Involvement of the claustrum in the cortico-basal ganglia circuitry: connectional study in the non-human primate

The claustrum is an ancient telencephalic subcortical structure displaying extensive, reciprocal connections with much of the cortex and receiving projections from thalamus, amygdala, and hippocampus. This structure has a general role in modulating cortical excitability and is considered to be engaged in different cognitive and motor functions, such as sensory integration and perceptual binding, salience-guided attention, top-down executive functions, as well as in the control of brain states, such as sleep and its interhemispheric integration. The present study is the first to describe in detail a projection from the claustrum to the striatum in the macaque brain. Based on tracer injections in different striatal regions and in different cortical areas, we observed a rough topography of the claustral connectivity, thanks to which a claustral zone projects to both a specific striatal territory and to cortical areas involved in a network projecting to the same striatal territory. The present data add new elements of complexity of the basal ganglia information processing mode in motor and non-motor functions and provide evidence for an influence of the claustrum on both cortical functional domains and cortico-basal ganglia circuits.

A Cortical Mechanism Linking Saliency Detection and Motor Reactivity in Rhesus Monkeys

Sudden and surprising sensory events trigger neural processes that swiftly adjust behavior. To study the phylogenesis and the mechanism of this phenomenon, we trained two male rhesus monkeys to keep a cursor inside a visual target by exerting force on an isometric joystick. We examined the effect of surprising auditory stimuli on exerted force, scalp electroencephalographic (EEG) activity, and local field potentials (LFPs) recorded from the dorsolateral prefrontal cortex. Auditory stimuli elicited (1) a biphasic modulation of isometric force, a transient decrease followed by a corrective tonic increase, and (2) EEG and LFP deflections dominated by two large negative-positive waves (N70 and P130). The EEG potential was symmetrical and maximal at the scalp vertex, highly reminiscent of the human "vertex potential." Electrocortical potentials and force were tightly coupled: the P130 amplitude predicted the magnitude of the corrective force increase, particularly in the LFPs recorded from deep rather than superficial cortical layers. These results disclose a phylogenetically preserved corticomotor mechanism supporting adaptive behavior in response to salient sensory events.Significance Statement Survival in the natural world depends on an animal's capacity to adapt ongoing behavior to abrupt unexpected events. To study the neural mechanisms underlying this capacity, we trained monkeys to apply constant force on a joystick while we recorded their brain activity from the scalp and the prefrontal cortex contralateral to the hand holding the joystick. Unexpected auditory stimuli elicited a biphasic force modulation: a transient reduction followed by a corrective adjustment. The same stimuli also elicited EEG and LFP responses, dominated by a biphasic wave that predicted the magnitude of the behavioral adjustment. These results disclose a phylogenetically preserved corticomotor mechanism supporting adaptive behavior in response to unexpected events.

Cortico-spinal modularity in the parieto-frontal system: A new perspective on action control

Classical neurophysiology suggests that the motor cortex (MI) has a unique role in action control. In contrast, this review presents evidence for multiple parieto-frontal spinal command modules that can bypass MI. Five observations support this modular perspective: (i) the statistics of cortical connectivity demonstrate functionally-related clusters of cortical areas, defining functional modules in the premotor, cingulate, and parietal cortices; (ii) different corticospinal pathways originate from the above areas, each with a distinct range of conduction velocities; (iii) the activation time of each module varies depending on task, and different modules can be activated simultaneously; (iv) a modular architecture with direct motor output is faster and less metabolically expensive than an architecture that relies on MI, given the slow connections between MI and other cortical areas; (v) lesions of the areas composing parieto-frontal modules have different effects from lesions of MI. Here we provide examples of six cortico-spinal modules and functions they subserve: module 1) arm reaching, tool use and object construction; module 2) spatial navigation and locomotion; module 3) grasping and observation of hand and mouth actions; module 4) action initiation, motor sequences, time encoding; module 5) conditional motor association and learning, action plan switching and action inhibition; module 6) planning defensive actions. These modules can serve as a library of tools to be recombined when faced with novel tasks, and MI might serve as a recombinatory hub. In conclusion, the availability of locally-stored information and multiple outflow paths supports the physiological plausibility of the proposed modular perspective.

