It has been proposed that the two hands play different roles during bimanual object interaction. The right hand takes on an explorative, highly precise, manipulative role while the left hand supports ...and stabilizes the object. Does this division of labour influence hand use during visually guided grasping? Three experiments were designed to address this question: right-handed individuals put together 3D models using big or small building blocks scattered across a tabletop. Participants were free to build the models; however, it felt comfortable (Experiment 1) or they were required to build on a large (Experiment 2) or small (Experiment 3) base plate. In Experiment 1, the right hand was preferred for grasping while the left hand stabilized the building model. When participants used the large base plate (Experiment 2), right hand use for grasping decreased and left hand use increased. The plate provided freedom to the left hand from having to stabilize the building model, but it also interfered with right/left hand movements directed towards the opposite side of the grasping hand (contralateral movements). To investigate which of these two factors would explain the change in hand use for grasping, a very small base plate was used in the last experiment. Results showed similar right hand use values to those seen in the first experiment (without the use of a plate), even though the left hand was ‘released from its stabilizing duties.’ The results predict a left-hemisphere right hand advantage in the control of grasping.
We rely on accurate body representations to successfully interact with the environment. As adults, we rely on many years of experience with a body that has stayed relatively the same size. Children, ...however, go through periods of rapid growth and whether or not their body representation matches this physical growth is unknown. To address this question, we examined the developmental trajectory of the body model of the hand. The body model is the representation of our bodies that underlies position sense. We recruited a group of children (8–16 years) and a control group of young adults (18–26 years) and asked them to complete the body model task. In this task, participants estimated the location of ten different landmarks (the tips and metacarpophalangeal joints of each of their five fingers). The position (XY location) of each estimate was tracked using an Optotrak camera. From the XY locations we derived hand width and finger length. Not surprisingly, children’s physical hand width and finger length were smaller than adults but remarkably, the body model, was similar for both groups. This result indicates that children overestimate hand size and suggests that the body model is ahead of physical growth. This result contradicts the notion that body representation lags physical growth during puberty, accounting for the clumsy motor behaviour characteristic of teens. We discuss the results in relation to the different taxonomies of body representation and how an enlarged representation of the hand during childhood may influence action.
Parkinson's disease (PD) is the most common movement neurodegenerative disorder. Although our understanding of the underlying mechanisms of pathogenesis in PD has greatly expanded, this knowledge ...thus far has failed to translate into disease‐modifying therapies. Therefore, it is of the utmost urgency to interrogate further the multifactorial etiology of PD. DNA repair defects cause many neurodegenerative diseases. An exciting new PD research avenue is the role that DNA damage and repair may play in neuronal death. The goal of this mini‐review was to discuss the evidence for the types of DNA damage that accumulates in PD, which has provided clues for which DNA repair pathways, such as DNA double‐strand break repair, are dysfunctional. We further highlight compelling data for activation of the DNA damage response in familial and idiopathic PD. The significance of DNA damage and repair is emerging in the PD field and linking these insights to PD pathogenesis may provide new insights into PD pathophysiology and consequently lead to new therapies.
Pronouncing nouns or verbs while grasping distinctly alters movement. Changes in hand speed and final position occur according to the meaning of the words spoken. These results are typically found ...when executing a single movement paired with a single word. For example, pronouncing the word ‘fast’ increased the speed of the hand when reaching to grasp. Our objective was to compare how verb and noun fluency tasks interact with grasping behaviour in a grasp-to-construct task. Because previous imaging research shows that verb and noun production activates distinct neural areas, we reasoned that grasping outcomes would differ according to the category of word produced by participants. Specifically, we hypothesized that verb pronunciation would distinctly affect grasping behaviour compared to producing nouns. We recruited 38 young adults who performed a grasp-to-construct task and two different verbal fluency tasks. Participants completed each task (grasp, verb fluency, and noun fluency) separately as control conditions, and the grasping and each speaking task simultaneously for dual-task conditions. We found that during the dual-task condition, when generating nouns and grasping, participants made significantly more grasping errors (inaccurate grasps) compared to the control and verb dual-task conditions. Moreover, our results revealed a relationship between the number of verbs generated and grasping performance. Participants who generated more verbs were faster and more accurate during the motor component of the dual-task condition. This relationship was not observed when nouns were produced, indicating a unique relationship between verb production and functional grasping. The result is a facilitation effect, diminishing the negative outcome on motor control associated with increased cognitive load (as observed during noun pronunciation).
