Multisensory Integration Processes Research Articles

The Influence of Diabetes on Multisensory Integration and Mobility in Aging.

(1) Background: one out of every four adults over the age of 65 are living with diabetes, and this alarming rate continues to increase with age. Diabetes in older adults is associated with many adverse health outcomes, including sensory and motor impairments. The objective of this exploratory study was to determine whether diabetes influences the interplay between multisensory integration processes and mobility in aging. (2) Methods: in this cross-sectional observational study, we recruited 339 non-demented older adults (76.59 ± 6.21 years; 52% female, 18% with diabetes). Participants completed a simple reaction time test in response to visual, somatosensory, and combined visual-somatosensory stimulation. Magnitude of visual-somatosensory integration was computed and served as the independent variable. (3) Results: logistic regression revealed that presence of diabetes was inversely associated with the magnitude of visual-somatosensory integration (β = −3.21; p < 0.01). Further, mediation models revealed that presence of diabetes negatively influenced the relationship of visual–somatosensory integration magnitude with balance (95% CI −0.16, −0.01) and gait (95% CI −0.09, −0.01). Participants with diabetes and taking insulin (n = 14) failed to integrate sensory information entirely; (4) conclusions: taken together, results from this exploration provide compelling evidence to support the adverse effect of diabetes on both multisensory and motor functioning in older adults.

Interoception and Empathy Impact Perspective Taking

Adopting the perspective of another person is an important aspect of social cognition and has been shown to depend on multisensory signals from one’s own body. Recent work suggests that interoceptive signals not only contribute to own-body perception and self-consciousness, but also to empathy. Here we investigated if social cognition – in particular adopting the perspective of another person – can be altered by a systematic manipulation of interoceptive cues and further, if this effect depends on empathic ability. The own-body transformation task (OBT) – wherein participants are instructed to imagine taking the perspective and position of a virtual body presented on a computer screen – offers an effective way to measure reaction time differences linked to the mental effort of taking an other’s perspective. Here, we adapted the OBT with the flashing of a silhouette surrounding the virtual body, either synchronously or asynchronously with the timing of participants’ heartbeats. We evaluated the impact of this cardio-visual synchrony on reaction times and accuracy rates in the OBT. Empathy was assessed with the empathy quotient (EQ) questionnaire. Based on previous work using the cardio-visual paradigm, we predicted that synchronous (vs. asynchronous) cardio-visual stimulation would increase self-identification with the virtual body and facilitate participants’ ability to adopt the virtual body’s perspective, thereby enhancing performance on the task, particularly in participants with higher empathy scores. We report that participants with high empathy showed significantly better performance during the OBT task during synchronous versus asynchronous cardio-visual stimulation. Moreover, we found a significant positive correlation between empathic ability and the synchrony effect (the difference in reaction times between the asynchronous and synchronous conditions). We conclude that synchronous cardio-visual stimulation between the participant’s body and a virtual body during an OBT task makes it easier to adopt the virtual body’s perspective, presumably based on multisensory integration processes. However, this effect depended on empathic ability, suggesting that empathy, interoception and social perspective taking are inherently linked.

Virtual reality alters cortical oscillations related to visuo-tactile integration during rubber hand illusion

Virtual reality (VR) enables the fast, free, and highly controllable setting of experimental body images. Illusions pertaining to a body, such as the rubber hand illusion (RHI), can be easily conducted in VR settings, and some phenomena, such as full-body illusions, are only realized in virtual environments. However, the multisensory-integration process in VR is not yet fully understood. Thus, it remains to be clarified if specific phenomena that occur under VR settings manifest in real life as well. One useful investigative approach is measuring brain activities during a psychological experiment. Electroencephalography (EEG) oscillatory activities provide insight into the human multisensory integration process. Nevertheless, EEG data can be vulnerable to VR noise, which causes measurement and analytical difficulties for EEG data recorded in VR environments. Here, we achieve an experimental RHI setting using a head-mounted display that provides a VR visual space and VR dummy hand along with EEG measurements. We compared EEG data collected in both real and VR environments and observed the gamma and theta band oscillatory activities. Ultimately, we observed statistically significant differences between congruent (RHI) and incongruent (not RHI) conditions in the real environment, which is consistent with previous studies. Differences in the VR condition were observed only on the late theta band oscillation, suggesting that the VR setting itself altered the perceptual and sensory integration mechanisms. Thus, we must model this difference between real and VR settings whenever we use VR to investigate our bodily self-perception.

