MI Regions Research Articles

Mechanisms of ventricular arrhythmias elicited by coexistence of multiple electrophysiological remodeling in ischemia: A simulation study.

Myocardial ischemia, injury and infarction (MI) are the three stages of acute coronary syndrome (ACS). In the past two decades, a great number of studies focused on myocardial ischemia and MI individually, and showed that the occurrence of reentrant arrhythmias is often associated with myocardial ischemia or MI. However, arrhythmogenic mechanisms in the tissue with various degrees of remodeling in the ischemic heart have not been fully understood. In this study, biophysical detailed single-cell models of ischemia 1a, 1b, and MI were developed to mimic the electrophysiological remodeling at different stages of ACS. 2D tissue models with different distributions of ischemia and MI areas were constructed to investigate the mechanisms of the initiation of reentrant waves during the progression of ischemia. Simulation results in 2D tissues showed that the vulnerable windows (VWs) in simultaneous presence of multiple ischemic conditions were associated with the dynamics of wave propagation in the tissues with each single pathological condition. In the tissue with multiple pathological conditions, reentrant waves were mainly induced by two different mechanisms: one is the heterogeneity along the excitation wavefront, especially the abrupt variation in conduction velocity (CV) across the border of ischemia 1b and MI, and the other is the decreased safe factor (SF) for conduction at the edge of the tissue in MI region which is attributed to the increased excitation threshold of MI region. Finally, the reentrant wave was observed in a 3D model with a scar reconstructed from MRI images of a MI patient. These comprehensive findings provide novel insights for understanding the arrhythmic risk during the progression of myocardial ischemia and highlight the importance of the multiple pathological stages in designing medical therapies for arrhythmias in ischemia.

Mental Health in Residential Healthcare Workers During the COVID-19 Pandemic: The Moderating Role of Selfobject Needs

The COVID-19 outbreak has affected healthcare across all levels. Older adults and those with chronic illness are at greatest risk for infection complications and mortality, which presents significant psychological distress for residential healthcare workers. The concept of selfobject needs, consisting of Mirroring, Idealizing, and Twinship, may be relevant in explaining psychological distress. This study seeks to enhance our understanding of the needs of healthcare workers responsible for elderly patients and evaluate the role of psychosocial support through selfobject needs to mitigate the effects of trauma during the pandemic. Participants (N = 103) employed in residential healthcare facilities in the metropolitan Detroit, MI (USA) region completed an online survey during the peak initial infection. Assessments included standardized measures of trauma-related symptoms, depression, anxiety, and general distress symptoms, as well as a validated measure of selfobject needs. Residential healthcare workers reported mental health symptoms across domains, including clinical elevations in symptoms of trauma, depression, and anxiety. Selfobject needs and mental health outcomes were positively correlated, indicating that greater unmet relational need was associated with greater severity of symptoms. Greater trauma symptom severity as a proxy index of current experience during the pandemic predicted high depressive symptoms, and greater Mirroring need worsened the effect. These results suggest that interventions targeting selfobject needs, specifically Mirroring, may be effective at mitigating acute mental health symptoms among healthcare workers during a distressing event.

CineCT imaging platform for in-vivo and ex-vivo measurement of myocardial biomechanics post myocardial infarction and following intramyocardial delivery of theranostic hydrogel