The parietal lobe evolution and the emergence of material culture in the human genus

Traditional and new disciplines converge in suggesting that the parietal lobe underwent a considerable expansion during human evolution. Through the study of endocasts and shape analysis, paleoneurology has shown an increased globularity of the braincase and bulging of the parietal region in modern humans, as compared to other human species, including Neandertals. Cortical complexity increased in both the superior and inferior parietal lobules. Emerging fields bridging archaeology and neuroscience supply further evidence of the involvement of the parietal cortex in human-specific behaviors related to visuospatial capacity, technological integration, self-awareness, numerosity, mathematical reasoning and language. Here, we complement these inferences on the parietal lobe evolution, with results from more classical neuroscience disciplines, such as behavioral neurophysiology, functional neuroimaging, and brain lesions; and apply these to define the neural substrates and the role of the parietal lobes in the emergence of functions at the core of material culture, such as tool-making, tool use and constructional abilities.

POS1267 LONG-TERM SURVEY STUDY OF THE IMPACT OF COVID-19 ON SYSTEMIC AUTOIMMUNE DISEASES. LOW DEATH RATE DESPITE THE INCREASED PREVALENCE OF SYMPTOMATIC INFECTION. ROLE OF PRE-EXISTING INTERSTITIAL LUNG DISEASE AND ONGOING TREATMENTS

Background

Patients with autoimmune systemic diseases (ASDs) can be counted among frail populations as regards the predisposition to COVID-19 due to the frequent visceral organ involvement and comorbidities, as well as the ongoing immunomodulating treatments.

Objectives

Our long-term multicenter telephone survey prospectively investigated the prevalence, prognostic factors, and outcomes of COVID-19 in Italian ASD patients during the first 3 pandemic waves.

Methods

A large series of 3,918 ASD patients (815 M, 3103 F; mean age 59±12SD years) was consecutively recruited at the 36 referral centers of COVID-19 & ASD Italian Study Group. In particular, ASD series encompassed the following conditions: rheumatoid arthritis (n: 981), psoriatic arthritis (n: 471), ankylosing spondylitis (n: 159), systemic sclerosis (n: 1,738), systemic lupus (172), systemic vasculitis (n: 219), and a miscellany of other ASDs (n: 178). The development of COVID-19 was recorded by means of telephone survey using standardized symptom-assessment questionnaire (1).

Results

A significantly increased prevalence of COVID-19 (8.37% vs 6.49%; p<0.0001) was observed in our ASD patients, while the cumulative death rate revealed statistically comparable to the Italian general population (3.65% vs 2.95%; p: ns). In particular, among the 328 ASD patients complicated by COVID-19, 57 (17%) needed hospitalization, while mild-moderate manifestations were observed in the large majority of individuals (83%). In addition, 12/57 hospitalized patients died due to severe interstitial pneumonia and/or cardiovascular manifestations.

Interestingly, a significantly higher COVID-19-related death rate was observed in systemic sclerosis patients compared to the Italian general population (6.29% vs 2.95%; p=0.018). Other adverse prognostic factors to develop COVID-19 were the patients’ older age, male gender, pre-existing ASD-related interstitial lung involvement, and chronic steroid treatment. Conversely, patients treated with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) showed a significantly lower prevalence of COVID-19 compared to those without (3.58% vs 46.99%; p=0.000), as well as the chronic administration of low dose aspirin in a subgroup of SSc patients (with 5.57% vs without 27.84%; p=0.000).

Conclusion

The cumulative impact of COVID-19 on ASD patients after the first 3 pandemic waves revealed less severe than that observed during the first phase of pandemic (1), especially with regards to the death rate that was comparable to the Italian general population in spite of the increased prevalence of complicating COVID-19 in the same ASD series.

Ongoing long-term treatments, mainly csDMARDs, might usefully contribute to generally positive outcomes of in this frail patients’ population.

Of note, a significantly increased COVID-19-related mortality was recorded in only SSc patients’ subgroup, possibly favored by pre-existing lung fibrosis. Among different ASD, SSc deserves special attention, since it shares the main pathological alterations with COVID-19, namely the interstitial lung involvement and the endothelial injury responsible for diffuse microangiopathy.

Besides SSc, the patients’ subgroups characterized by older age, chronic steroid treatment, pre-existing interstitial lung disease, and/or impaired COVID-19 vaccine response (1-3), may deserve well-designed prevention and management strategies.

