Ca2+-based neural activity recording for rapidly screening behavioral correlates of the claustrum in freely behaving mice.

The claustrum has been hypothesized to participate in high-order brain functions, but experimental studies to demonstrate these functions are currently lacking. Neural activity recording of the claustrum in freely-behaving animals allows for correlating claustral activities with specific behaviors. However, previously utilized methods for studying the claustrum make it difficult to monitor neural activity patterns of freely-behaving animals in real time. Here we applied fiber photometry to monitor Ca2+ activity in the claustrum of freely-behaving mice. Using this method, we were able to achieve Ca2+ activity recording in both anesthetized and freely-behaving mice. We found that the dynamics of Ca2+ activity depended on anesthesia levels. As compared to the use of genetically encoded Ca2+ indicators that requires a few weeks of virus-dependent expression, we used a synthetic fluorescent Ca2+-sensitive dye, Oregon green 488 BAPTA-1, that allows for rapidly screening neural activity of interest within a few hours that relates to certain behaviors. In this way, we found the correlation between Ca2+ activity and specific behaviors, such as approaching an object. Our work offers an effective method for recording neural activity in the claustrum and thus for rapidly screening any behavioral relevance of the claustrum in freely-behaving mice.

Characteristics of hepatocellular carcinoma in a high arsenicism area in Taiwan: a case-control study.

Arsenic contamination of drinking water is noticeably linked to the occurrence of skin, bladder, lung cancers, and hepatocellular carcinoma (HCC). Blackfoot disease (BFD) caused by arsenicosis is endemic in southwestern Taiwan, where artesian well water contains high concentrations of arsenic, and mortality from HCC shows a dose-response increase by concentration of arsenic in the well water. This case-control study was conducted to examine the clinical characteristics of HCC patients of BFD-endemic area. A total of 65 HCC cases (54 men and 11 women) were recruited from the BFD-endemic areas. The clinicopathological features were compared with 130 age- and sex-matched HCC control patients from non-BFD-endemic areas. Characteristics analyzed included hepatitis viral infection status, hepatitis activity, liver function, histological findings, computed tomography scan characteristics, and patient survival. No differences were observed between HCC patients or their tumors, from study and control areas.