Biology subjects

Barany, D. A.

Publications and source records attributed to Barany, D. A..

5 recordsLinked to original sources

bioRxiv2026

Motor Intention Drives Corticospinal Facilitation during Interception Planning

Intercepting a moving target requires integrating visual motion information with motor preparation, yet how active motor preparation and gaze strategy jointly shape corticospinal excitability during interception planning remains unclear. We applied single-pulse transcranial magnetic stimulation over primary motor cortex to probe corticospinal excitability while participants either prepared to intercept a moving target or passively viewed its motion. Targets moved at one of two speeds, and participants judged target speed relative to a reference after each trial. Across blocks, participants were instructed to either smoothly pursue the target or fixate their eyes on the interception zone. Motor-evoked potentials were elicited at baseline, after task instruction, early during target motion, or shortly before target arrival. Task and gaze strategy interacted to influence both perceptual judgments and corticospinal excitability. Preparing to intercept produced a robust facilitation of corticospinal excitability immediately before movement onset, regardless of gaze strategy. In contrast, corticospinal excitability during passive viewing did not differ from baseline. Smooth pursuit improved perceptual accuracy and reduced interception timing error compared with fixation but did not independently influence corticospinal facilitation. These findings demonstrate that active motor preparation is the primary determinant of the transition to a state of facilitated excitability during interception planning, whereas eye movements modulate perceptual estimates and support behavioral performance. New & NoteworthyThis study dissociates the contributions of visual tracking, eye movements, and active motor preparation to corticospinal excitability during interception. Here, we show that corticospinal facilitation emerges primarily when an action is planned, whereas passive viewing remains at baseline despite identical visual input. Smooth pursuit enhanced perceptual accuracy and interception timing but had a limited effect on corticospinal excitability, highlighting active motor preparation as the key driver of corticospinal output.

neuroscience↗

bioRxiv2025

Corticospinal excitability during timed interception depends on the speed of the moving target

Successfully intercepting a moving object requires precisely timing the optimal moment to act by integrating information about the targets visual motion properties. Neurophysiological evidence indicates that activity in the primary motor cortex (M1) during interception preparation is sensitive to both the targets kinematic features and motor planning. However, how visual motion signals are integrated within M1 to guide interception timing is unclear. In the present study, we applied single-pulse transcranial magnetic stimulation (TMS) over M1 to examine how a targets kinematics influence corticospinal excitability during interception preparation. Participants were instructed to abduct their right index finger to intercept a target moving horizontally at a constant speed toward a fixed interception zone. Target speed (Fast or Slow) and travel distance (Far or Close) were manipulated while controlling motion duration across conditions. Motor-evoked potentials (MEPs) were elicited at five latencies before target arrival at the interception zone. Consistent with previous behavioral findings, movement initiation occurred earlier for faster targets and was delayed when TMS was applied closer to the targets arrival. Though MEPs were generally suppressed relative to baseline at earlier timepoints and facilitated closer to movement initiation, we observed that target speed--but not distance--influenced the time course of MEP modulation. When adjusting for movement initiation times, there was an overall reduced suppression and increased facilitation for faster-moving targets, possibly reflecting a heightened urgency to move. These results suggest M1 activity during interception preparation integrates internal estimates of target motion, which may serve to optimize interception timing and performance. New & NoteworthyWhen intercepting a moving object, like catching a ball, we need to continuously combine visual motion signals to predict the objects future location and enable accurate movement. Here, we show that preparatory suppression and facilitation of corticospinal excitability depends on the speed, but not the distance, of the moving target. These findings reveal that differences in interception timing are closely linked to changes in motor system excitability.

neuroscience↗

bioRxiv2024

Neural Encoding of Direction and Distance across Reference Frames in Visually Guided Reaching

Goal-directed actions require transforming sensory information into motor plans defined across multiple parameters and reference frames. Substantial evidence supports the encoding of target direction in gaze- and body-centered coordinates within parietal and premotor regions. However, how the brain encodes the equally critical parameter of target distance remains less understood. Here, using Bayesian pattern component modeling of fMRI data during a delayed reach-to-target task, we dissociated the neural encoding of both target direction and the relative distances between target, gaze, and hand at early and late stages of motor planning. This approach revealed independent representations of direction and distance along the human dorsomedial reach pathway. During early planning, most premotor and superior parietal areas encoded a targets distance in single or multiple reference frames and encoded its direction. In contrast, distance encoding was magnified in gaze- and body-centric reference frames during late planning. These results emphasize a flexible and efficient human central nervous system that achieves goals by remapping sensory information related to multiple parameters, such as distance and direction, in the same brain areas. Significance statementMotor plans specify various parameters, e.g., target direction and distance, each of which can be defined in multiple reference frames relative to gaze, limb, or head. Combining fMRI, a delayed reach-to-target task, and Bayesian pattern component modeling, we present evidence for independent goal-relevant representations of direction and distance in multiple reference frames across early and late planning along the dorsomedial reach pathway. Initially, areas encoding distance also encode direction, but later in planning, distance encoding in multiple reference frames was magnified. These results emphasize central nervous system flexibility in transforming movement parameters in multiple reference frames crucial for successful goal-directed actions and have important implications for brain-computer interface technology advances with sensory integration.

