A tale of 2 diseases: ALD and MASLD requirements and monitoring for liver transplantation.

The requirements for eligibility and monitoring before and after liver transplantation for alcohol-associated liver disease (ALD) and metabolic dysfunction-associated steatotic liver disease (MASLD) are different and not as well defined for MASLD as they are for ALD. Two groups of patients with ALD considered for liver transplant (LT) include those with decompensated cirrhosis from alcohol and those with severe alcohol-associated hepatitis. Both groups are required to commit to lifelong abstinence from alcohol. Pretransplant eligibility criteria for LT in those with ALD varies between transplant centers, but generally, a period of alcohol abstinence with or without counseling is required to be considered for an LT, or the candidate must meet specific requirements. In contrast to ALD, the pre-LT requirements for patients with MASLD, such as weight loss goals or control of metabolic diseases, are not as well defined. Reviews and consensus statements on MASLD and LT discuss risk stratification and management for conditions associated with MASLD, but there are no consensus recommendations regarding obesity and metabolic disease goals before and after transplant. Candidates and recipients of LT may be held to more stringent requirements and monitoring for alcohol use compared to weight loss goals and metabolic parameters advised for patients with MASLD. Because of the disparities in requirements between ALD and MASLD, consensus recommendations should be developed for pre-LT and post-LT monitoring and requirements for candidates and recipients with MASLD.

Evaluating the Use of Mixed Reality to Teach Gross and Microscopic Respiratory Anatomy.

Advances in technology often evolve into instructional platforms. This study evaluated the applicability of mixed reality (MR) in anatomy instruction. First-year medical students were randomized into a control group using a cadaver and light microscopes, or an experimental group using HoloLens, to complete a learning activity on gross and microscopic respiratory anatomy. Compared with the control group, the experimental group reached an equivalent score on the post-activity knowledge assessment, performed better on follow-up assessment, had consistently higher perceived understanding, and rated the activity higher. Findings suggest MR is an effective teaching tool and provides a favorable learning experience.

Meta-adaptation in the auditory midbrain under cortical influence.

Neural adaptation is central to sensation. Neurons in auditory midbrain, for example, rapidly adapt their firing rates to enhance coding precision of common sound intensities. However, it remains unknown whether this adaptation is fixed, or dynamic and dependent on experience. Here, using guinea pigs as animal models, we report that adaptation accelerates when an environment is re-encountered-in response to a sound environment that repeatedly switches between quiet and loud, midbrain neurons accrue experience to find an efficient code more rapidly. This phenomenon, which we term meta-adaptation, suggests a top-down influence on the midbrain. To test this, we inactivate auditory cortex and find acceleration of adaptation with experience is attenuated, indicating a role for cortex-and its little-understood projections to the midbrain-in modulating meta-adaptation. Given the prevalence of adaptation across organisms and senses, meta-adaptation might be similarly common, with extensive implications for understanding how neurons encode the rapidly changing environments of the real world.

Imaging in posttraumatic stress disorder.

PURPOSE OF REVIEW: Posttraumatic stress disorder (PTSD) is an unusual diagnosis in requiring an external environmental stressor to be present, in addition to the conventional signs and symptoms. Early controversies surrounded the validity of its criteria and whether there was a common neural basis for this disorder. This review summarizes recent neuroimaging studies, which have begun to clarify the basis of PTSD by combining imaging data with investigations of the stress response, and by employing fear and extinction learning paradigms to probe the underlying neural changes in those with the disorder. RECENT FINDINGS: We examine the recent literature with three main aims. First, to assess whether structural changes in PTSD are causal of or secondary to the condition. Second, to summarize current understanding of the relationship between neural activation and the stress responses within the autonomic nervous system in PTSD patients and controls. Finally, we examine neural mechanisms underlying the response to fear and reward, demonstrating how these are altered in PTSD. SUMMARY: A greater understanding of the brain mechanisms underlying healthy responses to fear and stress, and their alterations in PTSD, has opened up a new spectrum of possible pharmacological agents by which to approach to PTSD therapy and has begun to reveal the neural processes underlying the common failure of response to current treatments.