. These results demonstrate the effectiveness of applying machine learning techniques to the classification of emotional states in PD patients in a user independent manner using EEG signals. The accuracy of the system can be improved by investigating the other HOS based features. This study might lead to a practical system for noninvasive assessment of the emotional impairments associated with neurological disorders.

Matched MeSH terms: Photic Stimulation
Fulltext An EEG Database and Its Initial Benchmark Emotion Classification Performance

Seal A, Reddy PPN, Chaithanya P, Meghana A, Jahnavi K, Krejcar O, et al.

Comput Math Methods Med, 2020;2020:8303465.
PMID: 32831902 DOI: 10.1155/2020/8303465

Human emotion recognition has been a major field of research in the last decades owing to its noteworthy academic and industrial applications. However, most of the state-of-the-art methods identified emotions after analyzing facial images. Emotion recognition using electroencephalogram (EEG) signals has got less attention. However, the advantage of using EEG signals is that it can capture real emotion. However, very few EEG signals databases are publicly available for affective computing. In this work, we present a database consisting of EEG signals of 44 volunteers. Twenty-three out of forty-four are females. A 32 channels CLARITY EEG traveler sensor is used to record four emotional states namely, happy, fear, sad, and neutral of subjects by showing 12 videos. So, 3 video files are devoted to each emotion. Participants are mapped with the emotion that they had felt after watching each video. The recorded EEG signals are considered further to classify four types of emotions based on discrete wavelet transform and extreme learning machine (ELM) for reporting the initial benchmark classification performance. The ELM algorithm is used for channel selection followed by subband selection. The proposed method performs the best when features are captured from the gamma subband of the FP1-F7 channel with 94.72% accuracy. The presented database would be available to the researchers for affective recognition applications.

Matched MeSH terms: Photic Stimulation
Flashing light as growth stimulant in cultivation of green microalgae, Chlorella sp. utilizing airlift photobioreactor

Fathurrahman L, Hajar AH, Sakinah DW, Nurhazwani Z, Ahmad J

Pak J Biol Sci, 2013 Nov 15;16(22):1517-23.
PMID: 24511694

One of the main limitations of productivity in photobioreactor is the inefficient conversion of the available light into biomass. Photoautotrophic cells such as microalgae only absorb a small fraction of supplied illumination due to limitation of its photosystem's (PS) absorbing rate. However, phenomenon of Flashing Light Effect (FLE) allows microalgae to utilize strong light exceptionally through intermittent exposure. Exposure of strong light at correct frequency of light and dark photoperiod would allow two pigment-protein complexes, PSI and PSII to be at the equilibrium mid-point potential to allow efficient light conversion. Narrow range of optimum frequency is crucial since overexposure to strong light would injured photosynthetic apparatus whereas longer dark period would contributed to loss of biomass due to triacylglycerol metabolism. The behaviour of microalgae towards various illumination conditions of FLE was determined at batch Photobioreactor (PBR) by varying the aeration flow rate: 16.94, 33.14 and 49.28 mL sec(-1) which yield, respectively the light exposure time of 3.99, 1.71 and 1.1 seconds per cycle. Maximum cell density in FLE-PBR was significantly higher at the exponential phase as compared to the continuously illuminated culture (p = 5.62 x 10(-5), a = 0.05) under the flow rate of 25.07 mL sec(-1). Maximum cell density yield of FLE-PBR and continuously illuminated PBR was, respectively 3.1125 x 10(7) and 2.947 x 10(7) cells mL(-1). Utilization of FLE as an innovative solution to increase the efficiency of microalgae to convert light into chemical energy would revolutionize the microalgae culture, reduce the time for cultivation and produce higher maximum biomass density.

Matched MeSH terms: Photic Stimulation

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