Tratamiento del consumo de alcohol y drogas en adolescentes / Treatment of alcohol and drug use among adolescents

El consumo problemático de sustancias entre los adolescentes, presenta tasas de prevalencia considerable a nivel mundial y se constituye en un problema de salud pública, indispensable de ser abordado, considerando la etapa del ciclo vital de esta población. El presente artículo tiene por objetivo, realizar un revisión del estado actual de los tratamientos indicados para los trastornos por abuso o dependencia de sustancias en adolescentes y de los resultados y evidencia que respaldan su efectividad, con el objetivo de orientar tanto a profesionales de la salud, como a los principales actores sociales que se relacionan con estos jóvenes (familiares, escuelas, centros comunitarios), en la posibilidad de optar por intervenciones que se ajusten a las necesidades específicas del joven, según su etapa evolutiva, nivel de desarrollo y su contexto natural más cercano.

Problematic substance use among adolescents presents significant rates worldwide prevalence and constitutes a public health problem, which is essential to be addressed, considering the stage of the life cycle of this population. This article aims, conduct a review of the current state of the indicated treatments for substance use disorders in adolescents, and the results and evidence supporting its effectiveness, with the aim of assisting both professionals health, as major social actors that relate to these young people (family, schools, community centers), the possibility of opting for interventions that meet the specific needs of the young, by evolutionary stage, level of development, and its closest natural context.

Trastornos conductuales: actualización en intervenciones con niños y adolescentes / Behavioral disorders: update on interventions with children and adolescents

El presente trabajo, es una revisión actualizada tanto de la conceptualización de los Trastornos Conductuales, como de las principales intervenciones psicoterapéuticas para el tratamiento de estos trastornos, en la infancia y adolescencia; para esto, se consideró las intervenciones que presentan evidencia positiva de su efectividad. Las últimas investigaciones realizadas sobre este trastorno concluyen que las intervenciones psicosociales debieran ser la primera línea de tratamiento y que se debiera considerar las intervenciones psicofarmacológicas sólo en casos específicos, para tratar la sintomatología asociada.

This paper is an updated review of both the conceptualization and the major psychotherapeutic interventions in Behavioral Disorders in childhood and adolescence. We considered the interventions that have positive evidence of their effectiveness. The latest research on Behavioral Disorders conclude that psychosocial interventions should be the first line of treatment and that psychopharmacological interventions should be considered only in specific cases, to treat associated symptoms.

El estrés escolar / School stress

El término estrés escolar ha sido una conceptualización de difícil acuerdo y compleja descripción para la literatura clínica. Los niños(as) y adolescentes en etapa escolar, se ven enfrentados a situaciones de alta demanda y requieren del despliegue de todas sus capacidades de afrontamiento para adaptarse a los estresores tanto internos como externos, de acuerdo a la etapa evolutiva alcanzada. Los síntomas aso- ciados a estrés acompañan a cuadros adaptativos, ansiosos, conductuales y emocionales. En este artículo se describen los principales síntomas asociados a la presencia de estrés escolar, que pueden ser foco de atención para los profesionales de la salud.

The term school stress has been a conceptualization of difficult agreement and complex description for clinical literature. The children and adolescents in school, are confronted by situations of high demand and require the deployment of all their coping capacities to adapt to both internal and external stressors according to the evolutionary stage reached. The symptoms associated with stress accompany adjustment, anxious, behavioral and emotional disorders. The main symptoms associated with the presence of school stress that may be a focus of attention for health professionals are described.

The As-contaminated Elqui river basin: a long lasting perspective (1975-1995) covering the initiation and development of Au-Cu-As mining in the high Andes of northern Chile.

The Elqui watershed (northern Chile) constitutes a highly contaminated river system, with arsenic exceeding by up to three orders of magnitude the average for river waters. There are three main reasons that explain this contamination: (1) the regional geology and hydrothermal (mineralizing) processes that developed in this realm during Miocene time; (2) the later unroofing-erosion-oxidation-leaching of As-Cu rich sulfide ores, a process that have been taking place for at least 10,000 years; and last but not least (3) mining activities at the high-altitude (>4000 m above sea level) Au-Cu-As El Indio mine, from the late 1970s onwards. The El Indio mineral deposit hosted large veins of massive sulfides, including the important presence of enargite (Cu(3)AsS(4)). The continuous natural erosion of these veins and their host rocks (also rich in As and Cu) during Holocene time, led to important and widespread metal dispersion along the river system. During the studied pre mining period (1975-1977), the high altitude river Toro waters already showed very large As concentrations (0.36-0.52 mg l(-1)). The initiation of full scale mining at El Indio (1980 onwards) led to an increase of these values, reaching a concentration of 1.51 mg l(-1) As in 1995. During the same year other rivers of the watershed reached peak As concentrations of 0.33 (Turbio) and 0.11 mg l(-1) (Elqui). These figures largely exceed the USEPA regulations for drinking water (0.01 mg l(-1) As), and about 10% of the total As data from the river Elqui (and 70% from the river Turbio) are above the maximum level allowed by the Chilean law for irrigation water (0.1 mg l(-1) As).

