Frequency Discrimination Task Research Articles

Modeling the sensory distributions and decision space of frequency-discrimination tasks with deviant stimuli.

Discrimination tasks with deviant stimuli are used often in electrophysiological studies of selective auditory attention [e.g., Rinne et al., Brain Res. 1077, 135–143 (2006)]; for example, participants may be asked to discriminate between complex tones differing in fundamental frequency (186 versus 196 Hz). Presentation probability is high (e.g., 0.82) for fixed level (e.g., 60-dB SL) standard stimuli and low (e.g., 0.18) for deviant stimuli that are 3–9 dB higher or 3–9 dB lower than the standard. Since the level differences are irrelevant to the frequency-discrimination task, the longer response time and higher error rate of deviant versus standard stimuli may be interpreted in terms of distraction caused by deviance. In this study, the sensory effects of standard and deviant stimuli were modeled in terms of two-dimension (frequency by level) probability distributions with densities proportional to presentation probability. It was assumed that the perceptual dimensions (pitch and loudness) are partly correlated, and that perceptual decisions are based on a decision criterion controlled mainly by the standard frequency difference. The model suggests that, in addition to distraction, other factors could also account for deviance effects.

Design, construction, and validation of an MRI-compatible vibrotactile stimulator intended for clinical use

Vibrotactile stimulation has been used successfully to activate the human somatosensory pathway in functional magnetic resonance imaging (fMRI) experiments. The design and characterization of these devices are of particular interest in frequency discrimination tasks and investigations of the somatopic organization of sensory areas. However, few have investigated the utility of vibrotactile stimulation in a clinical context. We have previously demonstrated that vibrotactile stimulation can provide robust activations in areas targeted in stereotactic functional neurosurgical procedures used for tumour resection (i.e.: primary and secondary somatosensory areas) and subcortical targets for thalamic pain and movement disorders (i.e.: sensory thalamus). The main contribution of this manuscript is the presentation of the design, materials, construction, and validation of a novel vibrotactile stimulator intended for clinical use. The thalamic activations are also compared to a digital atlas in order to evaluate anatomical localization. The proposed stimulator was constructed entirely from non-ferromagnetic parts, uses compressed air to deliver stimulation using computer control, and stimulates the entirety of the hand and fingers to ensure robust somatosensory activations. In addition, this stimulator is constructed entirely from “off-the-shelf” parts and would be easily replicated due to the simplicity of design and the relatively small expense of the parts required. The device was tested by stimulating the right hand of 10 normal controls (5 females, 5 males, all right handed; age range: 25–42 years, mean: 30.9 years, standard deviation: 5.2 years) during an fMRI experiment. The results demonstrate significant single subject activations of primary and secondary somatosensory cortices and of the sensory thalamus.

Gender differences in the ability to ignore distracters in frequency discrimination tasks.

Whether there are gender differences in the ability to ignore distracting auditory information remains a matter of debate; such differences could be in basic, involuntary, novelty responses or in elaborate, voluntary, directed attention. To investigate this issue, frequency discrimination thresholds (FDTs) were measured in 20 males and 20 females (young, healthy adults with normal hearing). Targets tones (T) were presented in isolation or followed by a distracter tone (D) after a 90‐ or a 250‐ms silent interval (ISI). Both tones were 1000 Hz, 70 dB SPL, and duration was 40 and 80 ms for T and D, respectively. Target frequency differences were specified by an adaptive rule targeting 71 percent‐correct FDTs; irrelevant differences in D frequency were 40 or 45 Hz. On each subject, FDTs were measured for T in isolation or followed by D, with or without irrelevant differences; a total of 12 trial blocks per condition were completed. Across gender, the largest FDT disparity was observed in conditions with irrelevant differences in D frequency and 90‐ms ISI; in the other conditions the gender effect was small or negligible. There appears to be a gender difference in the initial, involuntary, response to distracters.

