The lesson learned from COVID-19 and the climate crisis is not to let experts decide on policies: a response to Robert C. Schmidt.

This is a response to the commentary by Robert C. Schmidt in this journal, in which the author suggests that for specific problems such as climate change or the current pandemic, decisions on policies should be made by scientific experts rather than by politicians. We argue that such ideas, which were brought up in the late 1960s and reconsidered more recently, do not take sufficient account of the nature of science politics, and their interaction. Furthermore, problem structures and resulting challenges for science and politics are not similar, but essentially different between climate change and the pandemic. Therefore, different solutions to the problems are required. There is a need to improve politics' reliable recourse to scientific evidence in many cases. Yet, giving scientific experts such a strong position in decision-making ignores that most decisions, even if based on the state of scientific evidence (if there is such an uncontroversial state of evidence), ultimately require genuinely political choices about trade-offs of interests and normative issues that neither can nor should be made by scientists. Therefore, putting Schmidt's proposal into practice would not solve the existing problems but instead create new problems.

Post-traumatic Confusional State: A Case Definition and Diagnostic Criteria.

In response to the need to better define the natural history of emerging consciousness after traumatic brain injury and to better describe the characteristics of the condition commonly labeled posttraumatic amnesia, a case definition and diagnostic criteria for the posttraumatic confusional state (PTCS) were developed. This project was completed by the Confusion Workgroup of the American Congress of Rehabilitation Medicine Brain Injury Interdisciplinary Special Interest group. The case definition was informed by an exhaustive literature review and expert opinion of workgroup members from multiple disciplines. The workgroup reviewed 2466 abstracts and extracted evidence from 44 articles. Consensus was reached through teleconferences, face-to-face meetings, and 3 rounds of modified Delphi voting. The case definition provides detailed description of PTCS (1) core neurobehavioral features, (2) associated neurobehavioral features, (3) functional implications, (4) exclusion criteria, (5) lower boundary, and (6) criteria for emergence. Core neurobehavioral features include disturbances of attention, orientation, and memory as well as excessive fluctuation. Associated neurobehavioral features include emotional and behavioral disturbances, sleep-wake cycle disturbance, delusions, perceptual disturbances, and confabulation. The lower boundary distinguishes PTCS from the minimally conscious state, while upper boundary is marked by significant improvement in the 4 core and 5 associated features. Key research goals are establishment of cutoffs on assessment instruments and determination of levels of behavioral function that distinguish persons in PTCS from those who have emerged to the period of continued recovery.

Minimum Competency Recommendations for Programs That Provide Rehabilitation Services for Persons With Disorders of Consciousness: A Position Statement of the American Congress of Rehabilitation Medicine and the National Institute on Disability, Independent Living and Rehabilitation Research Traumatic Brain Injury Model Systems.

Persons who have disorders of consciousness (DoC) require care from multidisciplinary teams with specialized training and expertise in management of the complex needs of this clinical population. The recent promulgation of practice guidelines for patients with prolonged DoC by the American Academy of Neurology, American Congress of Rehabilitation Medicine (ACRM), and National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) represents a major advance in the development of care standards in this area of brain injury rehabilitation. Implementation of these practice guidelines requires explication of the minimum competencies of clinical programs providing services to persons who have DoC. The Brain Injury Interdisciplinary Special Interest Group of the ACRM, in collaboration with the Disorders of Consciousness Special Interest Group of the NIDILRR-Traumatic Brain Injury Model Systems convened a multidisciplinary panel of experts to address this need through the present position statement. Content area-specific workgroups reviewed relevant peer-reviewed literature and drafted recommendations which were then evaluated by the expert panel using a modified Delphi voting process. The process yielded 21 recommendations on the structure and process of essential services required for effective DoC-focused rehabilitation, organized into 4 categories: diagnostic and prognostic assessment (4 recommendations), treatment (11 recommendations), transitioning care/long-term care needs (5 recommendations), and management of ethical issues (1 recommendation). With few exceptions, these recommendations focus on infrastructure requirements and operating procedures for the provision of DoC-focused neurorehabilitation services across subacute and postacute settings.

