fMRI Findings Research Articles

Cross-paradigm integration shows a common neural basis for aversive and appetitive conditioning

Sharing imaging data and comparing them across different psychological tasks is becoming increasingly possible as the open science movement advances. Such cross-paradigm integration has the potential to identify commonalities in findings that neighboring areas of study thought to be paradigm-specific. However, even the integration of research from closely related paradigms, such as aversive and appetitive classical conditioning is rare – even though qualitative comparisons already hint at how similar the ‘fear network’ and ‘reward network’ may be. We aimed to validate these theories by taking a multivariate approach to assess commonalities across paradigms empirically. Specifically, we quantified the similarity of an aversive conditioning pattern derived from meta-analysis to appetitive conditioning fMRI data. We tested pattern expression in three independent appetitive conditioning studies with 29, 76 and 38 participants each. During fMRI scanning, participants in each cohorts performed an appetitive conditioning task in which a CS+ was repeatedly rewarded with money and a CS- was never rewarded. The aversive pattern was highly similar to appetitive CS+ > CS- contrast maps across samples and variations of the appetitive conditioning paradigms. Moreover, the pattern distinguished the CS+ from the CS- with above-chance accuracy in every sample. These findings provide robust empirical evidence for an underlying neural system common to appetitive and aversive learning. We believe that this approach provides a way to empirically integrate the steadily growing body of fMRI findings across paradigms.

Sleep loss leads to the withdrawal of human helping across individuals, groups, and large-scale societies.

Humans help each other. This fundamental feature of homo sapiens has been one of the most powerful forces sculpting the advent of modern civilizations. But what determines whether humans choose to help one another? Across 3 replicating studies, here, we demonstrate that sleep loss represents one previously unrecognized factor dictating whether humans choose to help each other, observed at 3 different scales (within individuals, across individuals, and across societies). First, at an individual level, 1 night of sleep loss triggers the withdrawal of help from one individual to another. Moreover, fMRI findings revealed that the withdrawal of human helping is associated with deactivation of key nodes within the social cognition brain network that facilitates prosociality. Second, at a group level, ecological night-to-night reductions in sleep across several nights predict corresponding next-day reductions in the choice to help others during day-to-day interactions. Third, at a large-scale national level, we demonstrate that 1 h of lost sleep opportunity, inflicted by the transition to Daylight Saving Time, reduces real-world altruistic helping through the act of donation giving, established through the analysis of over 3 million charitable donations. Therefore, inadequate sleep represents a significant influential force determining whether humans choose to help one another, observable across micro- and macroscopic levels of civilized interaction. The implications of this effect may be non-trivial when considering the essentiality of human helping in the maintenance of cooperative, civil society, combined with the reported decline in sufficient sleep in many first-world nations.

Simultaneous EEG + fMRI study of brain activity during an emotional Stroop task in individuals in remission from depression

Individuals in remission from depression (MDDR) tend to experience lingering cognitive and emotional processing alterations. However, little is known about the neural profiles underlying these features. Using simultaneous EEG+fMRI, we assessed neural profiles during the emotional word Stroop task (eStroop) in people with MDDR and healthy volunteers (HVs).Event-related potentials (ERPs) were extracted (N450, N2 & P3). Assessments of brain activation, as modulated by ERPs, were carried out, as were fMRI-informed ERP analyses. A trend for greater P3 amplitudes in MDDR versus HV groups existed. HV versus MDDR groups had greater brain activation to emotional versus neutral words in various regions, including the left amygdala, inferior frontal gyrus (IFG); this appeared to be driven by elevated activity to neutral words in the MDDR group (neutral > emotional). HVs showed greater activation (emotional > neutral) modulated by N450 amplitude in various regions, while MDDRs showed greater neutral > emotional activation modulated by N450 amplitude in the left IFG and left precuneus.Our EEG+fMRI findings indicate that people with MDDR appear to have blunted neural differentiation to emotional versus neutral stimuli or elevated neural responses to neutral information processing. This might represent altered neuronal processing (i.e., underlying attention and conflict processing) during a cognitive task with an emotional component in individuals remitted from depression, or elevated neural responses to ambiguous or neutral information. In sum, subtle lingering neuronal features not accompanied by performance differences appear to exist in people with MDDR.