neuroscience↗

bioRxiv2023

NEURAL BASIS OF SOUND-SYMBOLIC PSEUDOWORD-SHAPE CORRESPONDENCES

Non-arbitrary mapping between the sound of a word and its meaning, termed sound symbolism, is commonly studied through crossmodal correspondences between sounds and visual shapes, e.g., auditory pseudowords, like mohloh and kehteh, are matched to rounded and pointed visual shapes, respectively. Here, we used functional magnetic resonance imaging (fMRI) during a crossmodal matching task to investigate the hypotheses that sound symbolism (1) involves language processing; (2) depends on multisensory integration; (3) reflects embodiment of speech in hand movements. These hypotheses lead to corresponding neuroanatomical predictions of crossmodal congruency effects in (1) the language network; (2) areas mediating multisensory processing, including visual and auditory cortex; (3) regions responsible for sensorimotor control of the hand and mouth. Right-handed participants (n = 22) encountered audiovisual stimuli comprising a simultaneously presented visual shape (rounded or pointed) and an auditory pseudoword ( mohloh or kehteh) and indicated via a right-hand keypress whether the stimuli matched or not. Reaction times were faster for congruent than incongruent stimuli. Univariate analysis showed that activity was greater for the congruent compared to the incongruent condition in the left primary and association auditory cortex, and left anterior fusiform/parahippocampal gyri. Multivoxel pattern analysis revealed higher classification accuracy for the audiovisual stimuli when congruent than when incongruent, in the pars opercularis of the left inferior frontal (Brocas area), the left supramarginal, and the right mid-occipital gyri. These findings, considered in relation to the neuroanatomical predictions, support the first two hypotheses and suggest that sound symbolism involves both language processing and multisensory integration. HIGHLIGHTSO_LIfMRI investigation of sound-symbolic correspondences between auditory pseudowords and visual shapes C_LIO_LIFaster reaction times for congruent than incongruent audiovisual stimuli C_LIO_LIGreater activation in auditory and visual cortices for congruent stimuli C_LIO_LIHigher classification accuracy for congruent stimuli in language and visual areas C_LIO_LISound symbolism involves language processing and multisensory integration C_LI

neuroscience↗

bioRxiv2019

Perceptual decisions about object shape bias visuomotor coordination during rapid reaching and interception

Visual processing in parietal areas of the dorsal stream facilitates sensorimotor transformations for rapid movement. This action-related visual processing is hypothesized to play a distinct functional role from the perception-related processing in the ventral stream. However, it is unclear how the two streams interact when perceptual identification is a prerequisite to executing an accurate movement. In the current study, we investigated how perceptual decision-making involving the ventral stream influences arm and eye movement strategies. Participants (N = 26) moved a robotic manipulandum using right whole-arm movements to rapidly reach a stationary object or intercept a moving object on an augmented-reality display. On some blocks of trials, participants needed to identify the shape of the object (circle or ellipse) as a cue to either hit the object (circle) or move to a pre-defined location away from the object (ellipse). We found that during perceptual decision-making, there was an increased urgency to act during interception movements relative to reaching, which was associated with more decision errors. Faster hand reaction times were correlated with a strategy to adjust the movement post-initiation, and this strategy was more prominent during interception. Saccadic reaction times were faster and initial gaze lags and gains greater during decisions, suggesting that eye movements adapt to perceptual demands for guiding limb movements. Together, our findings suggest that the integration of ventral stream information with visuomotor planning depends on imposed (or perceived) task demands. New and NoteworthyVisual processing for perception and for action are thought to be mediated by two specialized neural pathways. Using a visuomotor decision-making task, we show that participants differentially utilized online perceptual decision-making in reaching and interception, and that eye movements necessary for perception influenced motor decision strategies. These results provide evidence that task complexity modulates how pathways processing perception versus action information interact during the visual control of movement.

neuroscience↗