MRI Compatible Lumbopelvic Movement Measurement System to Validate and Capture Task Performance During Neuroimaging.

Research suggests that structural and functional changes within the brain are associated with chronic low back pain, and these cortical alterations might contribute to impaired sensorimotor control of the trunk and hips in this population. However, linking sensorimotor brain changes with altered movement of the trunk and hips during task-based neuroimaging presents significant challenges. An MRI-safe pressure measurement system was developed to ensure proper task completion during neuroimaging by capturing movement patterns of the trunk (sensors under the lower back) and hips (sensors embedded in the foam roll under the knees). Pressure changes were measured outside of the scanner by digital differential pressure sensors to capture time-series data and analog pressure gauges for real-time determination of task performance occurring within an MRI bore during brain imaging. This study examined the concurrent validity of air pressure changes between the digital and analog sensors. The digital and analog data were compared in 23 participants during the performance of modified bilateral and unilateral right and left hip bridges. Spearman's correlations were calculated for each sensor during the three bridging tasks and showed high positive correlations, indicating that over 87% of pressure change from the analog gauge can be explained by the pressure from the digital sensor. Bland-Altman plots showed no bias and mean differences were under three mmHg. This pressure system improves the rigor of future studies by validating the digital data from the system and increasing the capabilities of capturing lumbopelvic task performance occurring inside the scanner bore.

Assessing sensorimotor control of the lumbopelvic-hip region using task-based functional MRI.

Recent brain imaging studies have suggested that cortical remodeling within sensorimotor regions are associated with persistent low back pain and may be a driving mechanism for the impaired neuromuscular control associated with this condition. This paper outlines a new approach for investigating cortical sensorimotor integration during the performance of small-amplitude lumbopelvic movements with functional MRI. Fourteen healthy right-handed participants were instructed in the lumbopelvic movement tasks performed during fMRI acquisition. Surface electromyography (EMG) collected on 8 lumbopelvic and thigh muscles captured organized patterns of muscle activation during the movement tasks. fMRI data were collected on 10 of 14 participants. Sensorimotor cortical activation across the tasks was identified using a whole brain analysis and further explored with regional analyses of key components of the cortical sensorimotor network. Head motion had low correlation to the tasks (r = -0.101 to 0.004) and head translation averaged 0.98 (0.59 mm) before motion correction. Patterns of activation of the key lumbopelvic and thigh musculature (average amplitude normalized 2-17%) were significantly different across tasks (P > 0.001). Neuroimaging demonstrated activation in key sensorimotor cortical regions that were consistent with motor planning and sensory feedback needed for performing the different tasks. This approach captures the specificity of lumbopelvic sensorimotor control using goal-based tasks (e.g., "lift your hip" vs. "contract your lumbar multifidus to 20% of maximum") performed within the confines of the scanner. Specific patterns of sensorimotor cortex activation appear to capture differences between bilateral and unilateral tasks during voluntary control of multisegmental movement in the lumbopelvic region.NEW & NOTEWORTHY We demonstrated the feasibility of using task-based functional magnetic resonance imaging (fMRI) protocols for acquiring the blood oxygen level-dependent (BOLD) response of key sensorimotor cortex regions during voluntary lumbopelvic movements. Our approach activated lumbopelvic muscles during small-amplitude movements while participants were lying supine in the scanner. Our data supports these tasks can be done with limited head motion and low correlation of head motion to the task. The approach provides opportunities for assessing the role of brain changes in persistent low back pain.

The N400 in processing repeated name and pronoun anaphors in sentences and discourse.

We report two EEG/ERP experiments that examined processing of repeated name (e.g., Bill; Experiment 1) and pronoun (e.g., he; Experiment 2) subject anaphors to single antecedents (e.g., Bill) and to antecedents embedded in a conjunction (e.g., Bill and Mary) within sentences and discourses. Experiment 1 replicated previous reports of repeated references to single antecedents eliciting greater N400 negativity than repeated references to conjoined antecedents within sentences, and extended these results to cross-sentence (discourse) references. Experiment 2 found that pronouns also elicited greater N400 negativity following single than conjoined antecedents. In both experiments, references to conjoined antecedents elicited greater frontal negativity than references to single antecedents in both sentences and discourse. Our results indicate that, in processing subject anaphors, the N400 is an index of reference predictability rather than a marker of the fit between antecedent salience and reference form, and that frontal negativity marks referential ambiguity elicited by conjoined phrases.

Resting state signatures of domain and demand-specific working memory performance.

