Sensory Interference Research Articles

Multitasking and task performance: Roles of task hierarchy, sensory interference, and behavioral response

This research examined how different types of multitasking affect task performance due to (a) task hierarchy, (b) sensory interference, and (c) behavioral response. This research used a 2 task hierarchy (primary vs. secondary multitasking) × 2 sensory interference (low vs. high) × 2 behavioral response (absent vs. present) between group experimental design. The results of two experiments showed that task performance was lower (a) when the given task was a secondary task, (b) when sensory interference was high, and (c) when behavioral response was present. In addition, there was an interaction between task hierarchy and sensory interference, such that the effect of task hierarchy was stronger when sensory interference was high (than low). Theoretical, practical, and methodological implications for future multitasking research are further discussed.

Visual sensory stimulation interferes with people\u2019s ability to echolocate object size

Echolocation is the ability to use sound-echoes to infer spatial information about the environment. People can echolocate for example by making mouth clicks. Previous research suggests that echolocation in blind people activates brain areas that process light in sighted people. Research has also shown that echolocation in blind people may replace vision for calibration of external space. In the current study we investigated if echolocation may also draw on ‘visual’ resources in the sighted brain. To this end, we paired a sensory interference paradigm with an echolocation task. We found that exposure to an uninformative visual stimulus (i.e. white light) while simultaneously echolocating significantly reduced participants’ ability to accurately judge object size. In contrast, a tactile stimulus (i.e. vibration on the skin) did not lead to a significant change in performance (neither in sighted, nor blind echo expert participants). Furthermore, we found that the same visual stimulus did not affect performance in auditory control tasks that required detection of changes in sound intensity, sound frequency or sound location. The results suggest that processing of visual and echo-acoustic information draw on common neural resources.

The Effect of Combined Core Stability and Neuromuscular Training on Postural Control in Students with Congenital Hearing Loss

Introduction: According to previous studies, weakness in maintaining balance is one of the main problems in people with congenital hearing loss; and balance is also an important factor affecting the quality of life. Strengthening and improving equilibrium functions must be emphasized to reduce the problems of this group of people and bring their quality of life closer to normal. This study purposed to assess the effect of a combination of core stability and neuromuscular training on postural control in students with congenital hearing loss. Materials and Methods: This semi-experimental study with pre/posttest design was performed on 24 students with congenital hearing loss who were randomly assigned to two equal groups of experiment and control. The control group continued their daily routines, while the experimental group performed a combination training of core stability and neuromuscular ones for six weeks in three sessions of 60 minutes per week. Subjects' ability to maintain a standing position was measured in different sensory states. The changes in maintaining the standing statuses in different sensory states were measured before and 6 weeks after of exercise. Paired t test was used to analyze the data via SPSS software at the significant level of P < 0.050. Results: After the exercise intervention, experimental group experienced a significant decrease in the number of first mode errors without any sensory interference (P = 0.009), second state error, and visual system predominance (P = 0.002), number of errors in the third state, and predominance of the body sensory system (P = 0.001), and number of faults in the fourth state, and the prevalence of the vestibular system (P = 0.001). However, no significant reduction was observed in any of the balance occasions in the control group. Conclusion: Combination form of core stability and neuromuscular exercises seems to improve postural balance in hearing impaired and can be used in conjunction with other training programs. However, this research has its own limits and further research is needed.

Nonlinear dynamics analysis of the human balance control subjected to physical and sensory perturbations.

Postural control after applying perturbation involves neural and muscular efforts to limit the center of mass (CoM) motion. Linear dynamical approaches may not unveil all complexities of body efforts. This study was aimed at determining two nonlinear dynamics parameters (fractal dimension (FD) and largest Lyapunov exponent (LLE)) in addition to the linear standing metrics of balance in perturbed stance. Sixteen healthy young males were subjected to sudden rotations of the standing platform. The vision and cognition during the standing were also interfered. Motion capturing was used to measure the lower limb joints and the CoM displacements. The CoM path length as a linear parameter was increased by elimination of vision (p<0.01) and adding a cognitive load (p<0.01). The CoM nonlinear metric FD was decreased due to the cognitive loads (p<0.001). The visual interference increased the FD of all joints when the task included the cognitive loads (p<0.01). The slightly positive LLE values showed weakly-chaotic behavior of the whole body. The local joint rotations indicated higher LLEs. Results indicated weakly chaotic response of the whole body. Increase in the task difficulty by adding sensory interference had difference effects on parameters. Linear and nonlinear metrics of the perturbed stance showed that a combination of them may properly represent the body behavior.

