Journal of Integrative Neuroscience - Volume 16, issue 2

Authors: Karimzadeh, Foroozan | Nami, Mohammad | Boostani, Reza

Article Type: Research Article

Abstract: The present study examined the relationship between the increment in cyclic alternating patterns (CAPs) in sleep electroencephalography (EEG) and neurocognitive decline in Obstructive Sleep Apnea Syndrome (OSAS) patients through source localization of the phase-A of CAPs. All-night polysomnographic recordings of 10 OSAS patients and 4 control subjects were acquired, along with their cognitive profile using the Addenbrooke Cognitive Examination (ACE) test. The neuropsychological assessment involved five key domains including attention and orientation, verbal fluency, memory, language and visuo-spatial skills. The standardized low-resolution brain electromagnetic tomography (sLORETA) tool was used to source-localize the phase-A of CAPs in sleep EEG aiming to …investigate the correlation between CAP phase-A and cognitive functions. Our findings suggested a significant increase in CAP rates among OSAS subjects versus control subjects. Moreover, sLORETA revealed that CAP phase-A is mostly activated in frontoparietal cortices. As CAP rate increases, the activity of phase-A in such areas is dramatically enhanced leading to arousal instability, lower sleep efficiency and a possibly impaired cortical capacity to consolidate cognitive inputs in frontal and parietal areas during sleep. As such, cognitive domains including verbal fluency, memory and visuo-spatial skills which predominantly relate to frontoparietal areas tend to be affected. Based on our findings, CAP activity may possibly be considered as a predictor of cognitive decline among OSAS patients. Show more

Keywords: Sleep EEG, cyclic alternating patterns, OSAS, cognitive performance, sleep microstructure

DOI: 10.3233/JIN-170004

Citation: Journal of Integrative Neuroscience, vol. 16, no. 2, pp. 127-142, 2017

Authors: Pigarev, Ivan N. | Pigareva, Marina L.

Article Type: Review Article

Abstract: It was noticed long ago that sleep disorders or interruptions to the normal sleep pattern were associated with various gastrointestinal disorders. We review the studies which established the causal link between these disorders and sleep impairment. However, the mechanism of interactions between the quality of sleep and gastrointestinal pathophysiology remained unclear. Recently, the visceral theory of sleep was formulated. This theory proposes that the same brain structures, and particularly the same cortical sensory areas, which in wakefulness are involved in processing of the exteroceptive information, switch during sleep to the processing of information coming from various visceral systems. We review …the studies which demonstrated that neurons of the various cortical areas (occipital, parietal, frontal) during sleep began to fire in response to activation coming from the stomach and small intestine. These data demonstrate that, during sleep, the computational power of the central nervous system, including all cortical areas, is engaged in restoration of visceral systems. Thus, the general mechanism of the interaction between quality of sleep and health became clear. Show more

Keywords: Sleep, cerebral cortex, visceral theory of sleep, stomach, intestine

DOI: 10.3233/JIN-170005

Citation: Journal of Integrative Neuroscience, vol. 16, no. 2, pp. 143-156, 2017

Authors: Sariya, Yogesh Kumar | Anand, R.S.

Article Type: Research Article

Abstract: Independent component analysis, a data-driven analysis method, has found significant applications in task-based as well as resting state fMRI studies. There are numbers of independent component analysis algorithms available, but only a few of them have been used frequently so far for fMRI images. With a view that algorithms that are overlooked may outperform the most opted, a comparative study is taken up in this paper to analyze their abilities for the purpose of synthesis of fMRI images. In this paper, ten independent component algorithms: Fast ICA, INFOMAX, SIMBEC, JADE, ERICA, EVD, RADICAL, ICA-EBM, ERBM, and COMBI are compared. Their …separation abilities are adjudged on both, synthetic and real fMRI images. Performance to decompose synthetic fMRI images is being monitored on the basis of spatial correlation coefficients, time elapsed to extract independent components and the visual appearance of independent components. Ranking of their performances on task-based real fMRI images are based on the closeness of time courses of identified independent components with model time course and the closeness of spatial maps of components with spatial templates while their competencies for resting state fMRI data are analyzed by examining how distinctly they decompose the data into the most consistent resting state networks. Sum of mutual information between all the permutations of decomposed components of resting state fMRI data are also calculated. Show more

Keywords: Brain, blood oxygenation level dependent signals, blind source separation, spatial sorting, temporal sorting, mutual information, resting state networks

DOI: 10.3233/JIN-170006

Citation: Journal of Integrative Neuroscience, vol. 16, no. 2, pp. 157-175, 2017

Authors: Li, Xiao | Xu, Qi | He, Jiping

Article Type: Research Article

Abstract: Computational software NEURON was used to simulate the stretch growth neurons in order to investigate the ability of dorsal root ganglion neurons to generate and propagate action potentials after a period of rapid axon stretch growth in vitro , and under what stimulating parameters can evoke action potentials. In the simulation, we found the stretch growth neuron had higher spike amplitude than from the static culture neuron in the soma and all axonal branch. In addition, the conduction velocity was also faster in the stretch growth axon. When the stimulating frequency was less than 15 Hz or the stimulating voltage …was lower than 15 mV, no spike was evoked. Increasing stimulating frequency from 15 Hz to 5000 Hz or stimulating voltage from 15 mV to 100 mV had almost no effect on the spike amplitude. Interestingly, the first spike time and absolute refractory period (ARP) in different axonal branches and somas decreased stepwise with incremental increase in the stimulating frequency. It is concluded that the stretch growth neuron had higher amplitude and faster conduction velocity than the static culture neuron. In addition, some stimulating parameters had been analyzed in this study, which provided guidelines for electrophysiological experiments in future. Show more

