Music therapy is a potential intervention for cognition of Alzheimer's Disease: a mini-review.

Alzheimer's Disease (AD) is a global health issue given the increasing prevalence rate and the limitations of drug effects. As a consequent, non-pharmacological interventions are of importance. Music therapy (MT) is a non-pharmacological way with a long history of use and a fine usability for dementia patients. In this review, we will summarize different techniques, diverse clinical trials, and the mechanisms of MT as it is helpful to the cognition in AD, providing reference for future research. Many articles have demonstrated that MT can reduce cognitive decline especially in autobiographical and episodic memories, psychomotor speed, executive function domains, and global cognition. MT is a promising intervention for strategy of dementia especially of AD and it must be started as early as possible. However, more evidences with prospective, randomized, blinded, uniform and rigorous methodological investigations are needed. And we should consider to combine MT with other cognitive stimulations such as dance, physical exercise, video game, art and so on.

Blunted Ambiguity Aversion During Cost-Benefit Decisions in Antisocial Individuals.

Antisocial behavior is often assumed to reflect aberrant risk processing. However, many of the most significant forms of antisocial behavior, including crime, reflect the outcomes of decisions made under conditions of ambiguity rather than risk. While risk and ambiguity are formally distinct and experimentally dissociable, little is known about ambiguity sensitivity in individuals who engage in chronic antisocial behavior. We used a financial decision-making task in a high-risk community-based sample to test for associations between sensitivity to ambiguity, antisocial behavior, and arrest history. Sensitivity to ambiguity was lower in individuals who met diagnostic criteria for Antisocial Personality Disorder. Lower ambiguity sensitivity was also associated with higher externalizing (but not psychopathy) scores, and with higher levels of aggression (but not rule-breaking). Finally, blunted sensitivity to ambiguity also predicted a greater frequency of arrests. Together, these data suggest that alterations in cost-benefit decision-making under conditions of ambiguity may promote antisocial behavior.

Representation of retrieval confidence by single neurons in the human medial temporal lobe.

Memory-based decisions are often accompanied by an assessment of choice certainty, but the mechanisms of such confidence judgments remain unknown. We studied the response of 1,065 individual neurons in the human hippocampus and amygdala while neurosurgical patients made memory retrieval decisions together with a confidence judgment. Combining behavioral, neuronal and computational analysis, we identified a population of memory-selective (MS) neurons whose activity signaled stimulus familiarity and confidence, as assessed by subjective report. In contrast, the activity of visually selective (VS) neurons was not sensitive to memory strength. The groups further differed in response latency, tuning and extracellular waveforms. The information provided by MS neurons was sufficient for a race model to decide stimulus familiarity and retrieval confidence. Together, our results indicate a trial-by-trial relationship between a specific group of neurons and declared memory strength in humans. We suggest that VS and MS neurons are a substrate for declarative memories.