Journal of Integrative Neuroscience

In this review paper, an overview is given of two emerging research topics that address the importance of long-range physical signaling in living biosystems. The first topic concerns the biophysical principles and the physiological significance of long-range cell-to-cell signaling through electrical signals facilitated by membrane nanotubes (MNTs) (also called "tunneling nanotubes"), namely long membrane extensions that connect cells, discovered about 10 years ago. This review paper looks at experimental results that showed electrical signals being propagated through MNTs, and that MNT-mediated electrical coupling between brain cells involves activation of low-voltage-gated calcium channels. The significance of electrical cell-to-cell coupling through MNT for neuronal communication is discussed. The second topic deals with endogenous electromagnetic fields generated by nerve cells. The review concludes that these fields are not just an "epiphenomenon" but play a fundamental role in neuronal processes. For example, electromagnetic fields from brain cells feed back to their generating cells and to other cells (ephaptic coupling) and, for example, modulate the spiking timing of them. It is also discussed that cell membranes of neurons have specific resonance properties which possibly determine the impact of endogenous electric field fluctuations with respect to field strength and frequency. In addition, it is reviewed how traveling and standing waves of the endogenous electromagnetic field produced by neuronal and non-neuronal cells may play an integral part in global neuronal network dynamics. Finally, an outlook is given on which research questions should be addressed in the future regarding these two topics.

Brain is the command center for the body and contains a lot of information which can be extracted by using different non-invasive techniques. Electroencephalography (EEG), Magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) are the most common neuroimaging techniques to elicit brain behavior. By using these techniques different activity patterns can be measured within the brain to decode the content of mental processes especially the visual and auditory content. This paper discusses the models and imaging techniques used in visual decoding to investigate the different conditions of brain along with recent advancements in brain decoding.

This paper concludes that it's not possible to extract all the information from the brain, however careful experimentation, interpretation and powerful statistical tools can be used with the neuroimaging techniques for better results.

The present review attempts to put together the available evidence and potential research paradigms at the interface of obstructive sleep apnea syndrome (OSAS), sleep micro- and macrostructure, cerebral vasoreactivity and cognitive neuroscience. Besides the significant health-related consequences of OSAS including hypertension, increased risk of cardio- and cerebrovascular events, notable neurocognitive lapses and excessive daytime somnolence are considered as potential burdens. The intermittent nocturnal hypoxia and hypercapnia which occur in OSAS are known to affect cerebral circulation and result in brain hypoperfusion. Arousal instability is then resulted from altered cyclic alternating patterns (CAPs) reflected in sleep EEG. In chronic state, some pathological loss of gray matter may be resulted from obstructive sleep apnea. This is proposed to be related to an upregulated proinflammatory state which may potentially result in apoptotic cell loss in the brain. On this basis, a pragmatic framework of the possible neural mechanisms which underpin obstructive sleep apnea-related neurocognitive decline has been discussed in this review. In addition, the impact of OSAS on cerebral autoregulation and sleep microstructure has been articulated.

It has been suggested that quantum coherence in the selectivity filter of ion channel may play a key role in fast conduction and selectivity of ions. However, it has not been clearly elucidated yet why classical coherence is not sufficient for this purpose. In this paper, we investigate the classical vibrational coherence between carbonyl groups oscillations in the selectivity filter of KcsA ion channels based on the data obtained from molecular dynamics simulations. Our results show that classical coherence plays no effective role in fast ionic conduction.

Previous studies suggest that the ventrolateral prefrontal cortex (VLPFC) is involved in modulating empathy. However, it is unclear whether VLPFC activation while an individual empathizes with others is related to subsequent altruistic behavior. In the present study, participants observed two people playing a card game while empathizing with one of them (target person); PFC activation during the task was measured using functional near-infrared spectroscopy (fNIRS). After this task, participants distributed money to the target person. Results showed that activation in the left VLPFC during empathizing with the target person, who lost a small amount of money, was positively correlated with the amount of money distributed; this activation mediated a relationship between norm of restitution toward helping and the amount of distributed money. These results suggest that activation in the left VLPFC during empathizing with others experiencing negative circumstances is associated with altruistic behavior.

We assess the anxiety-like behavior in the open field and elevated plus maze tests and measure the nociceptive response in the tail flick test following prenatal stress exposure in adult male and female Wistar rats. In both behavioral anxiety tests, prenatal stress increased the anxiety-like behavior in male PS rats, but not in females suggesting a strong sex-dependent anxiogenic effect. The tail flick results showed a hypersensitivity to pain in male and female PS rats with a subtle gender difference. These findings suggest that prenatal stress is an important risk factor for multiple mental disorders.

Threshold electrotonus changes have been studied following warming to 37°C and cooling to 25°C in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). To extend the tracking of these changes also during hypothermia (≤ 25°C) and hyperthermia (≥ 40°C), and to explain their mechanisms, we investigate the effects of temperature (from 20°C to 42°C) on polarizing nodal and internodal electrotonic potentials and their current kinetics in previously simulated case of 70% CIDP. The computations use our temperature-dependent multi-layered model of the myelinated human motor nerve fiber. While the changes of electrotonic potentials and their current kinetics are largely similar for the physiological range of 28–37°C, they are altered during hypothermia and hyperthermia in the normal and CIDP cases. The normal (at 37°C) resting membrane potential is further depolarized or hyperpolarized during hypothermia or hyperthermia, respectively, and the internodal current types defining these changes are the same for both cases. Unexpectedly, our results show that in the CIDP case, the lowest and highest critical temperatures for blocking of electrotonic potentials are 20°C and 39°C, while in the normal case the highest critical temperature for blocking of these potentials is 42°C. In the temperature range of 20–39°C, the relevant potentials in the CIDP case, except for the lesser value (at 39°C) in hyperpolarized resting membrane potential, are modified: (i) polarizing nodal and depolarizing internodal electrotonic potentials and their defining currents are increased in magnitude; (ii) inward rectifier (I_IR) and leakage (I_Lk) currents, defining the hyperpolarizing internodal electrotonic potential, are gradually increased with the rise of temperature from 20°C to 39°C, and (iii) the accommodation to long-lasting hyperpolarization is greater than to depolarization. The present results suggest that the electrotonic potentials in patients with CIDP are in high risk for blocking not only during hypothermia and hyperthermia, but they are also in risk for worsening at the temperature range of 37–39°C.

The need to determine the directionality of interactions between neural signals is a key requirement for analysis of multichannel recordings. Approaches most commonly used are parametric, typically relying on autoregressive models. A number of concerns have been expressed regarding parametric approaches, thus there is a need to consider alternatives. We present an alternative nonparametric approach for construction of directionality measures for bivariate random processes. The method combines time and frequency domain representations of bivariate data to decompose the correlation by direction. Our framework generates two sets of complementary measures, a set of scalar measures, which decompose the total product moment correlation coefficient summatively into three terms by direction and a set of functions which decompose the coherence summatively at each frequency into three terms by direction: forward direction, reverse direction and instantaneous interaction. It can be undertaken as an addition to a standard bivariate spectral and coherence analysis, and applied to either time series or point-process (spike train) data or mixtures of the two (hybrid data). In this paper, we demonstrate application to spike train data using simulated cortical neurone networks and application to experimental data from isolated muscle spindle sensory endings subject to random efferent stimulation.