Mental ability, P300, and mismatch negativity: Analysis of frequency and duration discrimination

Individual differences in mental ability (MA) were examined with event-related potentials (ERP). In addition to using an auditory frequency discrimination task, a duration discrimination task was used to elicit P300 and mismatch negativity (MMN) components of the ERP. Frequency and duration P300 latencies explained 9% and 10% of variance of MAB performance scores independently of each other and commonly 28% of variance. The finding that duration P300 latency explained variance of MA independent of that explained by frequency P300 latency, suggests that temporal information processing is partly dissociable from processing of frequency information in its prediction of MA. Duration and frequency MMNs were shown to be indices of discrimination ability and predicted 11% of variance of MAB performance scores. The outcome of the present study not only emphasizes the importance of both mental speed and discrimination ability for MA but also points to the significance of duration- and frequency-related ERP measures for the understanding of underlying brain mechanisms.

Tactile acuity in the blind: A closer look reveals superiority over the sighted in some but not all cutaneous tasks

Previous studies have shown that blind subjects may outperform the sighted on certain tactile discrimination tasks. We recently showed that blind subjects outperformed the sighted in a haptic 2D-angle discrimination task. The purpose of this study was to compare the performance of the same blind ( n = 16) and sighted ( n = 17, G1) subjects in three tactile discrimination tasks dependent solely on cutaneous inputs from the fingertip of the index finger, D2. A second group of sighted subjects ( n = 30, G2) were also tested. Texture discrimination thresholds were 0.62 (G1)–0.80 mm (G2) for the sighted subjects, and 0.64 mm for the blind (standard, 2 mm spatial period). Grating orientation thresholds were 0.99 (G1)–1.12 mm (G2) for the sighted subjects, and 0.96 mm for the blind. Finally, vibrotactile frequency discrimination thresholds (100 Hz standard) were 19.5 (G2) and 20.0 Hz (G1) for the sighted, and 16.5 Hz for the blind subjects. There were no significant differences in performance between the blind and the sighted subjects for the grating orientation or vibrotactile frequency discrimination tasks. In contrast, blind subjects outperformed the sighted for the texture discrimination task (G2 only), possibly reflecting the fact that the raised dot surfaces were similar to the dots forming Braille characters (all were fluent Braille readers).

Mental ability and pre-attentive processing: An analysis of mismatch negativity

Event Abstract Back to Event Mental ability and pre-attentive processing: An analysis of mismatch negativity Stefan Troche1*, M. E. Houlihan2, R. M. Stelmack3 and Thomas Rammsayer1 1 Department of Psychology, University of Bern, Switzerland 2 Department of Psychology, St. Thomas University, Fredericton, Canada 3 School of Psychology, University of Ottawa, Canada The association of higher discrimination ability with higher mental ability is a well-established effect. In the present study, mismatch negativity (MNN) was derived during acoustic frequency and duration discrimination tasks to determine whether the mental ability effects are extant at a pre-attentive level of discrimination processing. MMN was recorded from 83 participants. Deviant tones were of a longer duration in one sequence and a higher frequency in the other. In both conditions, there were three levels of discrimination difficulty. Participants were instructed to ignore the tones and to attend to an animated movie. All three frequency MMN amplitudes but none of the duration MMN amplitudes were significantly related to MA. Larger frequency MMN amplitudes went with higher mental ability. Overall, frequency MMN amplitudes explained 18% of variance of the performance scores of the Multidimensional Aptitude Battery. Because MMN amplitude decreased with task difficulty, one could argue that the greater MMN amplitude for higher MA is indicative of their greater discrimination ability. However, this view is challenged by the failure to observe a relation between MMN amplitude and the 75% difference threshold in any condition. Conference: MMN 09 Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications, Budapest, Hungary, 4 Apr - 7 Apr, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: Troche S, Houlihan ME, Stelmack RM and Rammsayer T (2009). Mental ability and pre-attentive processing: An analysis of mismatch negativity. Conference Abstract: MMN 09 Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications. doi: 10.3389/conf.neuro.09.2009.05.098 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Mar 2009; Published Online: 26 Mar 2009. * Correspondence: Stefan Troche, Department of Psychology, University of Bern, Bern, Switzerland, troche@psy.unibe.ch Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Stefan Troche M. E Houlihan R. M Stelmack Thomas Rammsayer Google Stefan Troche M. E Houlihan R. M Stelmack Thomas Rammsayer Google Scholar Stefan Troche M. E Houlihan R. M Stelmack Thomas Rammsayer PubMed Stefan Troche M. E Houlihan R. M Stelmack Thomas Rammsayer Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Generalization to Untrained Conditions Following Training with Identical Stimuli