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Health (NIH) Purpose Myocardial infarction (MI) induces acute regional changes in myocardial strain and stiffness in the infarct and the remote areas of the left ventricle (LV), which lead to adverse changes in LV geometry and function. We hypothesize that cineCT imaging could evaluate these biomechanical changes along with the effects of intramyocardial delivery of theranostic hydrogels. Introduction We present an experimental platform to assess changes in the deformation of the LV myocardium using contrast cineCT (CCT) imaging of the beating porcine heart (active deformation) before and after acute MI and intramyocardial delivery of an imageable theranostic hydrogel. We then assess the acute effects of hydrogel delivery early post-MI on biomechanics (passive deformation) using an ex vivo perfused heart preparation. Methods Contrast cineCT imaging was performed using 64-slice CT on 5 Yorkshire pigs without MI (n = 3) or with MI (n = 2). MI pigs had serial imaging performed before and 1 hour after acute surgical coronary occlusion to induce anterolateral MI. One MI pig was also imaged 1 hour after intramyocardial injection of a novel imageable theranostic iodinated hydrogel within the MI region. Post euthanasia, excised hearts were flushed with chilled UW cardioplegic solution and mounted on a custom inflation apparatus for cineCT imaging during LV inflation by external pump. LV pressure was cycled between 10 and 60 mmHg at 35 bpm. Dilute iohexol was injected into aortic root and UW perfusate (15 ml, 1 ml/sec). CineCT image series were reconstructed, contrast enhanced, resampled to the LV long axis (Z), and exported as a series of 10 CT volumes covering 0-90% of the cardiac/inflation cycle. Volumes were registered incrementally using nonlinear image registration (BioImageSuite) and the calculated displacement at each time point was exported at a resolution of 1 mm. A custom Matlab program was used to fit the displacement field to local trilinear polynomials and then calculate the displacement gradients and 3D Lagrangian strains. To estimate the accuracy of this approach, cardiac volumes were also numerically deformed using a 10 pixel translation and 5% triaxial stretch. Results We successfully acquired serial in-vivo and ex-vivo 3D CineCT images for assessment of the active and passive LV myocardial deformation and tracked deformation through the full cardiac/inflation cycle (Figure 2). Numerical deformation tests showed average tracking errors of < 0.2 mm (1/4 pixel) in the X,Y,Z directions of the volume. These resulted in Lagrangian strain errors of < 0.47% for the in-plane strains EXX and EYY (radial and circumferential plane) and < 0.5% for EZZ (long axis). Conclusions We have developed a novel CineCT imaging platform that allows for high resolution in-vivo and ex-vivo measurement of myocardial biomechanics post-MI and following intramyocardial delivery of imageable theranostic hydrogels, which may improve early active and passive biomechanics.

Children’s Multivitamin/Mineral Supplements: Label Claims and Measured Content Compared to Recommended Dietary Allowances and Tolerable Upper Intake Levels

Abstract Objectives US children ages 4 and older use multivitamin/mineral supplements (MVMs) formulated to meet the Daily Values for adults. To better evaluate the potential for nutrient adequacy and excess, it is helpful to determine actual ingredient content instead of amounts declared on labels. We tested children's MVMs and compared the products’ labeled and measured contents with Recommended Dietary Allowances (RDA) and Upper Tolerable Intake Levels (UL) established for children ages 4 to 8 years. Methods Children's MVMs were defined as dietary supplements (DSs) containing three or more vitamins with or without minerals and other bioactive components labeled for individuals ages 4 and older. Nationally representative children's MVMs were identified based on relative market share estimates (RMSE) derived from frequency of use and respondents’ weights in infant/pediatric MVM subsets of 2003–2006 National Health and Nutrition Examination Surveys, and store surveys. The 21 top and 43 lower market share DSs selected for this study represented ∼72% of the total RMSE. The DSs were purchased in 2008 from multiple market channels in regions of AL, CA, MI, MO, NY, and OK identified using a multistage probability-proportional-to-size approach. Vitamin and mineral content was measured by commercial labs in 3 to 6 lots of 47 chewable tablets, 11 gummies, 4 liquids, 1 gumball, and 1 powder DS. Results For 13 of 16 nutrients (copper, iodine, iron, zinc, folic acid, niacin, riboflavin, thiamin, vitamins A, B-12, B-6, D and E), most MVMs were labeled at or above the RDA but below UL levels. For calcium, magnesium and phosphorus, all the studied DSs were labeled below the RDAs. The DSs that contained zinc, niacin and retinol labeled above their ULs had overall mean RMSEs comparable to the DSs labeled within the RDA-UL ranges. Overages resulted in levels exceeding the UL for folic acid in 24 out of 29 DSs labeled at the UL and for retinol in 10 out 40 DSs labeled below the UL, including one of the three most highly consumed MVMs. Conclusions The prevalence of children's MVMs on the US market with labeled levels at or above the RDA, or at UL, combined with analytically verified overages, suggests risks of excess in intakes for zinc, niacin, retinol and folic acid, especially when MVM use is combined with diets containing many highly fortified foods. Funding Sources NIH ODS and USDA ARS.

