Functional neuroimaging of emotional learning and autonomic reactions

This article provides a selective overview of the functional neuroimaging literature with an emphasis on emotional activation processes. Emotions are fast and flexible response systems that provide basic tendencies for adaptive action. From the range of involved component functions, we first discuss selected automatic mechanisms that control basic adaptational changes. Second, we illustrate how neuroimaging work has contributed to the mapping of the network components associated with basic emotion families (fear, anger, disgust, happiness), and secondary dimensional concepts that organise the meaning space for subjective experience and verbal labels (emotional valence, activity/intensity, approach/withdrawal, etc.). Third, results and methodological difficulties are discussed in view of own neuroimaging experiments that investigated the component functions involved in emotional learning. The amygdala, prefrontal cortex, and striatum form a network of reciprocal connections that show topographically distinct patterns of activity as a correlate of up and down regulation processes during an emotional episode. Emotional modulations of other brain systems have attracted recent research interests. Emotional neuroimaging calls for more representative designs that highlight the modulatory influences of regulation strategies and socio-cultural factors responsible for inhibitory control and extinction. We conclude by emphasising the relevance of the temporal process dynamics of emotional activations that may provide improved prediction of individual differences in emotionality.

Movement control of manipulative tasks in patients with Gilles de la Tourette syndrome

When a hand-held object is moved, grip and load force are accurately coordinated for establishing grasp stability. In the present work, the question was raised whether patients with Gilles de la Tourette syndrome (TS), who show tic-like movements, are impaired in grip-load force control when executing a manipulative task. To this end, we assessed force regulation during action patterns that required rhythmical unimanual or bimanual (iso-directional/anti-directional) movements. Results showed that the profile of grip-load force ratio was characterized by maxima and minima that were realized at upward and downward hand positions, respectively. TS patients showed increased force ratios during unimanual and bimanual movements, compared with control subjects, indicative of an inaccurate specification of the precision grip. Functional imaging data complemented the behavioural results and revealed that secondary motor areas showed no (or greatly reduced) activation in TS patients when executing the movement tasks as compared with baseline conditions. This indicates that the metabolic level in the secondary motor areas was equal during rest and task performance. At the neuronal level, this observation suggests that these cortical areas were continuously involved in movement preparation. Based on these data, we conclude that the ongoing activation of secondary motor areas may be explained by the TS patients' involuntary urges to move. Accordingly, interference will prevent an accurate planning of voluntary behaviour. Together, these findings reveal modulations in movement organization in patients with TS and exemplify degrading consequences for manual function.

Development of dendritic tonic GABAergic inhibition regulates excitability and plasticity in CA1 pyramidal neurons

Synaptic plasticity rules change during development: while hippocampal synapses can be potentiated by a single action potential pairing protocol in young neurons, mature neurons require burst firing to induce synaptic potentiation. An essential component for spike timing-dependent plasticity is the backpropagating action potential (BAP). BAP along the dendrites can be modulated by morphology and ion channel composition, both of which change during late postnatal development. However it is unclear whether these dendritic changes can explain the developmental changes in synaptic plasticity induction rules. Here, we show that tonic GABAergic inhibition regulates dendritic action potential backpropagation in adolescent but not pre-adolescent CA1 pyramidal neurons. These developmental changes in tonic inhibition also altered the induction threshold for spike timing-dependent plasticity in adolescent neurons. This GABAergic regulatory effect upon backpropagation is restricted to distal regions of apical dendrites (>200 μm) and mediated by α5-containing GABA(A) receptors. Direct dendritic recordings demonstrate α5-mediated tonic GABA(A) currents in adolescent neurons which can modulate backpropagating action potentials. These developmental modulations in dendritic excitability could not be explained by concurrent changes in dendritic morphology. To explain our data, model simulations propose a distally-increasing or localized distal expression of dendritic α5 tonic inhibition in mature neurons. Overall, our results demonstrate that dendritic integration and plasticity in more mature dendrites are significantly altered by tonic α5 inhibition in a dendritic region-specific and developmentally-regulated manner.

Hand preference patterns in expert basketball players: Interrelations between basketball-specific and everyday life behavior

In the present study we examined the interrelation of everyday life handedness and hand preference in basketball, as an area of expertise that requires individuals being proficient with both their nondominant and dominant hand. A secondary aim was to elucidate the link between basketball-specific practice, hand preference in basketball and everyday life handedness. Therefore, 176 expert basketball players self-reported their hand preference for activities of daily living and for basketball-specific behavior as well as details about their basketball-specific history via questionnaire. We found that compared to the general population the one-hand bias was significantly reduced for both everyday life and basketball-specific hand preference (i.e., a higher prevalence of mixed-handed individuals), and that both concepts were significantly related. Moreover, only preference scores for lay-up and dribbling skills were significantly related to measures of basketball-specific practice. Consequently, training-induced modulations of lateral preference seem to be very specific to only a few basketball-specific skills, and do not generalize to other skills within the domain of basketball nor do they extend into everyday life handedness. The results are discussed in terms of their relevance regarding theories of handedness and their practical implications for the sport of basketball.

