Hierarchical organisation of neuro-anatomical constraints in interlimb coordination

Based on the observation that bimanual finger tapping movements tend toward mirror symmetry with respect to the body midline, despite the synchronous activation of non-homologous muscles, F. Mechsner, D. Kerzel, G. Knoblich, and W. Prinz (2001) [Perceptual basis of bimanual coordination. Nature, 414, 69-73] suggested that the basis of rhythmic coordination is purely spatial/perceptual in nature, and independent of the neuro-anatomical constraints of the motor system. To investigate this issue further, we employed a four finger tapping task similar to that used by F. Mechsner and G. Knoblich (2004) [Do muscle matter in bimanual coordination? Journal of Experimental Psychology: Human Perception and Performance, 30, 490-503] in which six male participants were required to alternately tap combinations of adjacent pairs of index (I), middle (M) and ring (R) fingers of each hand in time with an auditory metronome. The metronome pace increased continuously from 1 Hz to 3 Hz over the course of a 30-s trial. Each participant performed three blocks of trials in which finger combination for each hand (IM or MR) and mode of coordination (mirror or parallel) were presented in random order. Within each block, the right hand was placed in one of three orientations; prone, neutral and supine. The order of blocks was counterbalanced across the six participants. The left hand maintained a prone position throughout the experiment. On the basis of discrete relative phase analyses between synchronised taps, the time at which the initial mode of coordination was lost was determined for each trial. When the right hand was prone, transitions occurred only from parallel symmetry to mirror symmetry, regardless of finger combination. In contrast, when the right hand was supine, transitions occurred only from mirror symmetry to parallel but no transitions were observed in the opposite direction. In the right hand neutral condition, mirror and parallel symmetry are insufficient to describe the modes of coordination since the hands are oriented orthogonally. When defined anatomically, however, the results in each of the three right hand orientations are consistent. That is, synchronisation of finger tapping is determined by a hierarchy of control of individual fingers based on their intrinsic neuro-mechanical properties rather than on the basis of their spatial orientation.     

Influence of aesthetic perception on visual event-related potentials

The aim of the study was to assess the effects of visual aesthetic perception on event-related potentials (ERPs). Eight subjects assigned an aesthetic judgment (beautiful, neutral, or ugly) and a 10-step beauty estimation to the target stimuli, consisting of famous artistic pictures and geometric shapes. In a further task, the subjects performed a motor response to the previously judged pictures and geometric shapes. ERPs were recorded through 54 scalp electrodes during both tasks. The P3b amplitude was increased during the categorization of the geometric shapes compared to the artistic figures and during the vision of the beautiful targets preceding the motor response. The categorization of the aesthetic qualities of geometrical shapes seems to induce a higher level of attention, while a higher arousal variation was elicited by the recognition of beauty, in any form that was presented.     

Neuroticism and psychopathy predict brain activation during moral and nonmoral emotion regulation

Functional neuroimaging has identified brain regions associated with voluntary regulation of emotion, including the prefrontal cortex and amygdala. The neural mechanisms underlying individual differences in emotion regulation have not been extensively studied. We investigated the neural correlates of neuroticism and psychopathic personality traits in the context of an emotion regulation task. Results showed that amygdala activity elicited by unpleasant pictures was positively correlated with neuroticism and negatively correlated with a specific psychopathic trait related to emotional underreactivity. During active attempts to decrease emotional responses to unpleasant pictures, superior and ventrolateral prefrontal activity was positively correlated with psychopathy, but not with neuroticism. In contrast, dorsolateral prefrontal activity was positively correlated with neuroticism, but not with psychopathy. Psychopathy was also negatively correlated with medial prefrontal activity in response to pictures depicting moral violations, suggesting reduced emotional responses to moral stimuli in individuals with high levels of psychopathic traits. These results demonstrate dissociable influences of different personality traits on neural activity associated with responses to emotional stimuli and on the recruitment of regulation-related brain activity during the active down-regulation of responses to negative emotional stimuli. These results have implications for the etiology of trait-based psychopathology involving emotional dysregulation.     

