A correlation-based method for extracting subject-specific components and artifacts from group-fMRI data.

We present a simple but effective correlation-based method (maxCorr) for extracting subject-specific components from group-fMRI data. The method finds signal components that correlate maximally with the data set of one subject and minimally with the data sets of the other subjects. We show that such subject-specific components are often related to movement and physiological noise (e.g. cardiac cycle, respiration). We further demonstrate that removing the most subject-specific components for each subject reduces the overall data variance and improves the statistical identification of true fMRI activations. We compare the performance of maxCorr with CompCor, a commonly used artifact-finding method in fMRI analysis. We show that maxCorr is less likely than CompCor to remove actual stimulus-related activity, especially when no information about the stimulus is available. MaxCorr operates without stimulus information and is therefore well suitable for analyses of fMRI experiments employing naturalistic stimuli, such as movies, where stimulus regressors are difficult to construct, and for brain decoding techniques benefiting from reduced subject-specific variance in each subject's data.

Spatial variability of functional brain networks in early-blind and sighted subjects.

To further the understanding how the human brain adapts to early-onset blindness, we searched in early-blind and normally-sighted subjects for functional brain networks showing the most and least spatial variabilities across subjects. We hypothesized that the functional networks compensating for early-onset blindness undergo cortical reorganization. To determine whether reorganization of functional networks affects spatial variability, we used functional magnetic resonance imaging to compare brain networks, derived by independent component analysis, of 7 early-blind and 7 sighted subjects while they rested or listened to an audio drama. In both conditions, the blind compared with sighted subjects showed more spatial variability in a bilateral parietal network (comprising the inferior parietal and angular gyri and precuneus) and in a bilateral auditory network (comprising the superior temporal gyri). In contrast, a vision-related left-hemisphere-lateralized occipital network (comprising the superior, middle and inferior occipital gyri, fusiform and lingual gyri, and the calcarine sulcus) was less variable in blind than sighted subjects. Another visual network and a tactile network were spatially more variable in the blind than sighted subjects in one condition. We contemplate whether our results on inter-subject spatial variability of brain networks are related to experience-dependent brain plasticity, and we suggest that auditory and parietal networks undergo a stronger experience-dependent reorganization in the early-blind than sighted subjects while the opposite is true for the vision-related occipital network.

Functional parcellation of the human primary somatosensory cortex to natural touch.

Despite the significance of human touch, brain responses to interpersonal manual touch have been rarely investigated. We used functional magnetic resonance imaging to study brain activity in eight healthy adults whose left hand was touched by two individuals, in separate runs and in 20-s blocks, either by holding, smoothing, or poking. Acceleration was measured from both the subject's and the touching person's hands for postimaging control of the stimuli. Independent component analysis of the functional magnetic resonance imaging data unraveled three functional networks involving the primary somatosensory cortex (SI). One network comprised the contralateral and another the ipsilateral Brodmann area 3. The third network included area 2 bilaterally, left-hemisphere middle temporal gyrus and dorsolateral prefrontal regions, ventral prefrontal cortices bilaterally, and middle cingulate cortex. The response shapes and polarities varied between the three networks. The contralateral area 3 differentiated the responses between the three types of touch stimuli, and the response magnitudes depended on the variability of the touch within each block. However, the responses of the other two networks were strikingly similar to all stimuli. The subjects' reports on the pleasantness of the touch did not correlate with the characteristics of the SI responses. These findings imply area-specific processing of the natural human touch in three networks including the SI cortex, with only area 2 connected to a functional network of brain areas that may support social interaction.

Enabling successful change in a high-demand working environment: a case study in a health care organization.

PURPOSE: The anticipation of organizational change and the transition process often creates uncertainty for employees and can lead to stress and anxiety. It is therefore essential for all organizations, especially those that operate in high-demand working environments, to support the well-being of staff throughout the change process. DESIGN/METHODOLOGY/APPROACH: Research on how employees respond to the organizational change of relocating to a new work space is limited. To fill this gap in the research, we present a case study examining the well-being of clinical and health care employees before and after a disruptive change: relocation in workplace facilities. In addition, factors that enabled successful change in this high-stress, high-demand working environment were investigated. Interviews were conducted with 20 participants before the relocation and 11 participants after relocation. Following an inductive approach, data were analyzed using thematic analysis to identify key themes. FINDINGS: Our findings suggest that a supportive team, inclusive leadership and a psychologically safe environment, may buffer negative employee well-being outcomes during disruptive organizational change. ORIGINALITY/VALUE: This research contributes to the literature on successful organizational change in health care by highlighting the resources which support well-being throughout the change process and enabling the successful transition to a new facility.

