Effects of excitotoxic brain lesions on taste-mediated odor learning in the rat

The association learning between taste and odor is important in ingestive behavior. For a better understanding of this learning, we have developed a convenient and useful paradigm to assess the taste-mediated odor learning. In the training session, Wistar male rats drank water from two bottles in their home cages and from eight small glass dishes. In the learning session they were exposed in their home cages and also in a circular open-field apparatus to 0.005 M Na-saccharin and 0.02 M quinine hydrochloride which contained either banana or almond odors. One learning trial consisted of this pair of exposures. The preceding behavioral experiment has shown that these two odors are not aversive and are differentially perceived by rats. In the test session, the animals were put in the open-field apparatus equipped with eight dishes: four contained water with banana, and another four, with almond. Normal control rats preferred to drink water with the odor previously associated with saccharin. Stronger and more persistent preference was attained after two or three learning trials. To elucidate the brain sites responsible for this taste-mediated odor learning, the same procedure was assessed on brain-lesioned rats. Rats with lesions in the amygdala showed rapid extinction of preference to the saccharin-associated odor, whereas control rats did not. However, rats with lesions in the insular cortex showed retention of learning similar to that of the control rats. Rats with lesions in the sulcal prefrontal or cingulate cortices showed moderate disruptive effects on preference to the saccharin-associated odor. In conclusion, the odor learning established in our experimental paradigm is based on the association between the quality of odor and hedonics of taste. The amygdala may play a role in the formation, at least in the retention process, of this taste-odor association learning.     

Learning and memory in S100-beta transgenic mice: an analysis of impaired and preserved function

S100-beta, a calcium-binding astrocytic protein from chromosome 21, has been implicated in CNS function generally and the hippocampus in particular. Elevated levels of S100-beta have been observed reliably in the brains of patients with Alzheimer's Disease and Down Syndrome. Groups of transgenic mice, carrying multiple S100-beta gene copies, and nontransgenic controls were administered a series of behavioral tests (delayed spatial and nonspatial non-matching-to-sample, radial arm maze, socially acquired food preference) that assessed a wide range of cognitive functions. Consistent with the widespread presence of S100-beta throughout the brain, transgenic mice exhibited learning or memory impairment on all tasks. The dementia-like cognitive profile of S100-beta mice represents a promising model for studying comparable cognitive deficits associated with neurodegenerative diseases.     

Cognitive complexity and the validity of clinicians' judgments

Efforts to explain why some neuropsychologists are more accurate than others have been unsuccessful. In the present study, the relation between the cognitive complexity of clinicians and the validity of their judgments was investigated. Forty-two neuropsychologists completed a measure of cognitive complexity. The hypothesis that neuropsychologists who are high in cognitive complexity will be more accurate than those who are low in cognitive complexity was not supported. It is not clear why cognitive complexity was not significantly related to the validity of diagnostic ratings: One explanation is that the measure of cognitive complexity used in this study was inadequate but another possibility is that neuropsychologists who are low in cognitive complexity may still be able to achieve high levels of accuracy if they attend to normative data when they interpret test results.     

Evading detection on the MMPI-2: does caution produce more realistic patterns of responding?

Studies on MMPI and MMPI-2 malingering indexes often sacrifice generalizability in an attempt to control internal validity. This study improves external validity while still maintaining internal validity by providing graduate student participants with a realistic context for malingering on the MMPI-2 (n=94) and MMPI (n=30). Contextual parameters include a realistic life predicament, psychological knowledge, an incentive, the presence versus absence of a specific diagnosis, and a caution to be realistic. This study found that cautioning participants not to overexaggerate their responses significantly improves their ability to evade detection on the MMPI-2 and MMPI. Standard malingering indexes (Infrequency, F; Back Side, F, Fb; F-Correction, F-K; and Infrequency-Psychopathology, F(p)) were insufficiently sensitive in identifying simulators using common cutoff scores for these cautious simulators.     

Impact of intended emotion intensity on cue utilization and decoding accuracy in vocal expression of emotion

Actors vocally portrayed happiness, sadness, anger, fear, and disgust with weak and strong emotion intensity while reading brief verbal phrases aloud. The portrayals were recorded and analyzed according to 20 acoustic cues. Listeners decoded each portrayal by using forced-choice or quantitative ratings. The results showed that (a) portrayals with strong emotion intensity yielded higher decoding accuracy than portrayals with weak intensity, (b) listeners were able to decode the intensity of portrayals, (c) portrayals of the same emotion with different intensity yielded different patterns of acoustic cues, and (d) certain acoustic cues (e.g., fundamental frequency, high-frequency energy) were highly predictive of listeners' ratings of emotion intensity. It is argued that lack of control for emotion intensity may account for some of the inconsistencies in cue utilization reported in the literature.     

