Leftward Deviation and Asymmetric Speed of Egocentric Judgment between Left and Right Visual Fields.

The egocentric reference frame is essential for body orientation and spatial localization of external objects. Recent neuroimaging and lesion studies have revealed that the right hemisphere of humans may play a more dominant role in processing egocentric information than the left hemisphere. However, previous studies of egocentric discrimination mainly focused on assessing the accuracy of egocentric judgment, leaving its timing unexplored. In addition, most previous studies never monitored the subjects' eye position during the experiments, so the influence of eye position on egocentric judgment could not be excluded. In the present study, we systematically assessed the processing of egocentric information in healthy human subjects by measuring the location of their visual subjective straight ahead (SSA) and their manual reaction time (RT) during fixation (monitored by eye tracker). In an egocentric discrimination task, subjects were required to judge the position of a visual cue relative to the subjective mid-sagittal plane and respond as quickly as possible. We found that the SSA of all subjects deviated to the left side of the body mid-sagittal plane. In addition, all subjects but one showed the longest RT at the location closest to the SSA; and in population, the RTs in the left visual field (VF) were longer than that in the right VF. These results might be due to the right hemisphere's dominant role in processing egocentric information, and its more prominent representation of the ipsilateral VF than that of the left hemisphere.

Interaction between affordance and handedness recognition: a chronometric study

The visualization of tools and manipulable objects activates motor-related areas in the cortex, facilitating possible actions toward them. This pattern of activity may underlie the phenomenon of object affordance. Some cortical motor neurons are also covertly activated during the recognition of body parts such as hands. One hypothesis is that different subpopulations of motor neurons in the frontal cortex are activated in each motor program; for example, canonical neurons in the premotor cortex are responsible for the affordance of visual objects, while mirror neurons support motor imagery triggered during handedness recognition. However, the question remains whether these subpopulations work independently. This hypothesis can be tested with a manual reaction time (MRT) task with a priming paradigm to evaluate whether the view of a manipulable object interferes with the motor imagery of the subject's hand. The MRT provides a measure of the course of information processing in the brain and allows indirect evaluation of cognitive processes. Our results suggest that canonical and mirror neurons work together to create a motor plan involving hand movements to facilitate successful object manipulation.

Monitoramento do Tempo de Reação como estratégia de avaliação cognitiva e acompanhamento psicológico de judocas / Reaction Time monitoring as a cognitive assessment strategy and psychologicalaccompaniment of judokas

Medidas do tempo de reação manual têm sido extensivamente empregadas pela neurociência cognitiva para o estudo de funções psicomotoras em diferentes circunstâncias, incluindo modelos aplicados ao contexto do esporte de alto rendimento. O presente estudo teve a finalidade de investigar possíveis aplicações de um teste de reação manual específico - protocolo de Simon - como estratégia de avaliação cognitiva e acompanhamento de atletas na área da psicologia do esporte. Para isso, dois atletas de judô foram testados semanalmente, durante o período de um mês, com o teste de Simon. As análises demonstraram que é possível identificar variações no desempenho individual entre as diferentes sessões realizadas. O atleta 1 apresentou diferenças significativas entre as sessões de avaliação, reduzindo progressivamente seu tempo de reação ao longo das três primeiras sessões,mas lentificando novamente suas respostas na última sessão de avaliação. Por sua vez, o atleta 2, apresentou um perfil diferente, oscilando mais seu desempenho ao longo do acompanhamento mensal (lentificou suas respostas da primeira para a terceira sessão e reduziu seus tempos de resposta na quarta avaliação). Esses resultados trazem evidências a favor da utilização do teste de Simon como mais uma estratégia de avaliação cognitiva no esporte, apresentando sensibilidade às variações individuais de desempenho e também obedecendo ao princípio da individualidade biológica, permitindo a distinção dos padrões de resposta entre os indivíduos. Os resultados obtidos fortalecem o potencial das medidas psicofísicas ao revelarem uma forma alternativa de avaliação em comparação aos tradicionais métodos explícitos da psicologia do esporte, além de propiciarem uma abordagem informatizada para avaliação situacional de capacidades de integração sensório-motora, tomada de decisão e atenção espacial.

