The Contribution of Thalamocortical Core and Matrix Pathways to Sleep Spindles.

Sleep spindles arise from the interaction of thalamic and cortical neurons. Neurons in the thalamic reticular nucleus (TRN) inhibit thalamocortical neurons, which in turn excite the TRN and cortical neurons. A fundamental principle of anatomical organization of the thalamocortical projections is the presence of two pathways: the diffuse matrix pathway and the spatially selective core pathway. Cortical layers are differentially targeted by these two pathways with matrix projections synapsing in superficial layers and core projections impinging on middle layers. Based on this anatomical observation, we propose that spindles can be classified into two classes, those arising from the core pathway and those arising from the matrix pathway, although this does not exclude the fact that some spindles might combine both pathways at the same time. We find evidence for this hypothesis in EEG/MEG studies, intracranial recordings, and computational models that incorporate this difference. This distinction will prove useful in accounting for the multiple functions attributed to spindles, in that spindles of different types might act on local and widespread spatial scales. Because spindle mechanisms are often hijacked in epilepsy and schizophrenia, the classification proposed in this review might provide valuable information in defining which pathways have gone awry in these neurological disorders

Teologías protestantes y el problema del espacio sagrado: Relaciones divino/humanas en las capillas e iglesias norteamericanas desde 1945

The phrase sacred space, suggesting a spiritually evocative environment infused with divine or transcendent presence, is currently applied to almost all religious places, including almost all Christian churches and chapels. Yet Protestant leaders from the Reformation onward vigorously opposed such an understanding of God’s relationship to humanly created worship space. For them, God was not immanent in specific spaces or buildings. How is it that Protestants came to embrace the idea of sacred space and apply it to their own churches? This essay explores the concept of sacred space and its relationship to Protestant architecture, focusing on the second half of the 20th century, a period that brought significant transformation to this relationship. The essay asserts that cultural, theological, and academic transformations occurring in the United States in the post-World War II period, resulted in the development of a universalized view of the sacred that came to undergird new religious spaces, particularly chapels meant to accommodate several faith traditions, which in turn helped to advance that view. Both the ideas and the buildings reflected a growing interest in personal spirituality and new understandings of the relative immanence and transcendence of God.La expresión espacio sagrado, que sugiere un entorno espiritualmente evocador impregnado de presencia divina o trascendente, se aplica actualmente a casi todos los lugares religiosos, incluyendo casi todas las iglesias y capillas cristianas. Sin embargo, los sucesivos líderes protestantes de la Reforma se opusieron vigorosamente a tal comprensión de la relación de Dios con el espacio de culto creado por humanos. Para ellos, Dios no era inmanente en espacios o edificios específicos. ¿Cómo es que los protestantes llegaron a abrazar la idea del espacio sagrado y a aplicarlo a sus propias iglesias? Este ensayo explora el concepto de espacio sagrado y su relación con la arquitectura protestante, centrándose en la segunda mitad del siglo XX, un período en el que se produjo una transformación significativa a esta relación. El ensayo afirma que las transformaciones culturales, teológicas y académicas que ocurrieron en los Estados Unidos en el período posterior a la Segunda Guerra Mundial, dieron como resultado el desarrollo de una visión universalizada de lo sagrado que sirvió de soporte a nuevos espacios religiosos, particularmente capillas destinadas a acomodar a varias tradiciones de fe, que a su vez ayudaron a avanzar en esa visión. Tanto las ideas como los edificios reflejaban un creciente interés por la espiritualidad personal y nuevas comprensiones de la relativa inmanencia y trascendencia de Dios

Quantum mechanical calculation of the effects of stiff and rigid constraints in the conformational equilibrium of the Alanine dipeptide