How best to preserve and reveal the structural intricacies of cartilaginous tissue.

No single processing technique is capable of optimally preserving each and all of the structural entities of cartilaginous tissue. Hence, the choice of methodology must necessarily be governed by the nature of the component that is targeted for analysis, for example, fibrillar collagens or proteoglycans within the extracellular matrix, or the chondrocytes themselves. This article affords an insight into the pitfalls that are to be encountered when implementing the available techniques and how best to circumvent them. Adult articular cartilage is taken as a representative pars pro toto of the different bodily types. In mammals, this layer of tissue is a component of the synovial joints, wherein it fulfills crucial and diverse biomechanical functions. The biomechanical functions of articular cartilage have their structural and molecular correlates. During the natural course of postnatal development and after the onset of pathological disease processes, such as osteoarthritis, the tissue undergoes structural changes which are intimately reflected in biomechanical modulations. The fine structural intricacies that subserve the changes in tissue function can be accurately assessed only if they are faithfully preserved at the molecular level. For this reason, a careful consideration of the tissue-processing technique is indispensable. Since, as aforementioned, no single methodological tool is capable of optimally preserving all constituents, the approach must be pre-selected with a targeted structure in view. Guidance in this choice is offered.

N-terminal modifications improve the receptor affinity and pharmacokinetics of radiolabeled peptidic gastrin-releasing peptide receptor antagonists: examples of 68Ga- and 64Cu-labeled peptides for PET imaging

UNLABELLED Gastrin-releasing peptide receptors (GRPrs) are overexpressed on a variety of human cancers, providing the opportunity for peptide receptor targeting via radiolabeled bombesin-based peptides. As part of our ongoing investigations into the development of improved GRPr antagonists, this study aimed at verifying whether and how N-terminal modulations improve the affinity and pharmacokinetics of radiolabeled GRPr antagonists. METHODS The potent GRPr antagonist MJ9, Pip-d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH(2) (Pip, 4-amino-1-carboxymethyl-piperidine), was conjugated to 1,4,7-triazacyclononane, 1-glutaric acid-4,7 acetic acid (NODAGA), and 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) and radiolabeled with (68)Ga and (64)Cu. The GRPr affinity of the corresponding metalloconjugates was determined using (125)I-Tyr(4)-BN as a radioligand. The labeling efficiency of (68)Ga(3+) was compared between NODAGA-MJ9 and NOTA-MJ9 in acetate buffer, at room temperature and at 95°C. The (68)Ga and (64)Cu conjugates were further evaluated in vivo in PC3 tumor xenografts by biodistribution and PET imaging studies. RESULTS The half maximum inhibitory concentrations of all the metalloconjugates are in the high picomolar-low nanomolar range, and these are the most affine-radiolabeled GRPr antagonists we have studied so far in our laboratory. NODAGA-MJ9 incorporates (68)Ga(3+) nearly quantitatively (>98%) at room temperature within 10 min and at much lower peptide concentrations (1.4 × 10(-6) M) than NOTA-MJ9, for which the labeling yield was approximately 45% under the same conditions and increased to 75% at 95°C for 5 min. Biodistribution studies showed high and specific tumor uptake, with a maximum of 23.3 ± 2.0 percentage injected activity per gram of tissue (%IA/g) for (68)Ga-NOTA-MJ9 and 16.7 ± 2.0 %IA/g for (68)Ga-NODAGA-MJ9 at 1 h after injection. The acquisition of PET images with the (64)Cu-MJ9 conjugates at later time points clearly showed the efficient clearance of the accumulated activity from the background already at 4 h after injection, whereas tumor uptake still remained high. The high pancreas uptake for all radiotracers at 1 h after injection was rapidly washed out, resulting in an increased tumor-to-pancreas ratio at later time points. CONCLUSION We have developed 2 GRPr antagonistic radioligands, which are improved in terms of binding affinity and overall biodistribution profile. Their promising in vivo pharmacokinetic performance may contribute to the improvement of the diagnostic imaging of tumors overexpressing GRPr.

Brain systems underlying encounter expectancy bias in spider phobia.