Multisensory Integration and Sense Modalism

The Bayesian model of multisensory cue integration proposed by Ernst and Banks ([2002]) provides an attractive model for understanding a way that our sensory systems may interact. Moreover, it has been suggested that the process of multisensory integration that it models underpins conscious experiences with multisensory representational contents merged across modalities (de Vignemont [2014b]). Should we therefore take empirical support for the Bayesian model as evidence of the multimodality of perception? Focusing on evidence of integration across vision and touch, I argue that apparent support for the model does not warrant the rejection of the view that each of our conscious perceptual experiences is associated with one and only one sense modality.

Schizotypal traits are not related to multisensory integration or audiovisual speech perception.

Multisensory integration, the binding of sensory information from different sensory modalities, may contribute to perceptual symptomatology in schizophrenia, including hallucinations and aberrant speech perception. Differences in multisensory integration and temporal processing, an important component of multisensory integration, are consistently found in schizophrenia. Evidence is emerging that these differences extend across the schizophrenia spectrum, including individuals in the general population with higher schizotypal traits. In the current study, we investigated the relationship between schizotypal traits and perceptual functioning, using audiovisual speech-in-noise, McGurk, and ternary synchrony judgment tasks. We measured schizotypal traits using the Schizotypal Personality Questionnaire (SPQ), hypothesizing that higher scores on Unusual Perceptual Experiences and Odd Speech subscales would be associated with decreased multisensory integration, increased susceptibility to distracting auditory speech, and less precise temporal processing. Surprisingly, these measures were not associated with the predicted subscales, suggesting that these perceptual differences may not be present across the schizophrenia spectrum.

Altered local and distant functional connectivity density in chronic migraine: a resting-state functional MRI study.

Previous studies have indicated disrupted functional connectivity in multiple brain regions and resting-state networks in episodic migraine, but it is unclear how brain network property is disrupted in chronic migraine. Using resting-state functional magnetic resonance imaging and voxel-wise functional connectivity density analysis, we examined the large-scale functional connectivity pattern over the whole brain in 17 patients with chronic migraine without medication overuse compared to 35 healthy controls. The associations between functional connectivity density and clinical variables were also explored. Compared with controls, chronic migraine patients showed decreased local and distant functional connectivity density in the dorsolateral and medial prefrontal cortexes and precuneus and increased local and distant functional connectivity density in the hippocampal complex. The patients also presented increased local functional connectivity density in the orbital frontal gyrus and cerebellum and increased distant functional connectivity density in the temporal pole. Moreover, local functional connectivity density in several brain regions, such as the left superior temporal gyrus and dorsal anterior cingulate cortex, was found to be correlated with headache frequency or pain intensity. Chronic migraine is associated with functional connectivity alterations in regions involved in multisensory integration, affective and cognitive processing, and pain modulation. Both local and distant functional connectivity density are complementary biomarkers for investigating the neural mechanism of this disorder. Some local functional connectivity density alterations may be useful for assessing the disease burden of chronic migraine.

