5 research outputs found
Modulación contextual de la tolerancia asociativa al etanol
No full textThere is evidence that drug-paired cues not only become associated with the drug effects but also become occasion setters that modulate the association of other cues with the drug effects, contributing to the development of associative tolerance (Ramos, Siegel, & Bueno, 2002). Using a feature-positive discrimination training, we evaluated the contribution of contexts as occasion setters of the ataxic effect of ethanol in rats. The results suggest that the context acquire occasion setter properties of the drug tolerance, and that these properties can be extinguished.Existe evidencia que señala que las claves pareadas con drogas no sólo son asociadas con los efectos de éstas, sino que también adquieren propiedades modulatorias de la asociación entre otras claves y los efectos de la droga, contribuyendo así al desarrollo de la tolerancia asociativa (Ramos, Siegel & Bueno, 2002). Utilizando un procedimiento de discriminación de rasgo positivo, en la presente investigación evaluamos la contribución de los contextos como moduladores del efecto atáxico del etanol en ratas. Los resultados sugieren que el contexto adquiere propiedades modulatorias de la tolerancia a las drogas y que estas propiedades pueden ser extinguidas
Sleep-dependency of episodic-like memory consolidation in rats
No full textArtículo de publicación ISIEpisodic memory refers to the recollection of a representation that binds together into a unique past
experience “what” happened, “where” and “when”. Sleep has been identified as a state that optimizes
the consolidation of newly acquired memory. To determine if sleep is important for the consolidation
of episodic-like memory, we tested rats on an episodic-like memory task requiring the binding of an
object memory into a spatio-temporal context, as well as retention of its individual components, using
separate tests of novel-object recognition (“what”), object-place recognition (“where”) and temporal
memory (“when”), respectively. The 80-min retention interval between encoding of the task and retrieval
testing covered either a period of regular morning sleep or sleep deprivation or a period of evening
wakefulness. Sleep during the retention interval, compared with the other two retention conditions,
significantly enhanced retrieval in the episodic-like memory task as well as in the object-place recognition
and temporal memory tasks. In fact, when the rats stayed awake during the retention interval, there was
no significant memory left at retrieval testing for the learnt object place and temporal memory. Sleep
did not benefit novel-object recognition memory which unlike the other components of episodic-like
memory is considered not to critically rely on the hippocampus. In an additional delayed sleep condition,
episodic-like memory in rats which had stayed awake during the first 80-min interval after encoding, was
not recovered when they were allowed to sleep during a subsequent 80-min interval. Our results suggest
that sleep specifically supports the aspects in episodic memory most closely linked to hippocampal
function, i.e., the binding of an event into spatio-temporal context as well as the spatio-temporal context
itself. Sleep is particularly effective when it occurs shortly after encoding
Hippocampal Corticosterone Impairs Memory Consolidation During Sleep but Improves Consolidation in the Wake State
Get PDFArtículo de publicación ISIWe studied the interaction between glucocorticoid (GC)
level and sleep/wake state during memory consolidation. Recent
research has accumulated evidence that sleep supports memory consolidation
in a unique physiological process, qualitatively distinct from consolidation
occurring during wakefulness. This appears particularly true
for memories that rely on the hippocampus, a region with abundant
expression of GC receptors. Against this backdrop we hypothesized that
GC effects on consolidation depend on the brain state, i.e., sleep and
wakefulness. Following exploration of two objects in an open field, during
80 min retention periods rats received an intrahippocampal infusion
of corticosterone (10 ng) or vehicle while asleep or awake. Then the
memory was tested in the hippocampus-dependent object-place recognition
paradigm. GCs impaired memory consolidation when administered
during sleep but improved consolidation during the wake
retention interval. Intrahippocampal infusion of GC or sleep/wake
manipulations did not alter novel-object recognition performance that
does not require the hippocampus. This work corroborates the notion
of distinct consolidation processes occurring in sleep and wakefulnesss,
and identifies GCs as a key player controlling distinct hippocampal
memory consolidation processes in sleep and wake conditions
Condicionamiento aversivo de la respuesta ocular en un paradigma imagen-imagen
No full textFear conditioning is essential for understanding the etiology of anxiety disorders. In translational research, the ocular response (OR) stands out as a continuously measurable and non-invasive indicator of fear, generating a large volume of data without participant intervention. Although the OR varies in response to emotionally relevant stimuli, few studies use both visual conditioned stimulus (CS) and unconditioned stimulus (UCS) to assess learning by measuring the OR. This study aims to validate a model of fear conditioning by recording fixation time, number of fixations, first fixation latency, and expectation of EI occurrence during acquisition and extinction phases. The results demonstrate differential learning in the acquisition and extinction of the expectation of EI occurrence, as well as a greater number of fixations to aversive images.El presente estudio valida un modelo de condicionamiento al miedo registrando la Respuesta Ocular (RO) en un paradigma de imagen-imagen. Participaron 34 individuos que completaron las fases de adquisición, extinción y prueba, donde se midió la respuesta ante los estímulos condicionados (EC) e incondicionados (EI) usando la RO (tiempo de fijación, número de fijaciones, latencia de fijación) y la expectativa de ocurrencia del EI. Los resultados muestran aprendizaje diferencial en la adquisición de la latencia de fijación y en la expectativa de ocurrencia del EI. La extinción solo se observó en esta última medida. Hubo un aumento en el número de fijaciones ante las imágenes aversivas. La respuesta ocular resulta un método válido y prometedor para evaluar el aprendizaje del miedo, permitiendo abordar sesgos atencionales y evitación, características propias de los trastornos relacionados con la ansiedad. El presente estudio provee una base metodológica rigurosa para futuras investigacione
MODULACIÓN CONTEXTUAL DE LA TOLERANCIA ASOCIATIVA AL ETANOL
Get PDFExiste evidencia que señala que las claves pareadas con drogas no sólo son asociadas con
los efectos de éstas, sino que también adquieren propiedades modulatorias de la asociación entre otras claves y los efectos de la droga, contribuyendo así al desarrollo de la tolerancia
asociativa (Ramos, Siegel & Bueno, 2002). Utilizando un procedimiento de discriminación de
rasgo positivo, en la presente investigación evaluamos la contribución de los contextos como
moduladores del efecto atáxico del etanol en ratas. Los resultados sugieren que el contexto
adquiere propiedades modulatorias de la tolerancia a las drogas y que estas propiedades pueden
ser extinguidas