References

[1]Ferri C, et al. Ann Rheum Dis. 2020 Oct 14 doi: 10.1136/annrheumdis-2020-219113.

[2]Ferri C et al. J Autoimmun. 2021 Dec;125:102744. doi: 10.1016/j.jaut.2021.102744.

[3]Visentini M et al. Ann Rheum Dis. 2021 Nov 24. doi: 10.1136/annrheumdis-2021-221248

Disclosure of Interests

None declared

Wasted myocardial work may affect left ventricular remodelling occurrence after primary percutaneous coronary revascularization

Funding Acknowledgements

Type of funding sources: None.

Introduction

Left ventricular function recovery (LV-REC) or left ventricular adverse remodelling (LV-REM) after acute myocardial infarction (AMI) play an important role for identifying patients at risk of heart failure.

Purpose

In this study we aim to evaluate the usefulness of non-invasive myocardial work (MW), a new index of global and regional myocardial performance, to predict LV-REC or LV-REM after AMI.

Methods

Fifty patients with AMI (mean age, 63,8 ±13,4 years), treated by primary percutaneous coronary intervention (PCI), were prospectively enrolled.  They underwent a baseline transthoracic Doppler echocardiography (TTE) within 48 hours after PCI and a second TTE after a median of 31 days during the follow-up. MW was derived from the strain-pressure loops, integrating in its calculation the non-invasive arterial pressure, according to standard speckle tracking echocardiography recommendations. LV-REC was defined as an absolute improvement of left ventricular ejection fraction (LVEF) ≥ 5% from LVEF at baseline, whereas LV-REM was defined as an increase of ≥ 20% of the LV end diastolic volume (LVEDV) at 1 month follow up.

Results

We overall found a significant improvement from baseline to one-month follow-up for values of LVEF (49,8 ± 9,5 % vs 52,8 ± 9,3 %, p = 0.001), Global Longitudinal Strain (GLS) (-13,4 ± 3,9 % vs -18,7 ± 5,4 %, p = 0.016), Global Work Index (GWI) (1368,6 ±435,2 vs 1788 ±493 mmHg/%, p = 0.0001), Global Work Efficiency (GWE) (89,96 ± 9,3 % vs 91,3 ± 6,4 %,  p = 0.001), Global Constructive Work (GCW) (1619,16 ± 497,9 mmHg/% vs 2008,6 ± 535,3 mmHg/%, p = 0.0001), Global Wasted Work (GWW) (188,8 ± 19,8 mmHg/% vs 149,2 ± 16,5 mmHg/%). However, LV-REC at 1 month of follow-up was observed only in 36 % of the population enrolled, whereas LV-REM was described in 18% of cases. Using ROC curve analysis, we identified a cut off value of 202 mmHg/% for baseline GWW (Sensitivity 75%, Specificity 62%, AUC 0.6667, CI 95%: 0,51618 - 0,81715, p =0.0001) to identify patients with LV-REM at 1 month. With regards to conventional echo parameters, patients with LV-REC showed lower baseline Wall Motion Score Index (WMSI) than those without LV-REC (1,73 vs 1,38, p = 0.007).

Conclusions

Among standard and advanced TTE parameters, only baseline GWW is able to predict early LV-REM at 1 month after primary PCI. Therefore, it could be used during baseline evaluation of AMI patients for a more accurate stratification of those at higher risk of heart failure. However, further larger scale studies are needed to validate these findings. Abstract table 1  Abstract table 2

Impairment of LA strain and LV myocardial work in Ph+ Chronic myeloid leukaemia patients treated with TKis

Funding Acknowledgements

Type of funding sources: None.

Introduction

Worsening of cardiac function with increased arrhythmic risk is common in cancer patients undergoing chemotherapy. Impaired LV Global Longitudinal Strain (GLS) in these patients despite preserved ejection fraction is a common issue. Recently, myocardial work by speckle-tracking echocardiography has been used to overcome GLS limitations in various conditions, but little is known about its usefulness in the detection of cardiac toxicity. Moreover, left atrial (LA) toxicity may occur early in the course of cancer therapy. The main aim of the study was to assess the cardiotoxic effects of tyrosine kinase inhibitors (TKIs) on patients with Philadelphia chromosome-positive chronic myeloid leukaemia (Ph+ CML) by using novel echocardiographic tools as myocardial work and atrial strain analysis.

