Patients with Parkinson's disease (PD), a degenerative disorder primarily affecting the nigrostriatal dopamine system, exhibit deficits in selecting task-relevant stimuli in the presence of irrelevant stimuli, such as in visual search tasks. However, results from previous studies suggest that these deficits may vary as a function of whether selection must rely primarily on the "bottom-up" salience of the target relative to background stimuli, or whether "top-down" information about the identity of the target is available to bias selection. In the present study, moderate-to-severe medicated PD patients and age-matched controls were tested on six visual search tasks that systematically varied the relationship between bottom-up target salience (feature search, noisy feature search, conjunction search) and top-down target knowledge (Target Known versus Target Unknown). Comparison of slope and intercepts of the RT x set size function provided information about the efficiency of search and non-search (e.g., decision, response) components, respectively. Patients exhibited higher intercepts than controls as bottom-up target salience decreased, however these deficits were disproportionately larger under Target Unknown compared to Target Known conditions. Slope differences between PD and controls were limited to the Target Unknown Conjunction condition, where patients exhibited a shallower slope in the target absent condition, indicating that they terminated search earlier. These results suggest that under conditions of high background noise, medicated PD patients were primarily impaired in decision and/or response processes downstream from the target search itself, and that the deficit was attenuated when top-down information was available to guide selection of the target signal.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.neuropsychologia.2006.01.037 | DOI Listing |
ACS Nano
January 2025
Department of Orthopaedics, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing 400038, China.
Methicillin-resistant (MRSA) causes osteomyelitis (OM), which seriously threatens public health due to its antimicrobial resistance. To increase the sensitivity of antibiotics and eradicate intracellular bacteria, a Zn and vancomycin (Van) codelivered nanotherapeutic (named Man-Zn/Van NPs) was fabricated and characterized via mannose (Man) modification. Man-Zn/Van NPs exhibit significant inhibitory activity against extra- and intracellular MRSA and obviously decrease the minimum inhibitory concentration of Van.
View Article and Find Full Text PDFJ Agric Food Chem
January 2025
China-Kenya Joint Laboratory for Ecological Pest Control of Citrus, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Biopesticide and Chemical Biology, MOE, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
RNA pesticides have emerged as a promising alternative to conventional chemical pesticides due to their high specificity and minimal environmental impact. However, the instability of RNA molecules in the environment and the challenges associated with their effective delivery to target pests limit their broader application. This study addresses these challenges by developing a dual delivery system using chitosan (CS) and Metal-Organic Frameworks (MOFs) to enhance the delivery and efficacy of double-stranded RNA (dsRNA) and cycloxaprid against , a vector of citrus greening disease.
View Article and Find Full Text PDFJ Agric Food Chem
January 2025
College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, China.
Astaxanthin (AST), as a natural antioxidant, has broad application prospects in medicine and health products. However, its highly unsaturated structure and significant lipophilic characteristics limit its dispersibility and bioavailability, thereby restricting its application in food, medicines, and nutraceuticals. To overcome these limitations, researchers have proposed the use of nano delivery systems.
View Article and Find Full Text PDFJ Appl Biomater Funct Mater
January 2025
Faculty of Dentistry, Department of Periodontics, Complutense University of Madrid, Madrid, Spain.
Peri-implant diseases, such as peri-implantitis, affect up to 47% of dental implant recipients, primarily due to biofilm formation. Current decontamination methods vary in efficacy, prompting interest in polymeric nanoparticles (NPs) for their antimicrobial and protein-specific cleaning properties. This study evaluated the efficacy of polymeric nanoparticles (NPs) in decontaminating titanium dental implants by removing proteinaceous pellicle layers and resisting recontamination.
View Article and Find Full Text PDFCurr Top Med Chem
January 2025
Department of Chemistry, University of Swabi, Anbar 23561, Khyber Pakhtunkhwa, Pakistan.
Background: In continuation of our chemical and biological work on Tithonia tubaeformis, we evaluated the antipyretic activity of its extract which on fractionation gives a pure alkaloid galegine. Galegine a bioprivileged compound, is a hemiterpene bearing a guanidine group, which holds significant importance in medicinal chemistry. Biological activities such as antimicrobial, antidiabetic, anti-inflammatory, cardiovascular, anticancer, and antihypertensive, are often associated with guanidine-containing molecules.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!