Sensory responses in the medial prefrontal cortex of anesthetized rats. Implications for sensory processing

The medial prefrontal cortex (mPFC) plays a key role in higher functions such as memory and attention. In order to demonstrate sensory responses in the mPFC, we used electrophysiological recordings of urethane-anesthetized rats to record somatosensory-evoked potentials (SEPs) or auditory-evoked potentials (AEPs) elicited by whisker deflections and click stimulation, respectively. Contralateral whisker stimulation or auditory stimuli were also applied to study sensory interference in the mPFC. Interference with other sensory stimuli or recent stimulation history reduced whisker responses in the infralimbic and prelimbic cortices of the ventral mPFC. This effect could be mediated by activation of parvalbumin (PV) interneurons since the effect was blocked by the P/Q calcium channel antagonist ω-agatoxin. In contrast, sensory interference or the recent stimulation history was not detected by the dorsal mPFC or the primary somatosensory cortex. Results obtained from retrograde tracer injections in the dorsal and ventral regions of the mPFC indicated that somatosensory and auditory sensory inputs may arrive at the dorsal mPFC through secondary sensory cortical areas, and through the insular and temporal cortical areas. The ventral mPFC may receive sensory information through the strong anatomical connections between the dorsal and ventral mPFC areas. In conclusion, results suggest mPFC plays an important role in sensory processing, which may have important implications in attentional and memory processes.

Gamma and Beta Bursts Underlie Working Memory

Working memory is thought to result from sustained neuron spiking. However, computational models suggest complex dynamics with discrete oscillatory bursts. We analyzed local field potential (LFP) and spiking from the prefrontal cortex (PFC) of monkeys performing a working memory task. There were briefbursts of narrow-band gamma oscillations (45-100Hz), varied in time and frequency, accompanying encoding and re-activation of sensory information. They appeared at a minority of recording sites associated with spiking reflecting the to-be-remembered items. Beta oscillations (20-35Hz) also occurred in brief, variable bursts but reflected a default state interrupted by encoding and decoding. Only activity of neurons reflecting encoding/decoding correlated with changes in gamma burst rate. Thus, gamma bursts could gate access to, and prevent sensory interference with, working memory. This supports the hypothesis that working memory is manifested by discrete oscillatory dynamics and spiking, not sustained activity.

Odors enhance slow-wave activity in non-rapid eye movement sleep.

Most forms of suprathreshold sensory stimulation perturb sleep. In contrast, presentation of pure olfactory or mild trigeminal odorants does not lead to behavioral or physiological arousal. In fact, some odors promote objective and subjective measures of sleep quality in humans and rodents. The brain mechanisms underlying these sleep-protective properties of olfaction remain unclear. Slow oscillations in the electroencephalogram (EEG) are a marker of deep sleep, and K complexes (KCs) are an EEG marker of cortical response to sensory interference. We therefore hypothesized that odorants presented during sleep will increase power in slow EEG oscillations. Moreover, given that odorants do not drive sleep interruption, we hypothesized that unlike other sensory stimuli odorants would not drive KCs. To test these hypotheses we used polysomnography to measure sleep in 34 healthy subjects (19 women, 15 men; mean age 26.5 ± 2.5 yr) who were repeatedly presented with odor stimuli via a computer-controlled air-dilution olfactometer over the course of a single night. Each participant was exposed to one of four odorants, lavender oil (n = 13), vetiver oil (n = 5), vanillin (n = 12), or ammonium sulfide (n = 4), for durations of 5, 10, and 20 s every 9-15 min. Consistent with our hypotheses, we found that odor presentation during sleep enhanced the power of delta (0.5-4 Hz) and slow spindle (9-12 Hz) frequencies during non-rapid eye movement sleep. The increase was proportionate to odor duration. In addition, odor presentation did not modulate the occurrence of KCs. These findings imply a sleep-promoting olfactory mechanism that may deepen sleep through driving increased slow-frequency oscillations.

