scholarly journals Neural encoding of reliability and validity of directional information during the preparation of targeted movements

2020 ◽  
Author(s):  
Charidimos Tzagarakis ◽  
Sarah West ◽  
Giuseppe Pellizzer

AbstractVisual information about an upcoming target can be used to prepare an appropriate motor response and reduce its reaction time. However, when the anticipation is incorrect and the planned response must be changed, the reaction time is lengthened. Here, we investigated the brain mechanisms associated with the reliability and validity of visual information used for motor preparation. We recorded brain activity using magnetoencephalography (MEG) during a delayed reaching task in which a visual cue provided valid information about the location of the upcoming target with 50, 75 or 100% reliability. We found that reaction time increased as cue reliability decreased and that trials with invalid cues had longer reaction times than trials with valid cues. MEG channel analysis showed that beta-band power from left mid-anterior channels correlated with the reliability of the cue after cue onset but before target onset. This effect was source localized over a large motor-related cortical and subcortical network. In addition, during invalid-cue trials there was a phasic increase of theta-band power following target onset from left posterior channels, localized to the left occipito-parietal cortex. Furthermore, the theta-beta cross-frequency coupling between left mid-occipital and motor cortex also transiently increased before responses to invalid-cue trials. In conclusion, beta-band power in motor-related areas reflected the reliability of visual information used during motor preparation, whereas phasic theta-band activity signaled whether the target was at the expected location or not. These results elucidate mechanisms of interaction between attentional and motor processes.Significance StatementWe used magnetoencephalography to investigate how the brain mechanisms preparing a motor response take into account the reliability of information about the upcoming location of a target to reach, and how these mechanisms adjust when that information turns out to be incorrect. We found that during the response preparation, the power of motor-related beta-band oscillations changed with the reliability of the visual information. In addition, we found that after the onset of the target the power of the left occipito-parietal theta-band signaled whether the prior information was correct or not. The pattern of activity of the beta-band and theta-band explain the pattern of latency of responses in the task, and demonstrate how attentional and motor processes interact.

2021 ◽  
Vol 15 ◽  
Author(s):  
Charidimos Tzagarakis ◽  
Sarah West ◽  
Giuseppe Pellizzer

Visual information about the location of an upcoming target can be used to prepare an appropriate motor response and reduce its reaction time. Here, we investigated the brain mechanisms associated with the reliability of directional information used for motor preparation. We recorded brain activity using magnetoencephalography (MEG) during a delayed reaching task in which a visual cue provided valid information about the location of the upcoming target with 50, 75, or 100% reliability. We found that reaction time increased as cue reliability decreased and that trials with invalid cues had longer reaction times than trials with valid cues. MEG channel analysis showed that during the late cue period the power of the beta-band from left mid-anterior channels, contralateral to the responding hand, correlated with the reliability of the cue. This effect was source localized over a large motor-related cortical and subcortical network. In addition, during invalid-cue trials there was a phasic increase of theta-band power following target onset from left posterior channels, localized to the left occipito-parietal cortex. Furthermore, the theta-beta cross-frequency coupling between left mid-occipital and motor cortex transiently increased before responses to invalid-cue trials. In conclusion, beta-band power in motor-related areas reflected the reliability of directional information used during motor preparation, whereas phasic theta-band activity may have signaled whether the target was at the expected location or not. These results elucidate mechanisms of interaction between attentional and motor processes.


2021 ◽  
Author(s):  
Milou J.L. van Helvert ◽  
Leonie Oostwoud Wijdenes ◽  
Linda Geerligs ◽  
W. Pieter Medendorp

AbstractWhile beta-band activity during motor planning is known to be modulated by uncertainty about where to act, less is known about its modulations to uncertainty about how to act. To investigate this issue, we recorded oscillatory brain activity with EEG while human participants (n = 17) performed a hand choice reaching task. The reaching hand was either predetermined or of participants’ choice, and the target was close to one of the two hands or at about equal distance from both. To measure neural activity in a motion-artifact-free time window, the location of the upcoming target was cued 1000-1500 ms before the presentation of the target, whereby the cue was valid in 50% of trials. As evidence for motor planning during the cueing phase, behavioral observations showed that the cue affected later hand choice. Furthermore, reaction times were longer in the choice than in the predetermined trials, supporting the notion of a competitive process for hand selection. Modulations of beta-band power over central cortical regions, but not alpha-band or theta-band power, were in line with these observations. During the cueing period, reaches in predetermined trials were preceded by larger decreases in beta-band power than reaches in choice trials. Cue direction did not affect reaction times or beta-band power, which may be due to the cue being invalid in 50% of trials, retaining effector uncertainty during motor planning. Our findings suggest that effector uncertainty, similar to target uncertainty, selectively modulates beta-band power during motor planning.New & NoteworthyWhile reach-related beta-band power in central cortical areas is known to modulate with the number of potential targets, here we show, using a cueing paradigm, that the power in this frequency band, but not in the alpha or theta-band, is also modulated by the uncertainty of which hand to use. This finding supports the notion that multiple possible effector-specific actions can be specified in parallel up to the level of motor preparation.