Manual reaction measures have been extensively employed by cognitive neuroscience to psychomotor studies in different circumstances, including applied methods to the high performance sportive context. The present study aimed to studypossible applications of a specific reaction time procedure (Simon task) as a cognitive assessment strategy and accompaniment in the sport psychology area. In this study, two judo athletes were weekly evaluated with the Simon task during a period of one month. Analyses have shown that is possible to identify variations in individual performance between the different practiced sessions. The Athlete 1 showed significant differences between the assessment sessions, progressively reducing your reaction time over the first three sessions, but slowing the responses at the last session. The athlete 2, showed a different profile, varying his performance over the monthly monitoring (slowed your responses from the first to the third session and reduced the reaction time on fourth assessment). These results provide evidences in favour for the use of the Simon test as more one cognitive assessment strategy in sport, showing sensitivity to individual performance variations and also obeying the principle of biological individuality, allowing the distinction of response patterns between the individuals. The results strengthen the potential use of psychophysics measures revealing an alternative way for assessment compared totraditional explicit methods of sport psychology, providing a computerized approach for situational assessment of sensorimotor integration, decision making and spatial attention abilities (AU)

Monitoramento do tempo de reação como estratégia de avaliação cognitiva e acompanhamento psicológico de judocas / Reaction time monitoring as a cognitive assessment strategy and psychological accompaniment of judokas

Medidas do tempo de reação manual têm sido extensivamente empregadas pela neurociência cognitiva para o estudo de funções psicomotoras em diferentes circunstâncias, incluindo modelos aplicados ao contexto do esporte de alto rendimento. O presente estudo teve a finalidade de investigar possíveis aplicações de um teste de reação manual específico - protocolo de Simon - como estratégia de avaliação cognitiva e acompanhamento de atletas na área da psicologia do esporte. Para isso, dois atletas de judô foram testados semanalmente, durante o período de um mês, com o teste de Simon. As análises demonstraram que é possível identificar variações no desempenho individual entre as diferentes sessões realizadas. O atleta 1 apresentou diferenças significativas entre as sessões de avaliação, reduzindo progressivamente seu tempo de reação ao longo das três primeiras sessões,mas lentificando novamente suas respostas na última sessão de avaliação. Por sua vez, o atleta 2, apresentou um perfil diferente, oscilando mais seu desempenho ao longo do acompanhamento mensal (lentificou suas respostas da primeira para a terceira sessão e reduziu seus tempos de resposta na quarta avaliação). Esses resultados trazem evidências a favor da utilização do teste de Simon como mais uma estratégia de avaliação cognitiva no esporte, apresentando sensibilidade às variações individuais de desempenho e também obedecendo ao princípio da individualidade biológica, permitindo a distinção dos padrões de resposta entre os indivíduos. Os resultados obtidos fortalecem o potencial das medidas psicofísicas ao revelarem uma forma alternativa de avaliação em comparação aos tradicionais métodos explícitos da psicologia do esporte, além de propiciarem uma abordagem informatizada para avaliação situacional de capacidades de integração sensório-motora, tomada de decisão e atenção espacial.

Manual reaction measures have been extensively employed by cognitive neuroscience to psychomotor studies in different circumstances, including applied methods to the high performance sportive context. The present study aimed to studypossible applications of a specific reaction time procedure (Simon task) as a cognitive assessment strategy and accompaniment in the sport psychology area. In this study, two judo athletes were weekly evaluated with the Simon task during a period of one month. Analyses have shown that is possible to identify variations in individual performance between the different practiced sessions. The Athlete 1 showed significant differences between the assessment sessions, progressively reducing your reaction time over the first three sessions, but slowing the responses at the last session. The athlete 2, showed a different profile, varying his performance over the monthly monitoring (slowed your responses from the first to the third session and reduced the reaction time on fourth assessment). These results provide evidences in favour for the use of the Simon test as more one cognitive assessment strategy in sport, showing sensitivity to individual performance variations and also obeying the principle of biological individuality, allowing the distinction of response patterns between the individuals. The results strengthen the potential use of psychophysics measures revealing an alternative way for assessment compared totraditional explicit methods of sport psychology, providing a computerized approach for situational assessment of sensorimotor integration, decision making and spatial attention abilities

Priming effect of figures that represent external objects or human body parts

A visual stimulus (e.g., a letter, word, or object) may have a lasting effect on the processing of subsequent stimuli. The present study verified the priming effect of a figure (i.e., five-petal daisy) on manual reaction time (MRT) to another equal or different five-petal daisy. Two distinct groups were tested. One group was instructed that the five-petal daisy represented a human hand. The other group was instructed that the five-petal daisy represented a flower. The figures in the pairs of stimuli could share or not share some features such as handedness and view. In both groups, after being informed whether the five-petal daisy represented a flower or human hand, an uninformative flower was presented for 200 ms in the center of the screen. After 1000 ms, a second flower was presented in the same location until the observer responded by pressing a left or right switch. The results showed that prior presentation of the five-petal daisy affected MRT only when the figure represented a human hand. Furthermore, an opposite effect of view on MRT was found. The shorter MRT to the back (dorsal) view of the figure that represented a human hand could be attributable to a faster response to the dorsal view of a hand figure made with a prone posture of the participants' hand than to a front (palm) view. The longer MRT to the back view of the figure that represented a flower may be due to a mental rotation of the object along its vertical axis before selecting the correct response because the response was based on the position of the asymmetrical petal in the canonical front view of the daisy.(AU)