Methods

We retrospectively enrolled Ph+ CML patients treated with TKIs followed at the cardio-oncology outpatient clinic of our hospital from December 2018 to March 2019 who underwent clinical evaluation with ECG and echocardiogram (TTE) before and after one year of treatment with TKIs. Healthy subjects were enrolled in the control group matched for gender, age and cardiovascular risk factors. Myocardial work was derived from the strain-pressure relation, integrating in its calculation the non-invasive arterial pressure. LA longitudinal strain (reservoir, conduit and booster) was obtained from an optimized apical 4-chamber view of the LA.

Results

The study recruited 32 patients in Ph+ CML group and 32 healthy controls. 39% of patients were treated with Imatinib, 29.3% with Nilotinib, 4.9% with Dasatinib and 4.9% with Ponatinib. Main results are detailed in the Table 1. At one-year follow-up there was a significant reduction compared to baseline in Global Constructive Work (2555.22 ± 564.33 vs 2119.31 ± 700.19; p = 0.0001), Global Work Efficiency (96.13 ± 1.90 vs 94.00 ± 2.96; p = 0.002) and Global Work Index (2340.75 ± 579.57 vs 1938.46 ± 680.23; p = 0.001), and a non-significant reduction in Global Wasted Work (p = 0.393). Regarding left atrial strain analysis at the one-year follow-up there was a statistically significant reduction in LA contractile strain (booster= 14.63 ± 1.408 vs 12.38 ± 1.581; p= 0.018). LA contractile strain reduction was also observed in the comparison with controls (12.38 ± 2.99 vs 14.91 ± 3.09; p = 0.009). Any other significant difference was detected between baseline and FU TTE data in the Ph+ CML group.

Conclusions

New imaging methods for the study of cardiotoxicity provide an additional tool for early prediction of potential adverse effects of antineoplastic drugs. TKIs therapy leads to an impairment of atrial contractility, which can be detected by atrial strain e myocardial work analysis. Abstract table 1  Abstract figure 1

The functional characterization of callosal connections

•

The functional characterization of callosal connections is informed by anatomical data.

•

Callosal connections play a conditional driving role depending on the brain state and behavioral demands.

•

Callosal connections play a modulatory function, in addition to a driving role.

•

The corpus callosum participates in learning and interhemispheric transfer of sensorimotor habits.

•

The corpus callosum contributes to language processing and cognitive functions.

The brain operates through the synaptic interaction of distant neurons within flexible, often heterogeneous, distributed systems. Histological studies have detailed the connections between distant neurons, but their functional characterization deserves further exploration. Studies performed on the corpus callosum in animals and humans are unique in that they capitalize on results obtained from several neuroscience disciplines. Such data inspire a new interpretation of the function of callosal connections and delineate a novel road map, thus paving the way toward a general theory of cortico-cortical connectivity. Here we suggest that callosal axons can drive their post-synaptic targets preferentially when coupled to other inputs endowing the cortical network with a high degree of conditionality. This might depend on several factors, such as their pattern of convergence-divergence, the excitatory and inhibitory operation mode, the range of conduction velocities, the variety of homotopic and heterotopic projections and, finally, the state-dependency of their firing. We propose that, in addition to direct stimulation of post-synaptic targets, callosal axons often play a conditional driving or modulatory role, which depends on task contingencies, as documented by several recent studies.

Prediction of early left ventricular recovery and adverse remodelling in patients with acute myocardial infarction: the role of non-invasive myocardial work evaluation

Background

Left ventricular recovery (LVR) and adverse left ventricular remodelling (aLVR) after acute myocardial infarction (AMI) play an important prognostic role.

Purpose

Our aim was to evaluate the usefulness of non-invasive myocardial work (MW), a new index of global and regional myocardial performance, to predict LVR and aLVR.

Methods

Fifty patients with AMI (mean age, 63,8±13,4 years), treated by percutaneous coronary intervention (PCI), were prospectively enrolled and underwent a transthoracic Doppler echocardiography within 48 hours after PCI and a median of 31 days at follow-up. Myocardial work is derived from the strain-pressure relation, integrating in its calculation the non-invasive arterial pressure. Segmental LVR was defined as an absolute improvement of left ventricular ejection fraction (LVEF) ≥5% from LVEF at the baseline. The aLVR was defined as an increase of ≥20% of the LV end diastolic volume (LVEDV) at 1 month follow up.

