Neural substrates of latent inhibition: the switching model

Latent inhibition (LI) refers to decrement in conditioning to a stimulus as a result of its prior nonreinforced preexposure. It is a robust phenomenon that has been demonstrated in a variety of classical and instrumental conditioning procedures and in many mammalian species, including humans. The development of LI is considered to reflect decreased associability of, or attention to, stimuli that predict no significant outcome. The fact that LI is considered to be a reflection of attentional processes has become of increasing importance to neuroscientists who see LI as a convenient tool for measuring the effects of drug treatments and lesions on attention. The present article surveys the data on brain systems, which have been studied in regard to their involvement in LI. These are reviewed and discussed separately in sections on noradrenergic, cholinergic, dopaminergic, serotonergic, and septo-hippocampal manipulations. On the basis of these data, it is concluded that the neural substrates of LI include the mesolimbic dopaminergic system, the mesolimbic serotonergic system, and the hippocampus. It is proposed that the preexposed stimulus loses its capacity to affect behavior in conditioning, even though it predicts reinforcement, because the hippocampus inhibits the switching mechanism of the nucleus accumbens via the subiculum-accumbens pathway. This action of the hippocampus is modulated by the mesolimbic serotonergic system via its interactions with the hippocampal or mesolimbic dopaminergic systems, or both.     

An Attributional Analysis of Reactions to Magic Johnson1

Principles from attribution theory were used to analyze public reactions to the health status of Magic Johnson. An experimental study containing two distinct samples (college students and African-American adults) together with supplemental reports from local and national media confirm the value of this approach. The findings show that inferences about causal responsibility are related to affective reactions of sympathy and anger toward Magic Johnson. Implications for attribution theory, as well as for future attitudes toward Magic Johnson, are discussed.     

A randomized trial comparing the effects of self-help materials and proactive telephone counseling on teen smoking cessation.

We conducted a 2-arm randomized trial to test the efficacy of self-help materials with or without proactive telephone counseling to increase cessation among teen smokers. Teen smokers (N = 402) recruited from 11 shopping malls and 1 amusement park in the southeastern United States were randomized to 1 of 2 groups: written self-help material plus video; or written self-help material, video, and telephone counseling. Cessation rates based on 7-day point-prevalent abstinence for the self-help and counseling arms were 11% and 16%, respectively (p = .25), at 4 months postbaseline and 19% and 21%, respectively (p = .80), at 8 months postbaseline. Sustained abstinence, reflecting 7-day abstinence at both time points, in the self-help and counseling arms was 7% and 9% (p = .59). Results suggest that minimal self-help cessation approaches that target youth have comparable success to that shown among adult smokers. However, refinements in telephone-counseling approaches may be needed to achieve the success observed in adult populations.     

Visual landmarks facilitate rodent spatial navigation in virtual reality environments

Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain areas. Virtual reality offers a unique approach to ask whether visual landmark cues alone are sufficient to improve performance in a spatial task. We found that mice could learn to navigate between two water reward locations along a virtual bidirectional linear track using a spherical treadmill. Mice exposed to a virtual environment with vivid visual cues rendered on a single monitor increased their performance over a 3-d training regimen. Training significantly increased the percentage of time avatars controlled by the mice spent near reward locations in probe trials without water rewards. Neither improvement during training or spatial learning for reward locations occurred with mice operating a virtual environment without vivid landmarks or with mice deprived of all visual feedback. Mice operating the vivid environment developed stereotyped avatar turning behaviors when alternating between reward zones that were positively correlated with their performance on the probe trial. These results suggest that mice are able to learn to navigate to specific locations using only visual cues presented within a virtual environment rendered on a single computer monitor.     

Whose fault is it anyway: How do parents respond to their child’s setbacks?

We documented what parents report as the cause of their child’s academic and conduct setbacks and what they say they do in response. We recruited an opportunity sample of 479 parents and narrowed our sample to parents of children without disabilities between the ages of 5–18 (N = 312). Parents responded to open-ended questions, and we coded responses into categories of disciplinary tactics and types of attributions. Parents who reported experience with child setbacks significantly differed from parents who did not report such experience on several outcome variables. Parents did not exhibit hedonic biasing such that most reported causes of setbacks were controllable by the child; reported controllable causes correlated with the reported use of punishment. Our findings suggest that parental behavior change efforts must also address parents’ attributions, or verbal explanations, of causes of events. We discuss implications of our findings for child and parent researchers, educators, and practitioners.     

The Development of Graphophonological-Semantic Cognitive Flexibility and Its Contribution to Reading Comprehension in Beginning Readers

Reading-specific and general color-shape cognitive flexibility were assessed in 68 first and second graders to examine: 1) the development of graphophonological-semantic cognitive flexibility (the ability to process concurrently phonological and semantic aspects of print) in comparison to color-shape cognitive flexibility, 2) the contribution of reading experience to graphophonological-semantic flexibility, and 3) the unique contribution of graphophonological-semantic flexibility to reading comprehension. Second graders scored significantly higher than first graders on both cognitive flexibility tasks; the general flexibility task was easier for all children than the graphophonological-semantic flexibility task; reading experience contributed uniquely to children's graphophonological-semantic flexibility; and graphophonological-semantic flexibility contributed significant, unique variance to children's reading comprehension, consistent with Cartwright's (2002 Cartwright , K. B. ( 2002 ). Cognitive development and reading: The relation of reading-specific multiple classification skill to reading comprehension in elementary school children . Journal of Educational Psychology , 94 , 56 – 63 .[Crossref], [Web of Science ®] , [Google Scholar]) work with second- to fourth-grade students and adults (2007 Cartwright , K. B. ( 2007 ). The contribution of graphophonological-semantic flexibility to reading comprehension in college students: Implications for a less simple view of reading . Journal of Literacy Research , 39 , 173 – 193 .[Crossref], [Web of Science ®] , [Google Scholar]).     

Neural representations of faces and limbs neighbor in human high-level visual cortex: evidence for a new organization principle

Neurophysiology and optical imaging studies in monkeys and functional magnetic resonance imaging (fMRI) studies in both monkeys and humans have localized clustered neural responses in inferotemporal cortex selective for images of biologically relevant categories, such as faces and limbs. Using higher resolution (1.5 mm voxels) fMRI scanning methods than past studies (3–5 mm voxels), we recently reported a network of multiple face- and limb-selective regions that neighbor one another in human ventral temporal cortex (Weiner and Grill-Spector, Neuroimage, 52(4):1559–1573, 2010) and lateral occipitotemporal cortex (Weiner and Grill-Spector, Neuroimage, 56(4):2183–2199, 2011). Here, we expand on three basic organization principles of high-level visual cortex revealed by these findings: (1) consistency in the anatomical location of functional regions, (2) preserved spatial relationship among functional regions, and (3) a topographic organization of face- and limb-selective regions in adjacent and alternating clusters. We highlight the implications of this structure in comparing functional brain organization between typical and atypical populations. We conclude with a new model of high-level visual cortex consisting of ventral, lateral, and dorsal components, where multimodal processing related to vision, action, haptics, and language converges in the lateral pathway.