FMRI Findings in Cortical Brain Networks Interactions in Migraine Following Repetitive Transcranial Magnetic Stimulation.

BackgroundRepetitive transcranial magnetic stimulation (rTMS) is one of the high-potential non-pharmacological methods for migraine treatment. The purpose of this study is to define the neuroimaging markers associated with rTMS therapy in patients with migraine based on data from functional MRI (fMRI).Materials and MethodsA total of 19 patients with episodic migraine without aura underwent a 5-day course of rTMS of the fronto-temporo-parietal junction bilaterally, at 10 Hz frequency and 60% of motor threshold response of 900 pulses. Resting-state functional MRI (1.5 T) and a battery of tests were carried out for each patient to clarify their diagnosis, qualitative and quantitative characteristics of pain, and associated affective symptoms. Changes in functional connectivity (FC) in the brain's neural networks before and after the treatment were identified through independent components analysis.ResultsOver the course of therapy, we observed an increase in FC of the default mode network within it, with pain system components and with structures of the visual network. We also noted a decrease in FC of the salience network with sensorimotor and visual networks, as well as an increase in FC of the visual network. Besides, we identified 5 patients who did not have a positive response to one rTMS course after the first week of treatment according to the clinical scales results, presumably because of an increasing trend of depressive symptoms and neuroimaging criteria for depressive disorder.ConclusionsOur results show that a 5-day course of rTMS significantly alters the connectivity of brain networks associated with pain and antinociceptive brain systems in about 70% of cases, which may shed light on the neural mechanisms underlying migraine treatment with rTMS.

Alterations in resting-state functional activity and connectivity for major depressive disorder appetite and weight disturbance phenotypes.

Major depressive disorder (MDD) is often accompanied by changes in appetite and weight. Prior task-based functional magnetic resonance imaging (fMRI) findings suggest these MDD phenotypes are associated with altered reward and interoceptive processing. Using resting-state fMRI data, we compared the fractional amplitude of low-frequency fluctuations (fALFF) and seed-based connectivity (SBC) among hyperphagic (n = 77), hypophagic (n = 66), and euphagic (n = 42) MDD groups and a healthy comparison group (n = 38). We examined fALFF and SBC in a mask restricted to reward [nucleus accumbens (NAcc), putamen, caudate, ventral pallidum, and orbitofrontal cortex (OFC)] and interoceptive (anterior insula and hypothalamus) regions and also performed exploratory whole-brain analyses. SBC analyses included as seeds the NAcc and also regions demonstrating group differences in fALFF (i.e. right lateral OFC and right anterior insula). All analyses used threshold-free cluster enhancement. Mask-restricted analyses revealed stronger fALFF in the right lateral OFC, and weaker fALFF in the right anterior insula, for hyperphagic MDD v. healthy comparison. We also found weaker SBC between the right lateral OFC and left anterior insula for hyperphagic MDD v. healthy comparison. Whole-brain analyses revealed weaker fALFF in the right anterior insula, and stronger SBC between the right lateral OFC and left precentral gyrus, for hyperphagic MDD v. healthy comparison. Findings were no longer significant after controlling for body mass index, which was higher for hyperphagic MDD. Our results suggest hyperphagic MDD may be associated with altered activity in and connectivity between interoceptive and reward regions.

Activation network mapping for integration of heterogeneous fMRI findings.