Study of postural control and body balance in subjects with Down syndrome

PurposeBody imbalance and poor postural control have negative impact on gait and may increase the risk of falling in healthy individuals as well as those with Down syndrome (DS). Since people with DS have lower physical levels than people who do not present this condition, the purpose of our research was to compare features of postural control and body balance between subjects affected by DS and a control sampleMethodsParticipants enrolled were divided into the following two groups: a DS group (DSG; &lt;i&gt;n&lt;/i&gt; = 22; 9 females and 13 males; age range: 16–36 years) and an age-matched control group (CG; &lt;i&gt;n&lt;/i&gt; = 25; 11 females and 14 males; age range: 16–36 years). All participants were subjected to two stabilometric tests: eyes open (EO) and eyes closed (EC), 30 s each, in bipedal upright stance on a platformResultsThe main results showed significantly higher values for the ellipse sway area in DSG compared with CG, both in the EO (&lt;i&gt;p&lt;/i&gt; = 0.009) and in the EC trial (&lt;i&gt;p&lt;/i&gt; = 0.000). Moreover, significantly higher values were revealed for the sway path length (&lt;i&gt;p&lt;/i&gt; = 0.013), maximum speed of sway (&lt;i&gt;p&lt;/i&gt; = 0.001), and average speed of sway (&lt;i&gt;p&lt;/i&gt; = 0.046) in the EC than in the EO trial.ConclusionsWe infer that a delay in multi-sensory integration processes in the nervous system for controlling body posture could underlie lower body balance in DS.

Performing a task jointly enhances the sound-induced flash illusion.

Our senses are stimulated continuously. Through multisensory integration, different sensory inputs may or may not be combined into a unitary percept. Simultaneous with this stimulation, people are frequently engaged in social interactions, but how multisensory integration and social processing interact is largely unknown. The present study investigated if, and how, the multisensory sound-induced flash illusion is affected by a social manipulation. In the sound-induced flash illusion, a participant typically receives one visual flash and two auditory beeps and she or he is required to indicate the number of flashes that were perceived. Often, the auditory beeps alter the perception of the flashes such that a participant tends to perceive two flashes instead of one flash. We tested whether performing a flash counting task with a partner (confederate), who was required to indicate the number of presented beeps, would modulate this illusion. We found that the sound-induced flash illusion was perceived significantly more often when the flash counting task was performed with the confederate compared with performing it alone. Yet, we no longer find this effect if visual access between the two individuals is prevented. These findings, combined with previous results, suggest that performing a multisensory task jointly-in this case an audiovisual task-lowers the extent to which an individual attends to visual information, which in turn affects the multisensory integration process.

The Virtual Hand Illusion in Obesity: Dissociation Between Multisensory Interactions Supporting Illusory Experience and Self-Location Recalibration.

The Rubber Hand Illusion (RHI) is used widely to investigate the multisensory integration mechanisms that support bodily self-consciousness and, more specifically, body ownership and self-location. It has been reported that individuals affected by obesity show anomalous multisensory integration processes. We propose that these obesity-induced changes could lead to an unusual susceptibility to the RHI and anomalous bodily self-experience. To test this hypothesis, we administered a modified version of the RHI (using a picture of the participant's hand) to individuals affected by obesity and participants with a healthy weight. During synchronous and asynchronous stimulation, we compared the subjective experience of the illusion (using a questionnaire) and the effect of the illusion on self-location (i.e., proprioceptive drift). In accordance with the illusion phenomenology, both groups had a comparable subjective illusory experience after the synchronous stimulation. Nevertheless, individuals affected by obesity showed less recalibration of self-location than healthy weight participants. In light of a recent interpretation of the multisensory integration mechanisms that underpin the RHI, our findings suggest that in obesity visuo-tactile integration supporting the subjective experience of the illusion is preserved, whereas visuo-proprioceptive integration for self-location is reduced.

Neuroimaging investigation of memory changes in migraine: a systematic review.