Priming effect of figures that represent external objects or human body parts

A visual stimulus (e.g., a letter, word, or object) may have a lasting effect on the processing of subsequent stimuli. The present study verified the priming effect of a figure (i.e., five-petal daisy) on manual reaction time (MRT) to another equal or different five-petal daisy. Two distinct groups were tested. One group was instructed that the five-petal daisy represented a human hand. The other group was instructed that the five-petal daisy represented a flower. The figures in the pairs of stimuli could share or not share some features such as handedness and view. In both groups, after being informed whether the five-petal daisy represented a flower or human hand, an uninformative flower was presented for 200 ms in the center of the screen. After 1000 ms, a second flower was presented in the same location until the observer responded by pressing a left or right switch. The results showed that prior presentation of the five-petal daisy affected MRT only when the figure represented a human hand. Furthermore, an opposite effect of view on MRT was found. The shorter MRT to the back (dorsal) view of the figure that represented a human hand could be attributable to a faster response to the dorsal view of a hand figure made with a prone posture of the participants' hand than to a front (palm) view. The longer MRT to the back view of the figure that represented a flower may be due to a mental rotation of the object along its vertical axis before selecting the correct response because the response was based on the position of the asymmetrical petal in the canonical front view of the daisy.

Recognition of hand shape drawings on vertical and horizontal display

The visual recognition of body parts activates somato-motor representations in the brain. In the present study, we investigate the influence of the plane in which hand drawings are displayed (Vertical or Horizontal) on mental rotations evoked by a handedness recognition task. Sixteen right-handed volunteers participated in an experiment where the task was to evaluate the handedness of drawings of the human hand presented in different perspectives and orientations while the Manual Reaction Time (MRT) was measured. For eight volunteers, the hand drawings were displayed on a vertical screen monitor, while for the remainder a mirror was employed and the same drawings appeared on the horizontal plan. Our main finding was that there are no differences in MRTs among the drawings displayed vertically or horizontally, with some exceptions. However, the MRTs were longer when the hands in the drawings assumed configurations that were more awkward to perform using real movements. These results show that the implicit movements involved with handedness recognition are mainly dependent on biomechanical constraints for distal (hand), but not proximal (shoulder) movements.

Mental rotation of anthropoid hands: a chronometric study

It has been shown that mental rotation of objects and human body parts is processed differently in the human brain. But what about body parts belonging to other primates? Does our brain process this information like any other object or does it instead maximize the structural similarities with our homologous body parts? We tried to answer this question by measuring the manual reaction time (MRT) of human participants discriminating the handedness of drawings representing the hands of four anthropoid primates (orangutan, chimpanzee, gorilla, and human). Twenty-four right-handed volunteers (13 males and 11 females) were instructed to judge the handedness of a hand drawing in palm view by pressing a left/right key. The orientation of hand drawings varied from 0° (fingers upwards) to 90° lateral (fingers pointing away from the midline), 180° (fingers downwards) and 90° medial (finger towards the midline). The results showed an effect of rotation angle (F(3, 69) = 19.57, P < 0.001), but not of hand identity, on MRTs. Moreover, for all hand drawings, a medial rotation elicited shorter MRTs than a lateral rotation (960 and 1169 ms, respectively, P < 0.05). This result has been previously observed for drawings of the human hand and related to biomechanical constraints of movement performance. Our findings indicate that anthropoid hands are essentially equivalent stimuli for handedness recognition. Since the task involves mentally simulating the posture and rotation of the hands, we wondered if "mirror neurons" could be involved in establishing the motor equivalence between the stimuli and the participants' own hands.

Basic Cognitive Abilities of Developmental Stutterers in Processing Chinese Character / 中国康复理论与实践

@#Objective To examine the performance of developmental stutterers in processing Chinese character to determine their basic cognitive abilities of Chinese language.Methods The reaction time and error rates of developmental stutterers and fluent speakers were compared when they performed orthographic,phonetic and semantic judging tasks in the manual reaction time paradigm.Results The differences of reaction time in orthographic,phonetic and semantic judgment and the error rates in orthographic and semantic judgment between both groups were not significant(P>0.05);however,the difference of error rate in phonetic judgment between the both groups were nearly significant(P=0.053).Conclusion The only disability existed in developmental stutterers seems to be the in phonetic abstracting or encoding processes,which is partly in accordance with the covert repair hypothesis.