It has recently been documented that perceptual learning occurs in the absence of perceived differences between stimuli. This finding supports the notion that stimuli do not have to be highly discriminable in order to elicit learning effects. It is not clear, however, whether additional characteristics of perceptual learning, such as generalization of the learning gains, will be demonstrated in this type of training. Thus, the goals of the present study were to compare the effects of type of training, i.e. adaptive versus fixed with identical stimuli on (1) difference limen for frequency (DLF) thresholds; and (2) the extent of generalization of the learning gains to an untrained frequency and the untrained ear. Twelve adult participants with normal hearing were randomly assigned into two experimental groups: an 'adaptive' group and a 'fixed' group. A single-session frequency discrimination training/testing protocol was conducted in which participants were assessed using three 1,000 Hz DLF testing intervals separated by two training intervals. In the 'adaptive' group, each training interval consisted of tone pairs that varied in a 2-down 1-up adaptive procedure. In the 'fixed' group, each training interval consisted of identical 1,000 Hz tone pairs. Following the training/testing protocol, two untrained conditions were tested: a 2,000 Hz untrained frequency and the untrained ear. Results show that: (1) training on a DLF task with identical stimuli improved performance; (2) the type of training (i.e., 'adaptive' versus 'fixed' with identical stimuli) did not influence the amount of gains in performance; (3) learning generalized to an untrained frequency but to a lesser extent in the 'fixed' group with identical stimuli compared to the 'adaptive' group; and (4) learning generalized to the untrained ear for both groups. Thus, training with identical stimuli appears to promote auditory perceptual learning in a frequency discrimination task that generalizes, to some extent, to untrained conditions. These findings support the hypothesis that top-down attention processes and not only bottom-up processes may play an important role in auditory perceptual learning.

Neural Mechanisms of Selective Auditory Attention in Rats (Dissertation)

AbstractHow does attention modulate sensory representations? In order to probe the underlying neural mechanisms, we established a simple rodent model of modality-specific attention. Rats were trained to perform distinct auditory two-tone discrimination and olfactory odor discrimination in a two alternative choice (2AC) paradigm. To determine auditory cortex’s role in this frequency discrimination task, we used GABA-A receptor agonist muscimol to transiently and reversibly inactivate auditory cortexes bilaterally in rats performing simple interleaved auditory and olfactory discrimination. With olfactory discrimination performance serving as internal control for motivation and decision making capability, we found only auditory two-tone discrimination was selectively impaired in these rats. This shows the auditory cortex is involved in this two-tone discrimination task.To investigate the neural correlate of modality-specific attention in the auditory cortex, we trained rats to perform interleaved auditory and olfactory blocks (of 50~70 trials each) in a single session. In auditory blocks, pure tones were either presented with or without a neutral odor (caproic acid, n=2 and 3 respectively), and subjects were rewarded for discriminating auditory stimuli. In olfactory blocks, both task odors and pure tones were presented simultaneously, and subjects were rewarded for discriminating olfactory stimuli. We recorded neural responses in primary auditory cortex (area A1) in freely moving rats while subjects performed this behavior. Single unit responses to tones were heterogeneous, and included transient, sustained, and suppressed. We found 205 of 802 units recorded responsive to the stimuli we used. Of these 205 units, 18.5% showed modality-specific attentional modulation of the anticipatory activity before tone onset. In addition, we also observed in smaller proportion of units (11.2%) modality-specific attentional modulation of the tone-evoked responses; in most cases, the responses to a particular auditory stimulus was enhanced in the auditory block (or, equivalently, suppressed in the olfactory block). Attention increased choice probability of the population in the auditory block. We have also observed significant behavior choice probability in small proportions of units. Our results suggest that shifting attention between audition to olfaction tasks can modulate the activity of single neurons in primary auditory cortex.