Individuals with migraine usually complain about lower memory performance. Diagnostic methods such as neuroimaging may help in the understanding of possible morphologic and functional changes related to the memory of those individuals. Therefore, the aim of this review is to analyze the available literature on neuroimaging changes related to memory processing in migraine. We searched the following databases: Pubmed/Medline, Psycinfo, Science Direct, Cochrane and Web of Science. We used articles without restriction of year of publication. The combination of descriptors used for this systematic review of literature were Neuroimaging OR Imaging OR Brain AND Migraine OR Chronic Migraine AND Memory. Of the 306 articles found, nine were selected and all used magnetic resonance imaging (MRI). The studies used structural and functional MRI techniques with a predominance of 3 Tesla equipment and T1-weighted images. According to the results obtained reported by these studies, migraine would alter the activity of memory-related structures, such as the hippocampus, insula and frontal, parietal and temporal cortices, thereby suggesting a possible mechanism by which migraine would influence memory, especially in relation to the memory of pain. Migraine is associated to global dysfunction of multisensory integration and memory processing. This condition changes the activity of structures in various regions related to memory of pain, prospective memory, as well as in short- and long-term verbal and visuospatial memories. However, it is necessary to perform studies with larger samples in association with cognitive tests, and without the interference of medications to verify possible alterations and to draw more concrete conclusions.

Multisensory Integration Develops Prior to Crossmodal Recalibration.

It has been hypothesized that crossmodal recalibration plays a crucial role for the development of multisensory integration capabilities [1]. To test the developmental trajectory of multisensory integration and crossmodal recalibration, we used a combined ventriloquist/ventriloquist aftereffect paradigm [2] in children aged 5-9 years. The ventriloquist effect (indicating multisensory integration), that is, the shift of auditory localization toward simultaneously presented but spatially discrepant visual stimuli, was larger in children than in adults, which was attributed to a lower auditory localization precision in the children. In fact, the size of the ventriloquist effect depended on the visual stimulus reliability in both children and adults. In all groups, the ventriloquist effect was best explained by a causal inference model. In contrast to their multisensory integration capabilities, 5-year-old children did not recalibrate. The immediate ventriloquist aftereffect (indicating recalibration after a single exposure to a spatially discrepant audio-visual stimulus) emerged in 6- to 7-year-old children, whereas the cumulative ventriloquist aftereffect (reflecting recalibration to the audio-visual spatial discrepancies over the complete experiment) was not observed before the age of 8 years. First, in contrast to common beliefs, the present results provide evidence that multisensory integration precedes rather than follows crossmodal recalibration during development. Second, we report developmental evidence for a dissociation of the processes involved in multisensory integration and immediate as well as cumulative recalibration. We speculate that multisensory integration is a prerequisite for crossmodal recalibration, because the multisensory percept, rather than unimodal cues, might comprise a crucial signal for the calibration of the sensory systems.

Audiovisual Integration During Joint Action: No Effects for Motion Discrimination and Temporal Order Judgment Tasks.

In daily life, humans constantly process information from multiple sensory modalities (e.g., visual and auditory). Information across sensory modalities may (or may not) be combined to form the perception of a single event via the process of multisensory integration. Recent research has suggested that performing a spatial crossmodal congruency task jointly with a partner affects multisensory integration. To date, it has not been investigated whether multisensory integration in other crossmodal tasks is also affected by performing a task jointly. To address this point, we investigated whether joint task performance also affects perceptual judgments in a crossmodal motion discrimination task and a temporal order judgment task. In both tasks, pairs of participants were presented with auditory and visual stimuli that might or might not be perceived as belonging to a single event. Each participant in a pair was required to respond to stimuli from one sensory modality only (e.g., visual stimuli only). Participants performed both individual and joint conditions. Replicating earlier multisensory integration effects, we found that participants' perceptual judgments were significantly affected by stimuli in the other modality for both tasks. However, we did not find that performing a task jointly modulated these crossmodal effects. Taking this together with earlier findings, we suggest that joint task performance affects crossmodal results in a manner dependent on how these effects are quantified (i.e., via responses time or accuracy) and the specific task demands (i.e., whether tasks require processing stimuli in terms of location, motion, or timing).