Results

We found significant differences between the baseline and the follow-up value of LVEF (49,28 vs 52,80 p=0.001), Global Longitudinal Strain (GLS) (−13,41 vs −18,72, p=0.016), Global Work Index (GWI) (1368,68 vs 1788,08, p&lt;0.0001), Global Work Efficiency (GWE) (86,96 vs 91,36, p=0.001), and Global Constructive Work (GCW) (1619,16 vs 2008,68, p&lt;0.0001). The LVR at 1 month of follow-up was observed in 36% of the population enrolled, whereas aLVR was described in 18% of cases. Using ROC curve analysis, we identified a cut off value of 137 mmHg/% for baseline Global Wasted Work (Sensitivity 100%, Specificity 57,14%, AUC 0.6667, CI 95%: 0,51618- 0,81715, p&lt;0.0001) to identify patients with aLVR at 1 month. With regards to conventional echo parameters, patients with LVR showed lower baseline Wall Motion Score Index (WMSI) than those with LVR (1,73 vs 1,38, p=0.007).

Conclusions

Baseline global wasted work can predict early adverse left ventricular remodelling at 1 months after AMI. These parameters could be used at baseline in order to predict worse outcome in AMI patients. Further larger scale studies are needed to validate these findings.

Funding Acknowledgement

Type of funding sources: None.

POS1246 COVID-19 IN ITALIAN PATIENTS WITH RHEUMATIC AUTOIMMUNE SYSTEMIC DISEASES: RESULTS OF A NATIONWIDE SURVEY STUDY

Background:

SARS-CoV-2 infection poses a serious challenge for patients with rheumatic autoimmune systemic diseases (ASD), characterized by marked immune-system dysregulation and frequent visceral organ involvement.

Objectives:

To evaluate the impact of Covid-19 pandemic in a large series of Italian patients with ASD.

Methods:

Our multicenter telephone survey (8-week period, March-April 2020) included a large series of 2,994 patients (584 M, 2,410 F, mean age 58.9±13.4SD years) with ASD followed at 34 tertiary referral centers of 14 regions of northern, central, and southern Italian macro areas, characterized by different prevalence of SARS-CoV-2 infection. According to currently used criteria, Covid-19 was classified as definite Covid-19 (signs or symptoms of Covid-19 confirmed by positive oral/nasopharyngeal swabs at PCR testing) or highly suspected Covid-19 (signs or symptoms highly suggestive of Covid-19, but not confirmed by PCR testing due to limited availability of virological tests in that period). The results were analyzed performing the Odds Ratio by Java-Stat 2-way Contingency Table Analysis.

Results:

The main findings of the survey study revealed a significantly increased prevalence of Covid-19 in:

a.the whole series of ASD patients (definite Covid-19: 22/2994, 0.73%; p=0.0007;

definite Covid-19 plus highly suspected Covid-19: 74/2,994, 2.47%; p<0.0001) when compared to Italian general population of Covid-19 infected individuals (349/100000 = 0.34%; data from Italian Superior Institute of Health;

https://www.epicentro.iss.it/en/coronavirus/sars-cov-2-national-surveillance-system).

b.the subgroup of patients with connective tissue diseases or systemic vasculitis (n = 1,901) compared to the subgroup of inflammatory arthritis (n = 1,093), namely rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis (definite Covid-19: 19/1,901, 0.99%, vs 3/1,093, 0.27%; p=0.036; definite Covid-19 plus highly suspected Covid-19: 69/1,901, 3.6%, vs 5/1,093, 0.45%; p<0.0001)

c.the subgroup of patients with pre-existing interstitial lung involvement (n = 526) compared to those without (n = 2,468) (definite Covid-19: 10/526, 1.90%, vs 12/2,468, 0.48%; p=0.0015; definite Covid-19 plus highly suspected Covid-19: 33/526, 6.27%, vs 41/2,468, 1.66%; p<0.0001).