Post-disaster depression and vigilance: a functional near-infrared spectroscopy study.

The present study was designed to explore the relationships between post-disaster self-reports of depression, vigilance task performance, and frontal cerebral oxygenation. Forty participants (20 women) performed vigilance tasks following a magnitude 7.1 earthquake in Christchurch, New Zealand. In addition to performance, we measured self-reports of depression, anxiety, and stress anchored to the initial earthquake event, and frontal cerebral activity with functional near-infrared spectroscopy. Among the participants, one case may have been an outlier with extremely elevated levels of self-reported depressivity. Excluding the extreme case, there was a correlation between change in response time (response slowing) and depressivity. Including the case there was a correlation between depressivity and right hemisphere oxygenation. These results provide some support for a relationship between moderate depressivity and sustained attention difficulties.

Aberrant temporal and spatial brain activity during rest in patients with chronic pain.

In the absence of external stimuli, human hemodynamic brain activity displays slow intrinsic variations. To find out whether such fluctuations would be altered by persistent pain, we asked 10 patients with unrelenting chronic pain of different etiologies and 10 sex- and age-matched control subjects to rest with eyes open during 3-T functional MRI. Independent component analysis was used to identify functionally coupled brain networks. Time courses of an independent component comprising the insular cortices of both hemispheres showed stronger spectral power at 0.12 to 0.25 Hz in patients than in control subjects, with the largest difference at 0.16 Hz. A similar but weaker effect was seen in the anterior cingulate cortex, whereas activity of the precuneus and early visual cortex, used as a control site, did not differ between the groups. In the patient group, seed point-based correlation analysis revealed altered spatial connectivity between insulae and anterior cingulate cortex. The results imply both temporally and spatially aberrant activity of the affective pain-processing areas in patients suffering from chronic pain. The accentuated 0.12- to 0.25-Hz fluctuations in the patient group might be related to altered activity of the autonomic nervous system.

Psychotropic medications and the risk of sudden cardiac death during an acute coronary event.

AIMS: Psychotropic medication increases cardiac mortality, but the reasons for this association are not clear. We studied the role of psychotropic drugs as a triggering factor of sudden cardiac death (SCD) during an acute coronary event. METHODS AND RESULTS: The use of medication was compared between victims of SCD and survivors of an acute coronary event in a case-control study including a consecutive series of victims of SCD (n= 1814, mean age 65 ± 11 years) verified to be due to an acute coronary event at medico-legal autopsy and consecutive series of patients surviving an acute myocardial infarction (AMI; n= 1171, mean age 66 ± 12 years). The medication history was obtained from autopsy/hospital records and interviews with relatives of SCD victims and AMI patients. The use of antipsychotics [9.7 vs. 2.4%, odds ratio (OR) 4.4, 95% confidence interval (CI) 2.9-6.6; P< 0.001] and antidepressants (8.6 vs. 5.5%, OR: 1.6, 95% CI: 1.2-2.2; P= 0.003) was more common in the SCD than AMI group, but the use of benzodiazepines did not differ between the groups (11.7 vs. 13.2%; P= 0.270). The use of antipsychotics remained as a significant risk factor for SCD after adjustment for confounding variables (OR: 3.4, 95% CI: 1.8-6.5; P< 0.001). Combined use of phenothiazines and any antidepressant was associated with a very high risk of SCD (OR: 18.3, 95% CI: 2.5-135.3; P< 0.001). CONCLUSION: The use of psychotropic drugs, especially combined use of antipsychotic and antidepressant drugs, is strongly associated with an increased risk of SCD at the time of an acute coronary event.

Workplace ageism: discovering hidden bias.

