Levels of Gnostic Functions in Top Karate Athletes-A Pilot Study.

High-quality sensory perception and body scheme (somatognosis) are important aspects for sport performance. This study compares stereognosis, body scheme, and kinesthesia in a group of 36 competitive karate athletes against a control group of 32 general population participants. The stereognosis Petrie test, two body scheme tests, and three kinesthesia tests served as outcome measurement tools. No significant difference was found in the stereognosis Petrie test, for the dominant (p = .389) or the nondominant (p = .791) hand, nor in the kinesthesia test (dominant, p = .661 and nondominant, p = .051). Karate athletes performed significantly better in the body scheme tests, that is, fist width estimation (p = .024) and shoulder width estimation (p = .019), as well as in karate-specific kinesthesia tests, that is, single punch (p = .010) and triple punch (p = .001). This study confirms competitive karate athletes have significantly better somatognosis, and better accuracy when performing quick dynamic movements compared with the general population.

Selective interference of hand posture with grasping capability estimation.

Previous studies have shown that judgments about how one would perform an action are affected by the current body posture. Hence, judging one's capability to grasp an object between index and thumb is influenced by their aperture at the time of the judgment. This finding can be explained by a modification of the internal representation of one's hand through the effect of sensorimotor input. Alternatively, the influence of grip aperture might be mediated by a response congruency effect, so that a "less" vs. "more" open grip would bias the judgment toward a "less" vs. "more" capable response. To specify the role of sensorimotor input in prospective action judgments, we asked participants to estimate their capability to grasp circles between index and thumb while performing a secondary task that requires them to squeeze a ball with these two fingers (precision grip) or with a different hand configuration (palm grip). Experiment 1 showed that participants underestimated their grasping capability when the squeezing task involved the same grip as the judged action (precision grip) and their estimates were bound to the relative size of objects as revealed by size-contrast illusions (Ebbinghaus). Experiment 2 showed that the grip reduction caused by the squeezing task also interfered with the discrimination of large numbers in magnitude judgments, but this incongruency effect was only observed for the palm grip. The dissociated effects of the two grips in graspability and numerical judgments indicate that sensorimotor input may affect the perceived ability to grasp objects, independently of response congruency, by modifying the representation of the hand in action.

Free Will Emerges From a Multistage Process of Target Assignment and Body-Scheme Recruitment for Free Effector Selection.

Self-intended action implies an initial stage of assigning an external entity as target of action, with subsequent recruitment of body-scheme information serving the free selection of an appropriate effector system to achieve the action aim. This plurality underscores the concept that neuronal response freedom underlying the generation of such action is not necessarily restricted to a singular cerebral event at its initiation, but that such freedom is embedded in a series of successive processing steps. In this respect, action intention initially concerns the transition of a neutral object into a target of action, while the "will" to act further crystalizes with the recruitment of one's body scheme. The latter is a prerequisite for effector selection and indeed complements the emerging sense of agency. This temporal order of neuronal events fits a model of fronto-parietal interactions associated with volition. A concise behavioral experiment is additionally described, in which successively displayed balls represent either a recognizable object with distinct shape and color features, or a target of action. Instructions to write down the ball's characteristics were alternated by the command "action." When shifting from a neutral object to an action target, the ball was placed in one of three backgrounds: empty, an outdoor goal or indoor basket. In response to the action command, subjects reported intended actions such as kicking, seizing, throwing and heading, thus implicitly referring to the foot, hand, or head as chosen effector. For the latter the parietal cortex is strongly implicated, not only concerning predefined but also free selection. Although subjects were free to choose what to do with the ball, the environmental cues of the ball strongly influenced their choices. These results illustrate the temporal order in fronto-parietal processing associated with initial target assignment, instantly followed by the embodiment of will, i.e., the recruitment of body-scheme information for possible effector selection. Such multistage neuronal processing underlying free action selection underscores that the onset of brain signals prior to the perceived sense of free will is not a valid argument to reduce free will to an illusion.

Human Postural Control.

From ancient Greece to nowadays, research on posture control was guided and shaped by many concepts. Equilibrium control is often considered part of postural control. However, two different levels have become increasingly apparent in the postural control system, one level sets a distribution of tonic muscle activity ("posture") and the other is assigned to compensate for internal or external perturbations ("equilibrium"). While the two levels are inherently interrelated, both neurophysiological and functional considerations point toward distinct neuromuscular underpinnings. Disturbances of muscle tone may in turn affect movement performance. The unique structure, specialization and properties of skeletal muscles should also be taken into account for understanding important peripheral contributors to postural regulation. Here, we will consider the neuromechanical basis of habitual posture and various concepts that were rather influential in many experimental studies and mathematical models of human posture control.

