Extra-Axial Inflammatory Signal in Parameninges in Migraine with Visual Aura.

OBJECTIVE: Cortical spreading depression (CSD) underlies the neurobiology of migraine with aura (MWA). Animal studies reveal networks of microvessels linking brain-meninges-bone marrow. CSD activates the trigeminovascular system, evoking a meningeal inflammatory response. Accordingly, this study examines the upregulation of an inflammatory marker in extra-axial tissues in migraine with visual aura. METHODS: We used simultaneously acquired 11 C-PBR28 positron emission tomography/magnetic resonance imaging data of 18kDa translocator protein (an inflammatory marker) in MWA patients (n = 11) who experienced headaches and visual aura in the preceding month. We measured mean tracer uptake (standardized uptake value ratio [SUVR]) in 4 regions of interest comprising the meninges plus the adjacent overlying skull bone (parameningeal tissues [PMT]). These data were compared to healthy controls and patients with pain (chronic low back pain). RESULTS: MWA had significantly higher mean SUVR in PMT overlying occipital cortex than both other groups, although not in the PMT overlying 3 other cortical areas. A positive correlation was also found between the number of visual auras and tracer uptake in occipital PMT. INTERPRETATION: A strong persistent extra-axial inflammatory signal was found in meninges and calvarial bone overlying the occipital lobe in migraine with visual auras. Our findings are reminiscent of CSD-induced meningeal inflammation and provide the first imaging evidence implicating inflammation in the pathophysiology of migraine meningeal symptoms. We suspect that this inflammatory focus results from a signal that migrates from underlying brain and if so, may implicate newly discovered bridging vessels that crosstalk between brain and skull marrow, a finding of potential relevance to migraine and other neuroinflammatory brain disorders. ANN NEUROL 2020;87:939-949.

Autistic adults exhibit highly precise representations of others' emotions but a reduced influence of emotion representations on emotion recognition accuracy.

To date, studies have not yet established the mechanisms underpinning differences in autistic and non-autistic emotion recognition. The current study first investigated whether autistic and non-autistic adults differed in terms of the precision and/or differentiation of their visual emotion representations and their general matching abilities, and second, explored whether differences therein were related to challenges in accurately recognizing emotional expressions. To fulfil these aims, 45 autistic and 45 non-autistic individuals completed three tasks employing dynamic point light displays of emotional facial expressions. We identified that autistic individuals had more precise visual emotion representations than their non-autistic counterparts, however, this did not confer any benefit for their emotion recognition. Whilst for non-autistic people, non-verbal reasoning and the interaction between precision of emotion representations and matching ability predicted emotion recognition, no variables contributed to autistic emotion recognition. These findings raise the possibility that autistic individuals are less guided by their emotion representations, thus lending support to Bayesian accounts of autism.

Independent measurement of face perception, face matching, and face memory reveals impairments in face perception and memory, but not matching, in autism.

Multiple psychological processes are required in order for a face to be recognised from memory. However, when testing face memory using tasks such as the Cambridge Face Memory Task (CFMT), it is rare for studies to attempt to account for individual differences in face perception and face matching in order to isolate variance in face memory specifically. In Study 1, the Oxford Face Matching Test (OFMT) was used to assess face matching and face perception in a large sample of participants (N = 1,112). Results revealed independent contributions of face perception and matching to CFMT performance, and these results replicated with the Glasgow Face Matching Test. In Study 2, the same procedure was used to test face perception, face matching and face memory in a group of 57 autistic adults and a matched neurotypical control group. Results revealed impaired face perception and memory in the individuals with autism, but intact face matching. Face perception may therefore act as a potential intervention target for individuals with autism who exhibit face recognition impairments.

Face memory and face perception in autism.

LAY ABSTRACT: It is well known that some people with autism have difficulties recognizing faces. It is generally thought that this is not because autistic individuals cannot perceive faces, but because autistic individuals have greater problems than people without autism in remembering faces. Here, we worked with a group of autistic adults and a group of non-autistic adults to test their ability to perceive and remember faces. We also asked each person to report any difficulties that they have with recognizing faces in everyday life. We find that, as a group, people with autism have difficulties with both remembering and perceiving faces, and report more problems recognizing faces in everyday life. However, it is worth noting that we observed a wide range of scores in the group of people with autism, with some autistic participants scoring as well as the group of people without autism.