The winemaking industry can benefit greatly by implementing digital technologies to avoid guesswork and the development of off-flavors and aromas in the final wines. This research presents results on ...the implementation of near-infrared spectroscopy (NIR) and a low-cost electronic nose (e-nose) coupled with machine learning to detect and assess wine faults. For this purpose, red and white base wines were used, and treatments consisted of spiked samples with 12 faults that are traditionally formed in wines. Results showed high accuracy in the classification models using NIR and e-nose for red wines (94-96%; 92-97%, respectively) and white wines (96-97%; 90-97%, respectively). Implementing new and emerging digital technologies could be a turning point for the winemaking industry to become more predictive in terms of decision-making and maintaining and increasing wine quality traits in a changing and challenging climate.
In 1992, Goodale and Milner proposed to study the visual system based on function, thus dissociating vision for perception (ventral stream) and vision for action (dorsal stream). This became known as ...the Perception and Action model (PAM). Following the PAM in the visual system, a somatosensory PAM was proposed including a body representation for perception and a separate for action. This review explores the body model of the hand and how it relates to the PAM. The body model refers to the internal representation of the body that is responsible for position sense. Previous research has shown that the representation of the hand features systematic distortions: an overestimation of hand width and an underestimation of finger length. These distortions have been reported using different paradigms, different body parts, and in various settings. Thus, body model distortions appear to be a characteristic of human body representation. If the body model of the hand is distorted, how can actions like reaching and grasping be accurate? We review evidence that body model distortions may in fact provide a functional benefit to our actions, that cortical maps in the somatosensory and motor cortices reflect these distortions, and that actions rely on a distorted body model. We argue that the body model is a product of both the ventral and dorsal somatosensory streams. Further, we suggest that the body model is an example of the inextricable link between the two streams.
•The body model is a product of both ventral and dorsal somatosensory streams.•The body model informs both perception and action.•Body model distortions are a characteristic of human body representation.•The body model, body schema, and body image interact with one another.
Several tests of mental rotation ability have been used to investigate its development and the origins of sex differences. One of the most used tests is the mental rotation test (MRT) by Vandenberg ...and Kuse. A limitation of the MRT is that it is a pen-and-paper test with 2D images of 3D objects. This is a challenge to the ecological validity of the MRT because mental rotation typically involves physical 3D objects that are also physically manipulated. The purpose of the present study was to compare mental rotation ability as evaluated by the MRT to three new tasks with physical objects (toy bricks) that were physically manipulated. The different tasks allowed us to vary the processing demands on mental rotation while standardizing other aspects of the tasks. Fifty-nine females and twenty-eight males completed the LMR and HMR conditions (low- and high-mental rotation demands, respectively) of the brick building task (BBT), a visual search task, and the MRT. As demands on mental rotation for the BBT increased, performance decreased and a sex difference, with males outperforming females, increased. There were correlations between all tasks, but they were larger between the versions of the BBT with the MRT. The results suggest that spatial skill is an assembly of interrelated subskills and that the sex difference is sensitive to the demands on mental rotation and dimensionality crossing. The benefits of the BBT are that it is ecologically valid, avoids dimensionality crossing, and the demands on mental rotation can be manipulated.