Flexible motor adjustment of pecking with an artificially extended bill in crows but not in pigeons.

The dextrous foraging skills of primates, including humans, are underpinned by flexible vision-guided control of the arms/hands and even tools as body-part extensions. This capacity involves a visuomotor conversion process that transfers the locations of the hands/arms and a target in retinal coordinates into body coordinates to generate a reaching/grasping movement and to correct online. Similar capacities have evolved in birds, such as tool use in corvids and finches, which represents the flexible motor control of extended body parts. However, the flexibility of avian head-reaching and bill-grasping with body-part extensions remains poorly understood. This study comparatively investigated the flexibility of pecking with an artificially extended bill in crows and pigeons. Pecking performance and kinematics were examined when the bill extension was attached, and after its removal. The bill extension deteriorated pecking in pigeons in both performance and kinematics over 10 days. After the bill removal, pigeons started bill-grasping earlier, indicating motor adaptation to the bill extension. Contrastingly, pecking in crows was deteriorated transiently with the bill extension, but was recovered by adjusting pecking at closer distances, suggesting a quick adjustment to the bill extension. These results indicate flexible visuomotor control to extended body parts in crows but not in pigeons.

Neurocognitive aspects of body size estimation: a study of contemporary dancers

Abstract Dancers use multiple forms of body language when performing their functions in the contemporary dance scene. Some neurocognitive aspects are involved in dance, and we highlight the aspect of body image, in particular, the dimensional aspect of the body perception. The aim of this study is to analyze the perceptual aspect of body image (body size estimation) and its possible association with the motor aspect (dynamic balance) involved in the practice of dance, comparing contemporary dancers with physically active and inactive individuals. The sample consisted of 48 subjects divided into four groups: 1) Professional Group (PG); 2) Dance Student Group (SG); 3) Physically Active Group (AG); and 4) Physically Inactive Group (IG).Two tests were used: the Image Marking Procedure (body size estimation) and the Star Excursion Balance Test (dynamic balance). Was observed that dancing and exercising contribute to a proper body size estimation, but cannot be considered the only determining factor. Although dancers have higher ability in the motor test (dynamic balance), no direct relation to the perception of body size was observed, leading us to conclude it is a skill task/dependent acquired by repeating and training. In this study, we found a statistical significant association between educational level and body size estimation. The study opens new horizons in relation to the understanding of factors involved in the construction of the body size estimation.(AU)

[Body dysmorphic disorder : Anxiety about deformity]. / Körperdysmorphe Störung : Angst vor Missgestaltung.

Between 0.8 and 1.8 % of the German population suffers from a body dysmorphic disorder. In specific settings like dermatological offices up to 11.9 % of patients suffer from this disease. The highest prevalence could be found in the field of cosmetic dermatology with a prevalence of 13.1 %. Until now, the diagnosis has been made too rarely. The body dysmorphic disorder is a chronic psychic disease, in which the patients feel disfigured and experience shame and disgust at the same time. Comorbidities like social phobia, depression, suicidality, and eating disorders are frequent. The diagnosis is made using questionnaires (e.g., dysmorphic concern questionnaire) or by use of the DSM-5 manual. An early diagnosis seems to be important to avoid chronification and suicidal ideas. Therapeutic approaches should include cognitive behavioral therapies as well as the use of SSRIs.

Phantom phenomena and body scheme after limb amputation: a literature review.

Phantom phenomena are subject of various, often inconsistent, descriptions, and new concepts and treatment approaches emerge. The aim of the study is to describe contemporary terminology and developments in the field, and to share personal experience. A review of English and French language literature, published prior to 27th February, 2012, extracted from PubMed/MEDLINE, Google.fr, GoogleScholar databases, and by hand searching of selected full text papers and textbooks with correspondence to personal clinical experience was performed. The terminology and classification of phantom phenomena sensations, relations between intensity and character of phantom pain to the etiology and level of amputations, as well as the influence of presence and intensity of pre-operative limb pain and post-operative stump pain on phantom phenomena are described. The benefits of mirror therapy and early introduction of prosthesis and applying functional prosthesis are also presented, with a glance at other conservative and surgical treatment approaches.