Delusions and the Right Hemisphere: A Review of the Case for the Right Hemisphere as a Mediator of Reality-Based Belief.

Delusions are beliefs that remain fixed despite evidence that they are incorrect. Although the precise neural mechanism of delusional belief remains to be elucidated, there is a predominance of right-hemisphere lesions among patients with delusional syndromes accompanied by structural pathology, suggesting that right-hemisphere lesions, or networks with key nodes in the right hemisphere, may be playing a role. The authors discuss the potential theoretical basis and empiric support for a specific right-hemisphere role in delusion production, drawing on its roles in pragmatic communication; perceptual integration; attentional surveillance and anomaly/novelty detection; and belief updating.

Predictors of Recovery From Posttraumatic Amnesia.

This study examined the predictive value of variables known early in the course of posttraumatic amnesia (PTA) on length of PTA and functional outcome of acute rehabilitation. Forty patients with traumatic brain injury who had PTA at admission for acute inpatient rehabilitation were included (29 men and 11 women; aged 18-91 years). This article presents the characteristics of the patients who came out of PTA and those who did not emerge during the acute inpatient rehabilitation stay. These data suggest that the location of the lesion (specifically, parietal lobe lesions) and initial cognitive scores are helpful in prognosticating patient trajectories.

Functional connectivity of the posterior hippocampus is more dominant as we age.

The role of the hippocampus in memory is dependent on its interaction with distributed brain areas. Anterior and posterior hippocampus have different roles in memory processing, and are impacted differently by aging in terms of structural decline, however, functional connectivity of these hippocampal regions in aging is not well understood. Young (age 17-30) and aging (age 60-69) cognitively normal subjects underwent resting-state functional MRI revealing a shift from anterior hippocampus dominant hippocampus connectivity in younger age group to posterior hippocampus dominant connectivity in aging subjects. We identified a subset of neocortical regions that are connected to the anterior hippocampus in younger adults but to the posterior hippocampus among older subjects, suggesting an age-related reorganization of hippocampal networks supporting normal cognitive function. We also performed volumetric analysis which revealed no significant structural differences between groups. These findings provide evidence that "functional anatomy" which supports normal memory performance changes across the life span.

Aphasia due to isolated infarction of the corpus callosum.

A 63-year-old man with an isolated infarction of the corpus callosum developed expressive aphasia in addition to the deficits traditionally associated with a disconnection syndrome.

Regional white matter hyperintensity volume, not hippocampal atrophy, predicts incident Alzheimer disease in the community.

BACKGROUND New-onset Alzheimer disease (AD) is often attributed to degenerative changes in the hippocampus. However, the contribution of regionally distributed small vessel cerebrovascular disease, visualized as white matter hyperintensities (WMHs) on magnetic resonance imaging, remains unclear. OBJECTIVE To determine whether regional WMHs and hippocampal volume predict incident AD in an epidemiological study. DESIGN A longitudinal community-based epidemiological study of older adults from northern Manhattan, New York. SETTING The Washington Heights/Inwood Columbia Aging Project. PARTICIPANTS Between 2005 and 2007, 717 participants without dementia received magnetic resonance imaging scans. A mean (SD) of 40.28 (9.77) months later, 503 returned for follow-up clinical examination and 46 met criteria for incident dementia (45 with AD). Regional WMHs and relative hippocampal volumes were derived. Three Cox proportional hazards models were run to predict incident dementia, controlling for relevant variables. The first included all WMH measurements; the second included relative hippocampal volume; and the third combined the 2 measurements. MAIN OUTCOME MEASURE Incident AD. RESULTS White matter hyperintensity volume in the parietal lobe predicted time to incident dementia (hazard ratio [HR] = 1.194; P = .03). Relative hippocampal volume did not predict incident dementia when considered alone (HR = 0.419; P = .77) or with the WMH measures included in the model (HR = 0.302; P = .70). Including hippocampal volume in the model did not notably alter the predictive utility of parietal lobe WMHs (HR = 1.197; P = .049). CONCLUSIONS The findings highlight the regional specificity of the association of WMHs with AD. It is not clear whether parietal WMHs solely represent a marker for cerebrovascular burden or point to distinct injury compared with other regions. Future work should elucidate pathogenic mechanisms linking WMHs and AD pathology.

