Early tolerability of Comirnaty vaccine in patients with chronic neurological diseases.

Patients with chronic neurological diseases may have predisposing risk factors for severe COVID-19 and should be considered as priority candidates for SARS-CoV-2 vaccination. Nevertheless, the safety of RNA vaccine was evaluated in healthy volunteers or in patients with stable chronic medical conditions excluding patients with chronic neurological diseases. We report here the early tolerability of Comirnaty vaccine in 36 patients with chronic neurological diseases and demonstrate good early tolerability, better than found in healthy people in phase 3 trials.

[Auditory perception and language: functional imaging of speech sensitive auditory cortex]. / Perception auditive et langage: imagerie fonctionnelle du cortex auditif sensible au langage.

Since the description of cortical deafness, it has been known that the superior temporal cortex is bilaterally involved in the initial stages of language auditory perception but the precise anatomical limits and the function of this area remain debated. Here we reviewed more than 40 recent papers of positron emission tomography and functional magnetic resonance imaging related to language auditory perception, and we performed a meta-analysis of the localization of the peaks of activation in the Talairach's space. We found 8 studies reporting word versus non-word listening contrasts with 54 activation peaks in the temporal lobes. These peaks clustered in a bilateral and well-limited area of the temporal superior cortex, which is here operationally defined as the speech sensitive auditory cortex. This area is more than 4cm long, located in the superior temporal gyrus and the superior temporal sulcus, both anterior and posterior to Heschl's gyrus. It do not include the primary auditory cortex nor the ascending part of the planum temporale. The speech sensitive auditory cortex is not activated by pure tones, environmental sounds, or attention directed toward elementary components of a sound such as intensity, pitch, or duration, and thus has some specificity for speech signals. The specificity is not perfect, since we found a number of non-speech auditory stimuli activating the speech sensitive auditory cortex. Yet the latter studies always involve auditory perception mechanisms which are also relevant to speech perception either at the level of primitive auditory scene analysis processes, or at the level of specific schema-based recognition processes. The dorsal part of the speech sensitive auditory cortex may be involved in primitive scene analysis processes, whereas distributed activation of this area may contribute to the emergence of a broad class of "voice" schemas and of more specific "speech schemas/phonetic modules" related to different languages. In addition, this area is activated by language-related lip movement, suggesting that a multimodal integration of the auditory and the visual information relevant in speech perception occurs at this level. Finally, there is a task-related top-down modulation of the pattern of activation of the speech sensitive auditory cortex which may reflect the fact that the different parts of this structure are connected to different down-stream cortical regions involved in the neural processing of different types of tasks.

Neural substrates for the perception of acutely induced dyspnea.

Little is currently known about the brain regions involved in central processing of dyspnea. We performed a functional imaging study with positron emission tomography (PET) to assess brain activation associated with an important component of dyspnea, respiratory discomfort during loaded breathing. We induced respiratory discomfort in eight healthy volunteers by adding external resistive loads during inspiration and expiration. Brain activation was characterized by a significant increase in regional cerebral blood flow (rCBF) (Z score of peak activation > 3.09). As compared with the unloaded control condition, high loaded breathing was associated with neural activation in three distinct brain regions, the right anterior insula, the cerebellar vermis, and the medial pons (respective Z scores = 4.75, 4.44, 4.41). For these brain regions, we further identified a positive correlation between rCBF and the perceived intensity of respiratory discomfort (respective Z scores = 4.45, 4.75, 4.74) as well as between rCBF and the mean amplitude of mouth pressure swings (DeltaPm), the index of the main generating mechanism of the sensation (respective Z scores = 4.67, 4.36, 4.31), suggesting a common activation by these two parameters. Furthermore, we identified an area in the right posterior cingulate cortex where neural activation was specifically associated with perceived intensity of respiratory discomfort that is not related to DeltaPm (Z score = 4.25). Our results suggest that respiratory discomfort related to loaded breathing may be subserved by two distinct neural networks, the first being involved in the concomitant processing of the genesis and perception of respiratory discomfort and the second in the modulation of perceived intensity of the sensation by various factors other than its main generating mechanism, which may include emotional processing.

