A temporally distinct role for group I and group II metabotropic glutamate receptors in object recognition memory

Recognition memory, involving the ability to discriminate between a novel and familiar object, depends on the integrity of the perirhinal cortex (PRH). Glutamate, the main excitatory neurotransmitter in the cortex, is essential for many types of memory processes. Of the subtypes of glutamate receptor, metabotropic receptors (mGluRs) have received less study than NMDA receptors; thus, the reported experiments examined the role of mGluRs in familiarity discrimination in the rat PRH. Experiments 1 and 2 assessed the effects of systemic administration of MPEP, a group I mGluR (specifically mGluR5) antagonist, and/or LY341495, a group II mGluR antagonist, on a spontaneous object novelty preference task. Simultaneous antagonism of both group I and II mGluRs impaired familiarity discrimination following a 24-h but not a 15-min delay, while antagonism of either mGluR subtype alone had no effect at either delay. The impairment was in acquisition, as in Experiment 3 coadministration of MPEP and LY341495 did not affect recognition memory performance when administered either after the sample phase or prior to test. The impairment in long-term recognition memory was mediated by mGluRs in the PRH, as localized intracortical antagonism of group I and II mGluRs also produced a deficit (Experiment 4). No evidence was found for an involvement of group III mGluRs in the acquisition of long-term familiarity discrimination (Experiment 5). These findings establish that glutamatergic neurotransmission in the PRH via group I and II mGluRs is crucial for the acquisition, but not for the consolidation or retrieval of long-term object recognition memory.     

Understanding and Improving the Validity of Self-Report of Parenting

Although researchers using parental self-report data have questioned its validity (Holden, 2001) and called for more work in this area (Krevans & Gibbs, 1996; Locke & Prinz, 2002), methodological concerns regarding self-report about parenting practices have not been addressed adequately. The susceptibility of parental report to systematic distortions suggests a need for research on ways to improve self-report. This paper attempts to synthesize research findings from other fields (e.g., survey methodology) about ways to improve the validity of self-report, and to discuss the implications for self-report of parenting behaviors. Methods for improving self-report are presented for each of the 5 major tasks in responding to a question: (1) understanding the question, (2) recalling relevant behavior, (3) inference and estimation, (4) mapping the answer onto the response format, and (5) “editing” the answer for reasons of social desirability. Self-administered interviewing, audio-computer-assisted interviewing, pretesting, conversational interviewing, and the decompositional item may be among the best candidates for use in parental self-report. Recommendations are offered with respect to strategies that might prove useful in improving parental assessment of parenting, and to research efforts to evaluate the utility and potential costs of these strategies.     

Binocular coordination of the eyes during reading: word frequency and case alternation affect fixation duration but not fixation disparity

This experiment investigated whether properties of the text being read affect binocular coordination of the eyes during reading. Readers' binocular eye movements were recorded while they read sentences that contained high- and low-frequency words. In addition, half of the sentences were presented in normal case, and half were presented in alternating case (i.e., AlTeRnAtInG cAsE). Past research has suggested that the visual system tolerates less binocular fixation disparity with alternating than with normal case (Heller & Radach, 1999). While both word frequency and alternating case produced large effects on fixation durations on the target word, neither manipulation affected the magnitude of fixation disparity. It is concluded that linguistic and visual properties of the text being read do not influence binocular coordination of the eyes during reading. Additional analyses also showed no difference in fixation disparity between reading and a nonlinguistic task. Implications of these results for split-fovea models of reading are discussed.     

The hoarding dimension of OCD: psychological comorbidity and the five-factor personality model

Although hoarding has been associated with several psychological disorders, it is most frequently linked to obsessive-compulsive disorder (OCD). The present study assessed hoarding obsessions and compulsions in 204 individuals with OCD, and evaluated how hoarding was related to obsessive-compulsive symptom severity, psychological comorbidity, and personality as measured by the five-factor model. Results indicated that hoarding in OCD is a dimensional variable that is positively associated with dysphoria, total number of lifetime Axis I disorders, and lifetime histories of bipolar I, PTSD, and body dysmorphic disorder. Hoarding was negatively correlated with the NEO-Personality Inventory-Revised (NEO-PI-R) factor of Conscientiousness and positively associated with the NEO-PI-R factor of Neuroticism. When all personality and psychopathology variables were entered into a regression equation, dysphoria, bipolar II disorder, Conscientiousness, age, and Extraversion emerged as significant predictors of hoarding severity. Recommendations are made for clinicians and for future research.