PV and SST neurons in the anterior cingulate cortex regulate social disorders in adulthood induced by sensory abnormalities in childhood.

OBJECTIVE: Childhood sensory abnormalities experience has a crucial influence on the structure and function of the adult brain. The underlying mechanism of neurological function induced by childhood sensory abnormalities experience is still unclear. Our study was to investigate whether the GABAergic neurons in the anterior cingulate cortex (ACC) regulate social disorders caused by childhood sensory abnormalities experience. METHODS: We used two mouse models, complete Freund's adjuvant (CFA) injection mice and bilateral whisker trimming (BWT) mice in childhood. We applied immunofluorescence, chemogenetic and optogenetic to study the mechanism of parvalbumin (PV) neurons and somatostatin (SST) neurons in ACC in regulating social disorders induced by sensory abnormalities in childhood. RESULTS: Inflammatory pain in childhood leads to social preference disorders, while BWT in childhood leads to social novelty disorders in adult mice. Inflammatory pain and BWT in childhood caused an increase in the number of PV and SST neurons, respectively, in adult mice ACC. Inhibiting PV neurons in ACC improved social preference disorders in adult mice that experienced inflammatory pain during childhood. Inhibiting SST neurons in ACC improved social novelty disorders in adult mice that experienced BWT in childhood. CONCLUSIONS: Our study reveals that PV and SST neurons of the ACC may play a critical role in regulating social disorders induced by sensory abnormalities in childhood.

Characteristics of traumatic brain injury models: from macroscopic blood flow changes to microscopic mitochondrial changes.

Controlled cortical impingement is a widely accepted method to induce traumatic brain injury to establish a traumatic brain injury animal model. A strike depth of 1 mm at a certain speed is recommended for a moderate brain injury and a depth of > 2 mm is used to induce severe brain injury. However, the different effects and underlying mechanisms of these two model types have not been proven. This study investigated the changes in cerebral blood flow, differences in the degree of cortical damage, and differences in motor function under different injury parameters of 1 and 2 mm at injury speeds of 3, 4, and 5 m/s. We also explored the functional changes and mitochondrial damage between the 1 and 2 mm groups in the acute (7 days) and chronic phases (30 days). The results showed that the cerebral blood flow in the injured area of the 1 mm group was significantly increased, and swelling and bulging of brain tissue, increased vascular permeability, and large-scale exudation occurred. In the 2 mm group, the main pathological changes were decreased cerebral blood flow, brain tissue loss, and cerebral vasospasm occlusion in the injured area. Substantial motor and cognitive impairments were found on day 7 after injury in the 2 mm group; at 30 days after injury, the motor function of the 2 mm group mice recovered significantly while cognitive impairment persisted. Transcriptome sequencing showed that compared with the 1 mm group, the 2 mm group expressed more ferroptosis-related genes. Morphological changes of mitochondria in the two groups on days 7 and 30 using transmission electron microscopy revealed that on day 7, the mitochondria in both groups shrank and the vacuoles became larger; on day 30, the mitochondria in the 1 mm group became larger, and the vacuoles in the 2 mm group remained enlarged. By analyzing the proportion of mitochondrial subgroups in different groups, we found that the model mice had different patterns of mitochondrial composition at different time periods, suggesting that the difference in the degree of damage among traumatic brain injury groups may reflect the mitochondrial changes. Taken together, differences in mitochondrial morphology and function between the 1 and 2 mm groups provide a new direction for the accurate classification of traumatic brain injury. Our results provide reliable data support and evaluation methods for promoting the establishment of standard mouse controlled cortical impingement model guidelines.