Prefrontal and hippocampal contributions to encoding and retrieval of spatial memory

The prefrontal cortex is thought to be critical for goal-directed action and the hippocampus is known to be importantly involved in spatial memory. Several studies have been suggestive of a role for the orbitofrontal cortex (OFC) in spatial navigation. However, the medial prefrontal cortex (mPFC) receives projections directly from the intermediate CA1 (iCA1) region of hippocampus and this link may be critical for spatial navigation. The purpose of the present investigation was to test the performance of rats receiving bilateral or disconnection infusions of lidocaine into OFC, mPFC, or iCA1 to determine the contribution of these structures to encoding and retrieval of spatial memory using the Hebb–Williams maze. A total of 92 male Long-Evans rats received chronic bilateral, contralateral, or ipsilateral implantation of cannulas into OFC, mPFC, or iCA1. Prior to testing on day 1 or day 2, subjects received central infusions of saline or lidocaine. The number of errors committed on the first five trials compared to the second five trials of day 1 was used to determine encoding, whereas retrieval was determined by comparing the second five trials of day 1 with the first five trials of day 2. The present findings suggest that mPFC and iCA1 are necessary and interact during encoding and retrieval; however, the OFC does not appear to be essential for either process. While the nature of the interaction between mPFC and iCA1 during encoding and retrieval is unclear, it may be supported by the integration of goals and spatial cues or strategy switching.     

Developmental trajectory of number acuity reveals a severe impairment in developmental dyscalculia

Developmental dyscalculia is a learning disability that affects the acquisition of knowledge about numbers and arithmetic. It is widely assumed that numeracy is rooted on the “number sense”, a core ability to grasp numerical quantities that humans share with other animals and deploy spontaneously at birth. To probe the links between number sense and dyscalculia, we used a psychophysical test to measure the Weber fraction for the numerosity of sets of dots, hereafter called number acuity. We show that number acuity improves with age in typically developing children. In dyscalculics, numerical acuity is severely impaired, with 10-year-old dyscalculics scoring at the level of 5-year-old normally developing children. Moreover, the severity of the number acuity impairment predicts the defective performance on tasks involving the manipulation of symbolic numbers. These results establish for the first time a clear association between dyscalculia and impaired “number sense”, and they may open up new horizons for the early diagnosis and rehabilitation of mathematical learning deficits.     

A relational differential outcomes effect: pigeons can classify outcomes as “good” and “better”

In a conditional discrimination each of two sample stimuli indicates which of two comparison stimuli is correct. When correct choice following each conditional stimulus is followed by a different outcome (one kind of food following one, a different kind of food following the other) it often facilitates acquisition and improves memory. In transfer designs, in which two different conditional discriminations are followed by the same two differential outcomes, outcome expectation can be shown to be sufficient for comparison choice. That is, the samples from one conditional discrimination are matched to comparisons from the other conditional discrimination based on the common outcomes alone. In the present study we asked if for pigeons the relative value of the differential outcomes (higher versus lower value) can serve as the basis for comparison choice, independent of other characteristics of the outcomes and of differential sample responding. That is, would different outcomes that could be described as “good” and “better” form two stimulus classes. For one conditional discrimination, the differential outcomes involved differential probability of reinforcement for choice of the correct comparison stimulus (0.80 vs. 0.20 for correct choice of the two comparisons, respectively). For the other conditional discrimination, the differential outcomes involved differential responding to the two comparison stimuli (5 pecks vs. 20 pecks to the correct comparisons, respectively). On test trials, when conditional stimuli from the two conditional discriminations were interchanged and the relative value of the differential outcomes could serve as the only basis for comparison choice, we found positive transfer. The results indicate that relational attributes of outcomes can serve as effective cues for comparison choice.     

How trainees develop an initial theory of practice: A process model of tentative identifications

Aim: The increasing importance of integrative practice highlights the need to explore how trainees develop their theoretical stance. This investigation explored the experiences of trainees to elaborate a model of how they developed their personal theories of practice. Method: Seventeen Masters level trainee counsellors kept weekly journals recording how they developed a working theory of practice. Grounded theory analysis of the journals was used to develop a model of the process. Findings: The resulting Process Model of Tentative Identifications illustrates how a personal theory developed through trainees' tentative identifications with theories of practice, and how factors such as reading, personal philosophy, practice, and supervision interact to produce the identifications. A diagram of the model highlights the relationships among a variety of personal and professional factors that ranged from highly abstract to concrete and practice-based. Discussion: The model is consistent with several factors identified in previous research and highlights how trainees develop working theories of practice.     

A hit-and-miss investigation of asymmetries in wheelchair navigation

In contrast to the leftward inattention caused by right parietal damage, normal brain function shows a subtle neglect of the right and left sides in peripersonal and extrapersonal space, respectively. This study explored how these attentional biases cause healthy individuals to collide with objects on the right. In Experiment 1, participants navigated manual and electric wheelchairs through a narrow doorway. More rightward collisions were observed for the electric, but not the manual, wheelchair. Experiment 2 demonstrated that the rightward deviation for electric wheelchairs increased for wider doorways. Experiment 3 established that the rightward deviation is not the result of task-related vestibular input, using a remote control device to operate the wheelchair. The rightward deviation persisted in Experiment 4 when the doorway was removed, suggesting that the bias is the result of a mis-bisection of space. In Experiment 5, the rightward bias was replicated using an electric scooter, which is steered using handlebars. Finally, Experiment 6 required participants to point to the middle of the doorway, using a laser, before moving the scooter. Rightward mis-bisection was observed in both conditions. Rightward mis-bisection of lines in extrapersonal space provides the most parsimonious explanation of the rightward collisions and deviations.     