Inhibition of prefrontal protein synthesis following recall does not disrupt memory for trace fear conditioning.

BACKGROUND: The extent of similarity between consolidation and reconsolidation is not yet fully understood. One of the differences noted is that not every brain region involved in consolidation exhibits reconsolidation. In trace fear conditioning, the hippocampus and the medial prefrontal cortex (mPFC) are required for consolidation of long-term memory. We have previously demonstrated that trace fear memory is susceptible to infusion of the protein synthesis inhibitor anisomycin into the hippocampus following recall. In the present study, we examine whether protein synthesis inhibition in the mPFC following recall similarly results in the observation of reconsolidation of trace fear memory. RESULTS: Targeted intra-mPFC infusions of anisomycin or vehicle were performed immediately following recall of trace fear memory at 24 hours, or at 30 days, following training in a one-day or a two-day protocol. The present study demonstrates three key findings: 1) trace fear memory does not undergo protein synthesis dependent reconsolidation in the PFC, regardless of the intensity of the training, and 2) regardless of whether the memory is recent or remote, and 3) intra-mPFC inhibition of protein synthesis immediately following training impaired remote (30 days) memory. CONCLUSION: These results suggest that not all structures that participate in memory storage are involved in reconsolidation. Alternatively, certain types of memory-related information may reconsolidate, while other components of memory may not.

A role for the prefrontal cortex in recall of recent and remote memories.

Declarative memories are thought to be initially stored in the hippocampus, and then transferred to the neocortex. This is a key feature of the standard model of consolidation and is supported by studies reporting a requirement for activity within the neocortex for recall of remote, but not recent, hippocampal-dependent memories. New evidence from our and other laboratories, however, suggests that, for trace fear conditioning, memories are stored in the rodent medial prefrontal cortex and in the hippocampus from the time of training. Consistent with this, we show that activity in the medial prefrontal cortex is necessary for retrieval of recent and remote memories, suggesting that information stored in this neocortical structure from the time of training is necessary for memory recall.

A cell-permeable phospholipase Cgamma1-binding peptide transduces neurons and impairs long-term spatial memory.

Growth factor-mediated signaling has emerged as an essential component of memory formation. In this study, we used a phospholipase C gamma 1 (PLCgamma1) binding, cell-penetrating peptide to sequester PLCgamma1 away from its target, the phosphotyrosine residues within the activated growth factor receptor. Peptides appear to transduce neurons but not astrocytes or oligodendrocytes. The presence of the peptides in the hippocampus during training in the Morris water maze significantly impaired long-term memory, but not memory acquisition. These results, along with previous studies on extracellular signal-regulated kinase (ERK) and phosphoinositide-3 kinase (PI3K), implicate all three key growth factor receptor-activated intracellular signaling pathways in memory storage.

Intrahippocampal wortmannin infusion enhances long-term spatial and contextual memories.

The transition from short- to long-term memory involves several biochemical cascades, some of which act in an antagonistic manner. Post-training intrahippocampal administration of wortmannin, a pharmacological inhibitor of phosphatidylinositol 3-kinase, had no effect on memory tested 3 h later, but improved long-term memory tested 48 h following the completion of training. This effect was seen in two hippocampus-dependent tasks: the Morris water maze, using both massed and distributed training paradigms, and contextual fear conditioning. The improvement of long-term memory appears to be the result of enhanced consolidation, as wortmannin had no effect on memory recall. These results are consistent with the hypothesis that memory consolidation involves competing processes, and that blockade of an inhibitory constraint facilitates the consolidation process.