Enfoque teórico para repensar los espacios públicos en la ciudad de Puebla: parque del arte, parque del ajedrez y parque ecológico

Los parques citadinos constituyen parte fundamental del paisaje urbano y se pueden caracterizar como un bien complementario a la dotación de vivienda por los diversos beneficios que proporcionan a todos los grupos sociales que viven en la ciudad (Flores-Xolocotzi & González-Guillén, 2007, pág. 915). Su función principal es mejorar la calidad de vida urbana (Chiesura 2004 citado por Flores-Xolocotzi & González-Guillén, 2007). Sin embargo, un número muy reducido de personas deciden las acciones de mejoramiento de estos espacios, con lo cual no satisfacen las necesidades de las comunidades. Como consecuencia, se genera un desapego de la población hacia el espacio en cuestión, afectando de manera negativa su calidad de vida. Según estimaciones de la Organización de las Naciones Unidas (ONU), cerca de la mitad de la población mundial vive en zonas urbanas y este porcentaje se irá incrementando en las próximas décadas. En México, solamente en la década de 1970, la ciudad de México tenía más de un millón de habitantes, no obstante, para 1995 el número de ciudades con más de un millón de habitantes se incrementó a siete (de Gante Cabrera & Rodríguez Acosta, 2010). Es por lo anterior que los espacios públicos deben ser resultado de una vinculación entre las comunidades (con participación social en planes urbanos y asignación de áreas verdes) y las instituciones públicas y/o privadas con la finalidad de lograr que estos sean incluyentes y de usos variados, para que a su vez se genere una identidad con el espacio y emerja la necesidad de mantenerlo. Sin embargo, el diseño de algunos espacios públicos en la ciudad de Puebla destinados al entretenimiento y al deporte, obstaculizan la convivencia o la creación de vínculos con otros habitantes cercanos al entorno; a causa de la dificultad al accesar y hacer uso de ellos. Además de fomentar, directa o indirectamente, la segregación socio espacial de sectores de la población que no cuenten con los medios para hacer uso de estos. Por lo tanto, esta etapa de la investigación se realiza bajo un enfoque teórico que permita repensar los espacios públicos en la Ciudad de Puebla. De esta manera, se realizó un análisis de tres parques urbanos en dicha ciudad a fin de visibilizar los puntos positivos y negativos, además de los parámetros con los que evalúan la apropiación del espacio, los que propician la segregación socio espacial (en caso de que exista) y cómo la ciudadanía ha participado en la gestión de los espacios de los que hacen uso; para finalizar con una comparativa conceptual de los elementos que promueven o dificultan la convivencia en el espacio público

Reimplantable Microdrive for Long-Term Chronic Extracellular Recordings in Freely Moving Rats

Extracellular recordings of electrical activity in freely moving rats are fundamental to understand brain function in health and disease. Such recordings require a small-size, lightweight device that includes movable electrodes (microdrive) to record either a new set of neurons every day or the same set of neurons over time. Ideally, microdrives should be easy to implant, allowing precise and smooth displacement of electrodes. The main caveat of most commercially available microdrives is their relatively short half-life span, in average ranging from weeks to a month. For most experiments, recording days–weeks is sufficient, but when the experiment depends on training animals for several months, it is crucial to develop new approaches. Here, we present a low-cost, reusable, and reimplantable device design as a solution to extend chronic recordings to long-term. This device is composed of a baseplate that is permanently fixed to the rodent’s skull, as well as a reusable and replaceable microdrive that can be attached and detached from the baseplate, allowing its implantation and reimplantation. Reimplanting this microdrive is particularly convenient when no clear neuronal signal is present, or when the signal gradually decays across days. Our microdrive incorporates a mechanism for moving a 16 tungsten-wire bundle within a small (∼15 mm3) lightweight device (∼4 g). We present details of the design, manufacturing, and assembly processes. As a proof of concept, we show that recordings of the nucleus accumbens core (NAcc) in a freely behaving rat are stable over a month. Additionally, during a lever-press task, we found, as expected, that NAc single-unit activity was associated with rewarded lever presses. Furthermore, we also show that NAc shell (NAcSh) responses evoked by freely licking for sucrose, consistent with our previously published results, were conserved from a first implant to a second microdrive reimplant in the same rat, notably showing reimplantation is possible without overtly affecting the functional responses of the area of interest. In sum, here we present a novel microdrive design (low-cost, small size, and light weight) that can be used for long-term chronic recordings and reimplanted in freely behaving rats

NMDA and muscarinic receptors of the nucleus accumbens have differential effects on taste memory formation