UNLABELLED: BACKGROUND/STUDY CONTEXT: Research largely shows no performance differences between older and younger employees, or that older workers even outperform younger employees, yet negative attitudes towards older workers can underpin discrimination. Unfortunately, traditional "explicit" techniques for assessing attitudes (i.e., self-report measures) have serious drawbacks. Therefore, using an approach that is novel to organizational contexts, the authors supplemented explicit with implicit (indirect) measures of attitudes towards older workers, and examined the malleability of both. METHODS: This research consists of two studies. The authors measured self-report (explicit) attitudes towards older and younger workers with a survey, and implicit attitudes with a reaction-time-based measure of implicit associations. In addition, to test whether attitudes were malleable, the authors measured attitudes before and after a mental imagery intervention, where the authors asked participants in the experimental group to imagine respected and valued older workers from their surroundings. RESULTS: Negative, stable implicit attitudes towards older workers emerged in two studies. Conversely, explicit attitudes showed no age bias and were more susceptible to change intervention, such that attitudes became more positive towards older workers following the experimental manipulation. CONCLUSION: This research demonstrates the unconscious nature of bias against older workers, and highlights the utility of implicit attitude measures in the context of the workplace. In the current era of aging workforce and skill shortages, implicit measures may be necessary to illuminate hidden workplace ageism.

The effects of emotional stimuli on target detection: indirect and direct resource costs.

The present study was designed to explore the performance costs of negative emotional stimuli in a vigilance task. Forty participants (20 women) performed a vigilance task in two conditions: one with task-irrelevant negative-arousing pictures and one with task-irrelevant neutral pictures. In addition to performance, we measured subjective state (energetic arousal, tense arousal, task-related and task-unrelated thoughts) and frontal cerebral activity with near infrared spectroscopy. Overall performance in the negative picture condition was lower than in the neutral picture condition and the negative picture condition had elevated levels of energetic arousal, tense arousal and task-related thoughts. Moreover, there was a significant relationship between the impact of the negative pictures on tense arousal and task-related thoughts and the impact of the negative pictures on performance (in comparison to the neutral picture stimuli task). These results provide support for indirect cost models of negative emotional stimuli on target detection performance.

Imaging Real-Time Tactile Interaction With Two-Person Dual-Coil fMRI.

Studies of brain mechanisms supporting social interaction are demanding because real interaction only occurs when persons are in contact. Instead, most brain imaging studies scan subjects individually. Here we present a proof-of-concept demonstration of two-person blood oxygenation dependent (BOLD) imaging of brain activity from two individuals interacting inside the bore of a single MRI scanner. We developed a custom 16-channel (8 + 8 channels) two-helmet coil with two separate receiver-coil pairs providing whole-brain coverage, while bringing participants into a shared physical space and realistic face-to-face contact. Ten subject pairs were scanned with the setup. During the experiment, subjects took turns in tapping each other's lip versus observing and feeling the taps timed by auditory instructions. Networks of sensorimotor brain areas were engaged alternatingly in the subjects during executing motor actions as well as observing and feeling them; these responses were clearly distinguishable from the auditory responses occurring similarly in both participants. Even though the signal-to-noise ratio of our coil system was compromised compared with standard 32-channel head coils, our results show that the two-person fMRI scanning is feasible for studying the brain basis of social interaction.

Dependencies between stimuli and spatially independent fMRI sources: towards brain correlates of natural stimuli.

Natural stimuli are increasingly used in functional magnetic resonance imaging (fMRI) studies to imitate real-life situations. Consequently, challenges are created for novel analysis methods, including new machine-learning tools. With natural stimuli it is no longer feasible to assume single features of the experimental design alone to account for the brain activity. Instead, relevant combinations of rich enough stimulus features could explain the more complex activation patterns. We propose a novel two-step approach, where independent component analysis is first used to identify spatially independent brain processes, which we refer to as functional patterns. As the second step, temporal dependencies between stimuli and functional patterns are detected using canonical correlation analysis. Our proposed method looks for combinations of stimulus features and the corresponding combinations of functional patterns. This two-step approach was used to analyze measurements from an fMRI study during multi-modal stimulation. The detected complex activation patterns were explained as resulting from interactions of multiple brain processes. Our approach seems promising for analysis of data from studies with natural stimuli.

Investigating the structure of autobiographical memory using reaction times.