Functional neuroimaging techniques have been widely used to probe the neural substrates of facial emotion processing in healthy people. However, findings are largely inconsistent across studies. Here, we introduce a new technique termed activation network mapping to examine whether heterogeneous functional magnetic resonance imaging findings localize to a common network for emotion processing. First, using the existing method of activation likelihood estimation meta-analysis, we showed that individual-brain-based reproducibility was low across studies. Second, using activation network mapping, we found that network-based reproducibility across these same studies was higher. Validation analysis indicated that the activation network mapping-localized network aligned with stimulation sites, structural abnormalities and brain lesions that disrupt facial emotion processing. Finally, we verified the generality of the activation network mapping technique by applying it to another cognitive process, that is, rumination. Activation network mapping may potentially be broadly applicable to localize brain networks of cognitive functions.

Functional MRI in migraine.

The underlying mechanisms of migraine are complex and heterogenous. Advances in neuroimaging techniques during the past few decades have contributed to our understanding of migraine pathophysiology. Brain function in migraine patients has been widely explored using functional MRI (fMRI). This review will highlight the major fMRI findings that characterize the different phases of migraine. The migraine attack starts with hypothalamic hyperexcitability and early reorganization of the common ascending pain and central trigeminovascular pathways. Moreover, the visual cortex becomes hyperexcitable during the aura phase. During the headache phase, further disruptions of the pontine, thalamic, sensorimotor and visual networks occur, although the hypothalamic activity and connectivity normalizes. The visual cortex remains hyperexcitable during the postdromal phase. Asymptomatic migraine patients can also experience functional alternations of pain and visual processing brain areas. At present, the heterogeneity of the asymptomatic phase and fMRI findings make it difficult to find common denominator. fMRI studies have captured functional brain changes associated with migraine phases, leading to an improvement of our understanding of migraine pathophysiology. Further MRI studies are needed to disclose whether the migraine attack is triggered by intrinsic brain dysfunction or external factors.

Traumatic Autobiographical Memories: Preliminary fMRI Findings Among Men With Histories of Childhood Sexual Abuse.

Childhood sexual abuse (CSA) is associated with autobiographical memory (AM) disturbances. AM is important for future thinking, sense of self, and coping with negative emotions. CSA is under-researched among men, with research examining long-term neural correlates limited even further. This study explored the neural correlates of re-experiencing traumatic/negative memories to examine the influence of CSA on AM into adulthood. Fifteen males who experienced CSA, with and without posttraumatic stress disorder (PTSD; CSA+PTSD, n = 6; CSA–PTSD, n = 9) and control males without CSA histories nor PTSD (n = 11) completed a script-driven imagery paradigm during functional magnetic resonance imaging (fMRI). Males with CSA histories, with and without PTSD, processed their negative autobiographical memories with less activation compared to control males. The CSA+PTSD group of males had less activation in the left superior occipital, left superior parietal and left parahippocampal gyri compared to control participants. The CSA–PTSD group had reduced activation in the same regions to a lesser extent. This study provides preliminary empirical evidence to suggest CSA impacts AM for traumatic experiences, and the impact is notable even for men who experienced CSA but do not have PTSD. This study highlights the need for more research with men who have experienced CSA, so that, we can fully understand the neural correlates of emotional memories, and better support the mental health and continued wellness of men who experienced CSA.

P322. Development of the Monetary Incentive Reaction-Time Choice Task

Adolescent risk-taking has been attributed to earlier-developing motivational neurocircuitry that is poorly controlled by immature executive-control neurocircuitry. Functional magnetic resonance imaging (fMRI) findings of increased ventral striatum (VS) recruitment by rewards in adolescents compared to adults support this theory. Other studies found blunted VS recruitment by reward-predictive cues in adolescents compared to adults. Task features may explain this discrepancy, but have never been systematically explored within-subject in age-group comparison.

Age-Related Differences of Frequency-Dependent Functional Connectivity in Brain Networks and Their Link to Motor Performance.

