Prismatic displacement of vision induces transient changes in the timing of eye-hand coordination

Eye-hand coordination was investigated during a task of finger pointing toward visual targets viewed through wedge prisms. Hand and eye latencies and movement times were identical during the control condition and at the end of prism exposure. A temporal reorganization of eye and hand movements was observed during the course of adaptation. During the earlier stage of prism exposure, the time gap between the end of the eye saccade and the onset of hand movement was increased from a control time of 23 to 68 msec. This suggests that a time-consuming process occurred during the early prism-exposure period. The evolution of this time gap was correlated with the evolution of pointing errors during the early stage of prism exposure, in such a way that both measures increased at the onset of prism exposure and decreased almost back to control values within about 10 trials. However, spatial error was not entirely corrected, even late in prism exposure when the temporal organization of eye and hand had returned to baseline. These data suggest that two different adaptive mechanisms were at work: a rather short-term mechanism, involved in normal coordination of spatially aligned eye and hand systems, and a long-term mechanism, responsible for remapping spatially misaligned systems. The former mechanism can be strategically employed to quickly optimize accuracy in a situation involving misalignment, but completely adaptive behavior must await the slower-acting latter mechanism to achieve longterm spatial alignment.     

Effects of visual deprivation on space representation: immediate and delayed pointing toward memorised proprioceptive targets

Congenitally blind, late-blind, and blindfolded-sighted participants performed a pointing task at proximal memorised proprioceptive targets. The locations to be memorised were presented on a sagittal plane by passively positioning the left index finger. A 'go' signal for matching the target location with the right index finger was given 0 or 8 s after left-hand demonstration. Absolute distance errors were smaller in the blind groups, with both delays pooled together; signed distance and direction errors were underestimated with the longer delay, and were overestimated by blind groups, whereas the blindfolded-sighted group underestimated them. Elongation of the scatters was stretched but not affected by delay or group. The surface scatter was greater with the longer delay; and orientation of the main axis of the pointing ellipses shows the use of an egocentric frame of reference by the congenitally blind group for both delays, the use of egocentric (0 s) and exocentric (8 s) frame of reference by the blindfolded-sighted group, with the late-blind group using an intermediate frame of reference for both delays. Therefore, early and late visual-deprivation effects are distinguished from transient visual-deprivation effects as long-term deprivation leads to increased capabilities (absolute distance estimations), unaltered organisation (for surface and elongation), and altered organisation (amplitude and direction estimations, orientation of pointing distribution) of the spatial representation with proprioception. Besides providing an extensive exploration of pointing ability and mechanisms in the visually deprived population, the results show that cross-modal plasticity applies not only to neural bases but extends to spatial behaviour.     

Exaggerated leftward bias in the mental number line of patients with schizophrenia

Several visuo-motor tasks can be used to demonstrate biases towards left hemispace in schizophrenic patients, suggesting a minor right hemineglect. Recent studies in neglect patients used a new number bisection task to highlight a lateralized defect in their visuo-spatial representation of numbers. To test a possible lateralized representational deficit in schizophrenia, we used the number bisection task in 11 schizophrenic patients compared to 11 healthy controls. Participants were required to orally indicate the central number of an interval orally presented. Whereas healthy subjects showed no significant bias, schizophrenic patients presented a significant leftward bias. Therefore, these results suggest an impairment in higher order representations of the number space in patients with schizophrenia, an impairment that is qualitatively similar to the deficit described in neglect patients.     

Where Philosophy and Literature merge in the Platonic dialogues

It is no surprise if a good quality communication unit succeeds in seizing the attention of the intended audience (or readership) and is able to let people see precisely what the author wanted them to see, while avoiding that the average addressee become aware of what the author wants to convey in an almost subliminal way. In this respect Plato is no exception. Nevertheless the study of these resources, far from having been somewhat systematic, still is largely neglected, and only a minority of commentators find it important to pay head to the communicational strategies which are at work in Plato's dialogues. It will be argued that the shades of meaning and the contextualization of thought (a) systematically grant to Plato ample room for affecting the way a reader comes to perceive his points of doctrine and (b) often let him convey a biased perception of his arguments.The paper includes an outline of the already longstanding debate on these matters, a case study (Memo 80–82), and a sketchy typology of how the literary working-out is able to affect the reader's perception of the line of thought, esp. within the aporetic dialogues.     

New insights on eye blindness and hand sight: Temporal constraints of visuo-motor networks

Pioneer experiments on saccadic suppression have shown that this effect is not followed by motor disorientation: Conscious perception of a target displacement can be dissociated from correct manual target reaching. It has subsequently been demonstrated that movement corrections with the same latency and spatial characteristics can be produced in conditions allowing perceptual awareness of perturbation of a target as in condition inducing saccadic suppression. In addition to the qualitative dissociation between motor performance and conscious awareness, quantitative temporal dissociations in action can be observed by manipulating different features of the visual target. When the target of an ongoing simple action is perturbed, a temporal advantage is found for responses to perturbations of location relative to colour and shape. Furthermore, there seems to be a temporal advantage for automatic motor corrections made in response to a target displacement as compared to other responses (other ongoing movement adjustments, movement interruption, conditional motor response such as pressing a key, verbal response, delayed matching-to-sample tasks). Thus, this paper reviews evidence for the fact that the temporal characteristics of any given response to a stimulus are dependent both on the sensory processes and on the type of response generated. Accordingly, identification responses (such as verbal report) to a visual stimulus are much slower than motor corrections of an ongoing movement in response to a target location change because of different processing times of the stimulus features (“What” compared to “Where”) and of the response itself (“What” compared to “How”). The existence of two continua (What/Where and What/How) is proposed between these two extreme stimulus- response combinations. This model may be a useful framework to better understand visuo-motor transformations and the network of connections between visual and motor areas.     