Effect of acupuncture and moxibustion on brain functional connectivity network in patients with refractory facial paralysis

To observe the effects of acupuncture on resting-state functional connectivity (rs-FC) in patients with refractory peripheral facial paralysis, and to preliminarily explore the central mechanism of acupuncture for this disease. Twenty patients with refractory peripheral facial paralysis were selected as subject and treated with acupuncture at Qianzheng (EX-HN 16), Fengchi (GB 20), Cuanzhu (BL 2), Dicang (ST 4), Jiache (ST 6), Shuigou (GV 26), Chengjiang (CV 24), Yifeng (TE 17), Touwei (ST 8), Sibai (ST 2), Yingxiang (LI 20) and Hegu (LI 4), once every other day, three times a week, 15 times as a course of treatment. The 1-course treatment was given. The score of Sunnybrook (Toronto) facial grading system was used to evaluate the clinical efficacy before and after the treatment. In addition, 20 healthy volunteers were selected as control. For patients, the resting-state functional magnetic resonance imaging (rs-fMRI) scans were performed before and after treatment, for healthy volunteers, the scans were performed when they were recruited. The brain magnetic resonance images were analyzed with left primary motor area (LMⅠ) and right primary motor area (RMⅠ) as regions of interest. The differences of rs-FC between patients with refractory peripheral facial paralysis before and after treatment and healthy volunteers were compared. Compared before treatment, the Sunnybrook score was increased after the treatment (P<0.05). Compared with healthy volunteers, the functional connection between bilateral primary motor areas (MⅠ) and multiple brain areas were enhanced in patients before treatment, and most of brain areas were located in the anterior motor area (middle frontal gyrus, superior frontal gyrus), posterior central gyrus, anterior cuneiform lobe, middle temporal gyrus, inferior temporal gyrus and cerebellum lobe. Compared before treatment, the left inferior frontal gyrus was the strong functional connection area between LMⅠ and whole brain after acupuncture treatment, and there was no significant difference between RMⅠ and resting-state whole brain. Compared with healthy volunteers, the functional connections between bilateral MⅠ and multiple brain regions were enhanced after acupuncture, and most of the main brain regions were consistent with those before treatment. (1) Acupuncture could effectively improve the clinical symptoms of refractory peripheral facial paralysis. (2) The brain function of patients with refractory peripheral facial paralysis has been changed before acupuncture, which may be caused by the reactive compensation of the brain. (3) Acupuncture could enhance the functional connection between LMⅠ and left inferior frontal gyrus to promote the compensatory response, which may be one of the central mechanisms of acupuncture for refractory peripheral facial paralysis.

Application of Hybrid Matrix Metalloproteinase-Targeted and Dynamic 201Tl Single-Photon Emission Computed Tomography/Computed Tomography Imaging for Evaluation of Early Post-Myocardial Infarction Remodeling.

The induction of matrix metalloproteinases (MMPs) and reduction in tissue inhibitors of MMPs (TIMPs) plays a role in ischemia/reperfusion (I/R) injury post-myocardial infarction (MI) and subsequent left ventricular remodeling. We developed a hybrid dual isotope single-photon emission computed tomography/computed tomography approach for noninvasive evaluation of regional myocardial MMP activation with 99mTc-RP805 and dynamic 201Tl for determination of myocardial blood flow, to quantify the effects of intracoronary delivery of recombinant TIMP-3 (rTIMP-3) on I/R injury. Studies were performed in control pigs (n=5) and pigs following 90-minute balloon occlusion-induced ischemia/reperfusion (I/R) of left anterior descending artery (n=9). Before reperfusion, pigs with I/R were randomly assigned to intracoronary infusion of rTIMP-3 (1.0 mg/kg; n=5) or saline (n=4). Three days post-I/R, dual isotope imaging was performed with 99mTc-RP805 and 201Tl along with contrast cineCT to assess left ventricular function. The ischemic to nonischemic ratio of 99mTc-RP805 was significantly increased following I/R in saline group (4.03±1.40), and this ratio was significantly reduced with rTIMP-3 treatment (2.22±0.57; P=0.03). This reduction in MMP activity in the MI-rTIMP-3 treatment group was associated with an improvement in relative MI region myocardial blood flow compared with the MI-saline group and improved myocardial strain in the MI region. We have established a novel hybrid single-photon emission computed tomography/computed tomography imaging approach for the quantitative assessment of regional MMP activation, myocardial blood flow, and cardiac function post-I/R that can be used to evaluate therapeutic interventions such as intracoronary delivery of rTIMP-3 for reduction of I/R injury in the early phases of post-MI remodeling.

BOLD cardiac MRI for differentiating reversible and irreversible myocardial damage in ST segment elevation myocardial infarction.