Background: Aging affects the brain at the anatomical and functional levels, resulting in a decline in motor and cognitive performance. Functional magnetic resonance imaging (fMRI) studies documented lower connectivity within brain networks and higher connectivity between them, for older as compared with young adults. However, it is still unclear whether the reduced segregation between networks, as observed with fMRI, has neurophysiological underpinnings. Methods: We collected high-density electroencephalography (hdEEG) data in 24 young and 24 older adults at rest. Bimanual coordination performance was also measured in the same participants, using a computerized test. Using the hdEEG data, we reconstructed oscillatory power and functional connectivity for six large-scale brain networks, in delta, theta, alpha, beta and gamma frequency bands. We evaluated age-related differences in network power and connectivity between young and older participants, and their possible relationships with bimanual coordination performance. Results: We observed that the level of network segregation generally decreased with age, in line with fMRI findings. However, there was a relatively strong dependence on the frequency band and the brain network being considered. EEG connectivity in the sensorimotor network predicted motor performance differences across older individuals, particularly when neural oscillations in the beta frequency band were considered. Discussion: Our study provides electrophysiological evidence in support of the "de-differentiation hypothesis" for the aging brain, and for the existence of a clear link between the strength of EEG connectivity at rest and motor performance.

How aerobic exercise improves executive function in ADHD children: A resting-state fMRI study.

The aim of the study is to explore the functional magnetic resonance imaging (fMRI) characteristics of the improvement in executive function by aerobic exercise in children with attention deficit hyperactivity disorder (ADHD). Seventeen children with ADHD were selected for 8weeks of rope skipping aerobic training, and fMRI findings and executive function were examined before and after training. Regional homogeneity (ReHo) and degree centrality (DC) indexes were used in fMRI analysis, whereas the flanker task was used to test executive function. A paired t test was used to compare the fMRI indexes and response time of executive function before and after training. After aerobic exercise, the brain regions in which the ReHo value of ADHD children significantly increased included the left middle frontal gyrus and the right superior frontal gyrus; the brain region in which the DC value increased was the right posterior cingulate cortex. The flanker task response time decreased significantly (P < 0.05, after correction) after aerobic exercise. The study findings support the hypothesis that aerobic exercise can improve the executive function of ADHD children, and the brain mechanism involved is mainly related to the enhancement of spontaneous prefrontal lobe activity.

336 Connectivity Between Resting-State Networks and Mesial Temporal Regions May Distinguish Between Right and Left Mesial Temporal Lobe Epilepsy

INTRODUCTION: Mesial temporal lobe epilepsy (mTLE) is the most common surgical epilepsy. Confidently lateralizing mTLE preoperatively may be challenging with only noninvasive evaluations. Resting-state fMRI has been used to identify connectivity abnormalities in mTLE, involving mesial temporal structures and other networks such as default mode network (DMN). METHODS: We acquired 20 minutes of resting-state fMRI in 52 mTLE patients (28 females, 39.5 ± 12.2 years) and 52 age/gender matched controls. In mTLE patients versus controls, we evaluated fMRI functional connectivity of bilateral hippocampi/amygdalae and resting-state networks (default mode, central executive, salience, visual) using non-directed Pearson correlation (Z-scored), network-based statistic (NBS), and directed dynamic causal modeling (DCM). We separately acquired 2 minutes of resting-state SEEG in 17 unilateral mTLE patients (10 females, 34.6 ± 12.5 years). Using SEEG, we measured hippocampal versus extrahippocampal inward partial directed coherence (PDC) strength. RESULTS: Right mTLE patients demonstrated reduced undirected functional connectivity (Z) between right hippocampus and DMN compared to left mTLE patients and controls (p &lt; 0.001, corrected, ANOVA). These were not seen between the hippocampus and other resting-state networks. Focusing on mesial temporal and DMN nodes, NBS analysis demonstrated the network with most decreased connectivity in right versus left mTLE included right hippocampus/amygdala, bilateral inferior parietal, precuneus, and medial orbitofrontal, and right lateral orbitofrontal regions (9 of 14 nodes, p = 0.006, corrected). With model exceedance probabilities, DCM analysis revealed cross-hemispheric connectivity between hippocampi/amygdalae was mostly inward to epileptogenic-side. FMRI finding resembled SEEG findings, where inward PDC strength was higher in epileptogenic hippocampi compared to other regions in right/left mTLE (p &lt; 0.05, t-tests, corrected). CONCLUSION: If improved, this may aid surgical planning and reduce need for intracranial monitoring. Inward patterns using fMRI and SEEG appear altered at epileptogenic hippocampi, warranting further comparative study of directional connectivity between fMRI and SEEG.

