Efficient learning in children with rapid GABA boosting during and after training.

It is generally thought that children learn more efficiently than adults. One way to accomplish this is to have learning rapidly stabilized such that it is not interfered with by subsequent learning. Although γ-aminobutyric acid (GABA) plays an important role in stabilization, it has been reported that GABAergic inhibitory processing is not fully matured yet in children compared with adults. Does this finding indicate that more efficient learning in children is not due to more rapid stabilization? Here, we measured the concentration of GABA in early visual cortical areas in a time-resolved fashion before, during, and after visual perceptual learning (VPL) within subjects using functional MRS (fMRS) and then compared the concentrations between children (8 to 11 years old) and adults (18 to 35 years old). We found that children exhibited a rapid boost of GABA during visual training that persisted after training ended, whereas the concentration of GABA in adults remained unchanged. Moreover, behavioral experiments showed that children exhibited rapid development of resilience to retrograde interference, which indicates that children stabilize VPL much faster than adults. These results together suggest that inhibitory processing in children's brains is more dynamic and adapts more quickly to stabilize learning than in adults, making learning more efficient in children.

A behavioral training protocol using visual perceptual learning to improve a visual skill.

We describe a behavioral training protocol using visual perceptual learning (VPL) to improve visual detection skills in non-experts for subtle mammographic lesions indicative of breast cancer. This protocol can be adapted for the professional training of experts (radiologists) or to improve visual skills for other tasks, such as the detection of targets in photo or video surveillance. For complete details on the use and execution of this protocol, please refer to Frank et al. (2020a).

Altered Mental Status and Hyponatremia After 20 Hours of Amiodarone Therapy.

A 66-year-old woman with no relevant medical history presented at the emergency department with new-onset atrial fibrillation. We initiated intravenous amiodarone therapy. At 20 hours, the patient experienced severe neurologic symptoms, hyponatremia, and syndrome of inappropriate antidiuretic hormone. We discontinued amiodarone, infused saline solution, and restricted the patient's fluid intake. She recovered in 3 days. This case illustrates that amiodarone-induced syndrome of inappropriate antidiuretic hormone with hyponatremia can occur far earlier than expected during acute amiodarone therapy.

Supervised Learning Occurs in Visual Perceptual Learning of Complex Natural Images.

There have been long-standing debates regarding whether supervised or unsupervised learning mechanisms are involved in visual perceptual learning (VPL) [1-14]. However, these debates have been based on the effects of simple feedback only about response accuracy in detection or discrimination tasks of low-level visual features such as orientation [15-22]. Here, we examined whether the content of response feedback plays a critical role for the acquisition and long-term retention of VPL of complex natural images. We trained three groups of human subjects (n = 72 in total) to better detect "grouped microcalcifications" or "architectural distortion" lesions (referred to as calcification and distortion in the following) in mammograms either with no trial-by-trial feedback, partial trial-by-trial feedback (response correctness only), or detailed trial-by-trial feedback (response correctness and target location). Distortion lesions consist of more complex visual structures than calcification lesions [23-26]. We found that partial feedback is necessary for VPL of calcifications, whereas detailed feedback is required for VPL of distortions. Furthermore, detailed feedback during training is necessary for VPL of distortion and calcification lesions to be retained for 6 months. These results show that although supervised learning is heavily involved in VPL of complex natural images, the extent of supervision for VPL varies across different types of complex natural images. Such differential requirements for VPL to improve the detectability of lesions in mammograms are potentially informative for the professional training of radiologists.

Obesity-Associated Hypertension: the Upcoming Phenotype in African-American Women.

PURPOSE OF REVIEW: The present obesity epidemic particularly affects African-American women. Whether the obesity epidemic will alter the hypertension phenotype in African-American women is entertained. RECENT FINDINGS: The prevalence of morbid obesity is steadily increasing in African-American women, who are prone to developing hypertension (HTN) even in the absence of obesity. The obesity-associated hypertension phenotype is characterized by marked sympathetic nervous system activation and resistance/refractoriness to antihypertensive therapy. Weight loss achieved through lifestyle interventions and pharmacotherapy has a modest and rarely sustained antihypertensive effect. In contrast, bariatric surgery has a sustained antihypertensive effect, as evidenced by normalization of hypertension or lessening of antihypertensive therapy. The prevalence of HTN and its obesity-associated phenotype is likely to increase in African-American women over the next decades. Obese African-American women may be increasingly referred for bariatric surgery when hypertension remains uncontrolled despite lifestyle interventions and pharmacological therapy for weight loss and blood pressure (BP) control.