Visual memory and visual perception: when memory improves visual search

This study examined the relationship between memory and perception in order to identify the influence of a memory dimension in perceptual processing. Our aim was to determine whether the variation of typical size between items (i.e., the size in real life) affects visual search. In two experiments, the congruency between typical size difference and perceptual size difference was manipulated in a visual search task. We observed that congruency between the typical and perceptual size differences decreased reaction times in the visual search (Exp. 1), and noncongruency between these two differences increased reaction times in the visual search (Exp. 2). We argue that these results highlight that memory and perception share some resources and reveal the intervention of typical size difference on the computation of the perceptual size difference.     

The influence of contour fragmentation on recognition memory: an event-related potential study

The present study was carried out to examine how the event-related potentials to fragmentation predict recognition success. Stimuli were abstract meaningless figures that were either complete or fragmented to various extents but still recoverable. Stimuli were first encoded as part of a symmetry discrimination task. In a subsequent recognition phase, encoded stimuli were presented complete along with never presented stimuli and participants performed an old/new discrimination task. Fragmentation stimuli elicited more negative ERPs than complete figures over the frontal, central and parietal areas between 180 and 260 ms, and over the occipito-temporal areas between 220 and 340 ms. Only this latter effect was modulated as a function of whether stimuli were recognized or not during the recognition phase of the memory test. More specifically, the effect occurred for stimuli that were later forgotten and was absent for stimuli that were later recognized. This ERP to fragmentation, the occipito-temporal N(frag), possibly reflects the brain response to encoding difficulty, and is thus predictive of recognition performance.     

An fMRI investigation of a novel analogue to the Trail-Making Test

The Trail-Making Test (TMT) is a widely used neuropsychological measure that assesses visuomotor abilities and cognitive flexibility. For the TMT-A condition participants are required to locate and connect numbers (i.e. 1-2-3…) while in the TMT-B condition participants perform the set-shifting task of locating and connecting numbers and letters (i.e. 1-A-2-B…). The TMT-B condition has shown impairments in many clinical populations, particularly schizophrenia patients, but the neurobiological underpinning of the task can be difficult to discern given pragmatic obstacles in adapting the task for neuroimaging. In a behavioural testing experiment we demonstrated a close correspondence between performance on the standard TMT and a novel, computer programmed adaptation of the TMT (pcTMT). The pcTMT was designed for functional magnetic resonance imaging (fMRI) administration and neuroimaging data for this task were obtained in. A whole brain analysis revealed significantly greater activation during the pcTMT-B relative to the pcTMT-A in right inferior/middle frontal cortices, right precentral gyrus, left angular gyrus/left middle temporal gyrus. These results identify the regions that most likely underlie cognitive flexibility during the TMT and are candidate regions underlying the impairment of groups with poor set-shifting abilities.     

Anterior but not intralaminar thalamic nuclei support allocentric spatial memory

Medial thalamic damage is a common cause of severe memory disruption in humans. Both the anterior thalamic nuclei (ATN) and the intralaminar thalamic nuclei (ILN) have been suggested as primary sites of diencephalic injury underlying learning and memory deficits, but their respective roles have yet to be resolved. The present study explicitly compared two spatial memory tasks in male PVGc hooded rats with selective neurotoxic lesions to either (1) the ATN or (2) the rostral ILN (and adjacent lateral mediodorsal thalamic nuclei; ILN/LT lesions). As predicted, the ATN group, but not the ILN/LT group, exhibited clear deficits in the Morris water maze task for the initial acquisition of a fixed hidden platform and its reversal to a new position. The second task examined acquisition of egocentric spatial reference memory for a left or right body turn, using any three arms in an 8-arm water maze on any given trial; contrary to predictions, both lesion groups performed as well as the Sham group. The lack of deficits in ILN/LT rats on this second task contrasted with previous findings reporting a detrimental effect of ILN/LT lesions on egocentric working memory. The clear dissociation between the influence of ATN and ILN/LT lesions with respect to allocentric spatial reference memory in the Morris maze emphasizes that caution is required when interpreting the effects of non-ATN thalamic lesions on spatial memory when the lesions encroach substantial areas of the adjacent ATN region.     

Autonomous motivation, controlled motivation, and goal progress

Although the self-concordance of goals has been repeatedly shown to predict better goal progress, recent research suggests potential problems with aggregating autonomous and controlled motivations to form a summary index of self-concordance (Judge, Bono, Erez, & Locke, 2005). The purpose of the present investigation was to further examine the relations among autonomous motivation, controlled motivation, and goal progress to determine the relative importance of autonomous motivation and controlled motivation in the pursuit of personal goals. The results of three studies and a meta-analysis indicated that autonomous motivation was substantially related to goal progress whereas controlled motivation was not. Additionally, the relation of autonomous motivation to goal progress was shown to involve implementation planning. Together, the three studies highlight the importance for goal setters of having autonomous motivation and developing implementation plans, especially ones formulated in terms of approach strategies rather than avoidance strategies. The present research suggests that individuals pursuing goals should focus relatively greater attention on enhancing their autonomous motivation rather than reducing their controlled motivation.     