BOLD imaging is a quantitative MRI technique allowing the evaluation of the balance between supply/demand in myocardial oxygenation and myocardial haemorrhage. We sought to investigate the ability of BOLD imaging to differentiate reversible from irreversible myocardial injury as well as the chronological progression of myocardial oxygenation after reperfusion in patients with ST segment elevation myocardial infarction (STEMI). Twenty-two patients (age, 60 ± 11 years; 77.3% male) with STEMI underwent cardiac MRIs on four occasions: on days 1, 3, 7 and 30 after reperfusion. BOLD MRI was obtained with a multi-echo turbo field echo (TFE) sequence on a 3-T scanner to assess myocardial oxygenation in MI. T2* value in MI with intramyocardial haemorrhage (IMH) was the lowest (9.77 ± 3.29 ms), while that of the salvaged zone was the highest (33.97 ± 3.42 ms). T2* values in salvaged myocardium demonstrated a unimodal temporal pattern from days 1 (37.91 ± 2.23 ms) to 30 (30.68 ± 1.59 ms). T2* values in the MI regions were significantly lower than those in remote myocardium, although the trends in both were constant overall. There was a slightly positive correlation between T2* in MI regions and EF (Rho = 0.27, p < 0.05) or SV (Rho = 0.22, p = 0.04) and a slightly negative correlation between T2* in salvaged myocardium and LVEDV (Rho = - 0.23, p < 0.05). BOLD MRI performed in post-STEMI patients allows accurate evaluation of myocardial damage severity and could differentiate reversible from irreversible myocardial injury. The increased T2* values may imply the pathophysiological mechanism of salvaged myocardium. BOLD MRI could represent a more accurate alternative to the other currently available options. • Myocardial oxygenation and haemorrhage after myocardial infarction affect BOLD MRI values • BOLD MRI could be used to differentiate irreversible from reversible myocardial damage • Changed oxygenation implies the pathophysiological mechanism of salvaged myocardium.

Information processing from the motor cortices to the subthalamic nucleus and globus pallidus and their somatotopic organizations revealed electrophysiologically in monkeys.

To understand how the information derived from different motor cortical areas representing different body parts is organized in the basal ganglia, we examined the neuronal responses in the subthalamic nucleus (STN), and the external (GPe) and internal (GPi) segments of the globus pallidus (input, relay and output nuclei, respectively) to stimulation of the orofacial, forelimb and hindlimb regions of the primary motor cortex (MI) and supplementary motor area (SMA) in macaque monkeys under the awake state. Most STN and GPe/GPi neurons responded exclusively to stimulation of either the MI or SMA, and one‐fourth to one‐third of neurons responded to both. STN neurons responding to the hindlimb, forelimb and orofacial regions of the MI were located along the medial–lateral axis in the posterolateral STN, while neurons responding to the orofacial region of the SMA were located more medially than the others in the anteromedial STN. GPe/GPi neurons responding to the hindlimb, forelimb and orofacial regions of the MI were found along the dorsal–ventral axis in the posterolateral GPe/GPi, and neurons responding to the corresponding regions of the SMA were similarly but less clearly distributed in more anteromedial regions. Moreover, neurons responding to the distal and proximal forelimb MI regions were found along the lateral–medial axis in the STN and the ventral–dorsal axis in the GPe/GPi. Most STN and GPe/GPi neurons showed kinaesthetic responses with similar somatotopic maps. These observations suggest that the somatotopically organized inputs from the MI and SMA are well preserved in the STN and GPe/GPi with partial convergence.

Modulational instability and energy localization of twisted DNA with solvent interaction

We investigate the generation of soliton-like pulses along a DNA chain which takes into account both torsional and solvent interaction effects. Interactions between neighboring base pairs are described by a twist angle. Twisting is essential in the model to capture the importance of nonlinear effects for the thermodynamical properties. The nonlinear dynamics of the DNA is then modeled in the Hamiltonian approach by the generalized Dauxois–Peyrard–Bishop model (combination of several models). We introduce the generalized discrete nonlinear Schrödinger equation describing the dynamics of modulated wave through the twisted DNA with solvent interaction. The modulational instability is studied and we present an analytical expression for the MI gain to show the effects of twist angle on MI gain spectra as well as on stability diagram. With the increase of the twist angle the MI gain decreases then increases. Some interesting MI phenomena appear with an additional new MI region as the twist angle increases. The instability and stability diagrams are also affected. Numerical simulations are carried out to show the validity of the analytical approach. The result is that the initial wave breaks into a train of ultrashort pulses with repetition rates, which are trapped in some sites. The impact of the twist angle is investigated and we obtain that the twist angle affects the dynamics of stable patterns generated through the molecule. Thereafter, we study energy localization in the framework of twisted DNA with solvent interaction. While the twist angle leads to a stronger localization of energy, the solvent interaction delocalizes energy along the molecule.