Considerações sobre corporeidade e percepção no último Merleau-Ponty / Considerations about corporeity and perception in the late work of Merleau-Ponty / Consideraciones sobre corporeidad y percepción en el último Merleau-Ponty

No presente artigo, nosso propósito é estudar o problema da percepção do corpo próprio em produções de Merleau-Ponty referentes ao período em que lecionou no Collège de France. Tomamos por eixo da investigação as discussões em torno da noção de esquema corporal. Focalizamos dois cursos diretamente ligados aos avanços conceituais que levam Merleau-Ponty à elaboração da noção de carne: O mundo sensível e o mundo da expressão e A Natureza. Detemo-nos especialmente no primeiro deles, tendo em vista que as pesquisas acerca do diacronismo nos fenômenos da corporeidade adquirem um caráter de sustentação teórica em relação a progressos ulteriores. Consideramos que a condição diacrítica da posição do corpo no mundo liga-se ao tema do circuito que se forma entre o corpo, outrem e as coisas. Liga-se também ao princípio da reversibilidade, ao corpo como sentiente sensível...

Our aim in this paper is to study the problem of the perception of one's own body in Merleau-Ponty's productions during the period he taught at the Collège de France. Discussions about the notion of body scheme serve as the research axis. We focus on two courses directly connected with the conceptual advances that bring Merleau-Ponty to elaborate the notion of flesh: The sensitive world and the world of expression and Nature. We particularly look into the first, as research about the diachronism in corporeity phenomena turns into theoretical support in relation to later progress. We consider that the diacritic condition of the body's position in the world is related with the theme of the circuit established between the body, the other and things. This is also related to principle of reversibility, to the body as a sensitive sentient...

En el presente artículo, nuestro objetivo es estudiar el problema de la percepción del cuerpo propio en producciones de Merleau-Ponty referentes al período en que enseñó en el Collège de France. Tomamos como eje de la investigación las discusiones sobre la noción de esquema corporal. Enfocamos en dos cursos directamente ligados a los avances conceptuales que llevan Merleau-Ponty a la elaboración de la noción de carne: El mundo sensible y el mundo de la expresión y La Naturaleza. Nos detenemos especialmente en el primero, ya que las investigaciones acerca del diacronismo en los fenómenos de la corporeidad gañan un carácter de sustentación teórica con relación a progresos ulteriores. Consideramos que la condición diacrítica de la posición del cuerpo en el mundo está vinculada al tema del circuito que se forma entre el cuerpo, otros y las cosas. Está vinculada también al principio de la reversibilidad, al cuerpo como sentiente sensible...

Considerações sobre corporeidade e percepção no último Merleau-Ponty / Considerations about corporeity and perception in the late work of Merleau-Ponty / Consideraciones sobre corporeidad y percepción en el último Merleau-Ponty

No presente artigo, nosso propósito é estudar o problema da percepção do corpo próprio em produções de Merleau-Ponty referentes ao período em que lecionou no Collège de France. Tomamos por eixo da investigação as discussões em torno da noção de esquema corporal. Focalizamos dois cursos diretamente ligados aos avanços conceituais que levam Merleau-Ponty à elaboração da noção de carne: O mundo sensível e o mundo da expressão e A Natureza. Detemo-nos especialmente no primeiro deles, tendo em vista que as pesquisas acerca do diacronismo nos fenômenos da corporeidade adquirem um caráter de sustentação teórica em relação a progressos ulteriores. Consideramos que a condição diacrítica da posição do corpo no mundo liga-se ao tema do circuito que se forma entre o corpo, outrem e as coisas. Liga-se também ao princípio da reversibilidade, ao corpo como sentiente sensível.(AU)

Our aim in this paper is to study the problem of the perception of one's own body in Merleau-Ponty's productions during the period he taught at the Collège de France. Discussions about the notion of body scheme serve as the research axis. We focus on two courses directly connected with the conceptual advances that bring Merleau-Ponty to elaborate the notion of flesh: The sensitive world and the world of expression and Nature. We particularly look into the first, as research about the diachronism in corporeity phenomena turns into theoretical support in relation to later progress. We consider that the diacritic condition of the body's position in the world is related with the theme of the circuit established between the body, the other and things. This is also related to principle of reversibility, to the body as a sensitive sentient.(AU)

En el presente artículo, nuestro objetivo es estudiar el problema de la percepción del cuerpo propio en producciones de Merleau-Ponty referentes al período en que enseñó en el Collège de France. Tomamos como eje de la investigación las discusiones sobre la noción de esquema corporal. Enfocamos en dos cursos directamente ligados a los avances conceptuales que llevan Merleau-Ponty a la elaboración de la noción de carne: El mundo sensible y el mundo de la expresión y La Naturaleza. Nos detenemos especialmente en el primero, ya que las investigaciones acerca del diacronismo en los fenómenos de la corporeidad gañan un carácter de sustentación teórica con relación a progresos ulteriores. Consideramos que la condición diacrítica de la posición del cuerpo en el mundo está vinculada al tema del circuito que se forma entre el cuerpo, otros y las cosas. Está vinculada también al principio de la reversibilidad, al cuerpo como sentiente sensible.(AU)

Action-perception coupling in kinesthesia: a new approach.

