ABSTRACT
Resumen La investigación moderna, tanto en humanos como preclínica, que utiliza modelos animales indica que fumar durante la edad adolescente resulta en cambios cerebrales y psicológicos a corto y largo plazo en el fumador, así como en un aumento significativo en los riesgos de desarrollar adicción al tabaco durante la vida. Por lo tanto, en la presente revisión narrativa se describirán y profundizarán los hallazgos investigativos modernos de la psicobiología de la adolescencia y los efectos del tabaco en el desarrollo, con un énfasis particular en la comprensión de los efectos psicológicos y cerebrales del consumo de tabaco durante la adolescencia, tanto a corto como a largo plazo. Se considerarán de manera detallada los avances investigativos sobre la psicobiología de la adolescencia y sus riesgos en las adicciones desde los aspectos: conductual, cognitivo, reactividad al estrés y psicobiología. Sobre esta base, se revisará la investigación sobre la psicobiología de la adolescencia y la evidencia de vulnerabilidad a la adicción durante esta etapa. Al final, se abordarán los efectos del tabaco en el cerebro y conducta durante el desarrollo adolescente y vida posterior, ya que se ha encontrado evidencia relacionada con alteraciones cerebrales crónicas en los sistemas colinérgicos y regiones cerebrales asociadas con la dependencia de la nicotina. Se espera que la revisión y divulgación de esta información en el idioma español sea de valor para la comprensión de los problemas de vulnerabilidad y predisposiciones a la adicción al tabaco en el contexto de Latinoamérica.
Abstract Tobacco use and its harmful health-related problems have become one of the largest modern preventable public health issues. Current research strongly suggests that smoking during adolescence enhances addictive smoking behaviors during life, which can be related to adolescence as a critical ontogenetic period characterized by behaviors that can increase the probability of risk-related behaviors such as sensation and novelty seeking. Adolescent development is also a period of maturation of frontal and subcortical neural systems, brain changes that underlie higher impulsivity tendencies to promote adequate learning and adaptations necessary to succeed the novel challenges of the adult life, but those changes also enhance vulnerabilities to the addictive effects of drugs. Consistent with this, tobacco use affects brain development processes which underlie long-term psychobiological alterations and the enhanced risks for tobacco addiction during adult life. Thus, the present review describes current psychobiological approaches to understand general addiction processes and tobacco addiction, highlighting the behavioral and neural short-term effects of tobacco use during adolescence and its long-term effects during adulthood. Current research has advanced on four aspects for the understanding of both the psychobiology of adolescent development and the effects of drugs of abuse during this time. The first aspect is behavioral, as adolescence is related to important changes on motivational and emotional behaviors such as sensation seeking. Other important behavioral changes are social approach, a higher variety of opportunity for personal choices, and development of personal independence. Research on a second aspect has focused on cognition. A review of research is presented showing enhanced abilities during adolescence development for reading, abstract and logical thinking, and novel problem solving. Stress reactivity is the third aspect of reviewed psychobiological mechanisms. The stress biological system undergoes important changes during adolescence, including changes on stress-related hormones and neural architecture. An important issue is that exposure to early and/or chronic stressful circumstances during adolescence could be related to higher risk to the start and maintenance of addiction states, as suggested by research assessing the disruptive effects of stress on psychobiological homeostatic processes needed to maintain stable biological and emotional regulation. The fourth aspect is psychobiology. In this section research is reviewed related to the development of monoaminergic brain circuits underlying motivation, novelty-seeking, impulsivity, and addiction processes. Using as model the previous review integration, the effects of nicotine are discussed, the essential addictive component of tobacco, on the neurochemical systems underlying tobacco addiction. Following this, important research is introduced that describes psychobiological changes during adolescence and evidence of vulnerability to addiction during this life stage. Then, current research on both short-term and long-term effects of tobacco or nicotine administration during adolescence on the brain, behavior, and cognition is introduced. The current research advances and discussions on the psychobiology of addictions in general, and tobacco addiction in particular, have been possible to a large extent from the use of animal models and preclinical research, since animal models have become crucial to identify learning, motivational, emotional, and cognitive mechanisms that underlie addictive processes, and making possible to perform experimental procedures to discover the functioning and participation of biological components. One example of such components is the cholinergic system, which is activated by nicotine and is part of the neurochemical machinery on different brain areas important for both tobacco addiction and adolescence development such as the dorsal striatum, amygdala, ventral tegmental area, nucleus accumbens, prefrontal cortex, and hippocampus. The present review and research divulgation written in Spanish are expected to clarify modern research on addiction and encourage current scientific education on the vulnerabilities and predispositions for tobacco abuse in Latin-American countries.
ABSTRACT
The black-headed night monkey, Aotus nigriceps, has one of the largest distribution ranges of the 11 night monkey species found across Central and South America. Yet, only three studies have focused on their ecology, describing considerable variation in habitat, group composition, and population density. Therefore, we analyzed habitat use, group composition, population density, and diet of 14 groups at two field sites in southeastern Peru. All sampled groups were found in secondary tropical rainforest, often dominated by native bamboo species. Half of the observed sleeping sites were in bamboo stands, though groups also emerged from cane thickets and lianas. This contrasts with other Aotus studies which have found groups living in tree cavities and lianas. Population density estimates for both sites were 19 and 50 individuals per km2, outside the range previously reported for A. nigriceps (31−34 individuals per km2). We recovered seeds of 12 species from fecal samples over the course of two field seasons, belonging mainly to Cecropiaceae, Piperaceae and Moraceae. Our results suggest that the black-headed night monkey in Peru can survive and even thrive in secondary forest, feeding extensively on pioneer species, occupying a range of forest types, all while living near human settlements. (AU)