Emotional information affects fission illusion induced by audio-visual interactions

Multisensory integration is affected by various types of information coming from different sensory stimuli. It has been suggested that emotional information also influences the multisensory integration process. The perceptual phenomena induced by audio-visual integration are modulated by emotional signals through changing individuals’ emotional states. However, the direct effects of emotional information, without changing emotional states on the multisensory integration process have not yet been examined. The present study investigated the effects of an emotional signal on audio-visual integration. The experiments compared the magnitude of audio-visual fission and fusion illusions using facial expression stimuli and simple geometric shapes. Facial expression stimuli altered the criterion difference for discerning the number of flashes when two beeps were simultaneously presented in Experiment 1. These stimuli did not affect the fission illusion’s magnitude. For simple geometric shapes, emotional shapes perceptually induced a larger fission illusion in Experiment 2. The present study found that the emotional valence included in simple geometric shapes induced a larger fission illusion. Moreover, current results suggest that emotional faces modulate response criterion for fission illusion in discernment of the number of flashes. Future studies should elucidate in detail the mechanism of emotional valence effects on audio-visual integration.

Resting-State Functional Connectivity of the Thalamus in Complete Spinal Cord Injury

Background. Neuroimaging studies of spinal cord injury (SCI) have mostly examined the functional organization of the cortex, with only limited focus on the subcortical substrates of the injury. However, thalamus is an important modulator and sensory relay that requires investigation at a subnuclei level to gain insight into the neuroplasticity following SCI. Objective. To use resting-state functional magnetic resonance imaging to examine the functional connectivity (FC) of thalamic subnuclei in complete SCI patients. Methods. A seed-based connectivity analysis was applied for 3 thalamic subnuclei: pulvinar, mediodorsal, and ventrolateral nucleus in each hemisphere. A nonparametric 2-sample t test with permutations was applied for each of the 6 thalamic seeds to compute FC differences between 22 healthy controls and 19 complete SCI patients with paraplegia. Results. Connectivity analysis showed a decrease in the FC of the bilateral mediodorsal nucleus with right superior temporal gyrus and anterior cingulate cortex in the SCI group. Similarly, the left ventrolateral nucleus exhibited decreased FC with left superior temporal gyrus in SCI group. In contrast, left pulvinar nucleus demonstrated an increase in FC with left inferior frontal gyrus and left inferior parietal lobule in SCI group. Our findings also indicate a negative relationship between postinjury durations and thalamic FC to regions of sensorimotor and visual cortices, where longer postinjury durations (~12 months) is associated with higher negative connectivity between these regions. Conclusion. This study provides evidence for reorganization in the thalamocortical connections known to be involved in multisensory integration and affective processing, with possible implications in the generation of sensory abnormalities after SCI.

Welcoming back my arm: affective touch increases body ownership following right-hemisphere stroke.

Right-hemisphere stroke can impair the ability to recognize one’s contralesional body parts as belonging to one’s self. The study of this so-called ‘disturbed sense of limb ownership’ can provide unique insights into the neurocognitive mechanisms of body ownership. In this study, we address a hypothesis built upon experimental studies on body ownership in healthy volunteers. These studies have shown that affective (pleasant) touch, an interoceptive modality associated with unmyelinated, slow-conducting C-tactile afferents, has a unique role in the sense of body ownership. In this study, we systematically investigated whether affective touch stimulation could increase body ownership in patients with a disturbed sense of limb ownership following right-hemisphere stroke. An initial feasibility study in 16 adult patients with acute stroke enabled us to optimize and calibrate an affective touch protocol to be administered by the bedside. The main experiment, conducted with a different sample of 26 right hemisphere patients, assessed changes in limb ownership elicited following self- (patient) versus other- (experimenter) generated tactile stimulation, using a velocity known to optimally activate C-tactile fibres (i.e. 3 cm/s), and a second velocity that is suboptimal for C-tactile activation (i.e. 18 cm/s). We further examined the specificity and mechanism of observed changes in limb ownership in secondary analyses looking at (i) the influence of perceived intensity and pleasantness of touch, (ii) touch laterality and (iii) level of disturbed sense of limb ownership on ownership change and (iv) changes in unilateral neglect arising from touch. Findings indicated a significant increase in limb ownership following experimenter-administered, C-tactile-optimal touch. Voxel-based lesion-symptom mapping identified damage to the right insula and, more substantially, the right corpus callosum, associated with a failure to increase body ownership following experimenter-administered, affective touch. Our findings suggest that affective touch can increase the sense of body-part ownership following right-hemisphere stroke, potentially due to its unique role in the multisensory integration processes that underlie the sense of body ownership.