According to recent findings, intentional motor actions are controlled by resetting the referent position, R, at which neuromuscular elements, including reflexes, begin to act. It is suggested that somatosensory afferents inform the brain about the deviation (P) of body segments from the centrally set referent position. To perceive the actual position (Q) of body segments and form the position sense (PS), the central and afferent signals are combined: Q=R+P. In previous studies, the R has been shown to remain invariant during involuntary changes in the wrist position elicited by sudden unloading of muscles, suggesting that only the afferent component is responsible for the PS during this reflex. In contrast, the central PS component, R, is predominantly responsible for PS during intentional motion in isotonic conditions. We tested the hypothesis that the R and P are interchangeable PS components such that involuntary changes in wrist position elicited by the unloading reflex can easily be reproduced by making intentional changes in wrist position in isotonic conditions, in the absence of vision. The PS rule also suggests that PS is independent of sense of effort, which was tested by asking subjects to reproduce elbow joint angles under different constant loads. We also tested the hypothesis that tendon vibration may elicit motion that may not be perceived by subjects (no-motion illusion). These hypotheses were confirmed in three experiments. It is concluded that the R and P are additive components of PS and that, contrary to the conventional view, PS is independent of the sense of effort or efference copy. The PS rule also explains kinesthetic illusions and the phantom limb phenomenon. This study advances the understanding of action-perception coupling in kinesthesia.

Esquema corporal e nível de atividade física em adultos jovens universitários / Body schema and level of physical activity in university students young adults

O objetivo deste estudo foi analisar o esquema corporal, o nivel de atividade física e a associação existente entre estas variáveis. A amostra foi composta por 52 indivíduos com média de idade de 22,98 ± 4,85 anos, sendo 20 homens (23 ± 7,30 anos) e 32 mulheres (22,97 ± 3,19 anos). Os participantes assinaram um termo de consentimento livre e esclarecido e o trabalho foi aprovado pelo comitê de ética da Universidade São Judas Tadeu. As variáveis analisadas foram o esquema corporal, através do Image Marking Procedure (IMP) e o nível de atividade física, através do IPAq. Utilizou-se a estatística descritiva para caracterizar e conhecer a distribuição da amostra. Em seguida, os dados foram comparados utilizando o teste de análise de variância (ANOVA), seguido do teste de Bonferroni como post-hoc. A associação foi verificada com o teste qui-quadrado e o odds ratio. Os homens apresentaram uma maior porcentagem de indivíduos hipoesquemáticos e com esquema corporal adequado e as mulheres uma maior porcentagem de hiperesquematia. Quanto a simetria, somente a altura do trocânter no sexo feminino apresentou diferenças estatísticas (p = 0,02). A inatividade física foi evidente em todos os domínios para a amostra total, porem no domínio 4 verificou-se uma maior porcentagem de indivíduos fisicamente ativos no sexo masculino. O nível de atividade física geral apresentou uma maior porcentagem de indivíduos classificados como fisicamente ativos. Não houve associação entre o esquema corporal e o nível de atividade física. Nota-se que há uma tendência na população de perceberem suas dimensões corporais maiores, ou seja, tendem a hiperesquematia. O fato do esquema corporal está intimamente relacionado com as aferências cinestésicas e proprioceptivas, não foi confirmado nesta amostra ao comparar o nível de atividade física e o esquema corporal.

The objective of this study was to analyze the body scheme, the level of physical activity and the association between these variables. The sample comprised 52 individuals with mean age of 22.98 ± 4.85 years, 20 men (23 ± 7.30 years) and 32 women (22.97 ± 3.19 years). The participants signed an informed consent and the study was approved by the ethics committee of Universidade São Judas Tadeu. The variables analyzed were body image through the Image Marking Procedure (IMP) and the level of physical activity by IPAQ. We used descriptive statistics to characterize and understand the distribution of the sample. Then the data were compared using analysis of variance test (ANOVA) followed by Bonferroni test as post hoc. The association was found with chi-square and odds ratio. Men had a higher percentage of individuals with body scheme and hipoesquemáticos adequate and women a higher percentage of hiperesquematia. The symmetry, only the height of the trochanter in women showed no statistical differences (p = 0.02). Physical inactivity was evident in all areas for the total sample, however in the field 4 there was a higher percentage of physically active males. The level of overall physical activity had a greater percentage of individuals classified as physically active. There was no association between body scheme and physical activity level. Note that there is a trend in the population perceive their body size larger, that is, tend to hiperesquematia. The fact that body image is closely related to kinesthetic and proprioceptive afferents, was not confirmed in this sample to compare the level of physical activity and body scheme.