Evolutionary divergence of the PISTILLATA-like proteins inHedyosmum orientale(Chloranthaceae) after gene duplication

Gene duplication and diversification is a significant aspect of gene and genome evolution, even though the evolutionary mechanism following duplication almost certainly varies by genes or gene families. We have identified three PISTILLATA (PI)-like genes, HoPI_1, HoPI_2, and HoPI_3, from basal angiosperm Hedyosmum orientale (Chloranthaceae) and found a functional divergence of these duplicate paralogs in the B-function process. However, the mechanism underlying the divergence of the three HoPI copies remains unclear. In this study, we carefully compared the coding sequence of the three duplicate HoPI paralogs, and investigated their evolutionary process after duplication. Molecular evolutionary analyses suggested that the coding sequence of the relatively recent duplicate paralogs HoPI_1 and HoPI_3 may evolve under purifying selection, but the functional constraint that acted on the coding sequence of HoPI_2 may have been relaxed. Domain swapping and site-directed mutagenesis experiments further showed that HoPI_2 has lost class B-function activity through a gradual process of mutational degradation in MADS and I domains. Although we currently have no direct in vivo evidence that HoPI_2 has lost function in floral development, the relaxed selection, in combination with its inability to rescue pi-1 mutant phenotype, indicate that this distant paralog HoPI_2 might have been converted to be functionless in the B-function process. This study provides a detailed molecular characterization of duplicate PI lineage gene divergence in a single individual level, and our results suggest that mutations in the MI region are more likely to have negative effects on the biochemical activity of PI-like proteins.

Transplantation of autologous myoblasts transfected with VEGF165 improves heart function after myocardial infarction in rabbits

To determine the improvements of post-infarction heart function after transplantation of autologous skeletal myoblasts transfected with VEGF165 in rabbits. Myocardium infarction was induced in rabbits by left anterior descending coronary artery ligation. At 2 weeks, 1.75×10(7) autologous skeletal myoblasts transfected with pcDNA3.1-VEGF165 were infused into the region of MI via direct intramuscular injection; pcDNA3.1 served as a control. The DAPI-labeled and Desmin-positive immunostained skeletal myofibers were found throughout the infracted areas and border zones, and the density of blood capillary in the MI region transplanted by myoblasts with VEGF165 was increased (measured 4 weeks later and compared with controls). Heart function was examined by the Buxco system and demonstrated that maximum dp/dt [(1607.23±102.67) mmHg/s vs (1217.77±89.91) mmHg/s] and minimum dp/dt [(-1535.09 ± 81.34) mmHg/s vs (1174.58 ± 91.5) mmHg/s] were improved in the heart transplanted with the transfected myoblasts(P<0.05). Autologous skeletal myoblasts transfected with VEGF165 could ameliorate the blood supply in the MI region, and aid recovery of heart function more quickly in post-infarction hearts. This suggests an effective treatment for myocardium infarction.

Asymmetric bilateral effect of the supplementary motor area proper in the human motor system

Objective This study aimed to clarify the function of human supplementary motor area proper (SMA) by the single-pulse electric stimulation method and its clinical usefulness for SMA mapping. Methods We studied five patients with epilepsy or brain tumour who underwent invasive functional mapping with subdural electrodes. Single-pulse electric stimulation of primary motor area (MI) and SMA was carried out through pairs of subdural electrodes, and motor-evoked potentials (MEPs) were recorded from surface electromyogram on both sides and also cortico-cortical-evoked potentials (CCEPs) from electrocorticogram. Results SMA stimulation elicited: (1) MEPs and following silent periods (SPs) in the contralateral upper and lower extremities, (2) SPs with or without minimal MEPs in the ipsilateral upper extremity and (3) CCEPs in the somatotopically corresponding region of the ipsilateral MI. Compared with MI stimulation, SMA stimulation required higher stimulus intensities (mean 14.2 mA (SMA) vs. 8.5 mA (MI)) to elicit MEPs and showed significantly longer onset latencies in upper extremity (range: 4–10 ms). Conclusions The results demonstrated an asymmetric bilateral effect of human SMA upon the corticospinal pathway. Significance Single-pulse electric cortical stimulation would be clinically useful for distinguishing SMA from MI. The asymmetric bilateral effect of SMA might be conveyed through the direct descending pathway.