The study investigated the structure of autobiographical memory using reaction time measures. A total of 18 participants took photographs over their summer holidays and then reacted to pairs of these photographs displayed via a computer. They also subsequently sorted their photographs according to the autobiographical themes and events with which they were associated. When photographic sequence and the physical similarities in the photographs were controlled for by considering the results of "stranger" participants who were unfamiliar with the photographs, reaction times were significantly faster to pairs of photographs from the same theme or event. The results are consistent with currently held assumptions about the structure of autobiographical memory. Furthermore, the results suggest that reaction time measures may provide a valuable means by which aspects of autobiographical memory can be explored.

Employee Wellbeing: Evaluating a Wellbeing Intervention in Two Settings.

This research presents two studies conducted to evaluate the Wellbeing Game in two different contexts: In a student sample and in an organizational setting. Study 1 investigated the efficacy of the Wellbeing Game, in terms of its effect of wellbeing, stress, and an image valence test, among 60 university students. The results showed that after playing the Wellbeing Game, students reported a significant positive change in wellbeing compared to those who did not play the Wellbeing Game, but there was no decrease in stress or any change in classification of image valence. Study 2 evaluated the Wellbeing Game in an organizational context. Employees (n = 52) in a financial organization played the Wellbeing Game for 4 weeks and answered survey questions about wellbeing and stress at the beginning and end of this period. The results showed that after playing the Wellbeing Game, employees reported lower stress levels, and higher wellbeing levels for those who felt that it had helped them connect more with colleagues. The results from the two studies provide preliminary support that the Wellbeing Game may be an effective wellbeing intervention tool in both an organization and a non-organizational context.

Centrality of Social Interaction in Human Brain Function.

People are embedded in social interaction that shapes their brains throughout lifetime. Instead of emerging from lower-level cognitive functions, social interaction could be the default mode via which humans communicate with their environment. Should this hypothesis be true, it would have profound implications on how we think about brain functions and how we dissect and simulate them. We suggest that the research on the brain basis of social cognition and interaction should move from passive spectator science to studies including engaged participants and simultaneous recordings from the brains of the interacting persons.

Listening to an audio drama activates two processing networks, one for all sounds, another exclusively for speech.

Earlier studies have shown considerable intersubject synchronization of brain activity when subjects watch the same movie or listen to the same story. Here we investigated the across-subjects similarity of brain responses to speech and non-speech sounds in a continuous audio drama designed for blind people. Thirteen healthy adults listened for ∼19 min to the audio drama while their brain activity was measured with 3 T functional magnetic resonance imaging (fMRI). An intersubject-correlation (ISC) map, computed across the whole experiment to assess the stimulus-driven extrinsic brain network, indicated statistically significant ISC in temporal, frontal and parietal cortices, cingulate cortex, and amygdala. Group-level independent component (IC) analysis was used to parcel out the brain signals into functionally coupled networks, and the dependence of the ICs on external stimuli was tested by comparing them with the ISC map. This procedure revealed four extrinsic ICs of which two-covering non-overlapping areas of the auditory cortex-were modulated by both speech and non-speech sounds. The two other extrinsic ICs, one left-hemisphere-lateralized and the other right-hemisphere-lateralized, were speech-related and comprised the superior and middle temporal gyri, temporal poles, and the left angular and inferior orbital gyri. In areas of low ISC four ICs that were defined intrinsic fluctuated similarly as the time-courses of either the speech-sound-related or all-sounds-related extrinsic ICs. These ICs included the superior temporal gyrus, the anterior insula, and the frontal, parietal and midline occipital cortices. Taken together, substantial intersubject synchronization of cortical activity was observed in subjects listening to an audio drama, with results suggesting that speech is processed in two separate networks, one dedicated to the processing of speech sounds and the other to both speech and non-speech sounds.

Functional subdivision of group-ICA results of fMRI data collected during cinema viewing.

Independent component analysis (ICA) can unravel functional brain networks from functional magnetic resonance imaging (fMRI) data. The number of the estimated components affects both the spatial pattern of the identified networks and their time-course estimates. Here group-ICA was applied at four dimensionalities (10, 20, 40, and 58 components) to fMRI data collected from 15 subjects who viewed a 15-min silent film ("At land" by Maya Deren). We focused on the dorsal attention network, the default-mode network, and the sensorimotor network. The lowest dimensionalities demonstrated most prominent activity within the dorsal attention network, combined with the visual areas, and in the default-mode network; the sensorimotor network only appeared with ICA comprising at least 20 components. The results suggest that even very low-dimensional ICA can unravel the most prominent functionally-connected brain networks. However, increasing the number of components gives a more detailed picture and functionally feasible subdivision of the major networks. These results improve our understanding of the hierarchical subdivision of brain networks during viewing of a movie that provides continuous stimulation embedded in an attention-directing narrative.