Are Autistic and Alexithymic Traits Distinct? A Factor-Analytic and Network Approach.

Despite the heterogeneity in autism, socioemotional difficulties are often framed as universal. Increasing evidence, however, suggests that socioemotional difficulties may be explained by alexithymia, a distinct yet frequently co-occurring condition. If, as some propose, autistic traits are responsible for socioemotional impairments, then alexithymia may itself be a symptom of autism. We aimed to determine whether alexithymia should be considered a product of autism or regarded as a separate condition. Using factor-analytic and network approaches, we provide evidence that alexithymic and autistic traits are distinct. We argue that: (1) models of socioemotional processing in autism should conceptualise difficulties as intrinsic to alexithymia; and (2) assessment of alexithymia is crucial for diagnosis and personalised interventions.

Alexithymia explains atypical spatiotemporal dynamics of eye gaze in autism.

Recognition of emotional facial expressions is considered to be atypical in autism. This difficulty is thought to be due to the way that facial expressions are visually explored. Evidence for atypical visual exploration of emotional faces in autism is, however, equivocal. We propose that, where observed, atypical visual exploration of emotional facial expressions is due to alexithymia, a distinct but frequently co-occurring condition. In this eye-tracking study we tested the alexithymia hypothesis using a number of recent methodological advances to study eye gaze during several emotion processing tasks (emotion recognition, intensity judgements, free gaze), in 25 adults with, and 45 without, autism. A multilevel polynomial modelling strategy was used to describe the spatiotemporal dynamics of eye gaze to emotional facial expressions. Converging evidence from traditional and novel analysis methods revealed that atypical gaze to the eyes is best predicted by alexithymia in both autistic and non-autistic individuals. Information theoretic analyses also revealed differential effects of task on gaze patterns as a function of alexithymia, but not autism. These findings highlight factors underlying atypical emotion processing in autistic individuals, with wide-ranging implications for emotion research.

Imaging of neuroinflammation in migraine with aura: A [11C]PBR28 PET/MRI study.

OBJECTIVE: To determine if migraine with aura is associated with neuroinflammation, which has been suggested by preclinical models of cortical spreading depression (CSD) as well as imaging of human pain conditions. METHODS: Thirteen migraineurs with aura and 16 healthy controls received integrated PET/MRI brain scans with [11C]PBR28, a radioligand that binds to the 18 kDa translocator protein, a marker of glial activation. Standardized uptake value ratio (SUVR) was compared between groups, and regressed against clinical variables, using region of interest and whole-brain voxelwise analyses. RESULTS: Compared to healthy controls, migraineurs demonstrated SUVR elevations in nociceptive processing areas (e.g., thalamus and primary/secondary somatosensory and insular cortices) as well as in areas previously shown to be involved in CSD generation (visual cortex). SUVR levels in frontoinsular cortex, primary/secondary somatosensory cortices, and basal ganglia were correlated with frequency of migraine attacks. CONCLUSIONS: These findings demonstrate that migraine with aura is associated with neuroimmune activation/neuroinflammation, and support a possible link between CSD and glial activation, previously observed in animals.

Knowledge of resting heart rate mediates the relationship between intelligence and the heartbeat counting task.

Evidence suggests that intelligence is positively associated with performance on the heartbeat counting task (HCT). The HCT is often employed as measure of interoception - the ability to perceive the internal state of one's body - however it's use remains controversial as performance on the HCT is strongly influenced by knowledge of resting heart rate. This raises the possibility that heart rate knowledge may mediate the previously-observed association between intelligence and HCT performance. Study One demonstrates an association between intelligence and HCT performance (N = 94), and Study Two demonstrates that this relationship is mediated by knowledge of the average resting heart rate (N = 134). These data underscore the need to account for the influence of prior knowledge and beliefs when examining individual differences in cardiac interoceptive accuracy using the HCT.