Functional specificity of claustrum connections in the rat: interhemispheric communication between specific parts of motor cortex.

Recent evidence indicates that the rat claustrum interconnects the motor cortical areas in both hemispheres. To elucidate the functional specificity of the interhemispheric connections between the claustrum and primary motor (MI) cortex, anterograde tracer injections in specific parts of MI were paired with retrograde tracer injections in homotopic sites of the opposite hemisphere. In addition to injecting the MI forepaw (Fp) region in both hemispheres, we injected the region associated with whisker retractions (Re) and the more caudal rhythmic whisking (RW) region. While the MI-Fp region has few connections with the claustrum of either hemisphere, both whisker regions project to the contralateral claustrum, with those from the MI-RW region being denser and more extensive than those originating from the MI-Re region. Retrograde tracer injections in the MI-RW region produced more labeled neurons in the ipsilateral claustrum than retrograde tracer injections in the MI-Re. Consistent with these patterns, the overlap of labeled terminals and soma in the claustrum was greatest when both tracers were injected into the MI-RW region. When retrograde tracers were injected into the claustrum, the highest density of labeled neurons in MI appeared in the contralateral RW region. Tracer injections in the claustrum also revealed hundreds of labeled neurons throughout its rostrocaudal extent, thereby establishing the presence of long-range intraclaustral connections. These results indicate that the intrinsic and extrinsic connections of the rat claustrum are structured for rapid, interhemispheric transmission of information needed for bilateral coordination of the MI regions that regulate whisker movements.

Automated quantitative assessment of myocardial infarction in late enhancement MRI

Methods Twenty patients with known chronic myocardial infarction (all male, mean age 64 ± 8, range 45-82 years) referred for viability assessment were included. LE MR was performed in multiple short axis slices covering the entire LV (slice thickness 10 mm, 5 mm overlap). Endocardial and epicardial LV contours were derived semi-automatically taking into account corresponding cine MR data. Two independent observers manually outlined the MI regions from a total of 348 slices.

Differential topography of the bilateral cortical projections to the whisker and forepaw regions in rat motor cortex

Whisker and forelimb movements in rats have distinct behavioral functions that suggest differences in the neural connections of the brain regions that control their movements. To test this hypothesis, retrograde tracing methods were used to characterize the bilateral distribution of the cortical neurons that project to the whisker and forelimb regions in primary motor (MI) cortex. Tracer injections in each MI region revealed labeled neurons in more than a dozen cortical areas, but most labeling was concentrated in the sensorimotor areas. Cortical projections to the MI forepaw region originated primarily from the primary somatosensory (SI) cortex in the ipsilateral hemisphere. In contrast, most projections to the MI whisker region originated from the MI whisker region in the contralateral hemisphere. Tracer injections in the MI whisker region also revealed a higher proportion of labeled neurons in the claustrum and in the posterior parietal cortex. Injections of different tracers into the MI whisker and forepaw regions of some rats revealed a topographic organization of neuronal labeling in several sensorimotor regions. Collectively, these findings indicate that the MI whisker and forepaw regions receive different sets of cortical inputs. Whereas the MI whisker region is most strongly influenced by callosal projections, presumably to mediate bilateral coordination of the whiskers, the MI forepaw region is influenced mainly by ipsilateral SI inputs that convey somatosensory feedback.

Bilateral projections from rat MI whisker cortex to the neostriatum, thalamus, and claustrum: Forebrain circuits for modulating whisking behavior

In rats, whisking behavior is characterized by high-frequency synchronous movements and other stereotyped patterns of bilateral coordination that are rarely seen in the bilateral movements of the limbs. This suggests that the motor systems controlling whisker and limb movements must have qualitative or quantitative differences in their interhemispheric connections. To test this hypothesis, anterograde tracing methods were used to characterize the bilateral distribution of projections from the whisker and forepaw regions in the primary motor (MI) cortex. Unilateral tracer injections in the MI whisker or forepaw regions revealed robust projections to the corresponding MI cortical area in the contralateral hemisphere. Both MI regions project bilaterally to the neostriatum, but the corticostriatal projections from the whisker region are denser and more evenly distributed across both hemispheres than those from the MI forepaw region. The MI whisker region projects bilaterally to several nuclei in the thalamus, whereas the MI forepaw region projects almost exclusively to the ipsilateral thalamus. The MI whisker region sends dense projections to the contralateral claustrum, but those to the ipsilateral claustrum are less numerous. By contrast, the MI forepaw region sends few projections to the claustrum of either hemisphere. Bilateral deposits of different tracers in MI revealed overlapping projections to the neostriatum, thalamus, and claustrum when the whisker regions were injected, but not when the forepaw regions were injected. These results suggest that the bilateral coordination of the whiskers depends, in part, on MI projections to the contralateral neostriatum, thalamus, and claustrum.

