Are there right hemisphere contributions to visually-guided movement? Manipulating left hand reaction time advantages in dextrals

Delay of gaze fixation during reaching movement with the non-dominant hand to a distant target

The present study examined the effects of hand and task difficulty on eye-hand coordination related to gaze fixation behavior (i.e., fixating a gaze to the target until reach completion) in single reaching movements. Twenty right-handed young adults made reaches on a digitizer, while looking at a visual target and feedback of hand movements on a computer monitor. Task difficulty was altered by having three target distances. In a small portion of trials, visual feedback was randomly removed at the target presentation. The effect of a moderate amount of practice was also examined using a randomized trial schedule across target-distance and visual-feedback conditions in each hand. The results showed that the gaze distances covered during the early reaching phase were reduced, and the gaze fixation to the target was delayed when reaches were performed with the left hand and when the target distance increased. These results suggest that when the use of the non-dominant hand or an increased task difficulty reduces the predictability of hand movements and its sensory consequences, eye-hand coordination is modified to enhance visual monitoring of the reach progress prior to gaze fixation. The randomized practice facilitated this process. Nevertheless, variability of reach trajectory was more increased without visual feedback for right-hand reaches, indicating that control of the dominant arm integrates more visual feedback information during reaches. These results together suggest that the earlier gaze fixation and greater integration of visual feedback during right-hand reaches contribute to the faster and more accurate performance in the final reaching phase.

Developmental relations between mathematics anxiety, symbolic numerical magnitude processing and arithmetic skills from first to second grade

We investigated the levels of and changes in mathematics anxiety (MA), symbolic numerical magnitude processing (SNMP) and arithmetic skills, and how those changes are linked to each other. Children's (n = 264) MA, SNMP and arithmetic skills were measured in Grade 1, and again in Grade 2, also including a mathematics performance test. All three constructs correlated significantly within each time point, and the rank-order stability over time was high, particularly in SNMP and arithmetic skills. By means of latent change score modelling, we found overall increases in SNMP and arithmetic skills over time, but not in MA. Most interestingly, changes in arithmetic skills and MA were correlated (i.e. steeper increase in arithmetic skills was linked with less steep increase in MA), as were changes in SNMP and arithmetic skills (i.e. improvement in SNMP was associated with improvement in arithmetic skills). Only the initial level of arithmetic skills and change in it predicted mathematics performance. The only gender difference, in favour of boys, was found in SNMP skills. The differential effects associated with MA (developmentally only linked with arithmetic skills) and gender (predicting only changes in SNMP) call for further longitudinal research on the different domains of mathematical skills.

Predicting maths anxiety from mathematical achievement across the transition from primary to secondary education

The primary- to secondary-education transition is a substantive life event for many children. The transition can be associated with changes in the developmental trajectories of both emotional health and academic achievement. The current study looked at whether the trajectory of mathematical attainment and emotional health (anxiety) across this transition predicted later maths anxiety. A secondary analysis of data from the Twin Early Development Study (TEDS) was performed. The statistical models were fit on the 753 participants (one from each twin pair) for which there were measures of mathematical performance across the primary- to secondary-education transition and maths anxiety at age 18. Two multi-level growth models were fit predicting mathematical attainment and anxiety over the primary- to secondary-education transition. The intercepts and slopes for each child were extracted from these models and used as predictors of subsequent maths anxiety at age 18. These effects were adjusted for biological sex, socio-economic status, verbal cognitive ability and general anxiety. Maths anxiety at age 18 was significantly predicted by both pre-transition levels of anxiety and mathematical attainment and their rate of change across the primary- to secondary-education transition. However, the effects were small, suggesting that theories of maths anxiety may have overplayed the role of prior mathematical attainment and general anxiety.

How Emotions Modulate Arithmetic Performance

Abstract. The goal of the present study was to test whether and how emotions influence arithmetic performance. Participants had to verify arithmetic problems. True problems were either easier or harder problems. False problems were parity-match or parity-mismatch problems. The odd/even status of proposed and correct answers was the same in parity-match problems (e.g., 19 × 7 = 131) and different in parity-mismatch problems (e.g., 17 × 9 = 152). Before each problem, participants saw a positive (e.g., smiling baby), negative (e.g., mutilations), or neutral pictures (e.g., neutral face) selected from International Affective Picture System (IAPS). They had to decide whether each picture includes a person or not before verifying each arithmetic problem. Results showed different effects of emotion on true- and false problem verification. Participants’ performance on true problems showed decreased problem-difficulty after processing negative pictures and increased difficulty effects after processing positive pictures. On false problems, we found smaller parity-violation effects after negative pictures (i.e., decreased performance on parity-mismatch problems), together with larger parity-violation effects after positive pictures (i.e., decreased performance on parity-match problems). These findings suggest that emotions influence arithmetic performance via which strategy is used and how each strategy is executed on each problem. They have important implications for understanding the role of emotions on arithmetic performance, and more generally on how emotions influence cognition.

Asymmetries in initiation of aiming movements in schizophrenia

Several studies have reported motor symptoms in schizophrenia (SCZ), in some cases describing asymmetries in their manifestation. To date, biases were mainly reported for sequential movements, and the hypothesis was raised of a dopamine-related hemispheric imbalance. Aim of this research is to better characterize asymmetries in movement initiation in SCZ by exploring single actions. Fourteen SCZ patients and fourteen healthy subjects were recruited. On a trial-by-trial basis, participants were instructed to reach for one of eight possible targets. Measures of movement initiation and execution were collected. Starting point, target and moving limb were systematically varied to check for asymmetric responses. Results showed that SCZ patients, besides being overall slower than controls, additionally presented with a bias affecting both the moving hand and the side from which movements were initiated. This finding is discussed in relation to hemispheric lateralization in motor control.

Do left hand reaction time advantages depend on localising unpredictable targets?

Asymmetries in hand movements have routinely been attributed to properties of the two cerebral hemispheres. In right-handed participants, the non-dominant left hand tends to have shorter reaction times, with the dominant right hand achieving shorter movement durations as well as higher peak velocities. The root cause of the surprising left hand RT effect has been debated, largely in the context of right hemisphere specialisation in attention, visuospatial abilities, or "premotor" processes. Mieschke et al. (Brain Cognit 45:1, 2001) and Barthélémy and Boulinguez ( Behav Brain Res 133:1, 2002) both tried to dissociate "premotor" processes explaining the left hand RT advantage, using reaching paradigms where at least one condition required target detection, but no visually guided aiming movement. Unfortunately, the studies obtained conflicting results and conclusions. In the present study, we attempted to re-examine this kind of paradigm with methodological improvements, such as using a task with higher visuospatial demands. Our results demonstrate that whilst RTs are longer as movement complexity increases across three conditions, the left hand RT advantage is present across all conditions-and no significant interaction between hand and condition was found. No significant hand differences were found in peak velocity or duration. These results suggest that the left hand RT advantage cannot be due to movement planning advantages of the right hemisphere, and instead should be attributed to sustained attention/vigilance lateralisation to the right cerebral hemisphere.