Motor Imagery and Merleau-Pontyian Accounts of Skilled Action

Maurice Merleau-Ponty is often interpreted as claiming that opportunities for action are directly present in perceptual experience. However, he does not provide much evidence for how or why this would occur, and one can doubt that this is an appropriate interpretation of his phenomenological descriptions. In particular, it could be argued the Merleau-Pontyian descriptions mistakenly attribute pre-perceptual or post-perceptual elements such as allocation of attention or judgment to the perceptual experience itself. This paper argues for the Merleau-Pontyian idea that opportunities for action are present in perceptual experience. It further argues that the phenomenological descriptions can be supported and explained via reference to contemporary research on motor imagery. In particular, it will be argued that non-conscious, covert motor imagery is used to prepare for and regulate skilled actions, and that it is plausible that this imagery combines with perception (likely vision) to create a single experience of the environment as enabling action. The paper will also show that contemporary views on motor imagery are broadly compatible with Merleau-Ponty’s aims

Computational and theoretical aspects of biomolecular structure and dynamics

This is the final report for a project that sought to evaluate and develop theoretical, and computational bases for designing, performing, and analyzing experimental studies in structural biology. Simulations of large biomolecular systems in solution, hydrophobic interactions, and quantum chemical calculations for large systems have been performed. We have developed a code that implements the Fast Multipole Algorithm (FMA) that scales linearly in the number of particles simulated in a large system. New methods have been developed for the analysis of multidimensional NMR data in order to obtain high resolution atomic structures. These methods have been applied to the study of DNA sequences in the human centromere, sequences linked to genetic diseases, and the dynamics and structure of myoglobin

The Beginning and Evolution of the Universe

We review the current standard model for the evolution of the Universe from an early inflationary epoch to the complex hierarchy of structure seen today. We summarize and provide key references for the following topics: observations of the expanding Universe; the hot early Universe and nucleosynthesis; theory and observations of the cosmic microwave background; Big Bang cosmology; inflation; dark matter and dark energy; theory of structure formation; the cold dark matter model; galaxy formation; cosmological simulations; observations of galaxies, clusters, and quasars; statistical measures of large-scale structure; and measurement of cosmological parameters. We conclude with discussion of some open questions in cosmology. This review is designed to provide a graduate student or other new worker in the field an introduction to the cosmological literature.Comment: 69 pages. Invited review article for Publications of the Astronomical Society of the Pacific. Supplementary references, tables, and more concise PDF file at http://www.physics.drexel.edu/univers

Alanine Zipper-Like Coiled-Coil Domains Are Necessary for Homotypic Dimerization of Plant GAGA-Factors in the Nucleus and Nucleolus

GAGA-motif binding proteins control transcriptional activation or repression of homeotic genes. Interestingly, there are no sequence similarities between animal and plant proteins. Plant BBR/BPC-proteins can be classified into two distinct groups: Previous studies have elaborated on group I members only and so little is known about group II proteins. Here, we focused on the initial characterization of AtBPC6, a group II protein from Arabidopsis thaliana. Comparison of orthologous BBR/BPC sequences disclosed two conserved signatures besides the DNA binding domain. A first peptide signature is essential and sufficient to target AtBPC6-GFP to the nucleus and nucleolus. A second domain is predicted to form a zipper-like coiled-coil structure. This novel type of domain is similar to Leucine zippers, but contains invariant alanine residues with a heptad spacing of 7 amino acids. By yeast-2-hybrid and BiFC-assays we could show that this Alanine zipper domain is essential for homotypic dimerization of group II proteins in vivo. Interhelical salt bridges and charge-stabilized hydrogen bonds between acidic and basic residues of the two monomers are predicted to form an interaction domain, which does not follow the classical knobs-into-holes zipper model. FRET-FLIM analysis of GFP/RFP-hybrid fusion proteins validates the formation of parallel dimers in planta. Sequence comparison uncovered that this type of domain is not restricted to BBR/BPC proteins, but is found in all kingdoms

Preclinical Evidence Supporting Early Initiation of Citalopram Treatment in Machado-Joseph Disease