Working memory (WM) is one of the key constructs in understanding higher-level cognition. We examined whether patterns of activity in the resting state of individual subjects are correlated with their off-line working and short-term memory capabilities. Participants completed a resting-state fMRI scan and off-line working and short-term memory (STM) tests with both verbal and visual materials. We calculated fractional amplitude of low frequency fluctuations (fALFF) from the resting state data, and also computed connectivity between seeds placed in frontal and parietal lobes. Correlating fALFF values with behavioral measures showed that the fALFF values in a widespread fronto-parietal network during rest were positively correlated with a combined memory measure. In addition, STM showed a significant correlation with fALFF within the right angular gyrus and left middle occipital gyrus, whereas WM was correlated with fALFF values within the right IPS and left dorsomedial cerebellar cortex. Furthermore, verbal and visuospatial memory capacities were associated with dissociable patterns of low-frequency fluctuations. Seed-based connectivity showed correlations with the verbal WM measure in the left hemisphere, and with the visual WM measure in the right hemisphere. These findings contribute to our understanding of how differences in spontaneous low-frequency fluctuations at rest are correlated with differences in cognitive performance.

Evaluating methods for constructing average high-density electrode positions.

Accurate analysis of scalp-recorded electrical activity requires the identification of electrode locations in 3D space. For example, source analysis of EEG/ERP (electroencephalogram, EEG; event-related-potentials, ERP) with realistic head models requires the identification of electrode locations on the head model derived from structural MRI recordings. Electrode systems must cover the entire scalp in sufficient density to discriminate EEG activity on the scalp and to complete accurate source analysis. The current study compares techniques for averaging electrode locations from 86 participants with the 128 channel "Geodesic Sensor Net" (GSN; EGI, Inc.), 38 participants with the 128 channel "Hydrocel Geodesic Sensor Net" (HGSN; EGI, Inc.), and 174 participants with the 81 channels in the 10-10 configurations. A point-set registration between the participants and an average MRI template resulted in an average configuration showing small standard errors, which could be transformed back accurately into the participants' original electrode space. Average electrode locations are available for the GSN (86 participants), Hydrocel-GSN (38 participants), and 10-10 and 10-5 systems (174 participants).

Neuronal injury in the motor cortex after chronic stroke and lower limb motor impairment: a voxel-based lesion symptom mapping study.

Many studies have examined motor impairments using voxel-based lesion symptom mapping, but few are reported regarding the corresponding relationship between cerebral cortex injury and lower limb motor impairment analyzed using this technique. This study correlated neuronal injury in the cerebral cortex of 16 patients with chronic stroke based on a voxel-based lesion symptom mapping analysis. Neuronal injury in the corona radiata, caudate nucleus and putamen of patients with chronic stroke could predict walking speed. The behavioral measure scores were consistent with motor deficits expected after damage to the cortical motor system due to stroke. These findings suggest that voxel-based lesion symptom mapping may provide a more accurate prognosis of motor recovery from chronic stroke according to neuronal injury in cerebral motor cortex.

Partner discrepancies in distressed marriages.

Spousal discrepancy theory posits that partners with wide personality differences are at risk for marital distress. In this study, we assessed links between partner personality and interpersonal characteristics and marital distress in 244 couples who sought marital therapy. The sample was divided into three subgroups according to marital duration. Longer-married couples reflected significantly less impulsive, exploitive, and insensitive characteristics than couples in either shorter or intermediate marriages. Couples' marital distress was linked to larger discrepancies in personal distress, impulsivity, interpersonal insensitivity, and self-centered characteristics. While husbands' marital distress was linked to partner differences in personal distress and to impulsive, narcissistic, and competitive characteristics, wives' marital distress was primarily linked to partner discrepancies in self-centeredness.

Deception and the misinformation effect: an event-related potential study.

Research in the field of deception often tests participants' ability to lie about information with which they are familiar and have a strong recall of base truth. The current study examined the impact of uncertainty in memory on the ability to deceive, as may happen in real-world eye-witness scenarios. A visual misinformation paradigm was combined with event-related potentials (ERPs) to examine the impact of deception and misinformation on ERP components previously associated with deception and memory processes. Deception was associated with strong parietal P3b suppression and a large frontal negativity (N400). Misinformation was also associated with parietal P3b suppression and had effects on a late positive component (LPC) in occipital regions. The results indicate that while deception and memory uncertainty may have combined effects, they still both independently influence information processing.

Neural correlates of race-related social evaluations for African Americans and white Americans.