Prefrontal and posterior parietal contributions to the perceptual awareness of touch

Which brain regions contribute to the perceptual awareness of touch remains largely unclear. We collected structural magnetic resonance imaging scans and neurological examination reports of 70 patients with brain injuries or stroke in S1 extending into adjacent parietal, temporal or pre-/frontal regions. We applied voxel-based lesion-symptom mapping to identify brain areas that overlap with an impaired touch perception (i.e., hypoesthesia). As expected, patients with hypoesthesia (n = 43) presented lesions in all Brodmann areas in S1 on postcentral gyrus (BA 1, 2, 3a, 3b). At the anterior border to BA 3b, we additionally identified motor area BA 4p in association with hypoesthesia, as well as further ventrally the ventral premotor cortex (BA 6, BA 44), assumed to be involved in whole-body perception. At the posterior border to S1, we found hypoesthesia associated effects in attention-related areas such as the inferior parietal lobe and intraparietal sulcus. Downstream to S1, we replicated previously reported lesion-hypoesthesia associations in the parietal operculum and insular cortex (i.e., ventral pathway of somatosensory processing). The present findings extend this pathway from S1 to the insular cortex by prefrontal and posterior parietal areas involved in multisensory integration and attention processes.

LINKING VISUAL-SOMATOSENSORY INTEGRATION TO COGNITIVE AND MOTOR OUTCOMES IN AGING

Ability to successfully integrate simultaneous information relayed across multiple sensory systems is an integral aspect of daily functioning. Unisensory impairments have been individually linked to slower gait, functional decline, and increased risks for falls in aging. Yet, research investigating age-related changes in multisensory integration (MSI) processes still remains relatively scarce. To date, there has been converging evidence for larger behavioral multisensory effects in older compared to younger adults; however, the question of whether larger effects are actually beneficial remains largely unanswered. Findings from our studies provide support for differential multisensory processing in aging, where decreased magnitude of visual-somatosensory integration was associated with worse balance, increased falls, and slower gait. Furthermore, we established a link between visual-somatosensory integration and cognition in aging. That is, magnitude of visual-somatosensory integration was largest in older adults with normal cognitive functioning, and presence of MCI/dementia significantly decreased magnitude of visual-somatosensory integration which in turn adversely impacted balance and gait performance. While the effect of MSI has been attributed to basic degenerative changes in neuronal architecture during the aging process, this speculative interpretation has yet to be formally tested. Future studies are clearly needed to establish the structural and functional correlates of MSI in aging, specifically visual-somatosensory integration, in order to further establish the link between differential multisensory effects with other important age-related clinical outcomes. Nevertheless, these studies stress the importance of successful MSI in aging, and highlight the need for multisensory based interventions that could potentially ameliorate disability.

Vision Does Not Necessarily Stabilize the Head in Space During Continuous Postural Perturbations.

Vision favors head stabilization in space during perturbations of standing balance. This is particularly obvious under conditions of continuous predictable perturbations as during sinusoidal antero-posterior (A-P) translations of the supporting platform. We tested here the hypothesis that under this condition the head can instead undergo large A-P oscillations, when a precision visual task is concurrently performed. We compared the head oscillations across four conditions while standing on a continuously translating platform. Eyes open (EO, no visual task), EO while reading a text fixed to the moving platform (EO-TP), EO while reading a text fixed to earth-ground (EO-TG), eyes-closed (EC). The platform translated at 0.2 and 0.6 Hz. Participants were young adult subjects, who received no particular instruction except reading the text aloud when required. Markers fixed on head, platform and text-sheet were captured by an optoelectronic device. We found that head oscillations were larger with EC than under all EO conditions. The oscillations were the least with EO and EO-TG, and intermediate with EO-TP. This was true under both low and high translation frequency, in spite of broadly smaller head oscillations at high frequency, common to all visual conditions. The distance between the head and the text was quite constant with EO-TP but fluctuated with EO-TG. The basic whole-body coordination features were moderately similar under all conditions, as assessed by the head-platform correlation coefficients and time lags. It appears that vision does not produce head stabilization in space when a concurrent visual task requiring focusing on a reading-text moving with the platform is performed. Contrary to traditional views centered on the stabilizing effect of vision under both static and dynamic conditions, the results show that head stabilization, normally ensuring a reference for inertial guidance for body balance, can be revoked by the CNS to allow performance of a non-postural task. This novel paradigm can shift long-standing views on the effect of vision on equilibrium control and be considered a potential exercise treatment for enhancing the multisensory integration process in people with balance problems.