Orientations to conflict: Gender, attributions, resolution strategies, and self-monitoring

Gender differences in relationship quality, conflict perceptions, reported conflict strategy use, and self-monitoring orientations were examined in a sample of undergraduates. It was predicted that males and high self-monitoring individuals would see their relationships as less intimate, themselves as less committed, and would endorse more frequent use of uncooperative and avoidant strategies. Participants (n=124) completed the following: a measure of conflict perceptions; a Conflict Strategy Scale measuring frequency of Cooperative, Uncooperative, and Denial-Avoidant strategies; and Snyder’s Self-Monitoring Scale. Compared to females, males scored higher in self-monitoring, saw friendships as less intimate and stable, saw their conflicts as more stable, and endorsed more frequent use of Denial-Avoidant strategies. Masculine orientations to conflict reflected increased self-presentational concerns and perceptions that minimized the personal relevance of conflict.     

Structural problems for reductionism

Philosophical Studies - Universal reductionism—the sort of project pursued by Carnap in the Aufbau, Lewis in his campaign on behalf of Humean supervenience, Jackson in From Metaphysics to...     

Box for interaction with objects (BIO): A new device to synchronize the presentation of objects with electrophysiological recordings

Brain event-related potentials are a useful tool for investigating visual processing and action planning. This technique requires extremely accurate synchronization of stimulus delivery with recordings. The precision of the onset time of visual stimulus delivery is a major challenge when attempting to use real, three-dimensional objects as stimuli. Here, we present an innovative device, the “box for interaction with objects” (BIO), that is designed to synchronize the presentation of objects with electroencephalographic (EEG) recordings. To reach the required resolution of stimulus-onset timing, the BIO system features an interface with reflective glass and light-emitting diodes (LEDs). When the LEDs inside the BIO are turned on, the object inside becomes visible, and a synchronizing pulse is sent to the recording systems. The BIO was tested in a motivational study that focused on visual and motor event-related potentials. EEG signals were recorded during the presentation of an emotion-laden object that could be grasped and brought close to the participant’s chest. BIO successfully synchronized the appearance of a three-dimensional object with EEG recordings, which would allow for an analysis of visual and motor event-related potentials in the same experiment. The BIO device, through a high-quality psychophysiological approach, offers a new perspective for the study of the motivational factors that drive actions toward relevant stimuli.     

Modeling body state-dependent multisensory integration

The brain often integrates multisensory sources of information in a way that is close to the optimal according to Bayesian principles. Since sensory modalities are grounded in different, body-relative frames of reference, multisensory integration requires accurate transformations of information. We have shown experimentally, for example, that a rotating tactile stimulus on the palm of the right hand can influence the judgment of ambiguously rotating visual displays. Most significantly, this influence depended on the palm orientation: when facing upwards, a clockwise rotation on the palm yielded a clockwise visual judgment bias; when facing downwards, the same clockwise rotation yielded a counterclockwise bias. Thus, tactile rotation cues biased visual rotation judgment in a head-centered reference frame. Recently, we have generated a modular, multimodal arm model that is able to mimic aspects of such experiments. The model co-represents the state of an arm in several modalities, including a proprioceptive, joint angle modality as well as head-centered orientation and location modalities. Each modality represents each limb or joint separately. Sensory information from the different modalities is exchanged via local forward and inverse kinematic mappings. Also, re-afferent sensory feedback is anticipated and integrated via Kalman filtering. Information across modalities is integrated probabilistically via Bayesian-based plausibility estimates, continuously maintaining a consistent global arm state estimation. This architecture is thus able to model the described effect of posture-dependent motion cue integration: tactile and proprioceptive sensory information may yield top–down biases on visual processing. Equally, such information may influence top–down visual attention, expecting particular arm-dependent motion patterns. Current research implements such effects on visual processing and attention.