Visual hallucinations associated with multimodal hallucinations, suicide attempts and morbidity of illness in psychotic disorders

BACKGROUND

Visual hallucinations (VH) are a common, but understudied symptom of psychosis, experienced by individuals across diagnostic categories of psychotic and neuropsychiatric conditions. There are limited data on VH and associated clinical phenotypes in adult idiopathic psychotic disorders, which are needed to elucidate their relevance to psychotic illness paradigms.

METHOD

In this cross-sectional study, we examined clinical risk factors for VH in a well-characterized sample of 766 patients with adult psychotic disorders across diagnostic categories of schizophrenia (n = 227), schizoaffective disorder (n = 210), and bipolar I disorder (n = 329). The Structured Clinical Interview for DSM-IV-TR was used for diagnosis and symptom measurements.

RESULTS

The prevalence of VH was 26.1% (200/766). Multivariate logistic regression showed that VH were independently associated with the presence of hallucinations in other modalities, including auditory, tactile, olfactory, and gustatory hallucinations. History of a suicide attempt and catatonic behavior were also associated with VH. In addition, specific delusions were associated with VH, in particular, delusions of control, and religious, erotomanic and jealousy delusions. Diagnosis, negative symptoms, and family history of psychosis were not independent predictors of VH.

CONCLUSIONS

Results showed the clinical and disease relevance of VH as they were associated with severe morbidity of illness, including suicide attempts and catatonic behavior. Findings also suggest a phenotype associated with hallucinations in other modalities and specific types of delusions. Based on our findings, VH may be a significant factor in assessing for suicidality and illness severity, warranting clinical attention and further study of underlying mechanisms.

Aberrant brain dynamics in neuroHIV: Evidence from magnetoencephalographic (MEG) imaging

Magnetoencephalography (MEG) is a noninvasive, silent, and totally passive neurophysiological imaging method with excellent temporal resolution (~1ms) and good spatial precision (~3-5mm). While MEG studies of neuroHIV remain relatively rare, the number of studies per year has sharply increased recently and this trend will likely continue into the foreseeable future. The current in-depth review focuses on the studies that have been conducted to date, which include investigations of somatosensory and visual modalities, resting-state, as well as motor control and higher-level functions such as working memory and visual attention. The review begins with an introduction to the principles and methods of MEG, and then transitions to a review of each of the empirical studies that have been conducted to date, separated by sensory modality for the basic studies and cognitive domain for the higher-level investigations. As such, this review attempts to be exhaustive in its coverage of empirical MEG studies of neuroHIV. Across studies major themes emerge including aberrant neural oscillatory activity in HIV-infected adults, both in primary sensory regions of the brain and higher-order executive regions. Many studies have also connected the amplitude of neural oscillations to behavioral and/or neuropsychological function in the study population, making a vital connection to performance and improving the veracity of the findings. One conspicuous emerging area is the use of MEG to distinguish cognitively-impaired from unimpaired HIV-infected adults, with major success reported and future studies sure to come. The review concludes with a summary of findings and suggested focus areas for future studies.

A conceptual model of the visual control of posture

In order to isolate the visual contribution to the control of postural balance, experiments in which subjects are exposed to large-field visual motion (optokinetic) stimuli are reviewed. In these situations, at motion onset, the visual stimulus signals subject self-motion but inertial (vestibulo-proprioceptive) cues do not. Visually evoked postural responses (VEPR) thus induced can be quickly suppressed by cognitive status or simple repetition of the stimulus, if the inertial self-motion cues available to the subject are reliable. In the conceptual model presented here, the process of assessing the reliability, and degree of matching, of visual and inertial signals is carried out by a General comparator; in turn able to access the Gain control mechanism of the visuo-postural system. Complexity and congruency in the visual stimulus itself are assessed by a Visual comparator, e.g., the presence of motion parallax in the visual stimulus can reverse the sway response direction. VEPR can also be re-oriented according to the position of the eyes in the head and the head on the trunk. This indicates that ocular and cervical proprioceptors must also access the gain control mechanism so that visual stimuli can recruit and silence different postural muscles appropriately. The overall gain of the visuo-postural system is also influenced by less easily defined idiosyncratic factors, such as visual dependence and psychological traits; interestingly both these factors have been found to be associated with poor long term outcome in vestibular disorders. The experimental results and model presented illustrate that the visuo-postural system is a wonderful example of interaction between physics (e.g., stimuli geometry, body dynamics), neuroscience and the border zone between neurology and psycho-somatic medicine.

