Rapid and Accumulated Modulation of Action-Effects on Action

Auditory feedback to a keypress is used in many devices to facilitate the motor output. The timing of auditory feedback is known to have an impact on the motor output, yet it is not known if a keypress action can be modulated on-line by an auditory feedback or how quick an auditory feedback can influence an ongoing keypress. Furthermore, it is not clear if the prediction of auditory feedback already changes the early phase of a keypress action independent of sensory feedback, which would suggest that such prediction changes the motor plan. In the current study, participants pressed a touch-sensitive device with auditory feedback in a self-paced manner. The auditory feedback was given either after a short (60 msec) or long (160 msec) delay, and the delay was either predictable or not. Our results showed that the keypress peak force was modulated by the amount of auditory feedback delay even when the delay was unpredictable, thus demonstrating an on-line modulation effect. The latency of the on-line modulation was suggested to be as low as 70 msec, indicating a very fast sensory to motor mapping circuit in the brain. When the auditory feedback delay was predictable, a change in the very early phase of keypress motor output was found, suggesting that the prediction of sensory feedback is crucial to motor control. Therefore, even a simple keypress action contains rich motor dynamics, which depend on expected as well as on-line perceived sensory feedback.

Act Now, Play Later: Temporal Expectations Regarding the Onset of Self-initiated Sensations Can Be Modified with Behavioral Training

Mechanisms of motor-sensory prediction are dependent on expectations regarding when self-generated feedback will occur. Existing behavioral and electrophysiological research suggests that we have a default expectation for immediate sensory feedback after executing an action. However, studies investigating the adaptability of this temporal expectation have been limited in their ability to differentiate modified expectations per se from effects of stimulus repetition. Here, we use a novel, within-participant procedure that allowed us to disentangle the effect of repetition from expectation and allowed us to determine whether the default assumption for immediate feedback is fixed and resistant to modification or is amenable to change with experience. While EEG was recorded, 45 participants completed a task in which they repeatedly pressed a button to produce a tone that occurred immediately after the button press (immediate training) or after a 100-msec delay (delayed training). The results revealed significant differences in the patterns of cortical change across the two training conditions. Specifically, there was a significant reduction in the cortical response to tones across delayed training blocks but no significant change across immediate training blocks. Furthermore, experience with delayed training did not result in increased cortical activity in response to immediate feedback. These findings suggest that experience with action–sensation delays broadens the window of temporal expectations, allowing for the simultaneous anticipation of both delayed and immediate motor-sensory feedback. This research provides insights into the mechanisms underlying motor-sensory prediction and may represent a novel therapeutic avenue for psychotic symptoms, which are ostensibly associated with sensory prediction abnormalities.

Form-From-Motion: MEG Evidence for Time Course and Processing Sequence

The neural mechanisms and role of attention in the processing of visual form defined by luminance or motion cues were studied using magnetoencephalography. Subjects viewed bilateral stimuli composed of moving random dots and were instructed to covertly attend to either left or right hemifield stimuli in order to detect designated target stimuli that required a response. To generate form-from-motion (FFMo) stimuli, a subset of the dots could begin to move coherently to create the appearance of a simple form (e.g., square). In other blocks, to generate form-from-luminance (FFLu) stimuli that served as a control, a gray stimulus was presented superimposed on the randomly moving dots. Neuromagnetic responses were observed to both the FFLu and FFMo stimuli and localized to multiple visual cortical stages of analysis. Early activity in low-level visual cortical areas (striate/early extrastriate) did not differ for FFLu versus FFMo stimuli, nor as a function of spatial attention. Longer latency responses elicited by the FFLu stimuli were localized to the ventral-lateral occipital cortex (LO) and the inferior temporal cortex (IT). The FFMo stimuli also generated activity in the LO and IT, but only after first eliciting activity in the lateral occipital cortical region corresponding to MT/V5, resulting in a 50–60 msec delay in activity. All of these late responses (MT/V5, LO, and IT) were significantly modulated by spatial attention, being greatly attenuated for ignored FFLu and FFMo stimuli. These findings argue that processing of form in IT that is defined by motion requires a serial processing of information, first in the motion analysis pathway from V1 to MT/V5 and thereafter via the form analysis stream in the ventral visual pathway to IT.

