Glucocorticoid administration into the dorsal striatum [corrected] facilitates memory consolidation of inhibitory avoidance training but not of the context or footshock components

It is well established that glucocorticoid administration into a variety of brain regions facilitates memory consolidation of fear-conditioning tasks, including inhibitory avoidance. The present findings indicate that the natural glucocorticoid corticosterone administered into the dorsal striatum (i.e., caudate nucleus) of male Wistar rats produced dose- and time-dependent enhancement of inhibitory avoidance memory consolidation. However, as assessed with a modified inhibitory avoidance procedure that took place on two sequential days to separate context training from footshock training, corticosterone administration into the dorsal striatum did not enhance memory of either the contextual or aversively motivational aspects of the task.     

Strength and vulnerability integration: a model of emotional well-being across adulthood

The following article presents the theoretical model of strength and vulnerability integration (SAVI) to explain factors that influence emotion regulation and emotional well-being across adulthood. The model posits that trajectories of adult development are marked by age-related enhancement in the use of strategies that serve to avoid or limit exposure to negative stimuli but by age-related vulnerabilities in situations that elicit high levels of sustained emotional arousal. When older adults avoid or reduce exposure to emotional distress, they often respond better than younger adults; when they experience high levels of sustained emotional arousal, however, age-related advantages in emotional well-being are attenuated, and older adults are hypothesized to have greater difficulties returning to homeostasis. SAVI provides a testable model to understand the literature on emotion and aging and to predict trajectories of emotional experience across the adult life span.     

Coherent plaids are preattentively more than the sum of their parts

We investigated whether plaids activate preattentive mechanisms that are distinct from those activated by their component gratings. Observers searched for a target plaid, the sum of two perpendicular components in a circular window (radius = 0.65°). The target was present on half the trials. On all trials, half of the distractors had the same frequency and orientation as one component of the plaid, and the rest were the same as the other component. The target and the distractors were arrayed evenly on a circle (radius = 2.36°) around fixation. Target and distractor contrasts were randomly perturbed up to ±30%. The following results held for each of the 6 participants tested. (1) When F1 = 2 c/deg and F2 = 5.25 c/deg, response times (RTs) increased significantly when set size (number of distractors plus target, if present) was increased from four to eight. (2) When the spatial frequencies of both plaid components were the same (i.e., both 2 c/deg or both 5.25 c/deg), RTs increased very slightly, if at all, when set size was increased from four to eight. These results suggest the existence of a preattentive, plaid-sensitive mechanism with band-limited input that does not respond to individual grating components.     

Tuomela on deductive explanation

Almost every formal model of explanation thus far proposed has been demonstrated to be faulty. In this paper, a new model, proposed by Raimo Tuomela, is also demonstrated to be faulty. In particular, one condition of the model is shown to be too restrictive, and another condition of the model is shown to be too permissive.This research was supported by a grant from the Killam Foundation, administered by the Canada Council.     

Prediction outcome probabilities as determinants of choice reaction time

In a two-stimulus two-response choice reaction time (RT) task in which Ss made stimulus predictions, the probability of a correct prediction was manipulated between Ss. The magnitude of the difference in RT to correctly and incorrectly predicted stimuli (i.e., the prediction outcome effect) was an increasing function of the probability of a correct prediction This finding was primarily due to a reliable decrease in RT to correctly predicted stimuli as the probability of a correct prediction increased, since RT to incorrectly predicted stimuli was not affected by prediction outcome probability. These results were interpreted as partially supporting a continuous expectancy notion which involves facilitory and inhibitory mechanisms winch are differentially influenced by the probability of a correct prediction.