Inconvenient Truths about neural processing in primary motor cortex

Primary motor cortex (MI) plays an important role in voluntary motor behaviour, yet considerable debate remains on how neural processing within this brain region contributes to motor function. This article provides a brief review of the dominant conceptual frameworks used to interpret MI activity, notably servo-control during the 1970s and early 1980s, and sensorimotor transformations since that time. The former emphasized the use of feedback, but was abandoned because delays in sensory feedback could not permit sufficient feedback gains to generate observed patterns of limb movement. The latter framework focuses attention on identifying what coordinate frames, or representations, best describe neural processing in MI. However, studies have shown that MI activity correlates with a broad range of parameters of motor performance from spatial target location, hand or joint motion, joint torque and muscle activation patterns. Further, these representations can change across behaviours, such as from posture to movement. What do heterogeneous, labile neural representations mean and how do they help us understand how MI is involved in volitional motor control? Perhaps what is required is a new conceptual framework that re-focuses the experimental problem back on processes of control. Specifically, optimal feedback control has been proposed as a theory of the volitional motor system and it is argued here that it provides a rich, new perspective for addressing the role of MI and other brain regions in volitional motor control.

The Usefulness of Intracoronary Electrocardiography during Primary Percutaneous Coronary Intervention in Patients with Acute Myocardial Infarction

Background and Objectives：Measurements obtained using an intracoronary electrocardiogram (IC-ECG) reflect the electrical activity in various regions of the myocardium. This technique can be easily used in the catheterization laboratory during percutaneous coronary intervention (PCI) procedures. Furthermore, IC-ECG could be used to evaluate myocardial viability in patients with acute myocardial infarction (AMI). The aim of this study was to evaluate the usefulness of IC-ECG in predicting the microvascular integrity and late improvement of left ventricular (LV) function after primary PCI in patients with AMI. Subjects and Methods：A total of 78 patients (62 male, 16 female) who underwent primary PCI with stent implantation were enrolled in this study. After the implantation of the stent, IC-ECG was recorded from the tip of an insulated angioplasty guidewire before and after balloon occlusion of the infarct-related artery. The IC-ECG was obtained from the inferior and inferolateral areas in inferior wall MI, or apex and apical anterior wall regions in anterior wall MI. Significant ST segment elevation was defined as a further ST segment elevation of ≥0.2 mV at 80 msec after the J-point in comparison to the baseline value. The microvascular integrity of the myocardium was evaluated by myocardial contrast echocardiography (MCE) one day after the PCI was performed. Six months later, all of the patients were followed up by echocardiography and the wall motion score index (WMSI) and ejection fraction (EF) were measured. Results：Significant ST elevation was noted in 47 patients (Group A) after coronary occlusion. There was no significant change in the other 31 patients (Group B). MCE showed microvascular perfusion in 41 patients in group A (87%) and in four patients in group B (13%) (p<0.05). The six-month follow-up echocardiography showed that group A had a lower WMSI (1.20±0.18 vs 1.56±0.34, p<0.05) and higher EF (57.6±7 vs 47±11, p<0.05) than group B. The LV end diastolic dimension (LVEDD ) in group B was increased compared to group A (p=0.021). The LV end systolic dimension (LVESD ) was also increased in group B; however, the LVESD in group A was decreased after six months (p=0.002). Conclusion： IC-ECG during PCI is a simple and useful method for assessing the microvascular integrity of the myocardium and for predicting the long-term improvement of LV function. (Korean Circulation J 2007;37:148-153)