Right-hand preference has been demonstrated for visually guided reaching and grasping. Grasping, however, requires the integration of both visual and haptic cues. To what extent does vision influence ...hand preference for grasping? Is there a hand preference for haptically guided grasping? Two experiments were designed to address these questions. In Experiment 1, individuals were tested in a reaching-to-grasp task with vision (sighted condition) and with hapsis (blindfolded condition). Participants were asked to put together 3D models using building blocks scattered on a tabletop. The models were simple, composed of ten blocks of three different shapes. Starting condition (Vision-First or Hapsis-First) was counterbalanced among participants. Right-hand preference was greater in visually guided grasping but only in the Vision-First group. Participants who initially built the models while blindfolded (Hapsis-First group) used their right hand significantly less for the visually guided portion of the task. To investigate whether grasping using hapsis modifies subsequent hand preference, participants received an additional haptic experience in a follow-up experiment. While blindfolded, participants manipulated the blocks in a container for 5 min prior to the task. This additional experience did not affect right-hand use on visually guided grasping but had a robust effect on haptically guided grasping. Together, the results demonstrate first that hand preference for grasping is influenced by both vision and hapsis, and second, they highlight how flexible this preference could be when modulated by hapsis.
Visuospatial functions are particularly vulnerable to the aging process. Decline of these processes can seriously affect an individual’s functional independence and quality of life. Effectively ...assessing the spatial abilities of older adults is, therefore, crucial for identifying strategies to maintain cognitive functioning. The purpose of the present study was to use ecological tasks more comparable to activities of daily living to assess spatial ability in older adults. Three hands-on tasks (a visual search task, a low- and a high-mental rotation demand tasks) and a version of the well-known paper-based mental rotation of figures test (Shepard and Metzler, Science 171(3972):701–703, 1971) were given to 60–79-year-old female and male participants. The hands-on tasks required participants to locate, manipulate, and arrange real objects (i.e., toy bricks) in space. Age had a negative impact on visual search but not on mental rotation ability. Male participants outperformed females in the mental rotation tasks, but a trend for the opposite (better performance by females) was found for the visual search task. The results suggest that spatial abilities are not a monolithic construct and that sub-categories of this construct are affected by age and by sex differently. While visual search function is susceptible to decline during old age, mental rotation ability is not. In addition, unlike the paper-based test, the hands-on tasks were found to be age-appropriate with a feasible level of difficulty for all participants. The hands-on tasks may be more appealing as a tool to evaluate, maintain, and/or enhance spatial function in older adults.
Radioresistance of tumor cells gives rise to local recurrence and disease progression in many patients. MicroRNAs (miRNAs) are master regulators of gene expression that control oncogenic pathways to ...modulate the radiotherapy response of cells. In the present study, differential expression profiling assays identified 16 deregulated miRNAs in acquired radioresistant breast cancer cells, of which miR‐122 was observed to be up‐regulated. Functional analysis revealed that miR‐122 has a role as a tumor suppressor in parental cells by decreasing survival and promoting radiosensitivity. However, in radioresistant cells, miR‐122 functions as an oncomiR by promoting survival. The transcriptomic landscape resulting from knockdown of miR‐122 in radioresistant cells showed modulation of the ZNF611, ZNF304, RIPK1, HRAS, DUSP8 and TNFRSF21 genes. Moreover, miR‐122 and the set of affected genes were prognostic factors in breast cancer patients treated with radiotherapy. Our data indicate that up‐regulation of miR‐122 promotes cell survival in acquired radioresistant breast cancer and also suggest that miR‐122 differentially controls the response to radiotherapy by a dual function as a tumor suppressor an and oncomiR dependent on cell phenotype.
Radiotherapy exerts cytotoxic effects on primary tumor cells; nevertheless, some tumor cells eventually develop radioresistance via molecular reprogramming to acquire the ability to survive. miR‐122 has been categorized as a tumor suppressor in breast cancer. Here, we report a novel function of miR‐122 as an oncomiR in radioresistant breast cancer cells. OncomiR‐122 is essential to maintain the survival of radioresistant breast cancer cells via the control of a network of survival genes.
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