Visuospatial Attentional Shifts and Choice Responses of Adults and ADHD and Non-ADHD Children

18 adults, 17 ADHD children, and 18 non-ADHD children performed a choice-response task on which the spatial location of a target was sometimes compatible and sometimes incompatible with priming cues that varied between 50 and 1000 msec. Children's response latencies differed from adults' response latencies as a function of the delay between priming cue and target onset. A cost-benefit analysis indicated that valid stimulus cues facilitated performance and invalid stimulus cues impeded performance similarly for the three groups. Choice-response errors following invalid cues did not differ between ADHD and non-ADHD children; however, adults made more choice errors than children at 150-msec. and 300-msec. delay intervals. Developmental factors that may underlie differences between children's and adults' response speed and response accuracy are discussed.

Processing and Memory of Color, Contour, and Pattern Found in Computer Digitized Color Pictures for Elementary Children

Children in grades one, three, and five participated in three experiments which examined the active processing and short-term memory (STM) of color, contour, and interior pattern of shapes found in computer digitized pictures. No age-related differences were found at the level of active processing and at the onset of STM (10 msec delay) for the three dimensions, while age-related differences occurred for color and contour information at a longer memory lag time (100 msec delay). The study provides insights to the role of processing and memory for specific types of information found in color pictures, which has implications for effecting higher order cognitive behaviors.

Speech Disfluencies and Delayed Auditory Feedback Reactions of Stuttering and Non-Stuttering Children

25 male stutterers and 25 male non-stutterers matched by age and speaking task, read or recited under conditions of normal and 113-, 226-, 306-, 413-, and 520-msec. delayed auditory feedback. Disfluency counts were correlated with delayed auditory feedback reactions which were changes in disfluencies under delay conditions. Pearson product-moment correlations were negative and significant for the combined group of stutterers and non-stutterers under all delays used. Correlations for stutterers were negative and significant for 113, 226, 306, and 413 msec. delay. For the total group of non-stutterers, all correlations were negative and significant. Correlations for age groups within the stuttering and non-stuttering groups were also presented.

The Development of Auditory Feedback Monitoring: II. Delayed Auditory Feedback Studies on the Speech of Children Between Two and Three Years of Age

Two experiments were conducted to determine whether the auditory feedback monitoring system for speech is operative in children between two and three years of age. The procedure involved a 200 msec delay in the auditory feedback of the subject’s speech. Bilateral signal presentation was used for the synchronous (SAF) and delay (DAF) conditions. Phonation time scores under DAF and SAF conditions were compared. In Experiment I, 10 subjects, ages 2 years, 4 months to 2 years, 11 months, followed a standard object naming task. Speech samples obtained from a younger group of 5 subjects in Experiment II, ages 1 year, 9 months to 2 years, 2 months, consisted of all verbal responses which occurred under both DAF and SAF conditions. The results of Experiment I provide evidence that the auditory feedback monitoring system for speech is operative in this age group. The speech of the younger subjects in Experiment II was not strongly affected by the time delay in auditory feedback. The results of the present experiments, together with findings obtained in an earlier study with four- to nine-year-old subjects, suggest that older children show greater DAF effects than younger children.

The Development of Auditory Feedback Monitoring: I. Delayed Auditory Feedback Studies on Infant Cry

Vocal cry samples of 20 normal newborn infants were recorded under two test conditions: synchronous auditory feedback and a 200 msec delay in auditory feedback (DAF). Averages for cry duration, pause time, and maximum sound pressure level were obtained for 16 of the 20 subjects. An analysis of variance showed significant effects for cry duration and amplitude (p < 0.05) but not for pause time. Subjects tended to decrease the average duration of cry bursts by more than 100 msec during the DAF test conditions. The resus, while not conclusive, indicate that cry behavior may be under closed-loop auditory feedback control. It is suggested that the auditory monitoring of cry behavior be further investigated by the use of several delay times. If the magnitude and character of changes in crying behavior show consistent variation as a function of delay time, more persuasive evidence for an auditory feedback monitoring system will have been adduced.