Here, we demonstrate the first successful use of static neural stimulation patterns for specific information content. These static patterns were derived by a model that was applied to a subject's own ...hippocampal spatiotemporal neural codes for memory.
We constructed a new model of processes by which the hippocampus encodes specific memory items via spatiotemporal firing of neural ensembles that underlie the successful encoding of targeted content into short-term memory. A memory decoding model (MDM) of hippocampal CA3 and CA1 neural firing was computed which derives a stimulation pattern for CA1 and CA3 neurons to be applied during the encoding (sample) phase of a delayed match-to-sample (DMS) human short-term memory task.
MDM electrical stimulation delivered to the CA1 and CA3 locations in the hippocampus during the sample phase of DMS trials facilitated memory of images from the DMS task during a delayed recognition (DR) task that also included control images that were not from the DMS task. Across all subjects, the stimulated trials exhibited significant changes in performance in 22.4% of patient and category combinations. Changes in performance were a combination of both increased memory performance and decreased memory performance, with increases in performance occurring at almost 2 to 1 relative to decreases in performance. Across patients with impaired memory that received bilateral stimulation, significant changes in over 37.9% of patient and category combinations was seen with the changes in memory performance show a ratio of increased to decreased performance of over 4 to 1. Modification of memory performance was dependent on whether memory function was intact or impaired, and if stimulation was applied bilaterally or unilaterally, with nearly all increase in performance seen in subjects with impaired memory receiving bilateral stimulation.
These results demonstrate that memory encoding in patients with impaired memory function can be facilitated for specific memory content, which offers a stimulation method for a future implantable neural prosthetic to improve human memory.
Introduction. Recent research has focused on evaluating the impact of pharmalogical sources on fracture risk. The purpose of this study was to review the literature on anxiolytic medications that may ...be associated with an increased risk of fracture.
Methods. A search was conducted in MEDLINE and Embase databases to identify primary clinical studies of patients who sustained a fracture while prescribed anxiolytic medications and were published prior to July 2021. Anxiolytics defined by ATC Class N05B, beta blockers, and zolpidem were included. The search terms consisted of variations of the following: (“Psychotropic Drugs” or MeSH terms) AND (“Fracture” or MeSH terms).
Results. Of 3,213 studies, 13 (0.4%) met inclusion criteria and were evaluated. Fractures associated with benzodiazepine were reported in 12 of 13 studies; the highest risk occurred in patients aged 60 years and older, RR=2.29, 95% CI (1.48-4.40). The ATC Class N05B showed an increased fracture risk for those < 55 years of age that differed by sex: for men RR=5.42, 95% CI(4.86-6.05) and for women it was RR=3.33, 95% CI (3.03-3.66). Zolpidem also showed an increase fracture risk, RR=2.29, 95% CI(1.48-3.56), but only during the first 4 weeks of treatment. A relative risk of 0.77, 95% CI(.72-.83) was observed for beta blockers.
Conclusions. Fractures are a mainstay of traumatic injuries and are accompanied by economical, physiological, and psychological hardship. Fortunately, with proper assessment and prophylactic measures, fracture risk can be reduced dramatically. Anxiolytic medications have been described widely to increase fracture risk, such as benzodiazepines in 60+ year old patients, and ATC Class N05B Anxiolytics increased fracture risk of RR=5.42, 95% CI (4.86-6.05) in 55+ year old men and in 55+ year old women. Yet, some studies showed that at low doses, nitrazepam lowered fracture risk. Other anxiolytic medications, such as zolpidem and beta blockers, also showed a decrease in fracture risk; however, only one study has been published on each of these medications. Ultimately, this scoping review helped to illuminate the inconsistency of anxiolytic fracture risk assessment while simultaneously illustrating the necessary steps to guide future research.
Male Sprague Dawley rats were exposed to carbon fibers 7 μm in diameter and 20 to 60 μm in length, for six hours a day and five days a week for up to 16 weeks at an average chamber concentration of ...20 mg/m³. Rats were killed at 4, 8, 12, and 16 weeks of exposure and after a 32-week postexposure recovery period. A similar number of control rats exposed only to air were killed at the same times. Pulmonary function tests, conducted just prior to the animals' death, did not demonstrate any significant or consistent changes. The only pulmonary finding that could be causally related to the subchronic inhalation of carbon fibers was phagocytosis of the inhaled particles by alveolar macrophages. This physiologic response was not accompanied by any local reactive pulmonary inflammation or fibrosis.
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