2018 ◽  
Author(s):  
Johanna M. Zumer ◽  
Thomas P. White ◽  
Uta Noppeney

AbstractAsynchrony is a critical cue informing the brain whether sensory signals are caused by a common source and should be integrated or segregated. It is unclear how the brain binds audiotactile signals into behavioural benefits depending on their asynchrony. Participants actively responded (psychophysics) or passively attended (electroencephalogrpahy) to noise bursts, ‘taps-to-the-face’, and their audiotactile (AT) combinations at seven audiotactile asynchronies: 0, ±20, ±70, and ±500ms. Observers were faster at detecting AT than unisensory stimuli, maximally for synchronous stimulation and declining within a ≤70ms temporal integration window. We observed AT interactions for (1) near-synchronous stimuli within a ≤20ms temporal integration window for evoked response potentials (ERPs) at 110ms and ∼400ms, (2) specifically ±70ms asynchronies, across the P200 ERP and theta-band inter-trial coherence (ITC) and power at ∼200ms, with a frontocentral topography, and (3) beta-band power across several asynchronies. Our results suggest that early AT interactions for ERP and theta-band ITC and power mediate behavioural response facilitation within a ≤70ms temporal integration window, but beta-band power reflects AT interactions that are less relevant for behaviour. This diversity of temporal profiles and constraints demonstrates how audiotactile integration unfolds in a cascade of interactions to generate behavioural benefits.


Author(s):  
Srdan Medimorec ◽  
Petar Milin ◽  
Dagmar Divjak

Abstract. Implicit sequence learning is an integral part of human experience, yet the nature of the mechanisms underlying this type of learning remains a matter of debate. In the current study, we provide a test for two accounts of implicit sequence learning, that is, one that highlights sequence learning in the absence of any motor responses (with suppressed eye movements) and one that highlights the relative contribution of the motor processes (i.e., eye movements) to learning. To adjudicate between these accounts and determine whether a motor response is a requisite process in sequence learning, we used anticipation measures to compare performance on the standard oculomotor serial reaction time (SRT) task and on a version of the SRT task where the eye movements were restricted during the learning phase. our results demonstrated an increased proportion of correct anticipations in the standard SRT task compared to the restricted-movement task.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xinzhen Pei ◽  
Xiaoying Qi ◽  
Yuzhou Jiang ◽  
Xunzhang Shen ◽  
An-Li Wang ◽  
...  

Human brains are extremely energy costly in neural connections and activities. However, it is unknown what is the difference in the brain connectivity between top athletes with long-term professional trainings and age-matched controls. Here we ask whether long-term training can lower brain-wiring cost while have better performance. Since elite swimming requires athletes to move their arms and legs at different tempos in time with high coordination skills, we selected an eye-hand-foot complex reaction (CR) task to examine the relations between the task performance and the brain connections and activities, as well as to explore the energy cost-efficiency of top athletes. Twenty-one master-level professional swimmers and 23 age-matched non-professional swimmers as controls were recruited to perform the CR task with concurrent 8-channel EEG recordings. Reaction time and accuracy of the CR task were recorded. Topological network analysis of various frequency bands was performed using the phase lag index (PLI) technique to avoid volume conduction effects. The wiring number of connections and mean frequency were calculated to reflect the wiring and activity cost, respectively. Results showed that professional athletes demonstrated better eye-hand-foot coordination than controls when performing the CR task, indexing by faster reaction time and higher accuracy. Comparing to controls, athletes' brain demonstrated significantly less connections and weaker correlations in upper beta frequency band between the frontal and parietal regions, while demonstrated stronger connectivity in the low theta frequency band between sites of F3 and Cz/C4. Additionally, athletes showed highly stable and low eye-blinking rates across different reaction performance, while controls had high blinking frequency with high variance. Elite athletes' brain may be characterized with energy efficient sparsely wiring connections in support of superior motor performance and better cognitive performance in the eye-hand-foot complex reaction task.


1895 ◽  
Vol 20 ◽  
pp. 328-329
Author(s):  
Rutherford

Sensori-motor reaction time is the interval that elapses between the stimulation of a sense organ and a motor response. The physiological process involved consists of (a) an afferent factor,—the stimulation of a sensory terminal, and transmission of an impulse along sensory nerve fibres to the brain; (b) a psychical factor, involving an act of sensory perception and the voluntary production of a motor impulse; (c) an efferent factor,—the transmission of an impulse along motor nerve fibres, and consequent contraction of muscle.


