Introduction: Although schizophrenia is associated with a broad range of symptoms including hallucinations, delusions, and reduced motivation, measures of cognitive dysfunction, including cognitive flexibility and executive function, are the strongest predictors of functional outcomes. Antipsychotic medications are useful for reducing psychotic symptoms, but they are ineffective at improving cognitive deficits. Despite extensive investment by industry, the transition from preclinical to clinical trials has not been successful for developing precognitive medications for individuals with schizophrenia. Here, we describe the optimisation of a novel dynamic strategy shifting task (DSST) using standard operant chambers to investigate the optimal stimuli required to limit the extensive training times required in previous tasks.
Methods: We determined that optimal learning by male and female Sprague Dawley rats for the flexibility task incorporated dynamic strategy shifts between spatial rules, such as following a visual cue or responding at one location, and non-spatial rules, such as responding to a central visual or auditory cue. A minimum of 6 correct consecutive responses were required to make a within-session change in the behavioural strategies. As a proof of concept, we trained and tested 84 Sprague Dawley rats on the DSST, and then assessed their cognitive flexibility using a within-subject design after an acute dose of ketamine (0, 3, 10 mg/kg). Rats made fewer premature and more perseverant responses to initiate a trial following ketamine. The effects of ketamine on trials to criterion was dependent on the rule.
Results: Ketamine induced a significant improvement on the reversal of a non-spatial visual discrimination rule. There was no significant effect of ketamine on the spatial visual or response discrimination rules.
Discussion: The DSST is a novel assay for studying distinct forms of cognitive flexibility and offers a rapid and adaptable means of assessing the ability to shift between increasingly challenging rule conditions. The DSST has potential utility in advancing our understanding of cognitive processes and the underlying neurobiological mechanisms related to flexibility in neuropsychiatric and neurological conditions where executive dysfunctions occur.>.
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http://dx.doi.org/10.3389/fpsyt.2024.1303728 | DOI Listing |
East Asian Arch Psychiatry
December 2024
Department of Pathology, All India Institute of Medical Sciences-Madurai, Ramanthapuram, Tamil Nadu, India.
Background: Endophenotypes aid in studying the complex genetic basis of bipolar disorder. We aimed to compare first-degree relatives of patients with bipolar I disorder in a hospital in India with unrelated healthy controls in terms of neurocognition and affective temperament METHODS. This cross-sectional study was conducted between August and November 2012 at a tertiary hospital in India.
View Article and Find Full Text PDFJ Nutr Health Aging
December 2024
Faculty of Medicine and Health, School of Health Sciences and Sydney Medical School, University of Sydney, New South Wales, Australia, and Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Roslindale, MA, United States.
Commun Biol
December 2024
Department of Physiology and Pharmacology, Sapienza University, Rome, Italy.
Transitive inference allows people to infer new relations between previously experienced premises. It has been hypothesized that this logical thinking relies on a mental schema that spatially organizes elements, facilitating inferential insights. However, recent evidence challenges the need for these complex cognitive processes.
View Article and Find Full Text PDFJ Neurosci
December 2024
Neurobiology Laboratory, National Institute of Environmental Health Sciences, Division of Intramural Research, National Institute of Health, Research Triangle Park, North Carolina 27713, USA
Perineuronal nets (PNNs) are a specialized extracellular matrix that surround certain populations of neurons, including (inhibitory) parvalbumin (PV) expressing-interneurons throughout the brain and (excitatory) CA2 pyramidal neurons in hippocampus. PNNs are thought to regulate synaptic plasticity by stabilizing synapses and as such, could regulate learning and memory. Most often, PNN functions are queried using enzymatic degradation with chondroitinase, but that approach does not differentiate PNNs on CA2 neurons from those on adjacent PV cells.
View Article and Find Full Text PDFBrain Behav
January 2025
School of Physical Education, Shanghai University of Sport, Shanghai, China.
Objective: Whether athletes possess superior executive functions still needs further examination. Therefore, the aim of this study is to explore the executive function advantages of athletes and the differences in these advantages between open- and closed-skill sports through systematic review and meta-analysis.
Methods: Computer searches of CNKI, Web of Science, PubMed, ScienceDirect, and SPORTDiscus databases were conducted.
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