Visual Hyper-vigilance But Insufficient Mental Representation in Children with Overweight/Obesity: Event-related Potential Study with Visual Go/NoGo Test

PURPOSE

The neural processing of children with overweight/obesity (CWO), may affect their eating behavior. We investigated the visual information processing of CWO under response control condition, by event-related potential (ERP) study, an electrophysiologic study for cognitive mechanism.

METHODS

Seventeen CWO (mean age: 10.6±1.9), and 17 age-matched non-obese children (NOC), participated in the study. Neurocognitive function tests and visual ERP under Go/NoGo conditions, were implemented. Area amplitudes of major ERP components (P1, N1, P2, N2, and P3) from four scalp locations (frontal, central, parietal, and occipital), were analyzed.

RESULTS

For Go and NoGo conditions, CWO had significantly greater occipital P1, fronto-central N1, and P2 amplitudes compared with NOC. P2 amplitude was significantly greater in CWO, than in NOC, at the frontal location. N2 amplitude was not significantly different, between CWO and NOC. For CWO and NOC, Go P3 amplitude was highest at the parietal location, and NoGo P3 amplitude was highest at the frontal location. In Go and NoGo conditions, P3 amplitude of CWO was significantly less than in NOC.

CONCLUSION

The greater P1, N1, and P2 suggested hyper-vigilance to visual stimuli of CWO, but the smaller P3 suggested insufficient mental representation of them. Such altered visual processing, may affect the eating behavior of CWO.

Visual and Action-control Expressway Associated with Efficient Information Transmission in Elite Athletes

Effective information transmission for open skill performance requires fine-scale coordination of distributed networks of brain regions linked by white matter tracts. However, how patterns of connectivity in these anatomical pathways may improve global efficiency remains unclear. In this study, we hypothesized that the feeder edges in visual and motor systems have the potential to become "expressways" that increase the efficiency of information communication across brain networks of open skill experts. Thirty elite athletes and thirty novice subjects were recruited to participate in visual tracking and motor imagery tasks. We collected structural imaging data from these subjects, and then resolved structural neural networks using deterministic tractography to identify streamlines connecting cortical and subcortical brain regions of each participant. We observed that superior skill performance in elite athletes was associated with increased information transmission efficiency in feeder edges distributed between orbitofrontal and basal ganglia modules, as well as among temporal, occipital, and limbic system modules. These findings suggest that there is an expressway linking visual and action-control system of skill experts that enables more efficient interactions of peripheral and central information in support of effective performance of an open skill.

Assessing motor, visual and language function using a single 5-minute fMRI paradigm: three birds with one stone

Clinical functional Magnetic Resonance Imaging (fMRI) requires inferences on localization of major brain functions at the individual subject level. We hypothesized that a single "triple use" task would satisfy sensitivity and reliability requirements for successfully assessing the motor, visual and language domain in this context. This was tested here by the application in a group of healthy adults, assessing sensitivity and reliability at the individual subject level, separately for each domain.Our "triple use" task consisted of 2 conditions (condition 1, assessing motor and visual domain, and condition 2, assessing the language domain), serving mutually as active/control. We included 20 healthy adult subjects. Random effect analyses showed activation in primary motor, visual and language regions, as expected. Less expected regions were activated both for the motor and visual domains. Further, reliability of primary activation patterns was very high across individual subjects, with activation seen in 70-100% of subjects in primary motor, visual, and left-lateralized language regions.These findings suggest the "triple use" task to be reliable at the individual subject's level to assess motor, visual and language domains in the clinical fMRI context. Benefits of such an approach include shortening of acquisition time, simplicity of the task for each domain, and using a visual stimulus. Following establishment of reliability in adults, the task may also be a valuable addition in the pediatric clinical fMRI context, where each of these factors is of high relevance.

