The target article proposes that behavioral asymmetries evolved in response to social pressures, accounting for the unequal distribution of handedness across the population. In contrast, we provide evidence that human handedness reflects individual adaptations that enhance movement skill, and that the distribution across the population is best explained by a genetic polymorphism, either balanced or tending toward fixation for right-handedness.

In this volume the editors gather diverse perspectives on one agreed-upon condition: that the computational power of today's world has fundamentally transformed all aspects of this very world. This requires the investigation and questioning not only of the possible sites of critique but also of the concept of critique as such. If there used to be a critical subject constituted in the cultural techniques of modernity, and if digitality, as a condition, indicates itself as a product of modernity while at (...) the same time somehow being its very ending, what are the determinable ramifications? Digitality severely alters the critical subject and its spatio-temporal relations, and therefore interferes with its potentiality to be a critical subject. The authors of this volume therefore do not proclaim a crisis of critique, but rather ask how and what critique in the digital might be, to then look at specific settings of critique and critical practices. With contributions by Clemens Apprich, Timon Beyes, Mark Hansen, Erich Hörl, Holger Kuhn, Luciana Parisi, Ying Sze Pek, Claus Pias, Nelly Y. Pinkrah, Judith Sieber, Lotte Warnsholdt. (shrink)

The ipsilesional arm of stroke patients often has functionally limiting deficits in motor control and dexterity that depend on the side of the brain that is lesioned and that increase with the severity of paretic arm impairment. However, remediation of the ipsilesional arm has yet to be integrated into the usual standard of care for upper limb rehabilitation in stroke, largely due to a lack of translational research examining the effects of ipsilesional-arm intervention. We now ask whether ipsilesional-arm training, tailored (...) to the hemisphere-specific nature of ipsilesional-arm motor deficits in participants with moderate to severe contralesional paresis, improves ipsilesional arm performance and generalizes to improve functional independence. We assessed the effects of this intervention on ipsilesional arm unilateral performance [Jebsen–Taylor Hand Function Test ], ipsilesional grip strength, contralesional arm impairment level [Fugl–Meyer Assessment ], and functional independence [Functional independence measure ]. Intervention occurred over a 3 week period for 1.5 h/session, three times each week. All sessions included virtual reality tasks that targeted the specific motor control deficits associated with either left or right hemisphere damage, followed by graded dexterity training in real-world tasks. We also exposed participants to 3 weeks of sham training to control for the non-specific effects of therapy visits and interactions. We conducted five test-sessions: two pre-tests and three post-tests. Our results indicate substantial improvements in the less-impaired arm performance, without detriment to the paretic arm that transferred to improved functional independence in all three posttests, indicating durability of training effects for at least 3 weeks. We provide evidence for establishing the basis of a rehabilitation approach that includes evaluation and remediation of the ipsilesional arm in moderately to severely impaired stroke survivors. This study was originally a crossover design; however, we were unable to complete the second arm of the study due to the COVID-19 pandemic. We report the results from the first arm of the planned design as a longitudinal study. (shrink)

Zuidema et al. illustrate how empirical AGL studies can benefit from computational models and techniques. Computational models can help clarifying theories, and thus in delineating research questions, but also in facilitating experimental design, stimulus generation, and data analysis. The authors show, with a series of examples, how computational modeling can be integrated with empirical AGL approaches, and how model selection techniques can indicate the most likely model to explain experimental outcomes.

Chronic stroke survivors with severe contralesional arm paresis face numerous challenges to performing activities of daily living, which largely rely on the use of the less-affected ipsilesional arm. While use of the ipsilesional arm is often encouraged as a compensatory strategy in rehabilitation, substantial evidence indicates that motor control deficits in this arm can be functionally limiting, suggesting a role for remediation of this arm. Previous research has indicated that the nature of ipsilesional motor control deficits vary with hemisphere of (...) damage and with the severity of contralesional paresis. Thus, in order to design rehabilitation that accounts for these deficits in promoting function, it is critical to understand the relative contributions of both ipsilesional and contralesional arm motor deficits to functional independence in stroke survivors with severe contralesional paresis. We now examine motor deficits in each arm of severely paretic chronic stroke survivors with unilateral damage to determine whether hemisphere-dependent deficits are correlated with functional independence. Clinical evaluation of contralesional, paretic arm impairment was conducted with the upper extremity portion of the Fugl-Meyer assessment. Ipsilesional arm motor performance was evaluated using the Jebsen-Taylor Hand Function Test, grip strength, and ipsilesional high-resolution kinematic analysis during a visually targeted reaching task. Functional independence was measured with the Barthel Index. Functional independence was better correlated with ipsilesional than contralesional arm motor performance in the left hemisphere damage group [JTHFT: [r = −0.73, p = 0.017]; grip strength: [r = 0.64, p = 0.047]], and by contralesional arm impairment in the right hemisphere damage group [UEFM: [r = 0.66, p = 0.040]]. Ipsilesional arm kinematics were correlated with functional independence in the left hemisphere damage group only. Examination of hemisphere-dependent motor correlates of functional independence showed that ipsilesional arm deficits were important in determining functional outcomes in individuals with left hemisphere damage only, suggesting that functional independence in right hemisphere damaged participants was affected by other factors. (shrink)