Dynamics of cortical responses to tone pairs in relation to task difficulty: A MEG study

We investigated the effect of task difficulty on the dynamics of auditory cortical responses. Whole-scalp magnetoencephalographic (MEG) signals were recorded while subjects performed a same/different frequency discrimination task on equiprobable tone pairs applied in blocks of five, which were separated by a 10 s intertrial interval. Task difficulty was manipulated by the interpair frequency difference. The manipulation of task difficulty affected the amplitude of the N100m response to the first tone and the latency of the N100m response to the second tone in each pair. The N100m responses were smaller and peaked significantly later in the difficult than in the easy condition. The later processing field (PF) responses were longer in duration in the difficult condition. In both conditions, the duration of the PF response was negatively correlated with the subject's performance in the task, and was longer in the less successful subjects. The PF response may thus reflect the subjects' effort to resolve the task. The N100m and the PF responses did not differ between the tone pairs along the five-pair trial as a function of task difficulty, suggesting that changes in response along the five-pair trial are not easily affected by high-level manipulations.

The Role of Superior Temporal Cortex in Auditory Timing

Recently, there has been upsurge of interest in the neural mechanisms of time perception. A central question is whether the representation of time is distributed over brain regions as a function of stimulus modality, task and length of the duration used or whether it is centralized in a single specific and supramodal network. The answers seem to be converging on the former, and many areas not primarily considered as temporal processing areas remain to be investigated in the temporal domain. Here we asked whether the superior temporal gyrus, an auditory modality specific area, is involved in processing of auditory timing. Repetitive transcranial magnetic stimulation was applied over left and right superior temporal gyri while participants performed either a temporal or a frequency discrimination task of single tones. A significant decrease in performance accuracy was observed after stimulation of the right superior temporal gyrus, in addition to an increase in response uncertainty as measured by the Just Noticeable Difference. The results are specific to auditory temporal processing and performance on the frequency task was not affected. Our results further support the idea of distributed temporal processing and speak in favor of the existence of modality specific temporal regions in the human brain.

Enhanced discrimination of low-frequency sounds for subjects with high-frequency dead regions

Research using animals suggests that a lesion in the basal portion of the cochlea, causing a high-frequency 'dead region', leads to cortical reorganization, such that frequencies just below the edge frequency of the dead region, fe, become over-represented. We set out to determine if this reorganization has functional benefits. Two groups of subjects were tested, with and without acquired high-frequency dead regions, as assessed using the TEN(HL) test. For the ears with dead regions, the value of fe was close to 1000 or 1500 Hz. The two groups were matched in terms of audiometric thresholds for frequencies below fe and in terms of age. Three subjects with unilateral dead regions (with matched low-frequency audiometric thresholds across ears) were also tested. Three tasks were used: (i) frequency discrimination of sinusoidal tones. The level of every stimulus was roved over a 12-dB range to reduce the salience of loudness cues. The center frequencies used ranged from 250 Hz to just below fe; (ii) detection of sinusoidal amplitude modulation of a sinusoidal carrier. Carrier frequencies of 500 and 800 Hz were used with all subjects, and an additional carrier frequency of 1200 Hz was used for ears with fe close to 1500 Hz and their matched counterparts. Modulation frequencies were 4, 50 and 100 Hz; (iii) identification of consonants in nonsense syllables. The syllables were lowpass filtered at 1000 or 1500 Hz (depending on the value of fe) and complementary highpass-filtered noise was presented to prevent use of information from neurons tuned above fe. For the frequency-discrimination task, the ears with dead regions showed a significant local improvement ('enhanced' thresholds) for frequencies just below fe, as has been reported previously. For the subjects with unilateral dead regions, the enhancement occurred only for the ears with dead regions. For the amplitude-modulation detection task, thresholds were generally lower for the ears with dead regions than for the ears without, and this effect was statistically significant. For the subjects with unilateral dead regions, thresholds were lower for the ears with dead regions than for the ears without. Consonant identification was significantly better for the ears with than without dead regions, and this was true for the subjects with unilateral dead regions. We conclude that a dead region at high frequencies is associated with a better ability to process information at low frequencies. These effects may reflect cortical plasticity induced by the dead regions.