Spinocerebellar ataxias are dominantly inherited neurodegenerative disorders with no disease-modifying treatment. We previously identified the selective serotonin reuptake inhibitor citalopram as a safe and effective drug to be repurposed for Machado-Joseph disease. Pre-symptomatic treatment of transgenic (CMVMJD135) mice strikingly ameliorated mutant ataxin-3 (ATXN3) pathogenesis. Here, we asked whether citalopram treatment initiated at a post-symptomatic age would still show efficacy. We used a cohort of CMVMJD135 mice that shows increased phenotypic severity and faster disease progression (CMVMJD135hi) compared to the mice used in the first trial. Groups of hemizygous CMVMJD135hi mice were orally treated with citalopram. Behavior, protein analysis, and pathology assessment were performed blindly to treatment. Our results show that even when initiated after symptom onset, treatment of CMVMJD135hi mice with citalopram ameliorated motor coordination and balance, attenuating disease progression, albeit to a lesser extent than that seen with pre-symptomatic treatment initiation. There was no impact on ATXN3 aggregation, which contrasts with the robust reduction in ATXN3-positive inclusions observed in CMVMJD135 mice, when treated pre-symptomatically. Post-symptomatic treatment of CMVMJD135hi mice revealed, however, a limited neuroprotective effect by showing a tendency to repair cerebellar calbindin staining, and to increase the number of motor neurons and of NeuN-positive cells in certain brain regions. While supporting that early initiation of treatment with citalopram leads to a marked increase in efficacy, these results strengthen our previous observation that modulation of serotonergic signaling by citalopram is a promising therapeutic approach for Machado-Joseph disease even after symptom onset.European Regional Development Funds (FEDER), through the Competitiveness Factors Operational Programme (COMPETE), and by National funds, through the Foundation for Science and Technology (FCT), under the scope of the project POCI-01-0145-FEDER-007038. This article has been developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the FEDER. This work was also supported by FCT and COMPETE through the projects [PTDC/SAU-GMG/112617/2009] (to PM) and [EXPL/BIM-MEC/0239/2012] (to AT-C), by FCT through the project [POCI-01-0145-FEDER-016818 (PTDC/NEU-NMC/3648/2014)] (to PM), by National Ataxia foundation (to PM and to AT-C), and by Ataxia UK (to PM). SE, SD-S, SO, and AT-C were supported by the FCT individual fellowships, SFRH/BD/78554/2011, SFRH/BD/78388/2011, PD/BD/127818/2016, and SFRH/BPD/102317/2014, respectively. FCT fellowships are co-financed by POPH, QREN, Governo da República Portuguesa, and EU/FSEinfo:eu-repo/semantics/publishedVersio

Pheromone-sensing neurons regulate peripheral lipid metabolism in <i>Caenorhabditis elegans</i>

It is now established that the central nervous system plays an important role in regulating whole body metabolism and energy balance. However, the extent to which sensory systems relay environmental information to modulate metabolic events in peripheral tissues has remained poorly understood. In addition, it has been challenging to map the molecular mechanisms underlying discrete sensory modalities with respect to their role in lipid metabolism. In previous work our lab has identified instructive roles for serotonin signaling as a surrogate for food availability, as well as oxygen sensing, in the control of whole body metabolism. In this study, we now identify a role for a pair of pheromone-sensing neurons in regulating fat metabolism in C. elegans, which has emerged as a tractable and highly informative model to study the neurobiology of metabolism. A genetic screen revealed that GPA-3, a member of the Gα family of G proteins, regulates body fat content in the intestine, the major metabolic organ for C. elegans. Genetic and reconstitution studies revealed that the potent body fat phenotype of gpa-3 null mutants is controlled from a pair of neurons called ADL(L/R). We show that cAMP functions as the second messenger in the ADL neurons, and regulates body fat stores via the neurotransmitter acetylcholine, from downstream neurons. We find that the pheromone ascr#3, which is detected by the ADL neurons, regulates body fat stores in a GPA-3-dependent manner. We define here a third sensory modality, pheromone sensing, as a major regulator of body fat metabolism. The pheromone ascr#3 is an indicator of population density, thus we hypothesize that pheromone sensing provides a salient 'denominator' to evaluate the amount of food available within a population and to accordingly adjust metabolic rate and body fat levels