Visual perspective taking for avatars in a Simon task

In modern digital applications, users often interact with virtual representations of themselves or others, called avatars. We examined how these avatars and their perspectives influence stimulus–response compatibility in a Simon task. Participants responded to light/dark blue stimuli with left/right key presses in the presence of a task-irrelevant avatar. Changes in stimulus–response compatibility were used to quantify changes in the mental representation of the task and perspective taking toward this avatar. Experiments 1 and 2 showed that perspective taking for an avatar occurred in orthogonal stimulus–response mappings, causing a compatibility effect from the avatar’s point of view. In the following two experiments we introduced a larger variety of angular disparities between the participant and avatar. In Experiment 3, the Simon effect with lateralized stimulus positions remained largely unaffected by the avatar, pointing toward an absence of perspective taking. In Experiment 4, after avatar hand movements were added in order to strengthen the participants’ sense of agency over the avatar, a spatial compatibility effect from the avatar’s perspective was observed again, and hints of the selective use of perspective taking on a trial-by-trial basis were found. Overall, the results indicate that users can incorporate the perspective of an avatar into their mental representation of a situation, even when this perspective is unnecessary to complete a task, but that certain contextual requirements have to be met.     

An age-embedding effect: time sensitivity and time insensitivity when pricing health benefits

Benefits are often extended over time. One determinant of this benefit duration is how long a person will live to enjoy them. In four studies, we investigated whether people are sensitive to age when pricing benefits that will last for the remainder of one's life. In Study 1 drivers gave their willingness-to-pay (WTP) to cure a medical condition which would stop them from driving. Results showed an age-embedding effect: WTP was unrelated to the estimated number of driving years left. Study 2 tested whether age-embedding arose because people have a lot of information about themselves which dilutes the impact of age on their valuations. In Studies 3 and 4 we investigated whether people believed that age was an important consideration, or if they failed to properly incorporate it into their judgment. Results indicate that little weight is given to age when making individual pricing decisions, although people did not believe it was normatively irrelevant.     

Engaging refugee families in therapy: exploring the benefits of including referring professionals in first family interviews

The possible benefits of including referring professionals in the first family interviews are being explored as a way to engage refugee families in therapy. Families in exile confront a number of problems related both to premigration traumatic exposures and to present adaptation processes. Refugee clients and the referring professionals in the larger system frequently see the problems and their solutions quite differently. This situation may often result in unclear working alliances in a context of therapy. We will describe first family interviews in which referring professionals are interviewed about their reasons for referrals, and where the families are invited to discuss these considerations. The conversations permit families, referrers, and therapists to reflect upon differences in positions and perspectives. Their experiences suggest that agreements or contracts based on these joint interviews are less ambiguous and more clearly formulated than contracts based on interviews with families alone. Finally, these experiences are discussed as a potentially valuable approach in a cross-cultural context.     

A comparison of the cognitive deficits in reading disability and attention-deficit/hyperactivity disorder

This study used a nonreferred sample of twins to contrast the performance of individuals with reading disability (RD; n = 93), attention-deficit/hyperactivity disorder (ADHD; n = 52), RD and ADHD (n = 48), and neither RD nor ADHD (n = 121) on measures of phoneme awareness (PA) and executive functioning (EF). Exploratory factor analysis of the EF measures yielded underlying factors of working memory, inhibition, and set shifting. Results revealed that ADHD was associated with inhibition deficits, whereas RD was associated with significant deficits on measures of PA and verbal working memory. The RD + ADHD group was most impaired on virtually all measures, providing evidence against the phenocopy hypothesis as an explanation for comorbidity between RD and ADHD.     

The effect of practice on recall of emotional information in individuals with generalized social phobia

Understanding memory processes in social anxiety is important because these individuals often report negative memories of anxiety-provoking situations and because of the recent emphasis on learning and memory in models of anxiety. The authors examined the effect of learning on memory for negative social, positive social, and nonsocial information using the retrieval-induced forgetting paradigm in individuals with generalized social phobia (GSPs) and in nonanxious controls (NACs). Words were presented in 1 of 3 practice conditions: practiced words from a practiced category, unpracticed words from a practiced category, and unpracticed words from an unpracticed category. GSPs and NACs showed the same patterns of memory for practice categories for positive social and nonsocial words. However, for negative social words, GSPs benefited less from practice and were hurt less from the effect of practicing competing negative social information than were NACs. This pattern of processing may hamper GSPs' learning of, and habituation to, negative social information.