Frequency discrimination learning in children

Psychoacoustic thresholds of pure tone frequency discrimination (FD) in children are elevated relative to those of adults. It has been shown that it is possible to improve FD thresholds in adults, following a single (subhour) training session. To determine whether FD thresholds in children may be improved by training and, consequently, reduced to adult levels, 100 normally hearing 6- to 11-year-old children and adults received approximately 1 h of training on a FD task at 1 kHz. At the start of training, a quarter of all child participants had FD thresholds that resembled those of naive adults (adult-like subgroup). Another quarter achieved thresholds that were adult-like at some point during training (trainable subgroup). For the remainder (nonadult-like subgroup), thresholds did not reach those of naive adult listeners at any point in the training session. Subgroup membership was linked to the influence of three factors-age, nonverbal IQ, and attention. However, across subgroups, learning was found not to generalize to either a different standard frequency (4 kHz) or a variable (roving) presentation paradigm. The results indicate that it is possible for some children to achieve FD thresholds comparable to those of naive adults, either natively or after limited training.

Irrelevant visual stimuli improve auditory task performance

Multisensory behavioral benefits generally occur when one modality provides improved or disambiguating information to another. Here, we show benefits when no information is apparently provided. Participants performed an auditory frequency discrimination task in which auditory stimuli were paired with uninformative visual stimuli. Visual-auditory stimulus onset asynchrony was varied between -10 ms (sound first) to 80 ms without compromising perceptual simultaneity. In most stimulus onset asynchrony conditions, response times to audiovisual pairs were significantly shorter than auditory-alone controls. This suggests a general processing advantage for multisensory stimuli over unisensory stimuli, even when only one modality is informative. Response times were shortest with an auditory delay of 65 ms, indicating an audiovisual 'perceptual optimum' that may be related to processing simultaneity.

The effect of stimulus range on two-interval frequency discrimination

It has traditionally been thought that performance in two-interval frequency discrimination tasks decreases as the range over which the standard tone varies is increased. Recent empirical evidence and a reexamination of previous results suggest that this may not be the case. The present experiment found that performance was significantly better when the standard roved over a wide range (1500 Hz) than a narrow range (30 Hz). This pattern cannot readily be accommodated by traditional models of frequency discrimination based on memory or attention, but may be explicable in terms of neural plasticity and the formation of perceptual anchors.

Investigating the time course of tactile reflexive attention using a non-spatial discrimination task

Peripheral cues are thought to facilitate responses to stimuli presented at the same location because they lead to exogenous attention shifts. Facilitation has been observed in numerous studies of visual and auditory attention, but there have been only four demonstrations of tactile facilitation, all in studies with potential confounds. Three studies used a spatial (finger versus thumb) discrimination task, where the cue could have provided a spatial framework that might have assisted the discrimination of subsequent targets presented on the same side as the cue. The final study circumvented this problem by using a non-spatial discrimination; however, the cues were informative and interspersed with visual cues which may have affected the attentional effects observed. In the current study, therefore, we used a non-spatial tactile frequency discrimination task following a non-informative tactile white noise cue. When the target was presented 150ms after the cue, we observed faster discrimination responses to targets presented on the same side compared to the opposite side as the cue; by 1000ms, responses were significantly faster to targets presented on the opposite side to the cue. Thus, we demonstrated that tactile attentional facilitation can be observed in a non-spatial discrimination task, under unimodal conditions and with entirely non-predictive cues. Furthermore, we provide the first demonstration of significant tactile facilitation and tactile inhibition of return within a single experiment.

Frequency discrimination in children: Perception, learning and attention

It is generally believed that both sensory immaturity and inattention contribute to the poor listening of some children. However, the relative contribution of each factor, within and between individuals, and the nature of the inattention are poorly understood. In three experiments we examined the threshold and response variability of 6–11 y.o. children on pure tone frequency discrimination (FD) tasks. We first confirmed that younger children had both higher thresholds and greater within- and between-listener variability than older children and adults. Higher thresholds were mostly attributed to high response variability due to poor sustained attention. We next compared performance on the auditory FD task with that on visual spatial FD. No correlation was found between the thresholds or variability of individuals on the two tasks, suggesting involvement of modality-specific attention. Finally, we found lower thresholds for 8–9 y.o. children performing auditory FD training in a classroom than in the laboratory, possibly due to training session length or to a more familiar, motivating and focussed training environment. The adult-like performance of many younger children at times during their testing or training, together with the high response variability of immature performers, suggested that most elevated FD thresholds in children are due to inattention.

