Veranstaltungsprogramm

Objective: Blind individuals may gesture. However, their nonverbal behavior has also been described as “nervous” or “inappropriate”. We therefore investigated the neuropsychological functions of blind individuals nonverbal hand movements that may be rather related to self-stimulation as a consequence of sensory deprivation than the nonverbal depiction of mental images.

Methods: The (entire) nonverbal hand movement and gestural behavior of 11 right-handed healthy blind individuals, 11 (matched) sighted, and 11 (matched) sighted/blindfolded individuals was analyzed during a standardized interview situation by four independent certified raters employing the Neuropsychological Gesture (NEUROGES) Coding System.

Results: The results show no difference of the overall hand movement activity between blind, sighted, and sighted/blindfolded individuals. Increased position shifts and on body focused hand movements were found in blind individuals when compared to sighted and sighted/blindfolded individuals. Whereas blind individuals present pantomime gestures during an emotional situation sighted individuals increase egocentric deictic and pantomime gestures during the re-narration of an audio story.

Discussion: Blind individuals nonverbal hand movement behavior indicates desynchronization processes during conversation (shifts), increased self-stimulation (on body), and the reduced nonverbal transfer of mental images (pantomime). Thus, blind individuals gesture but for different neuropsychological functions.

Embodiment theories suggest that the way we perceive and interpret our environment and others’ actions embedded therein depends, among others, on our own action capabilities and sensorimotor simulation (Körner et al., 2015). Consequently, a skilled observer who is used to the specific rotational direction in an observed movement should perceive it as easier than an equally or less skilled individual who either does not obtain motor expertise or displays an opposing rotational direction in movement execution. Here, we tested the specificity of the sensorimotor simulation account (cf. Casasanto, 2009) by examining the link between rotational preferences for single gymnastic elements and the perceived difficulty for performing routines with these elements. We hypothesized that routines that run according to the individually preferred rotational direction (EC_pref) are considered easier to perform than routines that contain elements that are partially (EC_part) or completely (EC_non-pref) performed against the individually preferred rotational direction (EC_pref > EC_part > EC_non-pref). We tested this through an online study with N = 370 participants (age: 15-61 years; sex: 276 female, 89 male, 2 diverse, 3 not indicated; gymnastic experience: 196 with, 174 without). First, they were confronted with images of gymnastic elements (e.g. round-off and stretch jump with full turn) and asked to indicate their rotational preference. Then, they were presented with another set of images showing routines consisting of two (e.g. round-off left followed by stretch jump with full turn left) or three elements (backwards roll between rotational elements) and asked to rate the perceived difficulty of these routines on a scale from 1 (very difficult) to 10 (very easy) or to indicate that they cannot provide a rating. One-factorial repeated-measures ANOVA, conducted separately for 2-element and 3-element routines, revealed that mean ratings gradually decreased from the EC_pref over EC_part to EC_non-pref conditions with same effect size magnitudes (2- and 3-elements: η²_p = .19, 90% CI [.16, .22]). Exploratory analysis further revealed that this pattern was more pronounced in participants with gymnastic experience (2-elements: η²_p = .26, 90% CI [.21, .31]; 3-elements: η²_p = .27, 90% CI [.22, .32]) than in those without (2-elements: η²_p = .13, 90% CI [.08, .17]; 3-elements: η²_p = .10, 90% CI [.06, .14]). Collectively, our findings are interpreted in favour of the assumption of specificity in sensorimotor simulation underlying movement assessment. Potential practical implications as well as study limitations (e.g. use of images instead of videos) will be discussed.

Motor performance is often impeded when we fail to flexibly react to unexpected changes in our environment. Mental preparation for potential changes can increase our ability to flexibly react in unexpected situations. We investigated how the brain optimally prepares for potential action-relevant changes in the environment. Thirty-two participants performed a speeded motor response task where a repetitive motor action occasionally had to be replaced by an alternative response (Go/Change-Go task). On each trial, a predictive cue indicated the likelihood that a change in motor behaviour might be necessary. We measured neural reactivity via electroencephalography (EEG) during the preparatory pre-response phase of each trial. This allowed us to compare neural reactivity during the preparation for successful versus failed attempts to flexibly adjust one’s behaviour. We focussed our analysis on important neural correlates of executive control (specifically neural oscillations in the theta range, 4 – 7 Hz) and attentional processing (specifically oscillations in the alpha range, 8 – 14 Hz). Results indicate that the preparation for successful compared to failed motor adjustments were marked by significantly higher theta power on the frontal cortex, but significantly lower alpha power on the posterior cortex. In addition, during successful motor adjustments, higher frontal theta power and lower posterior alpha power predicted faster changes in motor behaviour. Our study suggests that frontal theta power increases and posterior alpha power decreases are markers of optimal preparation for efficient and flexible motor reactions. We will discuss the potential underlying cognitive and neural mechanisms related to this pattern, as well as its generalizability to other task contexts. Being able to identify brain states that predict successful adaptation of motor behaviour will be an important step in identifying how to best prepare for challenging motor tasks.

Movement information has to be transiently stored in working memory (WM) before it is converted to a motor program (Ohbayashi et al., 2003). The multicomponent model of WM (Baddeley, 2001) proposes two distinct, domain-specific stores: the visuospatial sketchpad for visual/spatial and the phonological loop for verbal information. Motor processes are commonly attributed to the spatial store, as movement execution has a larger disruptive effect (proxy for shared resources) on spatial than on verbal WM (Lawrence et al., 2004, Spiegel et al., 2013). To date, disruptive effects of motor planning and plan retention have only been measured in combination with execution. In the current study, we sought to disentangle individual processes’ disruptive effects on spatial and verbal WM.

To this end, we asked 21 participants (age 24.4 ± 2.8 (SD) years, 13 male) to execute a reaching task and a concurrent verbal (memorizing a string of letters) or spatial (memorizing symbols in a spatial matrix) WM task. For the reaching task, we used different combinations of motor planning, retention, and execution. Verbal/spatial recall performance was measured as the dependent variable. We calculated a generalized linear mixed model (GLMM) on the number of recalled items, with WM domain and each individual motor process as a factor. If a motor process required resources in WM, we expected a main effect of its associated factor. If the process was domain-specific, we expected an interaction of its associated factor with WM domain.

Results showed significant main effects of retention, z = -3.764, p < .001, R²_β* = .017, planning, z = -4.678, p < .001, R²_β* = .026, and execution, z = -5.352, p < .001, R²_β* = .030, indicating that each of these processes on its own reduced the recall performance. We found a significant interaction with WM domain for planning, z = 2.133, p = .033, R²_β* = .005, and execution, z = 2.576, p = .001, R²_β* = .008 (reflecting a larger disruptive effect on spatial than on verbal WM), but not for retention.

Our findings indicate that each individual motor process requires resources in WM. However, only motor planning and execution are domain-specific processes closely linked to spatial WM, whereas retention appears to be non-domain specific. This pattern of results is consistent with the idea that access and manipulation of motor information are the source of conflict between motor processes and spatial WM, while mere retention of information is not.