Functional magnetic resonance imaging of brain activity during hybrid assistive limb intervention in a chronic spinal cord injury patient with C4 quadriplegia

Hybrid assistive limb (HAL) is a wearable robot, which has recently been used for the treatment of patients with movement disorders including spinal cord injury (SCI). Although several studies have indicated the effectiveness of HAL for SCI patients, changes in brain activity during the HAL intervention have not yet been fully characterized. A 19-year-old man with a chronic SCI resulting in complete C4 quadriplegia underwent five weeks of HAL training for a total of ten sessions. We evaluated his brain activity using task-induced functional MRI (fMRI) after the fourth, sixth and tenth HAL sessions. We also assessed the spasticity of this patient using the modified Ashworth scale (mAs). As controls for the task-induced fMRI, we examined the brain activity in two healthy subjects. The fMRI findings indicated an increased response to a motor imagery task in the patient's cerebral cortex compared to controls. In addition, the activation pattern in his cortex changed during the five weeks of HAL intervention. We observed increased cerebral lateralization in his primary motor cortex. We also found that the laterality index calculated for the precentral gyrus had a significant negative correlation with the total mAs score over the course of the HAL treatment. Our results indicate that the cerebral cortex of the present SCI patient was hyperactive during the imagery task, and the cortical activation was reduced with progression of the HAL treatment.

Multimodal meta-analysis of structural gray matter, neurocognitive and social cognitive fMRI findings in schizophrenia patients.

Neuroimaging research has shown that patients with schizophrenia (SCZ) present brain structural and functional alterations, but the results across imaging modalities and task paradigms are difficult to reconcile. Specifically, no meta-analyses have tested whether the same brain systems that are structurally different in SCZ patients are also involved in neurocognitive and social cognitive tasks. To answer this, we conducted separate meta-analyses of voxel-based morphometry, neurocognitive functional magnetic resonance imaging (fMRI), and social cognitive fMRI studies. Next, with a multimodal approach, we identified the common alterations across meta-analyses. Further exploratory meta-analyses were performed taking into account several clinical variables (illness duration, medication status, and symptom severity). A cluster covering the dorsomedial prefrontal cortex (dmPFC) and the supplementary motor area (SMA), and the right inferior frontal gyrus (IFG), presented shared structural and neurocognitive-related activation decreases, while the right angular gyrus presented shared decreases between structural and social cognitive-related activation. The exploratory meta-analyses replicated to some extent these findings, while new regions of alterations appeared in patient subgroups with specific clinical features. In conclusion, we found task-specific correlates of brain structure and function in SCZ, which help summarize and integrate a growing literature.

Reflections of the sensory findings in the central nervous system in patients with neuropathic pain.

This study aimed to evaluate whether there was a difference in functional magnetic resonance imaging (fMRI) findings in patients who were found having hyperalgesia or hypoesthesia according to Quantitative Sensory Tests (QST). Forty participants were included in the study: 20 with neuropathic pain (NP) due to cervical disc pathology (NP group) and 20 healthy volunteers. After obtaining the socio-demographic and clinical data of the participants, the painDETECT questionnaire was administered, followed by QST analysis to show the presence of hypoesthesia and/or hyperalgesia, and fMRI examinations, which included sensory stimulation of both extremities. Sensory threshold tests were found to be higher in the NP group compared with the healthy volunteers, and the heat pain threshold was found to be lower in the tests showing pain thresholds in the intergroup analyses (p < 0.05). The changes described were found in both painful and non-painful limbs. In the hypoesthetic NP group, a lower somatosensory cortex activity was found in non-painful limbs compared with the healthy volunteers (p < 0.05). In the unilateral hyperalgesic NP group, a lower somatosensory cortex activity was found on the painful side, and if the hyperalgesia was widespread, lower blood oxygen-level-dependent activity was also found in the operculum and insular cortex (p < 0.05). The patients with different phenotypes of NP had different activities in the areas related to the processing of pain, and were more prominent in patients with widespread hyperalgesia. Studies with larger numbers of patients are required for a definite statement.