Data-based functional template for sorting independent components of fMRI activity.

In human brain imaging with naturalistic stimuli, hemodynamic responses are difficult to predict and thus data-driven approaches, such as independent component analysis (ICA), may be beneficial. Here we propose inter-subject correlation (ISC) maps as stimulus-sensitive functional templates for sorting the independent components (ICs) to identify the most stimulus-related networks without stimulus-dependent temporal covariates. We collected 3-T functional magnetic resonance imaging (fMRI) data during perception of continuous audiovisual speech. Ten adults viewed a video, in which speech intelligibility was varied by altering the sound level. Five ICs with strongest overlap with the ISC map comprised auditory and visual cortices, and the sixth was a left-hemisphere-dominant network (left posterior superior temporal sulcus, inferior frontal gyrus, anterior superior temporal pole, supplementary motor cortex, and right angular gyrus) that was activated stronger during soft than loud speech. Corresponding temporal-model-based analysis revealed only temporal- and parietal-lobe activations without involvement of the anterior areas. The performance of the ISC-based IC selection was confirmed with fMRI data collected during free viewing of movie. Since ISC-ICA requires no predetermined temporal models on stimulus timing, it seems feasible for fMRI studies where hemodynamic variations are difficult to model because of the complex temporal structure of the naturalistic stimulation.

Towards natural stimulation in fMRI--issues of data analysis.

In search for suitable tools to study brain activation in natural environments, where the stimuli are multimodal, poorly predictable and irregularly varying, we collected functional magnetic resonance imaging data from 6 subjects during a continuous 8-min stimulus sequence that comprised auditory (speech or tone pips), visual (video clips dominated by faces, hands, or buildings), and tactile finger stimuli in blocks of 6-33 s. Results obtained by independent component analysis (ICA) and general-linear-model-based analysis (GLM) were compared. ICA separated in the superior temporal gyrus one independent component (IC) that reacted to all auditory stimuli and in the superior temporal sulcus another IC responding only to speech. Several distinct and rather symmetric vision-sensitive ICs were found in the posterior brain. An IC in the V5/MT region reacted to videos depicting faces or hands, whereas ICs in the V1/V2 region reacted to all video clips, including buildings. The corresponding GLM-derived activations in the auditory and early visual cortices comprised sub-areas of the ICA-revealed activations. ICA separated a prominent IC in the primary somatosensory cortex whereas the GLM-based analysis failed to show any touch-related activation. "Intrinsic" components, unrelated to the stimuli but spatially consistent across subjects, were discerned as well. The individual time courses were highly consistent in sensory projection cortices and more variable elsewhere. The ability to differentiate functionally meaningful composites of activated brain areas and to straightforwardly reveal their temporal dynamics renders ICA a sensitive tool to study brain responses to complex natural stimuli.

Improved differentiation of tactile activations in human secondary somatosensory cortex and thalamus using cardiac-triggered fMRI.

Functional magnetic resonance imaging (fMRI) can reveal human brain activations with high precision. The accuracy may, however, be impaired by movement and deformation of brain tissue associated with cardiac pulsations. Here we corrected for such artifacts by time-locking the fMRI data acquisition to the cardiac cycle in ten subjects who received tactile stimuli to their lips, fingers, and toes. The imaged brain areas covered the parietal operculum and the thalamus, including the secondary somatosensory cortex (SII) bilaterally. Variance of the blood-oxygen-level-dependent signal decreased on average by 38-40% in the SII cortex and by 26% in the thalamus during cardiac triggering compared with conventional imaging. Consequently, statistically significant responses were seen both in the SII cortex and in the ventroposterior thalamus in a larger number of subjects. At the cortical level, the activation pattern revealed two distinct representations for both fingers and toes in the SII region, and the more medial representations were detected with enhanced clarity during cardiac-triggered imaging. In the group-level analysis, the thalamic response to finger stimulation was seen with cardiac triggering, only.