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The amygdala plays a role in emotion, learning, and memory and has been implicated in behavioral disorders. Better understanding of the amygdala circuitry is crucial to develop new therapies for these disorders. We used data from 200 healthy-subjects from the human connectome project. Using probabilistic tractography, we created population statistical maps of amygdala connectivity to brain regions involved in limbic, associative, memory, and reward circuits. Based on the amygdala connectivity with these regions, we applied k-means clustering to parcellate the amygdala into three clusters. The resultant clusters were averaged across all subjects and the main white-matter pathways of the amygdala from each averaged cluster were generated. Amygdala parcellation into three clusters showed a medial-to-lateral pattern. The medial cluster corresponded with the centromedial and cortical nuclei, the basal cluster with the basal nuclei and the lateral cluster with the lateral nuclei. The connectivity analysis revealed different white-matter pathways consistent with the anatomy of the amygdala circuit. This in vivo connectivity-based parcellation of the amygdala delineates three clusters of the amygdala in a mediolateral pattern based on its connectivity with brain areas involved in cognition, memory, emotion, and reward. The human amygdala circuit presented in this work provides the first step for personalized amygdala circuit mapping for patients with behavioral disorders.

BACKGROUND: Understanding the structural connectivity of key brainstem nuclei with limbic cortical regions is essential to the development of therapeutic neuromodulation for depression, chronic pain, addiction, anxiety and movement disorders. Several brainstem nuclei have been identified as the primary central nervous system (CNS) source of important monoaminergic ascending fibers including the noradrenergic locus coeruleus, serotonergic dorsal raphe nucleus, and dopaminergic ventral tegmental area. However, due to practical challenges to their study, there is limited data regarding their in vivo anatomic connectivity in humans. OBJECTIVE: To evaluate the structural connectivity of the following brainstem nuclei with limbic cortical areas: locus coeruleus, ventral tegmental area, periaqueductal grey, dorsal raphe nucleus, and nucleus tractus solitarius. Additionally, to develop a group average atlas of these limbic brainstem structures to facilitate future analyses. METHODS: Each nucleus was manually masked from 197 Human Connectome Project (HCP) structural MRI images using FSL software. Probabilistic tractography was performed using FSLs FMRIB Diffusion Toolbox. Connectivity with limbic cortical regions was calculated and compared between brainstem nuclei. Results were aggregated to produce a freely available MNI structural atlas of limbic brainstem structures. RESULTS: A general trend was observed for a high probability of connectivity to the amygdala, hippocampus and DLPFC with relatively lower connectivity to the orbitofrontal cortex, NAc, hippocampus and insula. The locus coeruleus and nucleus tractus solitarius demonstrated significantly greater connectivity to the DLPFC than amygdala while the periaqueductal grey, dorsal raphe nucleus, and ventral tegmental area did not demonstrate a significant difference between these two structures. CONCLUSION: Monoaminergic and other modulatory nuclei in the brainstem project widely to cortical limbic regions. We describe the structural connectivity across the several key brainstem nuclei theorized to influence emotion, reward, and cognitive functions. An increased understanding of the anatomic basis of the brainstems role in emotion and other reward-related processing will support targeted neuromodulatary therapies aimed at alleviating the symptoms of neuropsychiatric disorders.

For operation as power amplifiers in RF applications, high electron mobility transistor (HEMT) structures are subjected to a range of bias conditions, applied at both the gate and drain terminals, as the device is biased from the OFF- to ON-state conditions. The stability of the device threshold voltage (Vt) condition is imperative from a circuit-design perspective and is the focus of this study, where stresses in both the ON and OFF states are explored. We see rapid positive threshold voltage increases under negative bias stress and subsequent recovery (i.e., Vt reduces), whereas conversely, we see a negative Vt shift under positive stress and Vt increase during the subsequent relaxation phase. These effects are correlated with the thickness of the GaN layer and ultimately result from the deep carbon-acceptor levels in the C-GaN back barrier incorporated to screen the buffer between the silicon substrate and the epitaxially grown GaN layer. Methods to mitigate this effect are explored, and the consequences are discussed.

Amorphous indium gallium zinc oxide (a-IGZO) is becoming an increasingly important technological material. Transport in this material is conceptualized as the heavy disorder of the material causing a conduction or mobility band-edge that randomly varies and undulates in space across the entire system. Thus, transport is envisioned as being dominated by percolation physics as carriers traverse this varying band-edge landscape of “hills” and “valleys”. It is then something of a missed opportunity to model such a system using only a compact approach—despite this being the primary focus of the existing literature—as such a system can easily be faithfully reproduced as a true microscopic TCAD model with a real physically varying potential. Thus, in this work, we develop such a “microscopic” TCAD model of a-IGZO and detail a number of key aspects of its implementation. We then demonstrate that it can accurately reproduce experimental results and consider the issue of the addition of non-conducting band-tail states in a numerically efficient manner. Finally, two short studies of 3D effects are undertaken to illustrate the utility of the model: specifically, the cases of variation effects as a function of device size and as a function of surface roughness scattering.