Prefrontal-Temporal Pathway Mediates the Cross-Modal and Cognitive Reorganization in Sensorineural Hearing Loss With or Without Tinnitus: A Multimodal MRI Study.

Objective: Hearing loss, one main risk factor of tinnitus and hyperacusis, is believed to involve significant central functional abnormalities. The recruitment of the auditory cortex in non-auditory sensory and higher-order cognitive processing has been demonstrated in the hearing-deprived brain. The dorsolateral prefrontal cortex (dlPFC), which has dense anatomical connections with the auditory pathway, is known to play a crucial role in multi-sensory integration, auditory regulation, and cognitive processing. This study aimed to verify the role of the dlPFC in the cross-modal reorganization and cognitive participation of the auditory cortex in long-term sensorineural hearing loss (SNHL) by combining functional and structural measurements.Methods: Thirty five patients with long-term bilateral SNHL and 35 matched healthy controls underwent structural imaging, resting-state functional magnetic resonance imaging (rs-fMRI), diffusion tensor imaging (DTI), and neuropsychological assessments. Ten SNHL patients were with subjective tinnitus.Results: No differences in gray matter volume, spontaneous neural activity, or diffusion characteristics in the dlPFC were found between the SNHL and control groups. The functional connectivity (FC) between the dlPFC and the auditory cortex and visual areas, such as the cuneus, fusiform, lingual cortex, and calcarine sulcus was increased in patients with SNHL. ANOVA and post hoc tests revealed similar FC alterations in the SNHL patients with and without tinnitus when compared with the normal hearing controls, and SNHL patients with and without tinnitus showed no difference in the dlPFC FC. The FC in the auditory cortex was associated with the symbol digit modality test (SDMT) scores in the SNHL patients, which reflect attentional function, processing speed, and visual working memory. Hearing-related FC with the dlPFC was found in the lingual cortex. A tract-based spatial statistics (TBSS) analysis revealed decreased fractional anisotropy (FA) values, mainly in the temporal inferior fronto-occipital fasciculus (IFOF), which showed remarkable negative correlations with the mean hearing thresholds in SNHL.Conclusion: Higher functional coupling between the dlPFC and auditory and visual areas, accompanied by decreased FA along the IFOF connecting the frontal cortex and the occipito-temporal area, might mediate cross-modal plasticity via top-down regulation and facilitate the involvement of the auditory cortex in higher-order cognitive processing following long-term SNHL.

Intentional binding is unrelated to action intention.

The present study examined the role of voluntary motor commands in the subjective temporal attraction between an action and its sensory consequence termed as intentional binding. Participants either pressed a key voluntarily or involuntarily while seeing a rotating clock hand. The key press was followed by a short beep tone in some blocks of trials. Then, the position of the clock hand at action or tone occurrence was judged. Trials in which key presses and tones occurred separately provided baseline measures. A direct comparison of baseline uncorrected estimates between both action conditions indicated less binding for involuntary than for voluntary movements as reported by previous studies. However, this effect disappeared after a baseline correction and when we controlled for the temporal predictability of critical events. These results cast substantial doubts on a close link between action intention and intentional binding, but instead highlight the role of causal inference and multisensory integration processes. (PsycINFO Database Record (c) 2019 APA, all rights reserved).