Effect of range of heading differences on human visual-inertial heading estimation

Both visual and inertial cues are salient in heading determination. However, optic flow can ambiguously represent self-motion or environmental motion. It is unclear how visual and inertial heading cues are determined to have common cause and integrated vs perceived independently. In four experiments visual and inertial headings were presented simultaneously with ten subjects reporting visual or inertial headings in separate trial blocks. Experiment 1 examined inertial headings within 30° of straight-ahead and visual headings that were offset by up to 60°. Perception of the inertial heading was shifted in the direction of the visual stimulus by as much as 35° by the 60° offset, while perception of the visual stimulus remained largely uninfluenced. Experiment 2 used ± 140° range of inertial headings with up to 120° visual offset. This experiment found variable behavior between subjects with most perceiving the sensory stimuli to be shifted towards an intermediate heading but a few perceiving the headings independently. The visual and inertial headings influenced each other even at the largest offsets. Experiments 3 and 4 had similar inertial headings to experiments 1 and 2, respectively, except subjects reported environmental motion direction. Experiment 4 displayed similar perceptual influences as experiment 2, but in experiment 3 percepts were independent. Results suggested that perception of visual and inertial stimuli tend to be perceived as having common causation in most subjects with offsets up to 90° although with significant variation in perception between individuals. Limiting the range of inertial headings caused the visual heading to dominate the perception.

Comparative efficacy and safety of multiple antiplatelet therapies for secondary prevention of ischemic stroke or transient ischemic attack: A network meta-analysis

BACKGROUND

Antiplatelet therapies for secondary prevention of ischemic stroke or transient ischemic attack (TIA) is a highly active research topic with five critical drugs obtained by visual analysis. We aimed to compare and rank multiple antiplatelet therapies using a network meta-analysis.

METHODS

Relevant medical databases were searched. Eligible randomized controlled trials (RCTs) which examined any comparisons involving mono- or dual antiplatelet therapies, based on aspirin, clopidogrel, dipyridamole, ticlopidine, cilostazol and placebo for patients with noncardioembolic ischemic stroke or TIA, were included. 14 outcomes were assessed. Primary outcomes were stroke recurrence, composite events (stroke recurrence, myocardial infarction and vascular death), and intracranial hemorrhage. PROSPERO registered number CRD42017069728.

RESULTS

45 RCTs with 173,131 patients were included in network meta-analysis, involving eight antiplatelet therapies. Cilostazol and clopidogrel were statistically more efficacious than aspirin (odds ratio (OR) = 0.64, 95% confidence interval (CI) = 0.47-0.88; OR = 0.77, 95%CI = 0.62-0.95) and dipyridamole (OR = 0.64, 95%CI = 0.44-0.93; OR = 0.76, 95%CI = 0.58-0.99) in reducing stroke recurrence, and showed significant benefits in reducing composite events compared with aspirin (OR = 0.63, 95%CI = 0.45-0.89; OR = 0.90, 95%CI = 0.83-0.97). No significant difference was found between cilostazol and clopidogrel in intracranial hemorrhage. Weighted regression suggested cilostazol was hierarchically the optimum treatment in consideration of both efficacy and safety, followed by clopidogrel.

CONCLUSION

Cilostazol and clopidogrel are probably promising options for secondary prevention of ischemic stroke or TIA. Both of them reduce stroke recurrence similarly compared with aspirin or dipyridamole, and reduce composite events compared with aspirin. Further studies are needed to confirm this finding.

MEGALEX: A megastudy of visual and auditory word recognition

Using the megastudy approach, we report a new database (MEGALEX) of visual and auditory lexical decision times and accuracy rates for tens of thousands of words. We collected visual lexical decision data for 28,466 French words and the same number of pseudowords, and auditory lexical decision data for 17,876 French words and the same number of pseudowords (synthesized tokens were used for the auditory modality). This constitutes the first large-scale database for auditory lexical decision, and the first database to enable a direct comparison of word recognition in different modalities. Different regression analyses were conducted to illustrate potential ways to exploit this megastudy database. First, we compared the proportions of variance accounted for by five word frequency measures. Second, we conducted item-level regression analyses to examine the relative importance of the lexical variables influencing performance in the different modalities (visual and auditory). Finally, we compared the similarities and differences between the two modalities. All data are freely available on our website ( https://sedufau.shinyapps.io/megalex/ ) and are searchable at www.lexique.org , inside the Open Lexique search engine.

