Neuroscience
-
Previous studies have reported the essence of the sensory-based properties of human brain function, in which mental imagery is of great importance. In this study, we explored the association between the activities of two special regions, i.e., the primary visual area (PVA), which is the classically dominant sensory region, and the default mode network (DMN), which is the classical supra-sensory region, with a focus on their linkage in visual mental imagery. For this purpose, we collected fMRI data from 30 healthy participants (15 males; 22.37 ± 2.52 years) during the resting state and a mental rotation task state. ⋯ Furthermore, the results showed the steady and tight intrinsic association between the activities of the PVA and the DMN, with the prefrontal cortex and the MTL regions being found to be consistently involved in the resting-state brain. It also was suggested that the observed association between the PVA and the DMN was highly reproducible for the mental rotation task. Together, these observations, from the perspective of visual mental imagery, provided experimental evidence for the robustness and stability of the detailed map of the associations between the activities of the PVA and the DMN.
-
Distinguishing between familiar and unfamiliar individuals is an important task that shapes the expression of social behavior. As such, identifying the neural populations involved in processing and learning the sensory attributes of individuals is important for understanding mechanisms of behavior. Catecholamine-synthesizing neurons have been implicated in sensory processing, but relatively little is known about their contribution to auditory learning and processing across various vertebrate taxa. ⋯ The pattern of EGR-1 expression in the locus coeruleus was similar to that observed in two auditory processing areas implicated in auditory learning and memory, namely the caudomedial nidopallium (NCM) and the caudal medial mesopallium (CMM), suggesting a contribution of catecholamines to sensory processing. Consistent with this, the pattern of catecholaminergic innervation onto auditory neurons co-varied with the degree to which song playback affected the relative intensity of EGR-1 expression. Together, our data support the contention that catecholamines like norepinephrine contribute to social recognition and the processing of social information.
-
In Alzheimer's disease (AD) the blood-brain barrier (BBB) is compromised, thus therapeutic targeting of the BBB to enhance its integrity and function could be a unique approach to treat, slow or hold the progression of AD. Recently, we have developed an in vitro high-throughput screening assay to screen for compounds that increase the integrity of a cell-based BBB model. Results from primary screen identified multiple hit compounds that enhanced the monolayer integrity. ⋯ Such effects were associated with increased levels of tight junction proteins such as claudin-5 and/or ZO-1, and Aβ major transport proteins LRP1 and P-glycoprotein. In vivo studies for α-tocopherol were performed in AD mouse model; consistent with the in vitro results α-tocopherol significantly increased BBB integrity measured by IgG extravasation, and reduced brain Aβ levels. In conclusion, findings support our developed cell-based BBB model as a functional predictive in vivo tool to select hit compounds, and suggest that enhancing BBB tightness and function has the potential to reduce Aβ pathology associated with AD.
-
Astrocytes and microglia appear central to the initiation and progression of neuroinflammation in Alzheimer's disease (AD). In this study, inflammation was mimicked by Aβ1-42 treatment of rat astrocytes (RA) and N9 microglia cell lines. Inflammation induced by Aβ1-42 can be inhibited by pyrrolidine dithiocarbamic acid (PDTC), indicating that the NF-κB signal pathway is involved in inflammation. ⋯ In addition, Res decreased the nuclear translocation of NF-κB/p65 when checked by immunofluorescence. Furthermore, Res increased the expression of NF-κB/p65 and decreased the expression of p-IκB in the cytoplasm in both RA and N9 microglia. Taken together, the present data indicate that Res reduces inflammation in RA and N9 microglia, and the anti-NF-κB signal pathway may be one of the target mechanisms.
-
Cortices are non-uniform in their capacity for adaptive changes. In cat area 17, pinwheel centers of the orientation map demonstrated much greater selectivity shifts after the orientation adaptation than the iso-orientation domains (Dragoi et al., 2001a). However, whether this heterogeneity exists in other visual cortical regions remains unclear. ⋯ However, at either pinwheel centers or iso-orientation domains, the selectivity shifts in area 21a were all consistently greater than those in area 17, even though the heterogeneity in the orientation distribution was similar in the two areas. More importantly, in our short-term adaptation protocol, orientation adaptation in area 17 resulted in mostly repulsive shifts at the pinwheel center region, while in area 21a, it induced both repulsive and attractive effects. These results suggest that both common and distinct strategies exist for orientation adaptation across cortices and sub-regions.