Precentral gyrus and insula responses to stress vary with duration to diagnosis in functional seizures.

This study was undertaken to determine whether undiagnosed illness duration (time between functional seizures [FS] onset and diagnosis) is linked to differences in neural response and functional connectivity during processing of stressful experiences. Forty-nine participants with traumatic brain injury preceding the onset of FS confirmed by video-electroencephalography were recruited prospectively. Participants completed psychiatric symptom assessments before undergoing functional magnetic resonance imaging (fMRI) with an acute psychosocial stress task. Linear mixed effects (LME) analyses identified significant interactions between the factors of group (early vs. delayed diagnosis) and time lag to diagnosis on neural responses to stressful math performance and auditory feedback (corrected α=.05). Functional connectivity analysis utilized clusters from initial LME analyses as seed regions to determine significant interactions between these factors on network functional connectivity. Demographic and psychiatric symptom measures were similar between early (n=25) and delayed (n=24) groups. Responses to stressful math performance within the left anterior insula and functional connectivity between the anterior insula seed region and a precentral gyrus cluster were significantly negatively correlated with time lag to diagnosis for the early but not the delayed FS diagnosis group. There was no correlation between fMRI findings and psychiatric symptoms. This study indicates that aberrant left anterior insula activation and its functional connectivity to the precentral gyrus underlie differences in processing of stressful experiences in patients with delayed FS diagnosis. Follow-up comparisons suggest changes are associated with undiagnosed illness duration rather than psychiatric comorbidities and indicate a potential mechanistic association between neuropathophysiology, response to stressful experiences, and functional neuroanatomy in FS.

Electrophysiological resting state brain network and episodic memory in healthy aging adults

Recent studies have emphasized the changes in large-scale brain networks related to healthy aging, with the ultimate purpose to aid in differentiating normal neurocognitive aging from neurodegenerative disorders that also arise with age. Emerging evidence from functional Magnetic Resonance Imaging (fMRI) indicates that connectivity patterns within specific brain networks, especially the Default Mode Network (DMN), distinguish those with Alzheimer's disease from healthy individuals. In addition, disruptive alterations in the large-scale brain systems that support high-level cognition are shown to accompany cognitive decline at the behavioral level, which is commonly observed in the aging populations, even in the absence of disease. Although fMRI is useful for assessing functional changes in brain networks, its high costs and limited accessibility discourage studies that need large populations. In this study, we investigated the aging-effect on large-scale networks of the human brain using high-density electroencephalography and electrophysiological source imaging, which is a less costly and more accessible alternative to fMRI. In particular, our study examined a group of healthy subjects in the age range from middle- to older-aged adults, which is an under-studied range in the literature. Employing a high-resolution computation model, our results revealed age associations in the connectivity pattern of DMN in a consistent manner with previous fMRI findings. Particularly, in combination with a standard battery of cognitive tests, our data showed that in the posterior cingulate / precuneus area of DMN higher brain connectivity was associated with lower performance on an episodic memory task. The findings demonstrate the feasibility of using electrophysiological imaging to characterize large-scale brain networks and suggest that changes in network connectivity are associated with normal aging.

Involvement of brain structures in childhood epilepsy with centrotemporal spikes.