Metacognition across sensory modalities: Vision, warmth, and nociceptive pain

The distinctive experience of pain, beyond mere processing of nociceptive inputs, is much debated in psychology and neuroscience. One aspect of perceptual experience is captured by metacognition—the ability to monitor and evaluate one’s own mental processes. We investigated confidence in judgements about nociceptive pain (i.e. pain that arises from the activation of nociceptors by a noxious stimulus) to determine whether metacognitive processes contribute to the distinctiveness of the pain experience. Our participants made intensity judgements about noxious heat, innocuous warmth, and visual contrast (first-order, perceptual decisions) and rated their confidence in those judgements (second-order, metacognitive decisions). First-order task performance between modalities was balanced using adaptive staircase procedures. For each modality, we quantified metacognitive efficiency (meta-d’/d’)—the degree to which participants’ confidence reports were informed by the same evidence that contributed to their perceptual judgements—and metacognitive bias (mean confidence)—the participant’s tendency to report higher or lower confidence overall. We found no overall differences in metacognitive efficiency or mean confidence between modalities. Mean confidence ratings were highly correlated between all three tasks, reflecting stable inter-individual variability in metacognitive bias. However, metacognitive efficiency for pain varied independently of metacognitive efficiency for warmth and visual perception. That is, those participants who had higher metacognitive efficiency in the visual task also tended to have higher metacognitive efficiency in the warmth task, but not necessarily in the pain task. We thus suggest that some distinctive and idiosyncratic aspects of the pain experience may stem from additional variability at a metacognitive level. We further speculate that this additional variability may arise from the affective or arousal aspects of pain.

Three-dimensional versus two-dimensional high-definition laparoscopy in cholecystectomy: a prospective randomized controlled study

BACKGROUND

While 3D laparoscopy increases surgical performance under laboratory conditions, it is unclear whether it improves outcomes in real clinical scenarios. The aim of this trial was to determine whether the 3D laparoscopy can enhance surgical efficacy in laparoscopic cholecystectomy (LCC).

METHOD

This prospective randomized controlled study was conducted between February 2015 and April 2017 in a day case unit of an academic teaching hospital. Patients scheduled for elective LCC were assessed for eligibility. The exclusion criteria were: (1) planned secondary operation in addition to LCC, (2) predicted to be high-risk for conversion, and (3) surgeons with less than five previous 3D laparoscopic procedures. Patients were operated on by 12 residents and 3 attendings. The primary endpoint was operation time. All surgeons were tested for stereoaquity (Randot® stereotest). The study was registered in ClinicalTrials.gov (NCT02357589).

RESULTS

A total of 210 patients were randomized; 105 to 3D laparoscopy and 104 to 2D laparoscopy. Median operation time as similar in the 3D and 2D laparoscopy groups (49 min vs. 48 min, p = 0.703). Operation times were similar in subgroup analyses for surgeon's sex (male vs. female), surgeon's status (resident vs. attending), surgeon's stereovision (stereopsis 10 vs. less than 10), surgeon's experience (performed 200 LCCs or below versus over 200 LCCs), or patient's BMI (≤ 25 vs. 25-30 vs. > 30). No differences in intra- or postoperative complications were noted between the 3D and 2D groups.

CONCLUSION

3D laparoscopy did not show any advantages over 2D laparoscopy in LCC.

An epidemiological study on the prevalence of hallucinations in a general-population sample: Effects of age and sensory modality

Epidemiological studies have repeatedly shown that a significant minority of the general population have experienced hallucinations, however, a potential effect of age on the prevalence of hallucinations in the general population has never been previously examined in a specific study. The aim of the present study was thus to examine the effects of age and sensory modality on hallucination prevalence in a general population sample. A large, randomly selected and representative sample of the Norwegian population completed measures assessing different hallucination modalities (auditory, visual, olfactory, and tactile) and types (sensed presence and hypnagogic/hypnopompic hallucinations). Three age groups were identified and compared: young (19-30 years), middle (31-60) and old (61-96). There was a significant main-effect of age for all hallucination modalities and types, whereby hallucination prevalence significantly decreased with age. We also found that anxiety partially mediated the effect of age on hallucinations whilst depression was a partial suppressor. Concerning the co-occurrence of hallucination modalities, there was very little co-occurrence of auditory and visual hallucinations in all three age groups. In summary, a main-effect of age for hallucination prevalence was observed. Furthermore, individuals reported a more diverse variety of hallucination modalities compared to what is commonly reported in clinical populations.