The Effect of Age and Socio-Cultural Factors on Self-Rated Well-Being and Metacognitive and Mnestic Efficiency Among Healthy Elderly People

The aim of the present research was to investigate the effect of cross-cultural and age-related factors on self-referent metacognitive efficiency, psychological well-being, and mnestic performance in late adulthood. Ninety-three healthy adults recruited in individualistic northwest Italian and collectivistic Sardinian contexts were respectively assigned to the Old (i.e., 65–74 years) and Very Old (i.e., ≥ 75 years) groups and were individually administered a battery of well-being and metacognitive measures and working memory tasks. A series of MANOVAs was carried out on well-being and metacognitive measures and working memory tasks. Sardinians showed greater levels of perceived well-being, less marked psychological distress, and more preserved mnestic functions than the controls from the northwest Italian context. Moreover, participants from the Old group self-referred more coping strategies, emotional competencies, and personal satisfaction, and less depressive symptoms. Then, a hierarchical linear regressions where different socio-demographic, working memory metacognitive and social desirability measures were used as predictors of general psychological well-being shows that socio cultural context, social desirability, visuo-spatial sequential working memory and metamemory measures predict perceived well-being. Socio-cultural contexts emphasizing the positive social role of the elderly seem to promote psychological well-being, that is, life quality in late adulthood.     

Perceived Cognitive Efficiency and Subjective Well-Being in Late Adulthood: The Impact of Developmental Factors

The current literature shows cross-cultural differences related to implicit theories of ageing. Specifically, in the Western individualistic cultural context, elderly people are perceived as obsolete, weak and unable to contribute usefully to society, whereas in collectivistic cultures, older people are venerated as a source of knowledge and cultural traditions (e.g. Yoon et al. in Psychol Aging 15:694–704, 2000). The focus of the current study was to investigate the effect of age-related factors affecting self-referent well-being in the Italian population. One hundred and thirty-nine healthy adults (20–99 years) were recruited in Northern Italian (i.e. individualistic context) and Sardinian (i.e. collectivist context) contexts and were, respectively, assigned to the following groups: Young (20–30 years old), Old (65–74 years old) and Very Old (>75 years old). Participants were administered a battery of tests, including self-referent cognitive efficiency scales, subjective psychological well-being, depression and psychological distress scales. Participants from Sardinia showed greater levels of well-being and lower levels of psychological distress than adults from Northern Italy. Moreover, participants from the Old group reported more coping strategies, emotional competencies and personal satisfaction, as well as fewer depressive symptoms, than the Very Old group. One possible explanation is that sociocultural contexts emphasising the positive social role of the elderly like that prevailing in Sardinia promote psychological well-being in late adulthood.     

The Development of Behavioral Difficulties in Hard-of-Hearing and Deaf Youth

Abstract

This article critically reviews the existing literature examining the presence of behavioral difficulties in relation to language and parenting behaviors among hard-of-hearing youth. A collection of studies has researched the prevalence and development of externalizing behaviors in hard-of-hearing children that impact the well-being of the child and family. Previous literature has found that behavioral difficulties in hard-of-hearing youth contributed to increased parental stress and mental health concerns. Although the relationship between language and behavioral difficulties has been examined, minimal research evaluates the effects of parenting behaviors and parental stress on behavioral difficulties among hard-of-hearing youth. Further exploration within this population is necessary to inform treatment and prevention strategies.     

Christian Marabout,Soldier Monk: Charles de Foucauld between the French and the Tuareg

The life of Père Charles de Foucauld (1858–1916) epitomized many of the motifs and contradictions of French colonialism in North Africa: a cavalry officer turned incognito explorer of Morocco, he eventually renounced his worldly life and became a deeply ascetic Catholic monk, spending the last fifteen years of his life in the Algerian Sahara, primarily among the Muslim Tuareg population of the Ahaggar region. Foucauld remained close to the French military, but his approach to Christian–Muslim relations changed and matured over his time in Algeria. The present study examines Foucauld's complex relationship with colonialism and with the Tuareg during his lifetime, as well as his unexpected legacies in the present. In the Maghreb today, he is remembered for his work as a lexicographer and grammarian of the Tuareg language and its unique tifinagh alphabet – a contribution that was taken up and expanded upon by later Amazigh cultural revivalists. In addition, the Vatican in recent years has held Foucauld up as a model for interreligious dialogue and as a bridge between the Catholic Church and the Muslim world.