Intracranial recordings reveal high-frequency activity in the human temporal-parietal cortex supporting non-literal language processing

Objective

Non-literal expressions such as sarcasm, metaphor and simile refer to words and sentences that convey meanings or intentions that are different and more abstract than literal expressions. Neuroimaging studies have shown activations in a variety of frontal, parietal and temporal brain regions implicated in non-literal language processing. However, neurophysiological correlates of these brain areas underlying non-literal processing remain underexplored.

Methods

To address this, we investigated patterns of intracranial EEG activity during non-literal processing by leveraging a unique patient population. Seven neurosurgical patients with invasive electrophysiological monitoring of superficial brain activity were recruited. Intracranial neural responses were recorded over the temporal-parietal junction (TPJ) and its surrounding areas while patients performed a language task. Participants listened to vignettes that ended with non-literal or literal statements and were then asked related questions to which they responded verbally.

Results

We found differential neurophysiological activity during the processing of non-literal statements as compared to literal statements, especially in low-Gamma (30-70 Hz) and delta (1-4 Hz) bands. In addition, we found that neural responses related to non-literal processing in the high-gamma band (>70 Hz) were significantly more prominent at TPJ electrodes as compared to non-TPJ (i.e., control) electrodes in most subjects. Moreover, in half of patients, high-gamma activity related to non-literal processing was accompanied by delta-band modulation.

Conclusion

These results suggest that both low- and high-frequency electrophysiological activities in the temporal-parietal junction play a crucial role during non-literal language processing in the human brain. The current investigation, utilizing better spatial and temporal resolution of human intracranial electrocorticography, provides a unique opportunity to gain insights into the localized brain dynamics of the TPJ during the processing of non-literal language expressions.

The Association between Asthma and OSA in Children

Obstructive sleep apnea (OSA) and asthma are two of the most prevalent and commonly co-existing respiratory conditions seen in the pediatric population. Studies linking asthma and OSA in children are limited but indicate that there is a bi-directional relationship between them with significant overlap in the symptoms, risk factors, pathophysiology, comorbidities, and management. It is suggested that there is a reciprocal association between asthma predisposing to OSA, and OSA worsening symptom control and outcomes from asthma. It stands to reason that inflammation in the upper and/or lower airways can influence each other. Most of the pediatric literature that is available evaluates each aspect of this relationship independently such as risk factors, mechanisms, and treatment indications. This article highlights the relationship between OSA and asthma in the context of shared risk factors, pathophysiology, and available management recommendations in the pediatric population. Early recognition of the co-existence and association between OSA and asthma could ideally improve the treatment outcomes for these two conditions. Gaining a better understanding of the mechanism of this relationship can help identify nuances for medical management, optimize treatment and protect this population at risk from associated morbidity.

The Increasing Age of TBI Patients at a Single Level 1 Trauma Center and the Discordance Between GCS and CT Rotterdam Scores in the Elderly

Introduction: Traumatic brain injury (TBI) is frequently encountered in geriatric patients, but there is a paucity of data describing TBI in the elderly. Here, we show the age of patients with TBI is increasing at our medical center and discuss the relationship between age and injury severity with patient outcomes. Methods: This is a retrospective analysis of 3,179 adult patients with TBI treated at the University of California, Davis Level 1 Trauma Center between 2009 and 2016. Age, Glasgow Coma Scale (GCS), and CT Rotterdam Scores were recorded. Age was analyzed as both a continuous and categorical variable (18-34, 35-50, 51-65, >65 years-old). Extended Glasgow Outcome Scale was obtained at 3 and 6 months and dichotomized into favorable and unfavorable outcomes. Multivariable general linear regression models, chi-square, logistic regression analyses and ANOVA were used for statistical analyses; a p < 0.05 was considered significant. Results: The mean age of patients was 52.2 ± 21.9 years with a male predominance (69%). There was a significant trend (p = 0.002) toward an increase in mean age each year, increasing by 4.4 years (p = 0.008) over the course of the analysis. Older patients had a higher mean GCS compared to younger patients with the same CT Rotterdam Score (p = 0.027), this becoming more pronounced with worse CT Rotterdam Scores. The >65 group had a 4-fold increased risk for unfavorable outcome when compared to the 18-34 group, this effect being most pronounced after mild TBI. Conclusions: The mean age of TBI patients is increasing at our trauma center. The largest disparity in outcomes across age was seen in patients with a mild GCS and low CT Rotterdam Scores, suggesting that these markers of injury severity may underestimate the severity of injury in the elderly population. This information highlights the need for clinical trials and validation of outcome markers in geriatric TBI.

Internal Acoustic Canal Stenosis Due to Hyperostosis

Background  Exostoses and osteomas are benign, insidious lesions of the bone involving the internal acoustic canal (IAC). We present two cases of IAC exostoses managed with surgical decompression and review the clinical outcomes of previously reported cases in the literature. Methods  A comprehensive search was conducted using PubMed Central, Web of Science Core Collection, and Google Scholar databases to identify previous reports of IAC exostoses and osteomas. A total of 26 reported cases were identified, and patient presenting symptoms, management strategies, and response to surgery was obtained when available. Results  Of the 13 patients who underwent surgical decompression, 8 patients had resolution of vertigo symptoms, 10 patients had improvement of tinnitus symptoms, and all patients maintained some level of serviceable hearing. Conclusion  IAC exostoses and osteomas are rare lesions that lead to insidious onset of debilitating symptoms from vestibulocochlear nerve dysfunction. Although the role of surgical decompression remains unclear, it appears that patients presenting with vertigo have more favorable response to surgical decompression as compared with those presenting with tinnitus and sensorineural hearing loss.