Wittgenstein and Brouwer

In this paper, I present a summary of the philosophical relationship betweenWittgenstein and Brouwer, taking as my point of departure Brouwer's lecture onMarch 10, 1928 in Vienna. I argue that Wittgenstein having at that stage not doneserious philosophical work for years, if one is to understand the impact of thatlecture on him, it is better to compare its content with the remarks on logics andmathematics in the Tractactus. I thus show that Wittgenstein's position, in theTractactus, was already quite close to Brouwer's and that the points of divergence are the basis to Wittgenstein's later criticisms of intuitionism. Among the topics of comparison are the role of intuition in mathematics, rule following, choice sequences, the Law of Excluded Middle, and the primacy of arithmetic over logic.     

Validation of the shortened cope for use with breast cancer patients undergoing radiation therapy

To study the relationship between cancer and emotional adjustment, investigation of situation-specific coping behaviors with respect to narrowly defined Stressors has recently been promoted. The development and validation of shorter instruments, designed to facilitate completion by clinical populations, has also been recommended. The current study examined the coping skills used by French-Canadian women undergoing radiation therapy for breast cancer. A factor analysis of the 28-item shortened COPE (Carver, Scheier, & Weintraub, 1989) yielded the following eight factors: disengagement, self-distraction, active coping, using emotional support from husband/ partner, using emotional support from friends, turning to religion, humor, and substance use. The test-retest and Cronbach alpha internal consistency reliability coefficients of the French-Canadian shortened COPE were actually higher than those observed in the full-length version of the instrument. In addition, the eight factor-based scores correlated in a theoretically meaningful manner with existing measures of coping skills with illness (Coping with Health Injuries and Problems; CHIP) and mood disturbance (Profile of Mood States; POMS), thus suggesting good construct convergent and concurrent criterion validity. In particular, the disengagement COPE scale was correlated highly with anxiety, depression, and anger. While further validation is recommended, the results show promise for the shortened COPE in assessing coping in women with breast cancer, and also provide continued evidence for the notion that specific coping skills are associated with particular mood states.     

The hippocampus and prefrontal cortex are differentially involved in serial memory retrieval in non-stress and stress conditions

We previously showed that 24 h after learning, mice significantly remembered the first (D1) but not the second (D2) discrimination in a serial spatial task and that an acute stress delivered 5 min before the test phase reversed this memory retrieval pattern.A first experiment evaluated the effects of dorsal hippocampus (HPC) or prefrontal cortex (PFC) lesions, these two brain areas being well-known for their involvement in serial and spatial memory processes. For this purpose, six independent groups of mice were used: non-lesioned (controls), PFC or HPC-lesioned animals, submitted or not to an acute stress (electric footshocks; 0.9 mA). Results show that (i) non-stressed controls as well as PFC-lesioned mice (stressed or not) remembered D1 but not D2; (ii) stressed controls and HPC-lesioned mice (stressed or not) remembered D2 but not D1; (iii) stress significantly increased plasma corticosterone in controls and PFC-lesioned mice, but not in HPC-lesioned mice which already showed a significant plasma corticosterone increase in non-stressed condition.Since data from this first experiment showed that stress inhibited the hippocampal-dependent D1 memory retrieval, a second experiment evaluated the behavioral effect of intrahippocampal corticosterone injection in non-stressed mice. Results show that intrahippocampal corticosterone injection induced a reversal of serial memory retrieval pattern similar to that induced by acute stress.Overall, our study shows that (i) in non-stress condition, the emergence of D1 is HPC-dependent; (ii) in stress condition, the emergence of D2 requires the PFC integrity; moreover, intrahippocampal corticosterone injection mimicked the effects of stress in the CSD task.     

Children acquire the later‐greater principle after the cardinal principle

Many have proposed that the acquisition of the cardinal principle (CP) is a result of the discovery of the numerical significance of the order of the number words in the count list. However, this need not be the case. Indeed, the CP does not state anything about the numerical significance of the order of the number words. It only states that the last word of a correct count denotes the numerosity of the counted set. Here, we test whether the acquisition of the CP involves the discovery of the later‐greater principle – that is, that the order of the number words corresponds to the relative size of the numerosities they denote. Specifically, we tested knowledge of verbal numerical comparisons (e.g., Is ‘ten’ more than ‘six’?) in children who had recently learned the CP. We find that these children can compare number words between ‘six’ and ‘ten’ only if they have mapped them onto non‐verbal representations of numerosity. We suggest that this means that the acquisition of the CP does not involve the discovery of the correspondence between the order of the number words and the relative size of the numerosities they denote.