Magnetoencephalography and the infant brain

Magnetoencephalography (MEG) is a non-invasive neuroimaging technique that provides whole-head measures of neural activity with millisecond temporal resolution. Over the last three decades, MEG has been used for assessing brain activity, most commonly in adults. MEG has been used less often to examine neural function during early development, in large part due to the fact that infant whole-head MEG systems have only recently been developed. In this review, an overview of infant MEG studies is provided, focusing on the period from birth to three years. The advantages of MEG for measuring neural activity in infants are highlighted (See Box 1), including the ability to assess activity in brain (source) space rather than sensor space, thus allowing direct assessment of neural generator activity. Recent advances in MEG hardware and source analysis are also discussed. As the review indicates, efforts in this area demonstrate that MEG is a promising technology for studying the infant brain. As a noninvasive technology, with emerging hardware providing the necessary sensitivity, an expected deliverable is the capability for longitudinal infant MEG studies evaluating the developmental trajectory (maturation) of neural activity. It is expected that departures from neuro-typical trajectories will offer early detection and prognosis insights in infants and toddlers at-risk for neurodevelopmental disorders, thus paving the way for early targeted interventions.

Does dance training influence beat sensorimotor synchronization? Differences in finger-tapping sensorimotor synchronization between competitive ballroom dancers and nondancers

Sensorimotor synchronization is the coordination of rhythmic movement with an external beat. Dancers often synchronize each beat of their motion with an external rhythm. Compared with social dancing, competitive ballroom dancing requires a higher level of sensorimotor ability. Although previous studies have found that dance experience may facilitate sensorimotor synchronization, they did not examine this in competitive ballroom dancers. Thus, the present study compared sensorimotor synchronization in 41 nondancers and 41 skilled, competitive ballroom dancers as they performed a simple beat synchronization finger-tapping task. All participants finger-tapped freely at their preferred tempo before the formal experiments. Participants were then required to synchronize their finger-tapping with auditory, visual, or combined audiovisual signals in separate experiments and at varying tempos. To assess sensorimotor plasticity, the participants then repeated the free-tapping task after completing all three finger-tapping experiments. Compared with nondancers, dancers showed more accurate and stable beat synchronization. Dancers tapped before onset of all three types of sensorimotor stimulation, indicating a significant negative mean asynchrony and had a tendency to anticipate (predict) the stimuli. Dancers tended to auditory stimulation for beat sensorimotor synchronization, whereas nondancers tended to visual stimuli. Dancers had a faster tempo preference in the initial free-tapping task; however, the preferred tapping tempo increased in all participants in the second free-tapping task, suggesting that beat induction is affected by practice. Together these findings suggest that dance experience enhances sensorimotor synchronization and sensorimotor plasticity, with ballroom dancers tending to auditory stimulation for beat induction.

Prediction of individualized task activation in sensory modality-selective frontal cortex with 'connectome fingerprinting'

The human cerebral cortex is estimated to comprise 200-300 distinct functional regions per hemisphere. Identification of the precise anatomical location of an individual's unique set of functional regions is a challenge for neuroscience that has broad scientific and clinical utility. Recent studies have demonstrated the existence of four interleaved regions in lateral frontal cortex (LFC) that are part of broader visual attention and auditory attention networks (Michalka et al., 2015; Noyce et al., 2017; Tobyne et al., 2017). Due to a large degree of inter-subject anatomical variability, identification of these regions depends critically on within-subject analyses. Here, we demonstrate that, for both sexes, an individual's unique pattern of resting-state functional connectivity can accurately identify their specific pattern of visual- and auditory-selective working memory and attention task activation in lateral frontal cortex (LFC) using "connectome fingerprinting." Building on prior techniques (Saygin et al., 2011; Osher et al., 2016; Tavor et al., 2016; Smittenaar et al., 2017; Wang et al., 2017; Parker Jones et al., 2017), we demonstrate here that connectome fingerprint predictions are far more accurate than group-average predictions and match the accuracy of within-subject task-based functional localization, while requiring less data. These findings are robust across brain parcellations and are improved with penalized regression methods. Because resting-state data can be easily and rapidly collected, these results have broad implications for both clinical and research investigations of frontal lobe function. Our findings also provide a set of recommendations for future research.