Animals recognize a taste cue as aversive when it has been associated with post-ingestive malaise; this associative learning is known as conditioned taste aversion (CTA). When an animal consumes a new taste and no negative consequences follow, it becomes recognized as a safe signal, leading to an increase in its consumption in subsequent presentations (attenuation of neophobia, AN). It has been shown that the nucleus accumbens (NAcc) has an important role in taste learning. To elucidate the involvement of N-methyl-d-aspartate (NMDA) and muscarinic receptors in the NAcc during safe and aversive taste memory formation, we administrated bilateral infusions of DL-2-amino-5-phosphonopentanoic acid (APV) or scopolamine in the NAcc shell or core respectively. Our results showed that pre-training injections of APV in the NAcc core and shell disrupted aversive but not safe taste memory formation, whereas pre-training injections of scopolamine in the NAcc shell, but not core, disrupted both CTA and AN. These results suggest that muscarinic receptors seem to be necessary for processing taste stimuli for either safe or aversive taste memory, whereas NMDA receptors are only involved in the aversive taste memory trace formation

Glutamatergic activity in the amygdala signals visceral input during taste memory formation

Conditioned taste aversion (CTA) is a learning paradigm in which an animal avoids a taste (conditioned stimulus) previously associated with visceral toxic effects [or unconditioned stimulus (US)]. Although many studies have implicated glutamate-mediated neurotransmission in memory consolidation of different types of learning tasks, including CTA, the exact role of this neurotransmitter system in memory formation is not known. Thus, we set out to determine whether glutamate mediates signaling of the US in CTA. We present evidence obtained by in vivo microdialysis that the US (i.p. injection of lithium chloride) induced a dramatic increase in glutamate release in the amygdala and a modest but significant release in the insular cortex. Moreover, CTA can be elicited by intra-amygdalar microinjections of glutamate; consequently, when glutamate is administered just before the presentation of a weak US, a clear CTA is induced. In contrast, the injection of glutamate alone or glutamate 2 h after the suboptimal US did not have any effect on the acquisition of CTA. These results indicate that glutamate activation of the amygdala can partially substitute the US in CTA, thus providing a clear indication that the amygdala conveys visceral information for this kind of memory

Variations in Theta/Beta Ratio and Cognitive Performance in Subpopulations of Subjects with ADHD Symptoms: Towards Neuropsychological Profiling for Patient Subgrouping

ADHD is a neurodevelopmental disorder appearing in childhood but remaining in many cases in adults. There are both pharmacological and non-pharmacological approaches to treating ADHD, but they do not have the same efficacy in all subjects. Better knowledge of the neurophysiological basis of this disorder will allow for the design of more effective treatments. Studies performing qEEG analysis in children suggest the existence of subgroups of ADHD patients with different neurophysiological traits. There are fewer studies in adults, who might have undergone plastic changes allowing them to cope with ADHD symptoms along with brain maturation. Herein, we study cognitive performance and the theta/beta ratio in young adults with ADHD symptoms. We found that subjects with ADHD symptoms and low working memory performance (n = 30) present higher theta/beta ratios than controls (n = 40) at O2 and T6 in the eyes-closed condition, as well as a tendency toward a higher theta/beta ratio at O1 and Cz. Subjects with ADHD and high working memory performance (n = 50) do not differ from the controls in their theta/beta ratios at any derivation. Our results suggest that neuropsychological profiling could be useful for patient subgrouping. Further research will allow for the distinction of neuropsychological profiles and their neurophysiological correlates, leading to a better classification of ADHD subtypes, thus improving treatment selection

The K⁺-Dependent and -Independent Pyruvate Kinases Acquire the Active Conformation by Different Mechanisms

Eukarya pyruvate kinases possess glutamate at position 117 (numbering of rabbit muscle enzyme), whereas bacteria have either glutamate or lysine. Those with E117 are K+-dependent, whereas those with K117 are K+-independent. In a phylogenetic tree, 80% of the sequences with E117 are occupied by T113/K114/T120 and 77% of those with K117 possess L113/Q114/(L,I,V)120. This work aims to understand these residues’ contribution to the K+-independent pyruvate kinases using the K+-dependent rabbit muscle enzyme. Residues 117 and 120 are crucial in the differences between the K+-dependent and -independent mutants. K+-independent activity increased with L113 and Q114 to K117, but L120 induced structural differences that inactivated the enzyme. T120 appears to be key in folding the protein and closure of the lid of the active site to acquire its active conformation in the K+-dependent enzymes. E117K mutant was K+-independent and the enzyme acquired the active conformation by a different mechanism. In the K+-independent apoenzyme of Mycobacterium tuberculosis, K72 (K117) flips out of the active site; in the holoenzyme, K72 faces toward the active site bridging the substrates through water molecules. The results provide evidence that two different mechanisms have evolved for the catalysis of this reaction