Conduction velocity groups in the retino-tectal and retino-thalamic visual pathways of the pigeon (Columbia livia).

The anatomical characteristics of the avian visual system are well known. However, there are wide gaps in our knowledge with respect to the physiological characteristics of their visual system. For example, we lack both an operational identification of the different ganglion cell types present in the retinae of birds, and a description of their presumptive differential central projections. The results presented here address this latter point by classifying the conduction velocity groups of fibers present in the optic tract of the pigeon. We report the existence of at least 5 groups of axons in the optic tract of the pigeon, with conduction velocities of 22-18 m/s, 12-10 m/s, 8 m/s, 6 m/s and less than 2.5 m/s. All five groups project to the tectum but only the four fastest groups project to the dorsal thalamic complex. The homologies with the populations of retinal axons found in cats are discussed.

Brain, language and the origin of human mental functions.

We propose that to understand the biological and neurophysiological processes that give rise to human mental phenomena it is necessary to consider them as behavioral relational phenomena. In particular, we propose that: a) these phenomena take place in the relational manner of living that human language constitutes, and b) that they arise as recursive operations in such behavioral domain. Accordingly, we maintain that these phenomena do not take place in the brain, nor are they the result of a unique operation of the human brain, but arise with the participation of the brain as it generates the behavioral relational dynamics that constitutes language.

[Language and reality: the origin of man]. / Lenguaje y realidad: el origen de lo humano.

The author proposes: 1. That a lineage of living systems is constituted by the reproductive conservation of a manner of living under the form of an ontogenic phenotype. 2. That language is a manner of living in recurrent consensual coordinations of consensual coordinations of actions. 3. That the human manner of living entails among other things, a braiding of languaging and emotioning that we call conversation. 4. That human beings arise in the history of bipedal primates with the origin of language, and the constitution of a lineage defined by the conservation of an ontogenic phenotype that includes conversations as part of it. 5. That the magnitude of the involvement of the brain and anatomy of the larynx and face in speech as our main manner of languaging indicate that language cannot have arisen later than two to three millions year ago. 6. That rationally pertains to the operational coherences of languaging and that different rational domains are constituted by different basic notions that are accepted a priori. That is, on preference. 7. That responsibility and freedom are a function of our awareness of the participation of our emotions (preferences) in the constitution of the rational domains in which we operate.

Frontal and lateral visual system in birds. Frontal and lateral gaze.

Birds exhibit a variable retinal organization in terms of foveas and areas of high cell density. The distribution of these retinal structures in different species does not follow phylogenetic lines. In order to study this phenomenon, we presented chickens and pigeons with a luminous bar that could be moved at different speeds and directions in the visual field and could be located at various distances from the animal; head movements were monitored during the presentations. The results show that for a static or slow-moving stimulus the birds adopted a frontal gaze that stabilized the image in the retina, and for a fast-moving stimulus they adopted a lateral gaze that allowed the image to move across the retina. These results reveal that: (a) these two ways of looking correlate with the retinal anatomy, not with the phylogeny, of the species, and (b) these two ways of looking reflect two different sensorimotor systems that involve different anatomical features and neurophysiological properties of the visual system in birds.

Cytoarchitecture of the avian ventral lateral geniculate nucleus.

The avian thalamic ventral lateral geniculate nucleus (GLv) was studied by light microscopic techniques in order to understand its anatomy, neuronal composition, and the nature of its retinal and tectal afferents. The avian GLv is of considerable interest because physiological experiments show that it is the brain structure with the highest percentage of color-opponent responses (Maturana and Varela, '82). We used adult pigeons and quail for the present study. With Nissl techniques a predominance of medium-size neurons (58%) constitute the GLv. The shape, size, and orientation of the different neurons is highly variable throughout the GLv. With the Golgi methods, 5 classes of neurons are distinguished: I and IV (large), II (medium-size), III and V (small). Some class IV large neurons have bifurcated axons; no axons were distinguished on the small neurons. Optic fibers penetrating the GLv are often collateral branches of retinal axons that continue elsewhere. Fink-Heimer methods show that retinal axon terminals end around large and medium-size neurons and also reach the internal lamina of the GLv. HRP tracing shows that the large and medium-size neurons of the GLv project to the optic tectum. On the basis of comparisons between the cytoarchitecture of the GLv described here and the physiological findings previously reported (Maturana and Varela, '82; Pateromichelakis, '79), we suggest that: (1) large GLv neurons are the color-opponent units, (2) medium-size neurons are the movement-sensitive units, and (3) small neurons are either interneurons (local circuit neurons), or they might project to the area pretectalis or to some other GLv projection region not yet described.