Adjusting for the correspondence bias: Effects of causal uncertainty, cognitive busyness, and causal strength of situational information

This research examined the conditions under which people who have more chronic doubt about their ability to make sense of social behavior (i.e., are causally uncertain; [Weary and Edwards, 1994] and [Weary and Edwards, 1996]) are more likely to adjust their dispositional inferences for a target’s behaviors. Using a cognitive busyness manipulation within the attitude attribution paradigm, we found in Study 1 that higher causal uncertainty predicted increased correction of dispositional inferences, but only when participants had sufficient attentional resources to devote to the task. In Study 2, we found that higher-causal uncertainty predicted greater inferential correction, but only when the additional information provided a more compelling alternative explanation for the observed behavior. Results of this research are discussed in terms of their relevance to the Causal Uncertainty (Weary & Edwards, 1994) and dispositional inference models.     

Mattering to Others: Implications for the Counseling Relationship

Although first conceived in the 1980s, mattering to others has only recently earned well‐deserved attention in social science research and literature. Subsequently, it seems that mattering may serve as a powerful dynamic in strengthening counseling relationships. This article reviews the empirical validation study of mattering recently conducted by G. C. Elliott, S. Kao, and A. M. Grant (2004), which was published in the journal Self and Identity. Implications for counselors, the counseling relationship, and counseling research are considered.     

Comparing motivations of individual programmers and firms to take part in the open source movement: From community to business

The first urgent question for any scholar willing to study the Open Source (OS) movement has been clearly put by Glass (1999, 104): I don’t know who these crazy people are who want to write, read and even revise all that code without being paid anything for it at all. A growing body of economic literature has been addressing the motivations at the basis of the participation in the OS movement since when the new paradigm has become successful and triggered the entrance on the market of firms offering Open Source based products and services (Open Source firms). However, most of the empirical analyses focus on individual developers and neglect companies that adopt Open Source business models. This paper contributes to the literature by providing empirical evidence on the incentives of the firms that engage in OS activities. Findings on firms’ motivations are compared His recent research interests are in the economics of science, industrial dynamics in high technology industries, and theory and empirics of diffusion of technologies with network externality. He has authored or edited five books and written 80 papers in international journals and conferences. His studies have been published in several top refereed journals. He is member elected of the Executive Committee of the PRIME (Policies for Research and Innovation in the Move towards the European Research Area) Network of Excellence (6^th Framework Programme) and has previously coordinated or contributed actively to several EU research projects (within TACIS-ACE, DG III, DG XII and DG XXII). She got her Ph.D. in economics and management of innovation at Sant’ Anna School in November 2003. At present, she collaborates also with the Department of Electrical Systems and Automation of the University of Pisa. Her research interests deal with the economics of open source software (OSS) and focus on profit-oriented firms that offer open source-based products and services (open source firms). Under a theoretical point of view, she is now investigating the motivations that lead individuals to provide a continuous stream of contributions to collective goods that are immaterial in their nature (e.g., participation in OSS projects, participation in the scientific community). with the results of the surveys on individual programmers aiming at analyzing the role played by different classes of incentives (social, economic and technological) in determining the involvement in the movement of different typologies of agents (Individual vs. organizations).     

The social and economic impact of trichotillomania: results from two nonreferred samples

Behavior therapy has been widely used as a treatment for trichotillomania. However, behavioral treatments for TTM have tended to focus on behavior reduction, while not paying as much attention to social and economic impact. The current study sought to clarify the social and economic impact of Trichotillomania (TTM) in two samples of persons with TTM. Members of the first sample attended a TTM patient conference (N = 36) and members of the second responded to an online survey (N = 381). Both samples completed self‐report measures that examined the impact of TTM on avoiding activities and relationships, as well as financial costs. Results indicated that both groups reported similar amounts of avoidance in social situations, sought help from multiple health professionals, spent considerable time engaged in hair pulling activities, and had interference in both work and school. The study suggests a number of ways to decrease the negative impact of TTM. Copyright © 2006 John Wiley & Sons, Ltd.     

Why don't we see changes?: The role of attentional bottlenecks and limited visual memory

Seven experiments explore the role of bottlenecks in selective attention and access to visual short-term memory in the failure of observers to identify clearly visible changes in otherwise stable visual displays. Experiment One shows that observers fail to register a color change in an object even if they are cued to the location of the object by a transient at that location as the change is occurring. Experiment Two shows the same for orientation change. In Experiments Three and Four, attention is directed to specific objects prior to making changes in those objects. Observers have only a very limited memory for the status of recently attended items. Experiment Five reveals that observers have no ability to detect changes that happen after attention has been directed to an object and before attention returns to that object. In Experiment Six, attention is cued at rates that more closely resemble natural rates and Experiment Seven uses natural images. Memory capacity remains very small (<4 items).