Handedness modulates proprioceptive drift in the rubber hand illusion

Preference for use of either the left or right hand (‘handedness’) has been linked with modulations of perception and sensory processing—both of space and the body. Here we ask whether multisensory integration of bodily information also varies as a function of handedness. We created a spatial disparity between visual and somatosensory hand position information using the rubber hand illusion, and use the magnitude of illusory shifts in hand position (proprioceptive ‘drift’) as a tool to probe the weighted integration of multisensory information. First, we found drift was significantly reduced when the illusion was performed on the dominant vs. non-dominant hand. We suggest increased manual dexterity of the dominant hand causes greater representational stability and thus an increased resistance to bias by the illusion induction. Second, drift was generally greatest when the hand was in its habitual action space (i.e., near the shoulder of origin), compared to when it laterally displaced towards, or across the midline. This linear effect, however, was only significant for the dominant hand—in both left- and right-handed groups. Thus, our results reveal patterns of habitual hand action modulate drift both within a hand (drift varies with proximity to action space), and between hands (differences in drift between the dominant and non-dominant hands). In contrast, we were unable to find conclusive evidence to support, or contradict, an overall difference between left- and right-handers in susceptibility to RHI drift (i.e., total drift, collapsed across hand positions). In sum, our results provide evidence that patterns of daily activity—and the subsequent patterns of sensory input—shape multisensory integration across space.

Modulation of event-related potentials to food cues upon sensory-specific satiety

Tempting environmental food cues and metabolic signals are important factors in appetite regulation. Food intake reduces liking of food cues that are congruent to the food eaten (sensory-specific satiety). With this study we aimed to assess effects of sensory-specific satiety on neural processing (perceptual and evaluative) of visual and olfactory food cues. Twenty healthy female subjects (age: 20 ± 2 years; BMI: 22 ± 2 kg/m²) participated in two separate test sessions during which they consumed an ad libitum amount of a sweet or savoury meal. Before and after consumption, event-related potentials were recorded in response to visual and olfactory cues signalling high-energy sweet, high-energy savoury, low-energy sweet and low-energy savoury food and non-food items. In general, we observed that food intake led to event-related potentials with an increased negative and decreased positive amplitudes for food, but also non-food cues. Changes were most pronounced in response to high-energy sweet food pictures after a sweet meal, and occurred in early processes of perception (~80-150 ms) and later processes of cognitive evaluation (~300-700 ms). Food intake appears to lead to general changes in neural processing that are related to motivated attention, and sensory-specific changes that reflect decreased positive valence of the stimuli and/or modulation of top-down cognitive control over processing of cues congruent to the food eaten to satiety.

Prevalence and characteristics of multi-modal hallucinations in people with psychosis who experience visual hallucinations

Hallucinations can occur in single or multiple sensory modalities. Historically, greater attention has been paid to single sensory modality experiences with a comparative neglect of hallucinations that occur across two or more sensory modalities (multi-modal hallucinations). With growing evidence suggesting that visual hallucinations may be experienced along with other hallucinations, this study aimed to explore multi-modal hallucinations in a sample of people with psychotic disorders who reported visual hallucinations (n = 22). No participants reported just visual hallucinations i.e. all reported related or unrelated auditory hallucinations. Twenty-one participants reported multi-modal hallucinations that were serial in nature, whereby they saw visual hallucinations and heard unrelated auditory hallucinations at other times. Nineteen people out of the twenty two also reported simultaneous multi-modal hallucinations, with the most common being an image that talked to and touched them. Multi-modal related and simultaneous hallucinations appeared to be associated with greater conviction that the experiences were real, and greater distress. Theoretical and clinical implications of multi-modal hallucinations are discussed.

Visual biofeedback training reduces quantitative drugs index scores associated with fall risk

OBJECTIVE

Drugs increase fall risk and decrease performance on balance and mobility tests. Conversely, whether biofeedback training to reduce fall risk also decreases scores on a published drug-based fall risk index has not been documented. Forty-eight community-dwelling older adults underwent either treadmill gait training plus visual feedback (+VFB), or walked on a treadmill without feedback. The Quantitative Drug Index (QDI) was derived from each participant's drug list and is based upon all cause drug-associated fall risk. Analysis of covariance assessed changes in the QDI during the study, and data is presented as mean ± standard error of the mean.

RESULTS

The QDI scores decreased significantly (p = 0.031) for participants receiving treadmill gait training +VFB (- 0.259 ± 0.207), compared to participants who walked on the treadmill without VFB (0.463 ± 0.246). Changes in participants QDI scores were dependent in part upon their age, which was a significant covariate (p = 0.007). These preliminary results demonstrate that rehabilitation to reduce fall risk may also decrease use of drugs associated with falls. Determination of which drugs or drug classes that contribute to the reduction in QDI scores for participants receiving treadmill gait training +VFB, compared to treadmill walking only, will require a larger participant investigation. Trial Registration ISRNCT01690611, ClinicalTrials.gov #366151-1, initial 9/24/2012, completed 4/21/2016.

