María Angélica Sotomayor Saavedra

Quantitative models of Pavlovian conditioning

Over the last few years, research on learning and memory has become increasingly interdisciplinary. In the past, theories of learning, as a prerogative of psychologists, were generally formulated in purely verbal terms and evaluated exclusively at the behavioral level. At present, scientists are trying to build theories with a quantitative and biological flavor, seeking to embrace more complex behavioral phenomena. Pavlovian conditioning, one of the simplest and ubiquitous forms of learning, is especially suited for this multiple level analysis (i.e., quantitative, neurobiological, and behavioral), in part because of recent discoveries showing a correspondence between behavioral phenomena and associative properties at the cellular and systems levels, and in part because of its well established quantitative theoretical tradition. The present review, examines the mayor quantitative theories of Pavlovian conditioning and the phenomena to which they have been designed to account. In order to provide researchers from different disciplines with a simple guideline about the rationale of the different theoretical choices, all the models are described through a single formalism based on the neural network connectionist perspective.

Sex differences in aversive and appetitive conditioning in two strains of rats

In order to examine sex differences in non sexual behavior, 40 rats of each sex from two strains (gray, A x C and albino, Sprague-Dawley) were trained, using different experimental procedures. In Experiment I, aversive conditioning in a one-way (easy task) and a two-way (difficult task) active avoidance task was examined. Results consistently showed that males of both strains were inferior to females in the acquisition of the two-way avoidance task. A significant interaction between sex of both strains and the difficulty of the task was found. In Experiment II, rats were trained in a Sutherland Apparatus in an easy (black vs. white) and a difficult (horizontal vs. vertical) visual discrimination task, using appetitive reinforcement; no differences between sexes were observed. A significant interaction, however, was found between strain and task, indicating a lower performance of the A x C strain in the difficult task. The results are discussed within the theoretical framework of the Yerkes-Dodson Law, which states a relationship between drive level, performance and different degrees of task difficulty.

BIOÉTICA Y DISCAPACIDAD PSIQUIÁTRICA: ASPECTOS CLÍNICOS Y JURÍDICOS

This monography seeks to establish an interdisciplinary link between bioethics and the clinical and juridical aspects that connect with attention, protection and rehabilitation of persons with psychiatric illness. The analysis is centered those adults, on deprived of reasoning because of a psycopathologic process, entitled to civil rights, but with dificulties to exercise them due to their illness.This monography seeks to establish an interdisciplinary link between bioethics and the clinical and juridical aspects that connect with attention, protection...

Learning and relearning of a visual avoidance response after neocortical lesions in rats

Abstract The learning, retention and relearning of an instrumental visual avoidance response was studied in 98 rats, including normal rats and those with frontal, somatic, visual and auditory ablations. Significant differences were found in the postoperative learning of the damaged groups. Visual and frontal groups were the most impaired, therefore the principle of equipotentiality does not hold for cortical functions in this task. Lesions affected relearning less severely than learning. The hypothesis that previous experience would mainly influence the performance of those animals with ablations in the neocortical areas critical for the acquisition of the habit was supported. The effects produced by visual neocortex damage could be attributed to disturbances in the relaying of visual information to the superior colliculus which seems to be the center for visuomotor performance. No conclusion is reached concerning causes of frontal deficit.

Bioethics an psychiatric dissability: clinical an juridical apects

This monography seeks to establish an interdisciplinary link between bioethics and the clinical and juridical aspects that connect with attention, protection and rehabilitation of persons with psychiatric illness. The analysis is centered those adults, on deprived of reasoning because of a psycopathologic process, entitled to civil rights, but with dificulties to exercise them due to their illness.This monography seeks to establish an interdisciplinary link between bioethics and the clinical and juridical aspects that connect with attention, protection...

BIOETICA E INCAPACIDADE PSIQUIÁTRICA: ASPECTOS CLÍNICOS E JURÍDICOS

This monography seeks to establish an interdisciplinary link between bioethics and the clinical and juridical aspects that connect with attention, protection and rehabilitation of persons with psychiatric illness. The analysis is centered those adults, on deprived of reasoning because of a psycopathologic process, entitled to civil rights, but with dificulties to exercise them due to their illness.This monography seeks to establish an interdisciplinary link between bioethics and the clinical and juridical aspects that connect with attention, protection...