Spider-phobic individuals are characterized by exaggerated expectancies to be faced with spiders (so-called encounter expectancy bias). Whereas phobic responses have been linked to brain systems mediating fear, little is known about how the recruitment of these systems relates to exaggerated expectancies of threat. We used fMRI to examine spider-phobic and control participants while they imagined visiting different locations in a forest after having received background information about the likelihood of encountering different animals (spiders, snakes, and birds) at these locations. Critically, imagined encounter expectancies modulated brain responses differently in phobics as compared with controls. Phobics displayed stronger negative modulation of activity in the lateral prefrontal cortex, precuneus, and visual cortex by encounter expectancies for spiders, relative to snakes or birds (within-participants analysis); these effects were not seen in controls. Between-participants correlation analyses within the phobic group further corroborated the hypothesis that these phobia-specific modulations may underlie irrationality in encounter expectancies (deviations of encounter expectancies from objective background information) in spider phobia; the greater the negative modulation a phobic participant displayed in the lateral prefrontal cortex, precuneus, and visual cortex, the stronger was her bias in encounter expectancies for spiders. Interestingly, irrationality in expectancies reflected in frontal areas relied on right rather than left hemispheric deactivations. Our data accord with the idea that expectancy biases in spider phobia may reflect deficiencies in cognitive control and contextual integration that are mediated by right frontal and parietal areas.

Balanced bilinguals favor lexical processing in their opaque language and conversion system in their shallow language

Referred to as orthographic depth, the degree of consistency of grapheme/phoneme correspondences varies across languages from high in shallow orthographies to low in deep orthographies. The present study investigates the impact of orthographic depth on reading route by analyzing evoked potentials to words in a deep (French) and shallow (German) language presented to highly proficient bilinguals. ERP analyses to German and French words revealed significant topographic modulations 240-280ms post-stimulus onset, indicative of distinct brain networks engaged in reading over this time window. Source estimations revealed that these effects stemmed from modulations of left insular, inferior frontal and dorsolateral regions (German>French) previously associated to phonological processing. Our results show that reading in a shallow language was associated to a stronger engagement of phonological pathways than reading in a deep language. Thus, the lexical pathways favored in word reading are reinforced by phonological networks more strongly in the shallow than deep orthography.

Espacio modernista. Una mirada abarcadora

El presente trabajo se propone una nueva mirada sobre el extenso corpus modernista hispanoamericano, narrativo y lírico, para descubrir en él las modulaciones del espacio poético y describir, evitando una formulación dogmática, el trazo de un periplo que comienza en el espacio americano, se sumerge en espacios interiores y artificiales, se evade en lo exótico y lo antiguo para regresar nuevamente a América con una técnica transformada. Se subraya la semejanza de tal periplo con la traslación física y espiritual de los poetas modernistas más significativos.

Diagnosis del hombre moderno en Minotauroamor de Abelardo Arias

El análisis del discurso en Minotauroamor de Abelardo Arias, permite al lector acceder a una serie de conceptos acerca del hombre y de las realidades que le conciernen: el amor, la amistad, la belleza, el arte, el poder, entre otros. Si bien estos planteos alcanzan a todos los personajes, los mismos son focalizados, especialmente, en relación con los dos protagonistas: el Minotauro y Teseo. De hecho, Abelardo Arias ha declarado que lo que le impulsó a escribir esta novela fue, precisamente, un interrogante vital que lo asediaba: cuál era la verdadera condición del hombre moderno. El escritor mendocino parecía advertir, ya en ese entonces, una marcada degradación de los valores que han sido sostén de nuestra cultura e intenta despertar la conciencia de sus coetáneos a través de estas magníficas páginas. Es por ello que, en el presente trabajo, no sólo nos proponemos demostrar el enorme valor literario de la novela abelardariana y la riqueza de su contenido sino también señalar el vínculo que se establece entre los personajes con el concepto subyacente de “hombre normal". De este modo tratamos de dilucidar de qué modo, en este espacio literario, se proyectan las ideas sustentadas por el reconocido escritor mendocino. Con tal finalidad, se señalan, sucintamente, las coincidencias y modulaciones que se dan entre el mito original y la recreación que de él hace el autor mendocino para centrarnos en el análisis de los fragmentos que tienen como tema sustancial la “diagnosis" del hombre. Para este enfoque tomo en consideración un estudio de Alfonso López Quintás -Diagnosis del hombre actual-, publicado el mismo año de la obra que nos ocupa, y que plantea -desde otro lenguaje-, las mismas inquietudes que advertimos en el autor mendocino.