1996 ◽  
Vol 75 (1) ◽  
pp. 233-247 ◽  
Author(s):  
M. P. Deiber ◽  
V. Ibanez ◽  
N. Sadato ◽  
M. Hallett

1. Using positron emission tomography and measurement of regional cerebral blood flow (rCBF) as an index of cerebral activity we investigated the central processing of motor preparation in 13 healthy volunteers. 2. We used a motor reaction time paradigm with visual cues as preparatory and response signals. A preparatory stimulus (PS) provided either full, partial, or no information regarding two variables of a forthcoming right finger movement: finger type (index or little finger) and movement direction (abduction or elevation). After a variable delay period, a response stimulus (RS) prompted the movement. A condition was also tested in which the subject could freely select any of the four possible movements during the preparation period ("free" condition). The timing of events was designed to emphasize the motor preparation phase over the motor execution component during the scanning time of 1 min. 3. Distinct preparatory processes, which depended on the information contained in the PS, were demonstrated by significant differences in reaction time between conditions. The reaction time was shorter in the "full" and free conditions, intermediate in the two partial information conditions ("finger" and "direction"), and longer when no preparatory information was available ("none" condition). Conversely, movement time and movement amplitude were similar between conditions, establishing the constancy of the motor executive output. 4. In comparison with a "rest" condition, which had matched visual inputs, the different conditions of motor preparation were associated with increased rCBF in a common set of cerebral regions: the contralateral frontal cortex (sensorimotor, premotor, cingulate, and supplementary motor cortex), the contralateral parietal association cortex (anterior and posterior regions), the ipsilateral cerebellum, the contralateral basal ganglia, and the thalamus. This observation substantiates the participation of those cerebral structures in the preparation for movement. Furthermore, the similarity of the activated areas among the different conditions compared with the rest condition suggests a single anatomic substrate for motor preparation, independent of the movement information context. 5. Differing amounts of movement information contained in the PS affected rCBF changes in some cerebral regions. In particular, the rCBF in the anterior parietal cortex (Brodmann's area 40) was significantly larger in each of the full, finger, and direction conditions, individually, compared with the none condition. This observation supports the hypothesis that the anterior parietal association cortex plays a major role in the use of visual instructions contained in the PS for partial or complete preparation to perform a motor act. On the other hand, the posterior parietal association cortex (Brodmann's area 7) was more activated in the finger, direction, and none conditions than in the full condition. This increased activity with restricted advance information suggests that the posterior region of the parietal cortex is concerned with correct movement selection on the basis of enhanced spatial attention to the RS. 6. In contrast with the parietal cortex, the secondary motor areas (i.e, premotor cortex, cingulate cortex, and supplementary motor area) showed similar activity regardless of the degree of preparation allowed by the advance visual information. Thus the parietal cortex may play a more crucial role than the secondary motor areas in integrating visual information in preparation for movement. 7. The effect on brain activity of the internal (self-generated) versus the external (cued) mode of movement selection was assessed by comparing the free and full conditions, the preparatory component being matched in the two conditions. The anterior part of the supplementary motor area was the main area preferentially involved in the internal selection of movement, independently of motor preparation processes.


2011 ◽  
Vol 17 (4) ◽  
pp. 746-750 ◽  
Author(s):  
Naomi J. Goodrich-Hunsaker ◽  
Ling M. Wong ◽  
Yingratana McLennan ◽  
Flora Tassone ◽  
Danielle Harvey ◽  
...  

AbstractA previous study reported preliminary results of enhanced processing of simple visual information in the form of faster reaction times, in female fragile X premutation carriers (fXPCs). In this study, we assessed manual and oral motor reaction times in 30 female fXPCs and 20 neurotypical (NT) controls. Participants completed two versions of the reaction time task; one version required a manual motor response and the other version required an oral motor response. Results revealed that the female fXPCs displayed faster reaction times for both manual and oral motor responses relative to NT controls. Molecular measures including CGG repeat length, FMR1 mRNA levels, and age were not associated with performance in either group. Given previously reported age and CGG repeat modulated performance on a magnitude comparison task in this same group of premutation carriers, results from the current study seem to suggest that female fXPCs may have spared basic psychomotor functionality. (JINS, 2011, 17, 746–750)


2013 ◽  
Vol 109 (4) ◽  
pp. 996-1008 ◽  
Author(s):  
Welber Marinovic ◽  
Aymar de Rugy ◽  
Ottmar V. Lipp ◽  
James R. Tresilian

Previous research using a loud acoustic stimulus (LAS) to investigate motor preparation in reaction time (RT) tasks indicates that responses can be triggered well in advance of the presentation of an imperative stimulus (IS). This is intriguing given that high levels of response preparation cannot be maintained for long periods (≈ 200 ms). In the experiments reported here we sought to assess whether response-related activation increases gradually over time in simple RT tasks. In experiment 1, a LAS was presented at different times just prior to the presentation of the IS to probe the level of activation for the motor response. In experiment 2, the same LAS was presented at different times after the presentation of the IS. The results provide evidence that response-related activation does increase gradually in anticipation of the IS, but it remains stable for a short time after this event. The data display a pattern consistent with the response being triggering by the LAS, rather than a reaction to the IS.


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