BackgroundUnderstanding the structural connectivity of key brainstem nuclei with limbic cortical regions is essential to the development of therapeutic neuromodulation for depression, chronic pain, addiction, anxiety and movement disorders. Several brainstem nuclei have been identified as the primary central nervous system (CNS) source of important monoaminergic ascending fibers including the noradrenergic locus coeruleus, serotonergic dorsal raphe nucleus, and dopaminergic ventral tegmental area. However, due to practical challenges to their study, there is limited data regarding their in vivo anatomic connectivity in humans.ObjectiveTo evaluate the structural connectivity of the following brainstem nuclei with limbic cortical areas: locus coeruleus, ventral tegmental area, periaqueductal grey, dorsal raphe nucleus, and nucleus tractus solitarius. Additionally, to develop a group average atlas of these limbic brainstem structures to facilitate future analyses.MethodsEach nucleus was manually masked from 197 Human Connectome Project (HCP) structural MRI images using FSL software. Probabilistic tractography was performed using FSL's FMRIB Diffusion Toolbox. Connectivity with limbic cortical regions was calculated and compared between brainstem nuclei. Results were aggregated to produce a freely available MNI structural atlas of limbic brainstem structures.ResultsA general trend was observed for a high probability of connectivity to the amygdala, hippocampus and DLPFC with relatively lower connectivity to the orbitofrontal cortex, NAc, hippocampus and insula. The locus coeruleus and nucleus tractus solitarius demonstrated significantly greater connectivity to the DLPFC than amygdala while the periaqueductal grey, dorsal raphe nucleus, and ventral tegmental area did not demonstrate a significant difference between these two structures.ConclusionMonoaminergic and other modulatory nuclei in the brainstem project widely to cortical limbic regions. We describe the structural connectivity across the several key brainstem nuclei theorized to influence emotion, reward, and cognitive functions. An increased understanding of the anatomic basis of the brainstem's role in emotion and other reward-related processing will support targeted neuromodulatary therapies aimed at alleviating the symptoms of neuropsychiatric disorders.

We develop a compact physics model for hot-carrier degradation (HCD) that is valid over a wide range of gate and drain voltages (Vgs and Vds, respectively). Special attention is paid to the contribution of secondary carriers (generated by impact ionization) to HCD, which was shown to be significant under stress conditions with low Vgs and relatively high Vds. Implementation of this contribution is based on refined modeling of carrier transport for both primary and secondary carriers. To validate the model, we employ foundry-quality n-channel transistors and a broad range of stress voltages {Vgs,Vds}.

Objective: Extracorporeal membrane oxygenation (ECMO) is used to provide heart–lung bypass support in cases of acute respiratory and cardiac failure. The two main classifications of ECMO are venoarterial (VA) and venovenous (VV). After the patient recovers from an acute state, ECMO decannulation from the groin often requires femoral exploration and vessel repair. This study was performed to quantify the rate of surgical site infection (SSI) after ECMO decannulation. Methods: Retrospective single-institutional review of patients requiring ECMO from January 2016 to October 2019 was conducted. The study examined incidence of SSI. We evaluated preoperative risk factors, VA versus VV ECMO, Szilagyi infection score, and postoperative management. Results: Initial search began with 176 ECMO cases, of which 106 patients were deceased before development of any infection. Eighteen were eliminated because of central ECMO access, and four were lost to chart privacy. Of the 154 patients requiring femoral ECMO, 48 (31%) survived, with 22 VA and 26 VV ECMO. Twelve patients were classified as infected, resulting in an overall SSI rate of 25%. Surgical repair of the femoral arterial cannulation site was required in the 22 VA ECMO patients, and 10 of these became infected, resulting in an infection rate of 45%. The remaining two infected were VV ECMO and did not require surgery. The VV ECMO SSI rate was 7.7%. The infected group of VA ECMO consisted of eight primary surgical repairs and two patch repairs. Eight of the patients required multiple reoperations and two required antibiotics and wound care alone. There was no instance of limb loss. Statistical analysis showed intraoperative transfusion of >250 ml and blood loss of >300 ml as the only predictive factors of infection. The Szilagyi score was found to be worse in patients requiring patch angioplasty. Conclusion: Surgical repair of ECMO arterial cannulation sites had postoperative SSIs in nearly half of the patients (45%). The VV ECMO SSI rate was found to be 7.7%. Severity of infection was worse in more complicated repairs. Overall ECMO mortality was high at 69%. Although we found no clear correlation with common risk factors, transfusions >250 ml and blood loss >300 ml were found to be predictive. Vascular surgeons should be aware of high risk of SSI with repair of femoral ECMO cannulation sites.

We study how nitridation, applied to SiON gate layers, impacts the reliability of planar metal-oxide-semiconductor field effect transistors (MOSFETs) subjected to negative and positive bias temperature instability (N/PBTI) as well as hard breakdown (HBD) characteristics of these devices. Experimental data demonstrate that p-channel transistors with SiON layers characterized by a higher nitrogen concentration have poorer NBTI reliability compared to their counterparts with a lower nitrogen content, while PBTI in n-channel devices is negligibly weak in all samples independently of the nitrogen concentration. The Weibull distribution of HBD fields extracted from experimental data in devices with a higher N density are shifted towards lower values with respect to that measured in MOSFETs, and SiON films have a lower nitrogen concentration. Based on these findings, we conclude that a higher nitrogen concentration results in the aggravation of BTI robustness and HBD characteristics.