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.
A cichlid fish, the Nile tilapia (Oreochromis niloticus), is a maternal mouthbrooder, which exhibits minimum energy expenditure and slower ovarian cycles during mouthbrooding. The objective of this study was to observe changes in the gene expression of key neuropeptides involved in the control of appetite and reproduction, including neuropeptide Y a (NPYa), reproductive neuropeptides: gonadotropin-releasing hormone (GnRH1, GnRH2 and GnRH3) and kisspeptin (Kiss2) during mouthbrooding (4- and 12-days), 12-days of food restriction and 12-days of food restriction followed by refeeding. The food restriction regime showed a significant increase in npya mRNA levels in the telencephalon. However, there were no significant alterations in npya mRNA levels during mouthbrooding. gnrh1 mRNA levels were significantly lower in mouthbrooding female as compared with females with food restriction. gnrh3 mRNA levels were also significantly lower in female with 12-days of mouthbrooding, 12-days of food restriction followed by 12-days of refeeding when compared with controls. There were no significant differences in gnrh2 and kiss2 mRNA levels between groups under different feeding regimes. No significant changes were observed in mRNA levels of receptors for peripheral metabolic signaling molecules: ghrelin (GHS-R1a and GHS-R1b) and leptin (Lep-R). These results suggested that unaffected npya mRNA levels in the telencephalon might contribute to suppression of appetite in mouthbrooding female tilapia. Furthermore, lower gnrh1 and gnrh3 mRNA levels may influence the suppression of reproductive functions such as progression of ovarian cycle and reproductive behaviours, while GnRH2 and Kiss2 may not play a significant roles in reproduction under food restriction condition.
This paper discusses the application of a reagentless, selective microbiosensor as a useful alternative tool for monitoring D-serine in neural samples. The main components of the 125-μm-diameter disk biosensor were D-amino acid oxidase for D-serine sensitivity (linear region slope, 61 ± 7 μA cm(-2) mM(-1); limit of detection, 20 nM), and poly-phenylenediamine for rejection of electroactive interference. The response time of the biosensor was of the order of 1 s, ideal for 'real-time' monitoring, and detection of systemically administered D-serine in brain extracellular fluid is demonstrated. Exploitation of this probe might resolve queries involving regulation of D-serine in excitotoxicity, and modulation of N-methyl-D-aspartate receptor function by D-serine and glycine in the central nervous system.
The habenula is an evolutionarily conserved brain structure, which has recently been implicated in fear memory. In the zebrafish, kisspeptin (Kiss1) is predominantly expressed in the habenula, which has been implicated as a modulator of fear response. Hence, in the present study, we questioned whether Kiss1 has a role in fear memory and morphine-induced fear memory impairment using an odorant cue (alarm substances, AS)-induced fear avoidance paradigm in adult zebrafish, whereby the fear-conditioned memory can be assessed by a change of basal place preference (= avoidance) of fish due to AS-induced fear experience. Subsequently, to examine the possible role of Kiss1 neurons-serotonergic pathway, kiss1 mRNA and serotonin levels were measured. AS exposure triggered fear episodes and fear-conditioned place avoidance. Morphine treatment followed by AS exposure, significantly impaired fear memory with increased time-spent in AS-paired compartment. However, fish administered with Kiss1 (10-21 mol/fish) after morphine treatment had significantly lower kiss1 mRNA levels but retained fear memory. In addition, the total brain serotonin levels were significantly increased in AS- and Kiss1-treated groups as compared to control and morphine treated group. These results suggest that habenular Kiss1 might be involved in consolidation or retrieval of fear memory through the serotonin system.
Stress impairs the hypothalamic-pituitary-gonadal (HPG) axis, probably through its influence on the hypothalamic-pituitary-adrenal (= interrenals in the teleost, HPI) axis leading to reproductive failures. In this study, we investigated the response of hypothalamic neuropeptides, gonadotropin-inhibitory hormone (GnIH), a component of the HPG axis, and corticotropin-releasing hormone (CRH) a component of the HPI axis, to acute social defeat stress in the socially hierarchical male Nile tilapia (Oreochromis niloticus). Localization of GnIH cell bodies, GnIH neuronal processes, and numbers of GnIH cells in the brain during acute social defeat stress was studied using immunohistochemistry. Furthermore, mRNA levels of GnIH and CRH in the brain together with GnIH receptor, gpr147, and adrenocorticotropic hormone (ACTH) in the pituitary were quantified in control and socially defeated fish. Our results show, the number of GnIH-immunoreactive cell bodies and GnIH mRNA levels in the brain and the levels of gpr147 mRNA in the pituitary significantly increased in socially defeated fish. However, CRH and ACTH mRNA levels did not change during social defeat stress. Further, we found glucocorticoid type 2b receptor mRNA in laser captured immunostained GnIH cells. These results show that acute social defeat stress activates GnIH biosynthesis through glucocorticoid receptors type 2b signalling but does not change the CRH and ACTH mRNA expression in the tilapia, which could lead to temporary reproductive dysfunction.