If constraints are imposed on a macromolecule, two inequivalent classical models may be used: the stiff and the rigid one. This work studies the effects of such constraints on the Conformational Equilibrium Distribution (CED) of the model dipeptide HCO-L-Ala-NH2 without any simplifying assumption. We use ab initio Quantum Mechanics calculations including electron correlation at the MP2 level to describe the system, and we measure the conformational dependence of all the correcting terms to the naive CED based in the Potential Energy Surface (PES) that appear when the constraints are considered. These terms are related to mass-metric tensors determinants and also occur in the Fixman's compensating potential. We show that some of the corrections are non-negligible if one is interested in the whole Ramachandran space. On the other hand, if only the energetically lower region, containing the principal secondary structure elements, is assumed to be relevant, then, all correcting terms may be neglected up to peptides of considerable length. This is the first time, as far as we know, that the analysis of the conformational dependence of these correcting terms is performed in a relevant biomolecule with a realistic potential energy function.Comment: 37 pages, 4 figures, LaTeX, BibTeX, AMSTe

Neural Correlates of Auditory Perceptual Awareness and Release from Informational Masking Recorded Directly from Human Cortex: A Case Study.

In complex acoustic environments, even salient supra-threshold sounds sometimes go unperceived, a phenomenon known as informational masking. The neural basis of informational masking (and its release) has not been well-characterized, particularly outside auditory cortex. We combined electrocorticography in a neurosurgical patient undergoing invasive epilepsy monitoring with trial-by-trial perceptual reports of isochronous target-tone streams embedded in random multi-tone maskers. Awareness of such masker-embedded target streams was associated with a focal negativity between 100 and 200 ms and high-gamma activity (HGA) between 50 and 250 ms (both in auditory cortex on the posterolateral superior temporal gyrus) as well as a broad P3b-like potential (between ~300 and 600 ms) with generators in ventrolateral frontal and lateral temporal cortex. Unperceived target tones elicited drastically reduced versions of such responses, if at all. While it remains unclear whether these responses reflect conscious perception, itself, as opposed to pre- or post-perceptual processing, the results suggest that conscious perception of target sounds in complex listening environments may engage diverse neural mechanisms in distributed brain areas

Protein Patterns of Dragonfly Hemolymph as Shown by Gel Disc Electrophoresis

Acrylamide gel disc electrophoresis of the hemolymph of nymphs of the families Libellulidae and Aeschnidae showed a difference in the mobility of their protein components. Simultaneous comparisons of Anax iunius, Aeschna umbrosa, and Libellula pulchella gave clear separation of the species. Changes in protein composition associated with stage of nymphal development and transition from nymph to adult were apparent

Erratum to: Molecular modelling study of 2-phenylethynyladenosine (PEAdo) derivatives as highly selective A3 adenosine receptor ligands

A series of 2-phenylethynyladenosine (PEAdo) derivatives substituted in the N6- and 4′position was synthesised and the new derivatives were tested at the four human adenosine receptors stably transfected into Chinese hamster ovary (CHO) cells, using radioligand binding studies (A1, A2A, A3) or adenylyl cyclase activity assay (A2B). Binding studies showed that the presence of a phenyl ethynyl group in the 2 position of adenosine favoured the interaction with A3 receptors, resulting in compounds endowed with high affinity and selectivity for the A3 subtype. Additional substitution of the N6- and 4′position increases both A3 affinity and selectivity. The results showed that the new compounds have a good affinity for the A3 receptor and in particular, the N6-methoxy-2-phenylethynyl-5′N-methylcarboxamidoadenosine, with a Ki at A3 of 1.9 nM and a selectivity A1/A3 and A2A/A3 of 4,800- and 8,600-fold, respectively. Therefore, it is one of the most potent and selective agonists at the human A3 adenosine receptor subtype reported so far. Furthermore, functional assays of inhibition of 10 μM forskolin-stimulated cAMP production via the adenosine A3 receptor revealed that the new trisubstituted adenosine derivatives behave as full agonist of this receptor subtype. Docking analysis of these compounds was performed at a homology model of the human A3 receptor based on the bovine rhodopsin crystal structure as template, and the results are in accordance with the biological data