Category-Based Effect on False Memory of People with Down Syndrome.

Background: People with Down syndrome (DS) are deficient in verbal memory but relatively preserved in visuospatial perception. Verbal memories are related to semantic knowledge. Receptive ability is better than expressive ability in people with DS but still seriously lags behind their age-matched controls. This lag may result in the weak semantic integration of people with DS. Aims: This study aimed to examine the ability of semantic integration of people with DS by using false-memory tasks. Possible differences in the number of false memories induced by nouns and verbs were of focus. Methods and Procedures: Two phases were involved in the false-memory task. In the study phase, ten-word lists with semantically related associates were presented. In the recognition phase, judgments were to be made about whether the words presented had been heard before. Three types of words were tested: previously presented associates, semantically related lures, and semantically unrelated new words. Outcomes and Results: People with DS overall showed the lowest accuracy among groups in response to tested word types. In the processing of lures, people with DS were worse in recognition than MA controls. In processing unrelated words, people with DS responded least accurately to all types of words compared to control groups. In the processing of associates, people with DS showed similar recognition rates as the MA controls but were less accurate than the CA controls. No difference was observed between nouns and verbs in recognizing word types among groups, though faster responses to nouns than to verbs emerged in college students. Further analyses on topic-wised comparisons of errors across syntactic categories revealed differences in specific concepts among groups, suggesting people with DS were atypical in semantic organization. Conclusions and Implications: People with DS showed mixed patterns in semantic integration by false-memory tasks with delay to associates and deviance to lures together with unrelated words. People with DS showed distinct patterns in processing nouns and verbs while conducting topic-wise comparisons, suggesting that they formed false memories differently based on distinct syntactic categories. We concluded that people with DS develop a deviant semantic structure, hence showing problems in language and social cognition. Category-based rehabilitation is suggested to be implemented for people with DS to improve their semantic knowledge through lexical connections.

Computerized False Belief Tasks Impact Mentalizing Ability in People with Williams Syndrome.

People with Williams syndrome (WS) are characterized by hyper sociability, fluency in languages, and advantageous face-processing skills, leading to the proposal of a social module. Previous studies on the mentalizing abilities of people with WS using two-dimensional pictures, including normal-like, delayed, and deviant behaviors, have yielded mixed results. Thus, this study examined the mentalizing ability of people with WS through structured computerized animations of false belief tasks to investigate whether inferences about other people's minds can be improved in this population. Participants were shown animations containing unexpected location and content changes. After viewing each animation, participants had to answer four types of questions relating to character identification, reality, memory, and false belief. Their responses were recorded and analyzed. A comprehension of false belief was observed in 4-year-old healthy children, whereas children with WS showed enhanced comprehension of false belief (until they attained a chronological age [CA] of 5.9 years), suggesting an improvement in the theory of mind resulting from viewing structured computerized animations. This age is earlier than that reported by previous studies for using theory of mind to pass false belief tests (CA 9 years), even challenging the age at which individuals failed to pass the tests (CA 17.11 years). Structured computerized animations enhanced the mentalizing ability of people with WS to a certain extent. Compared to the typically developing controls, people with WS presented with a lower developmental level in processing false belief tasks. This study has educational implications for the development of computerized social skills interventions for people with WS.

Engineered Cell-Derived Microparticles Bi2Se3/DOX@MPs for Imaging Guided Synergistic Photothermal/Low-Dose Chemotherapy of Cancer.

Cell-derived microparticles, which are recognized as nanosized phospholipid bilayer membrane vesicles, have exhibited great potential to serve as drug delivery systems in cancer therapy. However, for the purpose of comprehensive therapy, microparticles decorated with multiple therapeutic components are needed, but effective engineering strategies are limited and still remain enormous challenges. Herein, Bi2Se3 nanodots and doxorubicin hydrochloride (DOX) co-embedded tumor cell-derived microparticles (Bi2Se3/DOX@MPs) are successfully constructed through ultraviolet light irradiation-induced budding of parent cells which are preloaded with Bi2Se3 nanodots and DOX via electroporation. The multifunctional microparticles are obtained with high controllability and drug-loading capacity without unfavorable membrane surface destruction, maintaining their excellent intrinsic biological behaviors. Through membrane fusion cellular internalization, Bi2Se3/DOX@MPs show enhanced cellular internalization and deepened tumor penetration, resulting in extreme cell damage in vitro without considering endosomal escape. Because of their distinguished photothermal performance and tumor homing target capability, Bi2Se3/DOX@MPs exhibit admirable dual-modal imaging capacity and outstanding tumor suppression effect. Under 808 nm laser irradiation, intravenous injection of Bi2Se3/DOX@MPs into H22 tumor-bearing mice results in remarkably synergistic antitumor efficacy by combining photothermal therapy with low-dose chemotherapy in vivo. Furthermore, the negligible hemolytic activity, considerable metabolizability, and low systemic toxicity of Bi2Se3/DOX@MPs imply their distinguished biocompatibility and great potential for tumor theranostics.