OBJECTIVE: To examine differences in patterns of brain activation associated with a race-related social evaluative task for a sample of African American and White American adults. METHOD: Participants were exposed to images of White American and African American targets embedded in various contexts across three emotional valences: angry/hostile, happy/joyful, and neutral/ambiguous. Functional magnetic resonance imaging was used to measure brain activity. RESULTS: Between-group comparisons revealed that African Americans, as compared to White Americans, exhibited activation in the inferior frontal gyrus and parahippocampal gyrus to images of happy (vs. neutral) same-race targets. White Americans, compared, to African Americans displayed activation in the inferior frontal gyrus and anterior cingulate cortex to images of happy (vs. neutral) same-race targets. Activation in limbic areas was observed for African Americans to neutral (vs. happy) images of White American targets, while no significant pattern of activation was found for White Americans to images of neutral/ambiguous African American targets. A significant correlation was found between scores for previous exposure to race-related incidents and amygdala activation for African Americans to White American targets. CONCLUSION: White Americans generally exhibited more activation in regions associated with conflict resolution and cognitive control, while African Americans exhibited activation mostly in areas associated with emotion and memory. Our findings further imply that previous exposure to race-related incidents for African Americans may alter neural responses to White American targets in imaging studies. Implications of the findings are discussed.

Repressors vs. low- and high-anxious coping styles: EEG differences during a modified version of the emotional Stroop task.

In this study of 49 undergraduate university women, those exhibiting a repressive coping style - characterized by defensiveness against negative emotions - were compared to women with low-anxious and high-anxious coping styles during neutral and negative versions of a computerized emotional Stroop task (EST). Using Weinberger, Schwartz, and Davidson's (1979) approach, the present study implemented the Marlowe-Crowne Social Desirability and the Spielberger Trait Anxiety scales for selection. Participants viewed neutral or negative words during the EST but responded to the color of the word. Analysis of continuous EEG recordings for the negative vs. neutral words revealed that the repressor group differed significantly from the other two groups in many aspects but that low- vs. high-anxious groups differed in fewer aspects. Based upon Eysenck and Derakshan's (1997) model, repressor women appear to differ from low- and high-anxious women by utilizing an inhibitory process to avoid perceiving low-intensity threatening stimuli.

Parent characteristics linked with daughters' attachment styles.

This study investigated links between parent characteristics and daughters' attachment styles for 90 female undergraduates and their married biological parents. Parents with a secure attachment pattern were rated as more accepting, less controlling, more competent, and more consistent in showing love and affection to their daughter in contrast to parents with an insecure attachment pattern. Significant positive associations were found between mothers' fearful attachment scores and the fearful, preoccupied, and dismissive attachment scores of daughters. Daughters of matched secure parents were more likely to report a secure attachment style, while daughters of matched insecure parents were more likely to report an insecure attachment style.

Links between parent characteristics and attachment variables for college students of parental divorce.

This study investigated links between offsprings' attachment patterns and parent characteristics in 157 females and 62 males of parental divorce. Secure females and males reported affection, respect, and closeness toward both biological parents. Offsprings' insecure attachment pattern was associated with negative parent characteristics. Participants who perceived their same-sex parent negatively were more likely to report an insecure attachment. Our findings suggest delayed negative consequences of parental divorce for college women and men.

Recollections of parent characteristics and attachment patterns for college women of intact vs. non-intact families.

This study contrasted offsprings' attachment patterns and recollections of parent characteristics in two college samples: 147 females from intact biological parents and 157 females of parental divorce. Secure females from intact or non-intact families rated parents positively, while insecure females rated parents as absent, distant, and demanding. In contrast to females from intact families, females of parental divorce reported a less secure attachment, lower self-esteem, a greater fearful avoidance pattern, and rated their biological fathers and mothers more negatively.

Practice effects, workload, and reaction time in deception.

Cognitive theorists argue that deception may involve attentional capture, working memory load, or perceived incongruity with memory, whereas psychophysiologists argue for stimulus salience, arousal, and emotion. This article presents a comprehensive model of deception and assesses the effect of practice on deceptive responding. A three-session longitudinal study examined the effect of practice on reaction time (RT) in relation to deception and response congruity. Participants evaluated self-referent sentences and responded truthfully or deceptively. Findings indicate that deceptive responding generates longer RTs than does truthful responding and that this relationship remains constant with practice. We use these findings to support a cognitive model of deception.

Reaction time of motor responses in two-stimulus paradigms involving deception and congruity with varying levels of difficulty.

Deception research has focused on identifying peripheral nervous system markers while ignoring cognitive mechanisms underlying those markers. Cognitive theorists argue that the process of deception may involve such constructs as attentional capture, working memory load, or perceived incongruity with memory, while psychophysiologists argue for stimulus salience, arousal, and emotion. Three studies were conducted to assess reaction time (RT) in relation to deception, response congruity, and preparedness to deceive. Similar to a semantic verification task, participants evaluated sentences that were either true or false, and then made truthful or deceptive evaluations of the sentence's base truth-value. Findings indicate that deceptive responses have a longer RT than truthful responses, and that this relationship remains constant across response type and preparedness to deceive. The authors use these findings in preliminary support of a comprehensive cognitive model of deception.