Temporal lobe dysfunction in childhood autism: a PET study. Positron emission tomography.

OBJECTIVE: The nature of the underlying brain dysfunction of childhood autism, a life-long severe developmental disorder, is not well understood. Although researchers using functional brain imaging have attempted to contribute to this debate, previous studies have failed to report consistent localized neocortical brain dysfunction. The authors reasoned that early methods may have been insensitive to such dysfunction, which may now be detectable with improved technology. METHOD: To test this hypothesis, regional cerebral blood flow was measured with positron emission tomography (PET) in 21 children with primary autism and in 10 nonautistic children with idiopathic mental retardation. Autistic and comparison groups were similar in average age and developmental quotients. The authors first searched for focal brain dysfunction in the autistic group by using a voxel-based whole brain analysis and then assessed the sensitivity of the method to detect the abnormality in individual children. An extension study was then performed in an additional group of 12 autistic children. RESULTS: The first autistic group had a highly significant hypoperfusion in both temporal lobes centered in associative auditory and adjacent multimodal cortex, which was detected in 76% of autistic children. Virtually identical results were found in the second autistic group in the extension study. CONCLUSIONS: PET and voxel-based image analysis revealed a localized dysfunction of the temporal lobes in school-aged children with idiopathic autism. Further studies will clarify the relationships between these temporal abnormalities and the perceptive, cognitive, and emotional developmental abnormalities characteristic of this disorder.

A cortical region sensitive to auditory spectral motion.

The functional architecture of human auditory cortex is still poorly understood compared with that of visual cortex, yet anatomical and electrophysiological studies in non-human primates suggest that the auditory cortex also might be functionally specialized, in a model of parallel and hierarchical organization. In particular, spectral changes such as the formant transitions of speech, or spectral motion (SM) by analogy with visual motion, could be processed in specialized cortical regions. In this study, positron emission tomography (PET) was used to identify which auditory cortical region are involved in SM analysis. We found that a bilateral secondary auditory cortical region, located in the caudal-lateral belt of auditory cortex, was more sensitive to auditory stimuli containing spectral changes than to matched stimuli with a stationary spectral profile. This result suggests that analogies between sensory systems could prove useful in the research into the functional organization of the auditory cortex.

The functional anatomy of sound intensity discrimination.

The human neuroanatomical substrate of sound intensity discrimination was investigated by combining psychoacoustics and functional neuroimaging. Seven normal subjects were trained to detect deviant sounds presented with a slightly higher intensity than a standard harmonic sound, using a Go/No Go paradigm. Individual psychometric curves were carefully assessed using a three-step psychoacoustic procedure. Subjects were scanned while passively listening to the standard sound and while discriminating changes in sound intensity at four different performance levels (d' = 1.5, 2.5, 3.5, and 4.5). Analysis of regional cerebral blood flow data outlined activation, during the discrimination conditions, of a right hemispheric frontoparietal network already reported in other studies of selective or sustained attention to sensory input, and in which activity appeared inversely proportional to intensity discriminability. Conversely, a right posterior temporal region included in secondary auditory cortex was activated during discrimination of sound intensity independently of performance level. These findings suggest that discrimination of sound intensity involves two different cortical networks: a supramodal right frontoparietal network responsible for allocation of sensory attentional resources, and a region of secondary auditory cortex specifically involved in sensory computation of sound intensity differences.

Lateralization of speech and auditory temporal processing.

To investigate the role of temporal processing in language lateralization, we monitored asymmetry of cerebral activation in human volunteers using positron emission tomography (PET). Subjects were scanned during passive auditory stimulation with nonverbal sounds containing rapid (40 msec) or extended (200 msec) frequency transitions. Bilateral symmetric activation was observed in the auditory cortex for slow frequency transitions. In contrast, left-biased asymmetry was observed in response to rapid frequency transitions due to reduced response of the right auditory cortex. These results provide direct evidence that auditory processing of rapid acoustic transitions is lateralized in the human brain. Such functional asymmetry in temporal processing is likely to contribute to language lateralization from the lowest levels of cortical processing.