We aimed to investigate electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) findings to elucidate the interictal epileptiform discharge (IED)-related functional alterations in deep brain structures and the neocortex in childhood epilepsy with centrotemporal spikes (CECTS). Ten children with CECTS (median age 8.2years), referred to our hospital within a year of onset, were eligible for inclusion. They underwent EEG-fMRI recording during sleep. Llongitudinal evaluations, including medical examinations, intelligence tests, and questionnaires about developmental disabilities, were performed. The initial evaluation was performed at the same time as the EEG-fMRI, and the second evaluation was performed over 2years after the initial evaluation. Three children were unable to maintain sleep during the EEG-fMRI recording, and the remaining seven children were eligible for further assessment. All patients showed unilateral-dominant centrotemporal spikes during scans. One patient had only positive hemodynamic responses, while the others had both positive and negative hemodynamic responses. All patients showed IED-related hemodynamic responses in the bilateral neocortex. For deep brain structures, IED-related hemodynamic responses were observed in the cingulate gyrus (n=4), basal ganglia (n=3), thalamus (n=2), and default mode network (n=1). Seizure frequencies at the second evaluation were infrequent or absent, and the longitudinal results of intelligence tests and questionnaires were within normal ranges. We demonstrated that IEDs affect broad brain areas, including deep brain structures such as the cingulate gyrus, basal ganglia, and thalamus. Deep brain structures may play an important role in the pathophysiology of CECTS.

Brain signals of a Surprise-Actor-Critic model: Evidence for multiple learning modules in human decision making

Learning how to reach a reward over long series of actions is a remarkable capability of humans, and potentially guided by multiple parallel learning modules. Current brain imaging of learning modules is limited by (i) simple experimental paradigms, (ii) entanglement of brain signals of different learning modules, and (iii) a limited number of computational models considered as candidates for explaining behavior. Here, we address these three limitations and (i) introduce a complex sequential decision making task with surprising events that allows us to (ii) dissociate correlates of reward prediction errors from those of surprise in functional magnetic resonance imaging (fMRI); and (iii) we test behavior against a large repertoire of model-free, model-based, and hybrid reinforcement learning algorithms, including a novel surprise-modulated actor-critic algorithm. Surprise, derived from an approximate Bayesian approach for learning the world-model, is extracted in our algorithm from a state prediction error. Surprise is then used to modulate the learning rate of a model-free actor, which itself learns via the reward prediction error from model-free value estimation by the critic. We find that action choices are well explained by pure model-free policy gradient, but reaction times and neural data are not. We identify signatures of both model-free and surprise-based learning signals in blood oxygen level dependent (BOLD) responses, supporting the existence of multiple parallel learning modules in the brain. Our results extend previous fMRI findings to a multi-step setting and emphasize the role of policy gradient and surprise signalling in human learning.

Region-of-interest analysis approaches in neuroimaging studies of body ownership: An activation likelihood estimation meta-analysis.

How do we feel that we own our body? By manipulating the integration of multisensory signals and creating the illusory experience of owning external body parts and entire bodies, researchers have investigated the neurofunctional correlates of body ownership. Recent attempts to synthesize the neuroimaging literature of body ownership through meta-analysis have shown partly inconsistent results. A large proportion of functional magnetic resonance imaging (fMRI) findings on body ownership include analyses based on regions of interest (ROIs). This approach can produce inflated findings when results are synthesized in meta-analyses. We conducted a systematic search of the fMRI literature of ownership of body parts and entire bodies. Three activation likelihood estimation (ALE) meta-analyses were conducted, testing the impact of including ROI-based findings. When both whole-brain and ROI-based results were included, frontal and posterior parietal multisensory areas were associated with body ownership. When only ROI-based results were included, larger areas of the frontal and posterior parietal cortices and the middle occipital gyrus were associated with body ownership. A whole-brain meta-analysis, excluding ROI-based results, found no significant convergence of activation across the brain. These findings highlight the difficulty of quantitatively synthesizing a neuroimaging field where a large part of the literature is based on findings from ROI-based analyses. We discuss these findings in the light of current practices within this field of research and highlight current problems of meta-analytic approaches of body ownership. We recommend the sharing of unthresholded data as a means to facilitate future meta-analyses of the neuroimaging literature of body ownership.