Una literatura peligrosa : relatos testimoniales y sectores subalternos en el programa estético-político de Rodolfo Walsh

El presente trabajo se ocupa de desarrollar una reflexión sobre los textos testimoniales escritos por Rodolfo Walsh durante los años setentas abordando las cuestiones estéticas, ideológicas y políticas que suscita una operación de lectura que pone en juego las inflexiones en la trayectoria del autor y ciertos debates de la intelectualidad de izquierda argentina y latinoamericana. En tal sentido, se intentará dar cuenta tanto de las continuidades como de las modulaciones que presenta la escritura testimonial de Rodolfo Walsh luego de una inflexión identificada en torno a los años 1968-1969, atendiendo a las marcas de la configuración de su habitus, a su posicionamiento en el campo intelectual y a sus intervenciones en el terreno de la militancia política. De este modo se buscará indagar sobre las implicancias y propuestas estéticopolíticas que esos textos generan en torno a los vínculos entre escritura, literatura, testimonio y sectores subalternos. Mi lectura, entonces, se centra en las prácticas de escritura testimonial walshianas que, en tanto articulan una narrativa de la experiencia histórica de los sectores populares, cuestionan los modos de concebir y producir el ejercicio de lo literario en tiempos de revuelta.

Memoria rota, tensión y armonía en crónicas mestizas novohispanas

Las crónicas de la conquista de México ponen en escena una peculiar tensión entre experiencia y saber como formas de acreditación del relato acerca del pasado. En estas polémicas, la apelación a la memoria (propia y de los antepasados) se convierte en un tópico, enunciado primero por el cronista y retomado, siglos después, por el analista. Aquí, se trata de poner en escena algunos de los usos de la memoria en crónicas de tradición mestiza, para responder a la pregunta acerca de la configuración textual del argumento memorialista. Así, al interrogar estas crónicas a partir del funcionamiento de la memoria, volvemos a asistir al cruce de concepciones y cosmovisiones: a las nociones de "memorial", "recuerdo" y "monumento" en la tradición occidental debemos sumarle las acepciones del término "memoria" en el mundo nahua. A analizar brevemente estas modulaciones dedicaremos estas páginas

Una crítica de pobres : Inflexiones teóricas en dos ensayos de Ángel Rama

El discurso crítico de Ángel Rama experimenta a lo largo de su desarrollo una serie de complejas inflexiones, producto del diálogo permanente con nuevos vocabularios teóricos y la participación en debates acerca del estudio de la literatura latinoamericana. Este desplazamiento se puede reconstruir a partir de la comparación del sentido y del uso dado por Rama a tres conceptos centrales en su lectura: el público lector, la clase social y la cultura. Con el fin de analizar las implicancias de estas reformulaciones, se propone el abordaje de dos textos del autor: "Rodolfo Walsh: la narrativa en el conflicto de las culturas" (1976) y Transculturación narrativa en América Latina (1982). En ellos, la construcción prepositiva "de/para los pobres" permite reflexionar acerca de la serie de revisiones, adquisiciones y modulaciones que atraviesa su práctica crítica en tres instancias de su formulación.

Imágenes y sueños de la ciudad futura (literatura y cine) : Biopolítica y ciencia ficción

En mi trabajo investigo las nuevas modulaciones de la ciencia ficción en el cine argentino de las últimas décadas observando cómo determinados saberes tales como la ciencia, la medicina y la biotecnología, están presente en su imaginario. Observaré cómo cierta fantasía futurista se encuentra impregnada de un substrato arcano que remite a un imaginario mitológico en diálogo permanente con los mitos del propio psicoanálisis y la antropología culturalista. Para ello, analizaremos cómo se articula o desarticula la máquina antropológica observando las tensiones en torno al tratamiento de los cuerpos y la configuración de las subjetividades

El poeta del pueblo / la poesía para el pueblo : En torno al proyecto de El Barrilete (primera época)

Perfilada por sus editores como una publicación atenta a 'lo popular', la colección de El Barrilete da cuenta de las búsquedas que desde finales de la década de 1950 y comienzos de la de 1960, impulsan diferentes grupos poéticos en función de lo que éstos conciben como la tarea urgente del escritor argentino: actuar en favor de la democratización de la cultura y de la sociedad en su conjunto. El presente trabajo indaga en el proyecto impulsado por los poetas en torno de la mencionada revista, a partir de la focalización de dos aspectos puntuales: por una parte, las autodefiniciones del grupo lírico como 'poetas del pueblo' y las modulaciones que dicha figuración adquiere en las páginas de la publicación; por otra, la polémica que los integrantes de El Barrilete entablan con el núcleo El pan duro, la que se orienta a establecer cuáles de estos actores sociales están mejor posicionados para ejercer la representación genuina del 'pueblo'