Top-Down Control of Visual Alpha Oscillations: Sources of Control Signals and Their Mechanisms of Action.

Alpha oscillations (8–12 Hz) are thought to inversely correlate with cortical excitability. Goal-oriented modulation of alpha has been studied extensively. In visual spatial attention, alpha over the region of visual cortex corresponding to the attended location decreases, signifying increased excitability to facilitate the processing of impending stimuli. In contrast, in retention of verbal working memory, alpha over visual cortex increases, signifying decreased excitability to gate out stimulus input to protect the information held online from sensory interference. According to the prevailing model, this goal-oriented biasing of sensory cortex is effected by top-down control signals from frontal and parietal cortices. The present study tests and substantiates this hypothesis by (a) identifying the signals that mediate the top-down biasing influence, (b) examining whether the cortical areas issuing these signals are task-specific or task-independent, and (c) establishing the possible mechanism of the biasing action. High-density human EEG data were recorded in two experimental paradigms: a trial-by-trial cued visual spatial attention task and a modified Sternberg working memory task. Applying Granger causality to both sensor-level and source-level data we report the following findings. In covert visual spatial attention, the regions exerting top-down control over visual activity are lateralized to the right hemisphere, with the dipoles located at the right frontal eye field (FEF) and the right inferior frontal gyrus (IFG) being the main sources of top-down influences. During retention of verbal working memory, the regions exerting top-down control over visual activity are lateralized to the left hemisphere, with the dipoles located at the left middle frontal gyrus (MFG) being the main source of top-down influences. In both experiments, top-down influences are mediated by alpha oscillations, and the biasing effect is likely achieved via an inhibition-disinhibition mechanism.

Load-Dependent Increases in Alpha-Band Power: Relevance to Sensory Cortex Excitability and Distractor Interference

Load-Dependent Increases in Alpha-Band Power: Relevance to Sensory Cortex Excitability and Distractor Interference

Distinguishing Feigned From Sincere Performance in Psychophysical Pain Testing

Self-report, the most widely used, gold standard measurement of pain, is crucial for pain research, diagnosis, and management. However, there are no accurate, reliable methods for detecting dishonesty in self-reports when there is incentive for pain deception. We introduce a novel approach to detecting pain deception by analyzing performance patterns of honest and dishonest psychophysical pain testing. Warmth sensation threshold (WST) and heat pain threshold (HPT) were measured in healthy individuals (N = 37) under 2 conditions: standard instruction (ie, provide sincere reports) and instructions to simulate intense pain (ie, provide feigned reports) with the intention of deceiving. In the feigned compared with sincere condition, participants had significantly increased WST and decreased HPT. Repeatability and variability indices were indistinguishable between conditions. In a second, separate cohort (N = 24), measurements were repeated with the addition of a sensory interference to influence task performance. When sensory interference during HPT measurement was introduced, feigned pain reports had significantly higher variability and poorer repeatability compared with sincere reports and were distinguishable from sincere reports, with high sensitivity (83%) and specificity (84%). The statistical properties of psychophysical performance under sensory interference provide a method for identifying feigned performance and could be applied to evaluations of pain malingering. PerspectiveThis article introduces a method to detect whether individuals are being dishonest in psychophysical pain testing. The method could help clinicians to detect chronic pain malingering in contexts in which there is incentive to deceive.

On-board recordings reveal no jamming avoidance in wild bats.