533 Study of the echocardiographic predictors for 10-year survival after thrombolytic therapy of acute myocardial infarction

s S87 Eur J Echocardiography Abstracts Supplement, December 2006 Results: Pts were divided in two groups: group I pts with FT 202 pts (26%), group II without FT 558 (74%). Left ventricle thrombi were found in 16 pts (8%) of group I and in 39 pts of group II (7%) p>0.05. In 6 pts of group I the thrombi were localized or connected to false tendon. These group of pts was treated by thrombolitics, had extensive antero-lateral MI (E?35%) and FT localized in the region of MI. Two patients of group I and 1 of group II had neurological ischemic stroke. As well we analyze frequency of thrombi occurrence dependency of therapy: PCI or thrombolitic. In group of 582 pts treated by PCI we observed thrombus in 23 (4%) cases, in 178 pts treated by thrombolitic therapy thrombi were found in 32 (18%) pts p 90 ms, E/A≤1.04, DT>150 ms). HRV indices and arrhythmic events were evaluated by 24 hour Holter monitoring (view Table; M±SD; *p <0.05). Time and frequency domain HRV indices were significantly reduced in patients with restrictive LV filling patterns compared to those with impaired LV relaxation. Early postinfarction patients with restrictive LV filling showed increased frequency of ventricular arrhythmias during the day. These findings reflect more expressed autonomous nervous imbalance and may predict higher mortality in these patients. Table 1. Correlation: HRV and LV filling patterns HRV indices and Abnormal LV relaxation Restrictive LV filling arrhythmic events (n=144) (n=57) SDNN, msec 115.8±5.48 94.03±2.34 * SDANN, msec 75.9±2.32 61. 8 ±1.47 * SDNN index, msec 51.2±3.61 50.07±l.03,n/s RMSSD, msec 27.0±2.19 22.5±1.26 * PNN50, % 7.1 ±1,38 8.1±0.91* LF, msec2 494.8±23.27 3 89.55±10.45* HF, msec2 9 3.1±7.26 7 9.66±4.86 * LF/HF 5.95±2.7 6.46±2.8* VPB, per day 45.4±10.61 70.14±26.97 * VPB pair, per day 3.02±0.84 5.04±1.76* VT, episodes per day 0.12±0.47 0.34±0.47* Heart Rate, beats/min. 65.0±2.28 79.45±1.66* VPB ventricular premature beats, VT ventricular tachicardia episode 535 Serial echocardiographical follow-up of ventricular function in patients with reperfusion for ST-elevation myocardial infarction correlations with BNP M. Dorobantu 1 ; A.G. Fruntelata 1 ; R. Onut 1 ; A. Scafa-Udriste 1 ; D. Constantinescu 1 ; M. Marinescu 1 ; A. Vasile 1 ; A. Alexandrescu 1 1Emergency Hospital of Bucharest, Cardiology Dept., Bucharest, Romania Background: Echocardiographical assessment of left ventricular ejection fraction and wall motion score index and also of ventricular long axis function, diastolic dysfunction and post-infarction remodeling is crucial for risk stratification in patients with ST-elevation myocardial infarction (STEMI). In this population, elevated brain natriuretic peptide (BNP) levels were significantly associated with adverse outcome beyond left ventricular ejection fraction (LVEF) and identified patients with survival benefit from early invasive strategy. However, correlations of BNP levels to echocardiographical measurements of ventricular function by serial follow-up to predict risk of future clinical events have not been

Somatotopically arranged inputs from putamen and subthalamic nucleus to primary motor cortex

Employing retrograde transsynaptic transport of rabies virus, we investigated the organization of basal ganglia inputs to hindlimb, proximal and distal forelimb, and orofacial representations of the macaque primary motor cortex (MI). Four days after rabies injections into these MI regions, neuronal labeling occurred in the striatum and the subthalamic nucleus (STN) through the cortico-basal ganglia loop circuits. In the striatum, two distinct sets of the labeling were observed: one in the dorsal putamen, and the other in the ventral striatum (ventromedial putamen and nucleus accumbens). The dorsal striatal labeling was somatotopically arranged and its distribution pattern was in good accordance with that of the corticostriatal inputs, such that the hindlimb, orofacial, or forelimb area was located in the dorsal, ventral, or intermediate zone of the putamen, respectively. The distribution pattern of the ventral striatal labeling was essentially the same in all cases. In the STN, the somatotopic arrangement of labeled neurons was in register with that of corticosubthalamic inputs. The present results suggest that the cortico-basal ganglia motor circuits involving the dorsal putamen and the STN may constitute separate closed loops based on the somatotopy, while the ventral striatum provides common multisynaptic projections to all body-part representations in the MI.