[Perception: behavioral configuration of the object]. / Percepción: configuración conductual del objeto.

The word perception is usually heard as connoting an operation of grasping an external reality through the process of receiving information from it. This, however, is constitutively impossible because living systems are dynamic structure determined systems, and everything happens in them determined at every instant by their structure. This means that the medium cannot specify what happens in a living system, and that it can only trigger in it structural changes determined in its structure. As a result a living system constitutively always operates in structural congruence with the medium, and exists as such only as long as this structural congruence (adaptation) is conserved; otherwise it desintegrates. In these circumstances, the phenomenon connoted by the word perception consists in the association, by the observer, of the behavioral regularities that he or she distinguishes in the observed organism with the conditions of the medium that he or she sees triggering them. The observer uses such behavioral regularities to characterize perceptual objects. This applies to all living systems including the observer. The explanation of perception in the context of the structural determinism of living systems invalidates any attempt to account for the phenomenon of cognition (including language) with notions that entail the denotation or connotation of a domain of reality independent of the distinctions of the observer.

Regional specialization of the quail retina: ganglion cell density and oil droplet distribution.

The ganglion cell density of the quail's retina was studied in sections and whole mounts. Two regions of high ganglion cell density were found, corresponding to an afoveate area centralis and an area dorsalis. Oil droplets were found to be isotropically distributed throughout the retina. It is proposed that the significance of such retinal regional specialization, in comparison to similar studies in the pigeon and the chick, is that regional specialization in the avian retina is more closely related to feeding habits than to phylogenetic descendence.

What is it to see?

We as neurobiologists studying vision usually do not ask the question what is it to see? because we considered it a philosophical and not a biological question, and do not realize that we answer it implicitly by doing what we do in our research. This implicit answer entails the basic assumption that we exist in an objective world independent of our acts of cognition and accessible to our knowledge. My contention is: a) that by answering the question what is it to see? one can show that this assumption cannot be sustained because the phenomenon of perception cannot consist in a process of grasping the features of an independent world of objects; and b) that by reflecting upon the nature of a scientific explanation one can show that this assumption is unnecessary because a scientific explanation is a particular kind of coordinations of actions in a community of observers that does not entail it. In this context, a) by putting objectivity in parenthesis, that is, by using the operational generation of scientific explanations and not the object as the criterion of validation of my statements, and, b) by recognizing that the nervous system operates as a closed neuronal network in the generation of its states of activity, I show that the phenomenon of perception arises in the description of an observer as a manner of referring to the operation of an organism in congruence with the particular environment in which it is observed. In these circumstances, my answer to the initial question is: to see is a particular manner of operating as a closed neuronal system component of an organism in a domain of structural coupling. Finally, I propose that by dwelling in language as a peculiar system of coordinations of actions, we human beings bring forth an objective world through using our own changes of states as describers that specify the objects that constitute it.

Color-opponent responses in the avian lateral geniculate: a study in the quail (Coturnix coturnix japonica).

Extracellular recordings were made from cells in the ventral lateral geniculate (GLv) of the Japanese quail (Coturnix coturnix japonica), and their responses studied with chromatic stimuli. A total of 156 units were studied, and of these, 124 were found to be optimally responsive to changes in hue, and not to changes of contrast or motion of the stimuli in their receptive fields. These chromatic responses can be characterized as follows: (1) they have large (average 15 degrees x 15 degrees) receptive fields; (2) these receptive fields are mostly located in the anterior part of the visual field; (3) the receptive fields are organized in a (rough) retinotopy in agreement with anatomical findings; (4) units exhibit a sustained response in the dark or under white illumination, which is strongly modulated by changes in hue of stimuli of equal illuminance; (4) the units have a complementary inhibitory response, thus exhibiting a color-opponent pattern of responses; (5) the inhibitory and excitatory areas of the receptive fields are uniform and superimposed; (6) there is a tendency of units of the same optimal chromatic responses to be clustered together in the Glv; (7) although units of all preference are found, the population is dominated by units with preferences in the short wavelength end of the spectrum (48%). This is the first report of a region in the avian brain where color-opponent responses are found in significant numbers, thus making it apparent that the difficulty of finding similar units in the optic tract, tectum, dorsal geniculate, or telencephalon, is not due to a lack of appropriate retinal afferents. The relationship between the present findings and other reports on the Glv's anatomy and physiology are discussed, as well as its possible roles in the generation of chromatic behavioral discrimination of birds.