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We provide a high resolution, all-atom, femto-second molecular dynamics (MD) simulation of the passage of K+ ions and H2O molecules through the selectivity filter of the KcsA potassium ion channel, based on first principle physical methods. Our results show that a change in the length of the selectivity filter of as little as 3%, regardless of whether the filter is made longer or shorter, will reduce the K+ ion current by around 50%. In addition, further squeezing or stretching by about 9% can effectively stop the current. Our results demonstrate optimized conformational dynamics that associate an increased mobility of parts in the filter linings with a standard configuration, leading to maximized conduction rates that are highly sensitive to geometrical distortions. We discuss this latter aspect in relation to lateral membrane effects on the filter region of ion channels and the 'force from lipids' hypothesis.

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We present a comparison of a classical and a quantum mechanical calculation of the motion of K+ ions in the highly conserved KcsA selectivity filter motive of voltage gated ion channels. We first show that the de Broglie wavelength of thermal ions is not much smaller than the periodic structure of Coulomb potentials in the nano-pore model of the selectivity filter. This implies that an ion may no longer be viewed to be at one exact position at a given time but can better be described by a quantum mechanical wave function. Based on first principle methods, we demonstrate solutions of a non-linear Schrödinger model that provide insight into the role of short-lived (~1 ps) coherent ion transition states and attribute an important role to subsequent decoherence and the associated quantum to classical transition for permeating ions. It is found that short coherences are not just beneficial but also necessary to explain the fast-directed permeation of ions through the potential barriers of the filter. Certain aspects of quantum dynamics and non-local effects appear to be indispensable to resolve the discrepancy between potential barrier height, as reported from classical thermodynamics, and experimentally observed transition rates of ions through channel proteins.

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Subject-object relations reflect the relation of phenomenology and physics and are at the centre of interest in brain research and neuro-psychology. The unresolved dichotomy behind this relation is one of the most challenging questions of our time. Setting out from causal modelling I suggest a particular topology for subject-object relations and argue that we can find a physical realization in living organism that provides a continuous transform between both domains. In a geometrical metaphor this transform has the topological properties of a one-sided surface or non-orientable flat. I argue that such a surface can be found within the electronic organization of atomic linings in the filter region of ion-conducting membrane proteins. Electron transfer along these atomic surfaces makes chiral induced spin changes to a promising signature of subject-object relations and has found experimental evidence in previous studies. I finally advocate the view that there is a basic dualism between subject and object which is physical on both sides and realized by an inversion relation along one-sided surfaces. The transition between these two aspects however is non-physical and hosts the phenomenology that characterizes subjectivity.

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In this paper we present a mechanistic model that integrates subneuronal structures, namely ion channels, membrane fatty acids, lipid rafts, G proteins and the cytoskeleton in a dynamic system that is finely tuned in a healthy brain. We also argue that subtle changes in the composition of the membrane's fatty acids may lead to down-stream effects causing dysregulation of the membrane, cytoskeleton and their interface. Such exquisite sensitivity to minor changes is known to occur in physical systems undergoing phase transitions, the simplest and most studied of them is the so-called Ising model, which exhibits a phase transition at a finite temperature between an ordered and disordered state in 2- or 3-dimensional space. We propose this model in the context of neuronal dynamics and further hypothesize that it may involve quantum degrees of freedom dependent upon variation in membrane domains associated with ion channels or microtubules. Finally, we provide a link between these physical characteristics of the dynamical mechanism to psychiatric disorders such as major depression and antidepressant action.

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The impact of evolving migratory behavior on brain organization in birds has been a foundational question in the emerging field of neuroecology. One generalization that seems to be approaching consensus is that migratory species/populations have smaller brain volumes than their nonmigratory comparison groups. The lark sparrow (Chondestes grammacus) is a North American species characterized by migratory and nonmigratory populations. Consistent with what has been observed in other species/population comparisons, we found that, relative to body weight, migratory females from Nebraska have smaller brain volumes than nonmigratory females from Texas. We also carried out an exploratory, higher-order analysis of possible differences in the volumes of a number of telencephalic subdivisions. Although our small sample size precluded statistical verification of any difference, noteworthy was that, although there seemed to be no indication of a difference in the relative hippocampal volume between the two populations, the migratory birds from Nebraska showed a clear trend toward a smaller nidopallium. The importance of higher-resolution, brain subdivisional analyses has been discussed.

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Voltage-gated channel proteins cooperate in the transmission of membrane potentials between nerve cells. With the recent progress in atomic-scaled biological chemistry, it has now become established that these channel proteins provide highly correlated atomic environments that may maintain electronic coherences even at warm temperatures. Here we demonstrate solutions of the Schrödinger equation that represent the interaction of a single potassium ion within the surrounding carbonyl dipoles in the Berneche-Roux model of the bacterial KcsA model channel. We show that, depending on the surrounding carbonyl-derived potentials, alkali ions can become highly delocalized in the filter region of proteins at warm temperatures. We provide estimations on the temporal evolution of the kinetic energy of ions depending on their interaction with other ions, their location within the oxygen cage of the proteins filter region, and depending on different oscillation frequencies of the surrounding carbonyl groups. Our results provide the first evidence that quantum mechanical properties are needed to explain a fundamental biological property such as ion selectivity in transmembrane ion currents and the effect on gating kinetics and shaping of classical conductances in electrically excitable cells.

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Primary-process experiences, both raw affects and perceptions, are self-creating processes, and the associated motoric-action tendencies serve survival values, providing the raw materials for learning. Actions seem to play a key role in providing 'meaning' for the primary sensations and associated feelings. We suggest, that one important type of action are those that can promote on-going maintenance of sensory invariance, especially when other actions would remove animals from their affective comfort zones. The epigenetic determinants of such developmentally emerging states of 'feeling', especially when the alternatives are experienced as aversive or threatening, arise from these sensory invariant principles. In accordance with this view, a number of recent studies also suggest that experiences require reproducible neuronal response patterns to sensory stimuli to gain 'meaning' or conscious awareness of sensory states. We demonstrate some of these aspects by a standard precocial avian model of social attachment. The behaviour of isolated chicks in a polarized maze effectively reveals motoric patterns that serve the establishment of perceptual invariance. Chicks actively and spontaneously seek for and explore ways to maintain invariance of internal affective-perceptual states. In the following work, we summarize behaviour patterns that display the ongoing dynamics of internal states as newborn chicks seek proximity to other friendly beings in the world, in this case, the 'actor outside' that is used to access this process is their own mirror image.

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Neuronal stem cells are like other tissue-specific stem cells, undifferentiated cells which can proliferate and may give rise to glia and neurons. They are present in mammalians throughout the entire life and are supposed to play an important role in renewal of neurons. However, little is known about the origin, phenotypic expression and function of neuronal stem cells in the adult brain. In the present review the occurrence and origin of neuronal stem cells as well as specific markers, which allow their identification in the brain is being described. Finally the role of these cells in the adult brain and their potential use in neuropathy is discussed.

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