How would you describe a familiar route or put in order the landmarks along it? It depends on your cognitive style!

Cognitive style refers to the preference in perceiving, organizing and remembering information. Different cognitive styles have been identified across the years. Amongst others, field-dependence/independence cognitive style is the extent to which the person perceives part of a field as discrete from the surrounding environment as a whole, rather than embedded in the field. Instead, visualizer/verbalizer cognitive style involves the preference in processing visual versus verbal information. Both cognitive styles can influence navigational behaviour. The present study aimed at clarifying the extent to which field-dependence/independence and visualizer/verbalizer cognitive styles affect route-based navigational tasks. Therefore, 44 healthy participants from L'Aquila City were assessed for their cognitive styles and were asked to perform two different navigational tasks: reorder paths using a series of photos depicting landmarks from L'Aquila (visually presented task, visual path task-VisPT); orally describe specific paths of L'Aquila (verbally presented task, verbal path task-VerPT). Results showed that the field-independence cognitive style predicted response times of VisPT, whereas the visualizer/verbalizer cognitive style predicted the instructions given when performing the VerPT, namely, the number of metrical distance indicators provided by participants. By investigating two different cognitive styles, the study clarifies that field-dependence/independence and visualizer/verbalizer cognitive styles can play a different role in spatial navigation and suggests that the material by which a navigational task is presented affects its performance.

Altered neural responsivity to food cues in relation to food preferences, but not appetite-related hormone concentrations after RYGB-surgery

BACKGROUND

After Roux-en-Y gastric bypass (RYGB) surgery, patients report a shift in food preferences away from high-energy foods.

OBJECTIVE

We aimed to elucidate the potential mechanisms underlying this shift in food preferences by assessing changes in neural responses to food pictures and odors before and after RYGB. Additionally, we investigated whether altered neural responsivity was associated with changes in plasma endocannabinoid and ghrelin concentrations.

DESIGN

19 RYGB patients (4 men; age 41 ± 10 years; BMI 41 ± 1 kg/m² before; BMI 36 ± 1 kg/m² after) participated in this study. Before and two months after RYGB surgery, they rated their food preferences using the Macronutrient and Taste Preference Ranking Task and BOLD fMRI responses towards pictures and odors of high-, and low-energy foods and non-food items were measured. Blood samples were taken to determine plasma endocannabinoid and ghrelin concentrations pre- and post-surgery.

RESULTS

Patients demonstrated a shift in food preferences away from high-fat/sweet and towards low-energy/savory food products, which correlated with decreased superior parietal lobule responsivity to high-energy food odor and a reduced difference in precuneus responsivity to high-energy versus low-energy food pictures. In the anteroventral prefrontal cortex (superior frontal gyrus) the difference in deactivation towards high-energy versus non-food odors reduced. The precuneus was less deactivated in response to all cues. Plasma concentrations of anandamide were higher after surgery, while plasma concentrations of other endocannabinoids and ghrelin did not change. Alterations in appetite-related hormone concentrations did not correlate with changes in neural responsivity.

CONCLUSIONS

RYGB leads to changed responsivity of the frontoparietal control network that orchestrates top-down control to high-energy food compared to low-energy food and non-food cues, rather than in reward related brain regions, in a satiated state. Together with correlations with the shift in food preference from high- to low-energy foods this indicates a possible role in new food preference formation.

Effects of early eye removal on the morphology of a multisensory neuron in the chicken optic tectum

The midbrain is a subcortical area involved in central functions such as integrating sensory modalities, movement initiation and bottom-up and top-down attention. In chicken, the midbrain roof is termed optic tectum (TeO) and consists of 15 layers with distinct in- and output regions. Visual input targets the superficial layers, while auditory input terminates in deeper layers. It has been shown that ablation of sensory epithelia leads to changes in the cellular patterning and structural organization of the sensory pathways. For the tectum, ablation of the eye anlagen was shown to affect retinorecipient neurons. While the gross morphology remained intact after enucleation, the shape of dendritic endings was changed presumably due to missing presynaptic input during synaptic pruning. We investigated the effect of deafferentation in a multisensory cell type, the Shepherd's crook neuron (SCN) in the TeO. SCNs have distinct dendritic branches in retinorecipient layers (superficial layers 1 to 5 and 7) and in layers where auditory input terminates. To assess whether removal of a single sensory input only affects the dendrites recipient for that input, we removed the eye anlagen and retrogradely labeled SCNs later in embryogenesis to visualize the morphology in lesioned and non-lesioned embryos. We found no changes in the gross morphology or in the basal dendrites, but an altered growth of the fine structures at the apical dendrite of SCNs in the retinorecipient layers. Our data indicate that the neuronal morphology of SCNs is mostly predefined before retinal innervation affect the fine structure.