Animals often deal with situations in which vast sensory input is received simultaneously. They therefore must possess sophisticated mechanisms to select important input and ignore the rest. In bat echolocation, this problem is at its extreme. Echolocating bats emit sound signals and analyse the returning echoes to sense their environment. Bats from the same species use signals with similar frequencies. Nearby bats therefore face the difficulty of distinguishing their own echoes from the signals of other bats, a problem often referred to as jamming. Because bats commonly fly in large groups, jamming might simultaneously occur from numerous directions and at many frequencies. Jamming is a special case of the general phenomenon of sensory segregation. Another well-known example is the human problem of following conversation within a crowd. In both situations, a flood of auditory incoming signals must be parsed into important versus irrelevant information. Here, we present a novel method, fitting wild bats with a miniature microphone, which allows studying jamming from the bat's 'point of view'. Previous studies suggested that bats deal with jamming by shifting their echolocation frequency. On-board recordings suggest otherwise. Bats shifted their frequencies, but they did so because they were responding to the conspecifics as though they were nearby objects rather than avoiding being jammed by them. We show how bats could use alternative measures to deal with jamming instead of shifting their frequency. Despite its intuitive appeal, a spectral jamming avoidance response might not be the prime mechanism to avoid sensory interference from conspecifics.

Sensory and response interference is resolved locally

Sensory and response interference is resolved locally

The onset of data-driven mental archeology.

The onset of data-driven mental archeology.

Modulation of the N30 generators of the somatosensory evoked potentials by the mirror neuron system

The N30 component of the somatosensory evoked potential is known to be modulated by sensory interference, motor action, movement ideation and observation. We introduce a new paradigm in which the observation task of another person's hand movement triggers the somatosensory stimulus, inducing the N30 response in participants. In order to identify the possible contribution of the mirror neuron network (MNN) to this early sensorimotor processing, we analyzed the N30 topography, the event-related spectral perturbation and the inter-trial coherence on single electroencephalogram (EEG) trials, and we applied swLORETA to localize the N30 sources implicated in the time–frequency domain at rest and during observation, as well as the generators differentiating these two contextual brain states. We found that N30 amplitude increase correlated with increased contralateral precentral alpha, frontal beta, and contralateral frontal gamma power spectrum, and with central and precentral alpha and parietal beta phase-locking of ongoing EEG signals. We demonstrate specific activation of the contralateral post-central and parietal cortex where the angular gyrus (BA39), an important MNN node, is implicated in this enhancement during observation. We conclude that this part of the MNN, involved in proprioceptive processing and more complex body-action representations, is already active prior to somatosensory input and may enhance N30.

TMS-induced neural noise in sensory cortex interferes with short-term memory storage in prefrontal cortex

In a previous study, Harris et al. (2002) found disruption of vibrotactile short-term memory after applying single-pulse transcranial magnetic stimulation (TMS) to primary somatosensory cortex (SI) early in the maintenance period, and suggested that this demonstrated a role for SI in vibrotactile memory storage. While such a role is compatible with recent suggestions that sensory cortex is the storage substrate for working memory, it stands in contrast to a relatively large body of evidence from human EEG and single-cell recording in primates that instead points to prefrontal cortex as the storage substrate for vibrotactile memory. In the present study, we use computational methods to demonstrate how Harris et al.'s results can be reproduced by TMS-induced activity in sensory cortex and subsequent feedforward interference with memory traces stored in prefrontal cortex, thereby reconciling discordant findings in the tactile memory literature.

An adaptive filter model of cerebellar zone C3 as a basis for safe limb control?

The review asks how the adaptive filter model of the cerebellum might be relevant to experimental work on zone C3, one of the most extensively studied regions of cerebellar cortex. As far as features of the cerebellar microcircuit are concerned, the model appears to fit very well with electrophysiological discoveries concerning the importance of molecular layer interneurons and their plasticity, the significance of long-term potentiation and the striking number of silent parallel fibre synapses. Regarding external connectivity and functionality, a key feature of the adaptive filter model is its use of the decorrelation algorithm, which renders it uniquely suited to problems of sensory noise cancellation. However, this capacity can be extended to the avoidance of sensory interference, by appropriate movements of, for example, the eyes in the vestibulo-ocular reflex. Avoidance becomes particularly important when painful signals are involved, and as the climbing fibre input to zone C3 is extremely responsive to nociceptive stimuli, it is proposed that one function of this zone is the avoidance of pain by, for example, adjusting movements of the body to avoid self-harm. This hypothesis appears consistent with evidence from humans and animals concerning the role of the intermediate cerebellum in classically conditioned withdrawal reflexes, but further experiments focusing on conditioned avoidance are required to test the hypothesis more stringently. The proposed architecture may also be useful for automatic self-adjusting damage avoidance in robots, an important consideration for next generation 'soft' robots designed to interact with people.

