bioRxiv Subject Collection: Neuroscience's Journal
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Sunday, February 11th, 2024
| Time |
Event |
| 4:42a |
SARS-COV-2 induces blood-brain barrier and choroid plexus barrier impairments and vascular inflammation in mice
The coronavirus disease of 2019 (COVID-19) pandemic that has led to more than 700 million confirmed cases and near 7 million deaths. Although Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) virus mainly infects the respiratory system, neurological complications are widely reported in both acute infection and long-COVID cases. Despite the success of vaccines and antiviral treatments, neuroinvasiveness of SARS-CoV-2 remains as an important question, which is also centered on the mystery whether the virus is capable of breaching the barriers into the central nervous system. By studying the K18-hACE2 infection model, we observed clear evidence of microvascular damage and breakdown of the blood-brain barrier (BBB). Mechanistically, SARS-CoV-2 infection caused pericyte damage, tight junction loss, endothelial activation and vascular inflammation, which together drive microvascular injury and BBB impairment. In addition, the blood-cerebrospinal fluid barrier at the choroid plexus was also impaired after infection. Therefore, cerebrovascular and choroid plexus dysfunctions are important aspects of COVID-19 and may contribute to the neurological complications both acutely and in long COVID. | | 2:31p |
The Mouse Inferior Colliculus Responds Preferentially to Non-Ultrasonic Vocalizations
The inferior colliculus (IC), the midbrain auditory integration center, analyzes information about social vocalizations and provides substrates for higher level processing of vocal signals. We used multi-channel recordings to characterize and localize responses to social vocalizations and synthetic stimuli within the IC of female and male mice, both urethane-anesthetized and unanesthetized. We compared responses to ultrasonic vocalizations (USVs) with other vocalizations in the mouse repertoire and related vocal responses to frequency tuning, IC subdivisions, and sex. Responses to lower frequency, broadband social vocalizations were widespread in IC, well represented throughout the tonotopic axis, across subdivisions, and in both sexes. Responses to USVs were much more limited. Although we observed some differences in tonal and vocal responses by sex and subdivision, representations of vocal responses by sex and subdivision were largely the same. For most units, responses to vocal signals occurred only when frequency response areas overlapped with spectra of the vocal signals. Since tuning to frequencies contained within the highest frequency USVs is limited (< 15% of IC units), responses to these vocalizations are correspondingly limited (< 5% of sound-responsive units). These results highlight a paradox of USV processing in some rodents: although USVs are the most abundant social vocalization, their representation and the representation of corresponding frequencies is less than lower frequency social vocalizations. We interpret this paradox in light of observations suggesting that USVs with lower frequency elements (<50 kHz) are associated with increased emotional intensity and engage a larger population of neurons in the mouse auditory system. | | 3:45p |
Exploring the impact of interthalamic adhesion on human cognition: insights from healthy subjects and thalamic stroke patients
Background and Objectives: Interthalamic adhesion (IA), also known as the massa intermedia, is a structure that connects the median borders of both thalami across the third ventricle. Given it is difficult to identify on routine neuroimaging, its anatomical variants and function remain poorly studied. The main objective of this study was to clarify the role of IA on cognition. Our main hypothesis was that thalamus stroke patients with an IA would show better performance on neuropsychological tests than individuals without an IA through possible compensatory mechanisms. Methods: The study comprised a group of healthy subjects and a cohort of patients with isolated thalamic strokes at the chronic stage. All participants underwent 3T research T1w and FLAIR MRI as well as a neuropsychological assessment. The presence or absence of an IA and type of IA anatomical variant were evaluated by two independent reviewers. Results: 42 healthy subjects (mean age= 49) and 40 patients (mean age= 51) were finally included. 76% of participants had an IA, with a higher prevalence among women (92%) than men (61%). The presence or absence of an IA did not effect the neuropsychological performance of healthy subjects nor did the type of IA variant. Across all the tests, patients with an IA (n = 18) showed the lowest BF10 (157) while those without an IA (n = 10) exhibited the highest BF10 (10648) when compared to healthy subjects using a Bayesian rmANOVA. More specifically, patients without an IA performed more poorly in the verbal memory or Stroop task versus healthy subjects than patients with an IA. This effect was not explained by age, laterality of the infarct, volume or, localization of the lesion. Patients with an IA and lesions extending into the IA presented a similar trend to non-IA subjects which could however be explained by a greater volume of lesions. Discussion: IA does not appear to have a major role in cognition for healthy subjects but could play a compensatory part in patients with thalamic lesions. |
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