A Real-Time Neurophysiologic Stress Test for the Aging Brain: Novel Perioperative and ICU Applications of EEG in Older Surgical Patients.

As of 2022, individuals age 65 and older represent approximately 10% of the global population [1], and older adults make up more than one third of anesthesia and surgical cases in developed countries [2, 3]. With approximately > 234 million major surgical procedures performed annually worldwide [4], this suggests that > 70 million surgeries are performed on older adults across the globe each year. The most common postoperative complications seen in these older surgical patients are perioperative neurocognitive disorders including postoperative delirium, which are associated with an increased risk for mortality [5], greater economic burden [6, 7], and greater risk for developing long-term cognitive decline [8] such as Alzheimer's disease and/or related dementias (ADRD). Thus, anesthesia, surgery, and postoperative hospitalization have been viewed as a biological "stress test" for the aging brain, in which postoperative delirium indicates a failed stress test and consequent risk for later cognitive decline (see Fig. 3). Further, it has been hypothesized that interventions that prevent postoperative delirium might reduce the risk of long-term cognitive decline. Recent advances suggest that rather than waiting for the development of postoperative delirium to indicate whether a patient "passed" or "failed" this stress test, the status of the brain can be monitored in real-time via electroencephalography (EEG) in the perioperative period. Beyond the traditional intraoperative use of EEG monitoring for anesthetic titration, perioperative EEG may be a viable tool for identifying waveforms indicative of reduced brain integrity and potential risk for postoperative delirium and long-term cognitive decline. In principle, research incorporating routine perioperative EEG monitoring may provide insight into neuronal patterns of dysfunction associated with risk of postoperative delirium, long-term cognitive decline, or even specific types of aging-related neurodegenerative disease pathology. This research would accelerate our understanding of which waveforms or neuronal patterns necessitate diagnostic workup and intervention in the perioperative period, which could potentially reduce postoperative delirium and/or dementia risk. Thus, here we present recommendations for the use of perioperative EEG as a "predictor" of delirium and perioperative cognitive decline in older surgical patients.

Predictors of Academic Neurosurgical Career Trajectory among International Medical Graduates Training Within the United States.

BACKGROUND: Within the literature, there has been limited research tracking the career trajectories of international medical graduates (IMGs) following residency training. OBJECTIVE: To compare the characteristics of IMG and US medical school graduate (USMG) neurosurgeons holding academic positions in the United States and also analyze factors that influence IMG career trajectories following US-based residency training. METHODS: We collected data on 243 IMGs and 2506 USMGs who graduated from Accreditation Council for Graduate Medical Education (ACGME)-accredited neurosurgery residency programs. We assessed for significant differences between cohorts, and a logistic regression model was used for the outcome of academic career trajectory. RESULTS: Among the 2749 neurosurgeons in our study, IMGs were more likely to pursue academic neurosurgery careers relative to USMGs (59.7% vs 51.1%; P = .011) and were also more likely to complete a research fellowship before beginning residency (odds ratio [OR] = 9.19; P < .0001). Among current US academic neurosurgeons, USMGs had significantly higher pre-residency h-indices relative to IMGs (1.23 vs 1.01; P < .0001) with no significant differences between cohorts when comparing h-indices during (USMG = 5.02, IMG = 4.80; P = .67) or after (USMG = 14.05, IMG = 13.90; P = .72) residency. Completion of a post-residency clinical fellowship was the only factor independently associated with an academic career trajectory among IMGs (OR = 1.73, P = .046). CONCLUSION: Our study suggests that while IMGs begin their US residency training with different research backgrounds and achievements relative to USMG counterparts, they attain similar levels of academic productivity following residency. Furthermore, IMGs are more likely to pursue academic careers relative to USMGs. Our work may be useful for better understanding IMG career trajectories following US-based neurosurgery residency training.

Identifying Parabrachial Neurons Selectively Regulating Satiety for Highly Palatable Food in Mice.

Food consumption is necessary for organisms to maintain metabolic homeostasis. Both extrinsic and intrinsic processes, relayed via intricate neural circuitry, orchestrate the initiation and termination of food intake. More specifically, there are functionally distinct neural circuits that mediate either homeostatic or hedonic suppression of feeding. Notably, being satiated is a positive feeling whereas food aversion is a negative feeling. While significant progress has been made toward elucidating neural circuitry underlying aversive appetite suppression in mice, the circuitry underlying homeostatic satiety is not fully understood. The lateral parabrachial nucleus (PBL) is known as a node that regulates various sensory and visceral processes. Here, we identified and selectively labeled neurons in the caudal lateral region of PBL (PBcl) that are activated by consumption of condensed milk, chocolate Ensure, or peanut butter, which we refer to as PBcl-palatable-food activated neurons (PANs). Specific optogenetic activation of PANs induced positive place preference but decreased the consumption of high-caloric foods such as condensed milk, whereas silencing these cells significantly increased condensed milk consumption in feeding assays. Thus, the PBcl PANs revealed here represent a novel neural substrate regulating caloric-sufficiency mediated satiation.

Publisher Correction: A craniofacial-specific monosynaptic circuit enables heightened affective pain.

In the version of this article initially published, ORCID links were missing for authors Erica Rodriguez, Koji Toda and Fan Wang. The error has been corrected in the HTML and PDF versions of the article.

A craniofacial-specific monosynaptic circuit enables heightened affective pain.

Humans often rank craniofacial pain as more severe than body pain. Evidence suggests that a stimulus of the same intensity induces stronger pain in the face than in the body. However, the underlying neural circuitry for the differential processing of facial versus bodily pain remains unknown. Interestingly, the lateral parabrachial nucleus (PBL), a critical node in the affective pain circuit, is activated more strongly by noxious stimulation of the face than of the hindpaw. Using a novel activity-dependent technology called CANE developed in our laboratory, we identified and selectively labeled noxious-stimulus-activated PBL neurons and performed comprehensive anatomical input-output mapping. Surprisingly, we uncovered a hitherto uncharacterized monosynaptic connection between cranial sensory neurons and the PBL-nociceptive neurons. Optogenetic activation of this monosynaptic craniofacial-to-PBL projection induced robust escape and avoidance behaviors and stress calls, whereas optogenetic silencing specifically reduced facial nociception. The monosynaptic circuit revealed here provides a neural substrate for heightened craniofacial affective pain.

Endovascular treatment of a left carotid artery "bowtie" pseudoaneurysm with a covered Wallgraft stent.

The authors present an unusual case of a young male patient with a large left common carotid artery pseudoaneurysm in a shape similar to that of a bowtie treated with a covered Wallgraft. The Wallgraft is a covered stent originally designed to be used in the treatment of tracheobronchial fistula and peripheral arterial applications. The favorable outcome of this case illustrates its endovascular application in nonsurgical traumatic injuries of the carotid artery.