Keywords: Dorsal root ganglion, axon stretch growth, computer simulation, unmyelinated axon, action potential

DOI: 10.3233/JIN-170007

Citation: Journal of Integrative Neuroscience, vol. 16, no. 2, pp. 177-187, 2017

Authors: Ghali, Michael George Zaki

Article Type: Review Article

Abstract: The sympathetic nervous system maintains and regulates arterial pressure and tissue perfusion, via control of cardiac output and vasomotor tone. Sympatho-vascular-mediated increases in blood pressure are effected by arterioloconstriction, which causes an increase in afterload, and/or venoconstriction, which increases venous return, left ventricular preload, and consequently, the force of cardiac contraction via Frank-Starling mechanisms; withdrawal of sympathetic drive elicits reciprocal effects. Spinalization reduces mammalian arterial pressure to 40–50 mm Hg consequent to the elimination of descending medullary pre-sympathetic bulbospinal drive to preganglionic sympathetic fibers in the intermediolateral cell column of the spinal cord. Beyond agreement that sympathetic tone is generated supraspinally, …there is only controversy. One hypothesis posits that pre-sympathetic medullary regions, such as the rostral ventrolateral medulla (RVLM) and caudal raphé group, possess intrinsic tonic activity. Alternatively, pre-sympathetic medullary regions may receive tonic excitation from other areas in the brainstem. Neurons in the lateral tegmental field (LTF), an exclusively propriobulbar entity (cf. pre-Bötzinger complex – the propriobulbar inspiratory rhythmogenic kernel of the respiratory network), fire before and project to pre-sympathetic units in RVLM and caudal raphé and exhibit activity correlated to the cardiac-related rhythm in sympathetic nerve discharge, making the LTF a likely candidate for the primary source of basal sympathoexcitation. The LTF is additionally involved in a variety of cardiovascular and sympathetic reflexes (i.e., baroreflex, Bezold–Jarisch reflex). As it receives descending afferents from the infralimbic cortex and associated limbic structures, suggesting a role in the sympathetic response to fear, as well as vestibular inputs, consistent with a role in coordinating the sympathetic response with emesis proper, the LTF appears to play an extensive integrative role. In this review, we discuss the LTF, a once mysterious, poorly-characterized, and ill-defined region, the contribution of which to cardiovascular reflexes and basal sympathoexcitation has been more thoroughly elucidated in recent years and any model of central control of sympathetic output must take into consideration the contribution of this important region. Show more

Keywords: Medulla, reticular formation, sympathetic, blood pressure, fast oscillations

DOI: 10.3233/JIN-170010

Citation: Journal of Integrative Neuroscience, vol. 16, no. 2, pp. 189-208, 2017

Authors: Lado, María J. | Cuesta, P. | García Caballero, Alejandro | Vila, Xosé A.

Article Type: Research Article

Abstract: Previous studies have examined the elicitation of emotions by exposing individuals to relevant stimuli, using spectral analysis of Heart Rate Variability (HRV). If a correlation exists between HRV and emotional responses, spectral analysis can be used to study emotion regulation by external stimuli. In this work, we studied the relationship between visual elicitation and emotion regulation, employing HRV. Images (with pleasant, unpleasant and neutral emotional content) were selected from the IAPS (International Affective Picture System) dataset. Ninety-eight participants were enrolled, and viewed all images, displayed in random order for each participant. Heart rate was recorded during the experiment, and HRV …analysis was performed. Spectral values were studied for the response to different images. The presentation order of images was relevant, mainly when unpleasant images were viewed first; this significantly affects HRV values. Spectral values were higher for men, this increase was greater when pleasant pictures were displayed. Age and gender dependences of spectral indexes were found. The influence of visual elicitation, with different emotional content, on HRV, was assessed. Results indicate that HRV parameters are affected when individuals are subject to external, emotional-based stimuli. Show more

Keywords: Heart rate variability, emotion regulation, international affective picture system, arousal, valence

DOI: 10.3233/JIN-170014

Citation: Journal of Integrative Neuroscience, vol. 16, no. 2, pp. 209-226, 2017

Authors: AlRyalat, Saif Aldeen

Article Type: Research Article

Abstract: Gender similarities and differences have long been a matter of debate in almost all human research, especially upon reaching the discussion about brain functions. This large scale meta-analysis was performed on functional MRI studies. It included more than 700 active brain foci from more than 70 different experiments to study gender related similarities and differences in brain activation strategies for three of the main brain functions: Visual-spatial cognition, memory, and emotion. Areas that are significantly activated by both genders (i.e. core areas) for the tested brain function are mentioned, whereas those areas significantly activated exclusively in one gender are the …gender specific areas. During visual-spatial cognition task, and in addition to the core areas, males significantly activated their left superior frontal gyrus, compared with left superior parietal lobule in females. For memory tasks, several different brain areas activated by each gender, but females significantly activated two areas from the limbic system during memory retrieval tasks. For emotional task, males tend to recruit their bilateral prefrontal regions, whereas females tend to recruit their bilateral amygdalae. This meta-analysis provides an overview based on functional MRI studies on how males and females use their brain. Show more

Keywords: Brain, fMRI, gender, thinking, memory, emotion

DOI: 10.3233/JIN-170015

Citation: Journal of Integrative Neuroscience, vol. 16, no. 2, pp. 227-240, 2017