Youth or Young Adults: Which Group Is at Highest Risk for Tobacco Use Onset?

PURPOSE

Historically, adolescence has been regarded as the time when most tobacco use initiation occurs. This study examines the initiation of tobacco product use, including cigarettes, e-cigarettes, cigar products, and hookah, among contemporary youth and young adults, to determine whether the developmental timing (youth vs. young adulthood) of initiation has changed.

METHODS

Three cohort studies were used to examine the onset of ever use and current (past 30 days) use of each tobacco product among never-using youth (11 to <17 years) and young adults (18-24 years) at baseline (2013-2015) to one-year follow-up (2015-2016). These studies include the national Population Assessment of Tobacco and Health Study, and two Texas cohort studies, the Texas Adolescent Tobacco and Marketing Surveillance System (TATAMS), and the Marketing and Promotions Across Colleges in Texas (M-PACT) project. Estimations of onset were computed using generalized linear mixed models for TATAMS and M-PACT. The rates of initiation in Population Assessment of Tobacco and Health Study were compared to standardized incidence rates from TATAMS to M-PACT.

RESULTS

Young adults had significantly higher incidence rates than youth to initiate ever and current use of each/all tobacco products for all comparisons.

CONCLUSIONS

These findings extend prior research on the timing of the onset of tobacco use by using longitudinal analyses from three contemporary cohort studies to include not just cigarettes, but also e-cigarettes, cigar products, and hookah. Among those who were never-users of tobacco products, young adults began to ever and currently use all tobacco products more than youth in these samples, a marked departure from prior decades of research.

Streptozotocin-induced changes in cardiac gene expression in the absence of severe contractile dysfunction

Diabetes mellitus alters energy substrate metabolism and gene expression in the heart. It is not known whether the changes in gene expression are an adaptive or maladaptive process. To answer this question, we determined both the time-course and the extent of the alteration of gene expression induced by insulin-deficient diabetes. Transcript analysis with real-time quantitative polymerase chain reaction (PCR) was performed in rat hearts 1 week (acute group) or 6 months (chronic group) after administration of streptozotocin (55 mg/kg). In the acute group, insulin-dependent diabetes induced a 55-70% decrease of both glucose transporter 1 (GLUT1) and GLUT4 transcripts, a slight decrease of liver-specific carnitine palmitoyltransferase I (CPT I), and no change in muscle-specific CPT I. The uncoupling protein UCP-3 increased three-fold, with no change in UCP-2. These metabolic alterations were accompanied by an isoform switching from the normally expressed alpha myosin heavy chain (MHC) to the fetal isoform betaMHC mRNA, by a 50% decrease of cardiac alpha-actin mRNA, a 30% decrease of the sarcoplasmic Ca++-ATPase mRNA, and a 50% decrease of muscle creatine kinase (P<0.01 v controls). All genomic changes were also present in the chronic group. Genomic markers of ventricular dysfunction [tumor necrosis factor alpha (TNF-alpha), inducible nitric oxide synthase, cyclo-oxygenase-2] were not affected by chronic diabetes. In both groups, there were no changes in resting left ventricular function by echocardiography.

CONCLUSION

The heart adapts to insulin-deficient diabetes by a rapid and simultaneous response of multiple genes involved in cardiac metabolism and function. This genomic adaptation resembles the adaptation of cardiac hypertrophy, remains stable over time, and does not lead to major contractile dysfunction.

Isolation and characterization of pcp, a gene encoding a pyrrolidone carboxyl peptidase in Staphylococcus aureus

The pcp gene, encoding a pyrrolidone carboxyl peptidase (PYRase), was cloned from a lambda GT11 genomic library prepared from Staphylococcus aureus FDA 574 and sequenced. The pcp gene is located 740 bp downstream from cna, a gene that encodes a collagen-binding adhesin in S. aureus. S. aureus pcp encodes a 212-amino-acid (aa) polypeptide. The pcp gene was overexpressed in Escherichia coli and the PYRase purified to homogeneity. The recombinant enzyme exhibited biological activity, as determined using the chromogenic substrate L-pyroglutamyl-beta-napthylamide. Biochemical analysis of the PYRase using thiol-blocking chemicals suggested that the enzyme belongs to the cysteine peptidase family. Moreover, multiple sequence alignment revealed a high degree of similarity to previously described bacterial PYRases. This family of peptidases has been used to selectively remove the N-terminal pyrrolidone carboxylic acid residue found on certain blocked proteins and peptides prior to aa sequencing. However, the exact biological role of PYRases has yet to be elucidated.

Critical residues in the ligand-binding site of the Staphylococcus aureus collagen-binding adhesin (MSCRAMM)

We have identified a discrete collagen-binding site within the Staphylococcus aureus collagen adhesin that is located in a region between amino acids Asp209 and Tyr233. Polyclonal antibodies raised against a recombinant form of the collagen adhesin inhibited the binding of collagen type II to S. aureus. When overlapping synthetic peptides mimicking segments of the adhesin fragment were tested for their ability to neutralize the inhibitory activity of the antibody only one peptide, CBD4 was found to be active. CBD4 bound directly to collagen and at high concentrations inhibited the binding of collagen to S. aureus. A synthetic peptide derivative of CBD4 lacking 2 carboxyl-terminal residues (Asn232, Tyr233) had no inhibitory activity. The importance of these residues for collagen binding was confirmed by biospecific interaction analysis. Mutant adhesin proteins N232-->A and Y233-->A exhibited dramatic changes in collagen binding activity. The dominant dissociation rate for the binding of mutant adhesin protein N232-->A to immobilized collagen II decreased almost 10-fold, while the Y233-->A and the double mutant exhibited even more significant decreases in affinity and apparent binding ratio when compared to the wild type protein.