Neuromagnetic evidence of broader auditory cortical tuning in schizophrenia

Deficits in basic auditory perception have been described in schizophrenia. Previous electrophysiological imaging research has documented a structure–function disassociation in the auditory system and altered tonotopic mapping in schizophrenia. The present study examined auditory cortical tuning in patients with schizophrenia. Eighteen patients with schizophrenia and 15 comparison subjects were recorded in a magnetoencephalographic (MEG) experiment of auditory tuning. Auditory cortical tuning at 1 kHz was examined by delivering 1 kHz pure tones in conjunction with pure tones at 5 frequencies surrounding and including 1 kHz. Source reconstruction data were examined for evidence of frequency specificity for the M100 component. There was a significant broadening of tuning in the schizophrenia group evident for the source amplitude of the M100. The frequently reported reduction in anterior–posterior source asymmetry for individuals with schizophrenia was replicated in this experiment. No relationships between symptom severity ratings and MEG measures were observed. This finding suggests that the frequency specificity of the M100 auditory evoked field is disturbed in schizophrenia, and may help explain the relatively poor behavioral performance of schizophrenia patients on simple frequency discrimination tasks.

Age-dependent changes of auditory evoked potentials—Effect of task difficulty

The goal of this study was to evaluate the patterns of age-dependent changes of P3 components of auditory event-related potentials exploring the effects of task difficulty. The participants (age span: 19–68 years, n=55, divided into five age groups) took part in an easy and in a difficult two-tone oddball frequency discrimination task with speed or accuracy instructions, and in a novelty oddball task. The latency of the P3 components increased with aging. While in the easy task a linear P3b latency increase could be seen, in the difficult tasks (difficult frequency discrimination or distracting novel stimuli) an accelerated latency increase was observed for the P3b and P3a. In the two-tone oddball paradigm age had no effect on P3b amplitude, but in the novelty oddball task the amplitude of P3 potentials decreased with age. These results indicate that distracting stimuli increase task demands, and in difficult tasks decay can be observed more easily due to the accumulation of various processing mechanisms characterizing aging.

Functional MRI of working memory and selective attention in vibrotactile frequency discrimination

BackgroundFocal lesions of the frontal, parietal and temporal lobe may interfere with tactile working memory and attention. To characterise the neural correlates of intact vibrotactile working memory and attention, functional MRI was conducted in 12 healthy young adults. Participants performed a forced-choice vibrotactile frequency discrimination task, comparing a cue stimulus of fixed frequency to their right thumb with a probe stimulus of identical or higher frequency. To investigate working memory, the time interval between the 2 stimuli was pseudo-randomized (either 2 or 8 s). To investigate selective attention, a distractor stimulus was occasionally presented contralaterally, simultaneous to the probe.ResultsDelayed vibrotactile frequency discrimination, following a probe presented 8 s after the cue in contrast to a probe presented 2 s after the cue, was associated with activation in the bilateral anterior insula and the right inferior parietal cortex. Frequency discrimination under distraction was correlated with activation in the right anterior insula, in the bilateral posterior parietal cortex, and in the right middle temporal gyrus.ConclusionThese results support the notion that working memory and attention are organised in partly overlapping neural circuits. In contrast to previous reports in the visual or auditory domain, this study emphasises the involvement of the anterior insula in vibrotactile working memory and selective attention.

Divided Attention Impairs Human Motor Adaptation But Not Feedback Control

When humans experience externally induced errors in a movement, the motor system's feedback control compensates for those errors within the movement. The motor system's predictive control then uses information about those errors to inform future movements. The role of attention in these two distinct motor processes is unclear. Previous experiments have revealed a role for attention in motor learning over the course of many movements; however, these experimental paradigms do not determine how attention influences within-movement feedback control versus across-movement adaptation. Here we develop a dual-task paradigm, consisting of movement and audio tasks, which can differentiate and expose attention's role in these two processes of motor control. Over the course of several days, subjects performed horizontal reaching movements, with and without the audio task; movements were occasionally subjected to transient force perturbations. On movements with a force perturbation, subjects compensated for the force-induced movement errors, and on movements immediately after the force perturbation subjects exhibited adaptation. On every movement trial, subjects performed a two-tone frequency-discrimination task. The temporal specificity of the frequency-discrimination task allowed us to divide attention within and across movements. We find that divided attention did not impair the within-movement feedback control of the arm, but did reduce subsequent movement adaptation. We suggest that the secondary task interfered with the encoding and transformation of errors into changes in predictive control.