Analysis of sensory system aspects of postural stability during quiet standing in adolescent idiopathic scoliosis patients

Background

The aim of this study was to quantitatively analyze quite standing postural stability of adolescent idiopathic scoliosis (AIS) patients in respect to three sensory systems (visual, vestibular, and somatosensory).

Method

In this study, we analyzed the anterior-posterior center of pressure (CoP) signal using discrete wavelet transform (DWT) between AIS patients (n = 32) and normal controls (n = 25) during quiet standing.

Result

The energy rate (∆E_EYE%) of the CoP signal was significantly higher in the AIS group than that in the control group at levels corresponding to vestibular and somatosensory systems (p < 0.01).

Conclusions

This implies that AIS patients use strategies to compensate for possible head position changes and spinal asymmetry caused by morphological deformations of the spine through vestibular and somatosensory systems. This could be interpreted that such compensation could help them maintain postural stability during quiet standing. The interpretation of CoP signal during quiet standing in AIS patients will improve our understanding of changes in physical exercise ability due to morphological deformity of the spine. This result is useful for evaluating postural stability before and after treatments (spinal fusion, bracing, rehabilitation, and so on).

Reading without words or target detection? A re-analysis and replication fMRI study of the Landolt paradigm

The Landolt paradigm is a visual scanning task intended to evoke reading-like eye-movements in the absence of orthographic or lexical information, thus allowing the dissociation of (sub-) lexical vs. visual processing. To that end, all letters in real word sentences are exchanged for closed Landolt rings, with 0, 1, or 2 open Landolt rings as targets in each Landolt sentence. A preliminary fMRI block-design study (Hillen et al. in Front Hum Neurosci 7:1-14, 2013) demonstrated that the Landolt paradigm has a special neural signature, recruiting the right IPS and SPL as part of the endogenous attention network. However, in that analysis, the brain responses to target detection could not be separated from those involved in processing Landolt stimuli without targets. The present study presents two fMRI experiments testing the question whether targets or the Landolt stimuli per se, led to the right IPS/SPL activation. Experiment 1 was an event-related re-analysis of the Hillen et al. (Front Hum Neurosci 7:1-14, 2013) data. Experiment 2 was a replication study with a new sample and identical procedures. In both experiments, the right IPS/SPL were recruited in the Landolt condition as compared to orthographic stimuli even in the absence of any target in the stimulus, indicating that the properties of the Landolt task itself trigger this right parietal activation. These findings are discussed against the background of behavioural and neuroimaging studies of healthy reading as well as developmental and acquired dyslexia. Consequently, this neuroimaging evidence might encourage the use of the Landolt paradigm also in the context of examining reading disorders, as it taps into the orientation of visual attention during reading-like scanning of stimuli without interfering sub-lexical information.

Modality-dependent effect of motion information in sensory-motor synchronised tapping

Synchronised action is important for everyday life. Generally, the auditory domain is more sensitive for coding temporal information, and previous studies have shown that auditory-motor synchronisation is much more precise than visuo-motor synchronisation. Interestingly, adding motion information improves synchronisation with visual stimuli and the advantage of the auditory modality seems to diminish. However, whether adding motion information also improves auditory-motor synchronisation remains unknown. This study compared tapping accuracy with a stationary or moving stimulus in both auditory and visual modalities. Participants were instructed to tap in synchrony with the onset of a sound or flash in the stationary condition, while these stimuli were perceived as moving from side to side in the motion condition. The results demonstrated that synchronised tapping with a moving visual stimulus was significantly more accurate than tapping with a stationary visual stimulus, as previous studies have shown. However, tapping with a moving auditory stimulus was significantly poorer than tapping with a stationary auditory stimulus. Although motion information impaired audio-motor synchronisation, an advantage of auditory modality compared to visual modality still existed. These findings are likely the result of higher temporal resolution in the auditory domain, which is likely due to the physiological and structural differences in the auditory and visual pathways in the brain.