Memory for Words Representing Modal Concepts

The recent grounded cognition literature suggests that modal perception and conceptual representations share common modal systems and modal resources. We sought to show that memory and memory of words predominantly related to a visual modality (e.g., Light) or to an auditory modality (e.g., Song) are hindered more by sensory interference from a related than an unrelated modality. This result cannot be explained by semantic interference, because the present study manipulated interference using meaningless stimuli. Rather, we suggest that people spontaneously access conceptual sensory attributes when detecting words and when trying to memorize words, and that this process comes with modality-specific costs. We discuss this finding in the broader context of grounded cognition and compare it to previous findings using closely related sensory-conceptual designs.

Single degree-of-freedom exoskeleton mechanism design for thumb rehabilitation.

This paper presents the kinematic design of a spatial, 1-degree-of-freedom closed linkage to be used as an exoskeleton for thumb motion. Together with an already-designed finger mechanism, it forms a robotic device for hand therapy. The goal for the exoskeleton is to generate the desired grasping and pinching path of the thumb with one degree of freedom, rather than using a system actuating all its joints independently. In addition to the path of the thumb, additional constraints are added in order to control the position and size of the exoskeleton, reducing physical and sensory interference with the user.

Sleep's Influence on a Reflexive Form of Memory That Does Not Require Voluntary Attention

Studies to date have examined the influence of sleep on forms of memory that require voluntary attention. The authors examine the influence of sleep on a form of memory that is acquired by passive viewing. Induction of the McCollough effect, and measurement of perceptual color bias before and after induction, and before and after intervening sleep, wake, or visual deprivation. Sound-attenuated sleep research room. 13 healthy volunteers (mean age = 23 years; age range = 18-31 years) with normal or corrected-to-normal vision. N/A. ) ENCODING: sleep preceded adaptation. On separate nights, each participant slept for an average of 0 (wake), 1, 2, 4, or 7 hr (complete sleep). Upon awakening, the participant's baseline perceptual color bias was measured. Then, he or she viewed an adapter consisting of alternating red/horizontal and green/vertical gratings for 5 min. Color bias was remeasured. The strength of the aftereffect is the postadaptation color bias relative to baseline. A strong orientation contingent color aftereffect was observed in all participants, but total sleep duration (TSD) prior to the adaptation did not modulate aftereffect strength. Further, prior sleep provided no benefit over prior wake. Retention: sleep followed adaptation. The procedure was similar except that adaptation preceded sleep. Postadaptation sleep, irrespective of its duration (1, 3, 5, or 7 hr), arrested aftereffect decay. By contrast, aftereffect decay was arrested during subsequent wake only if the adapted eye was visually deprived. Sleep as well as passive sensory deprivation enables the retention of a color aftereffect. Sleep shelters this reflexive form of memory in a manner akin to preventing sensory interference.

Diffusion modeling of interference in vibrotactile working memory

The nature of interference in working memory has been a subject of discussion for decades. It has previously been argued that irrelevant stimuli can interfere with working memory by being encoded into memory. Previous findings have suggested that irrelevant sensory activity can interfere with the storage of information in tactile working memory. More recently, it has been suggested that this type of interference may operate through the overwriting of stored information by interfering sensory stimuli, even when participants are instructed to ignore such stimuli. Such a mechanism of interference is consistent with previous theoretical proposals. In the present study, we use a computational diffusion model to demonstrate that previous empirical findings are best explained by the encoding of irrelevant sensory information and subsequent interference.