Of interest, the prevalence of Covid-19 did not correlate with presence/absence of different comorbidities, mainly diabetes, cardio-vascular and/or renal disorders, as well as of ongoing treatments with biological DMARDs; while patients treated with conventional DMARDs showed a significantly lower prevalence of Covid-19 compared to those without. Covid-19 was more frequently observed in the patients’ populations from northern and central compared to southern Italian macro area with lower diffusion of pandemic. Clinical manifestations of Covid-19, observed in 74 patients, were generally mild or moderate; 4/9 individuals requiring hospital admission died for severe pneumonia.

Conclusion:

The prevalence of Covid-19 observed in ASD patients during the first wave of pandemic was significantly higher than that observed in Italian general population; moreover, the actual prevalence of Covid-19 might be underestimated due to the high number of mild variants as well as the possible clinical overlapping between these two conditions. Patients with ASD should be invariably regarded as ‘frail patients’ during the pandemic course, considering the risk of worse outcome in the acute phase of Covid-19, as well as the potential long-term effects of viral infection.

The statistically significant association of Covid-19 with connective tissue diseases/systemic vasculitis, as well as with pre-existing interstitial lung involvement, suggests the presence of distinct clinico-pathological ASD subsets, characterized by markedly different patients’ vulnerability to SARS-CoV-2 infection.

Disclosure of Interests:

None declared

On the cortical connectivity in the macaque brain: A comparison of diffusion tractography and histological tracing data

Diffusion-weighted magnetic resonance imaging (DW-MRI) tractography is a non-invasive tool to probe neural connections and the structure of the white matter. It has been applied successfully in studies of neurological disorders and normal connectivity. Recent work has revealed that tractography produces a high incidence of false-positive connections, often from "bottleneck" white matter configurations. The rich literature in histological connectivity analysis studies in the macaque monkey enables quantitative evaluation of the performance of tractography algorithms. In this study, we use the intricate connections of frontal, cingulate, and parietal areas, well established by the anatomical literature, to derive a symmetrical histological connectivity matrix composed of 59 cortical areas. We evaluate the performance of fifteen diffusion tractography algorithms, including global, deterministic, and probabilistic state-of-the-art methods for the connectivity predictions of 1711 distinct pairs of areas, among which 680 are reported connected by the literature. The diffusion connectivity analysis was performed on a different ex-vivo macaque brain, acquired using multi-shell DW-MRI protocol, at high spatial and angular resolutions. Across all tested algorithms, the true-positive and true-negative connections were dominant over false-positive and false-negative connections, respectively. Moreover, three-quarters of streamlines had endpoints location in agreement with histological data, on average. Furthermore, probabilistic streamline tractography algorithms show the best performances in predicting which areas are connected. Altogether, we propose a method for quantitative evaluation of tractography algorithms, which aims at improving the sensitivity and the specificity of diffusion-based connectivity analysis. Overall, those results confirm the usefulness of tractography in predicting connectivity, although errors are produced. Many of the errors result from bottleneck white matter configurations near the cortical grey matter and should be the target of future implementation of methods.

Diversity of Cortico-descending Projections: Histological and Diffusion MRI Characterization in the Monkey

The axonal composition of cortical projections originating in premotor, supplementary motor (SMA), primary motor (a4), somatosensory and parietal areas and descending towards the brain stem and spinal cord was characterized in the monkey with histological tract tracing, electron microscopy (EM) and diffusion MRI (dMRI). These 3 approaches provided complementary information. Histology provided accurate assessment of axonal diameters and size of synaptic boutons. dMRI revealed the topography of the projections (tractography), notably in the internal capsule. From measurements of axon diameters axonal conduction velocities were computed. Each area communicates with different diameter axons and this generates a hierarchy of conduction delays in this order: a4 (the shortest), SMA, premotor (F7), parietal, somatosensory, premotor F4 (the longest). We provide new interpretations for i) the well-known different anatomical and electrophysiological estimates of conduction velocity; ii) why conduction delays are probably an essential component of the cortical motor command; and iii) how histological and dMRI tractography can be integrated.

Corticocortical Systems Underlying High-Order Motor Control

Cortical networks are characterized by the origin, destination, and reciprocity of their connections, as well as by the diameter, conduction velocity, and synaptic efficacy of their axons. The network formed by parietal and frontal areas lies at the core of cognitive-motor control because the outflow of parietofrontal signaling is conveyed to the subcortical centers and spinal cord through different parallel pathways, whose orchestration determines, not only when and how movements will be generated, but also the nature of forthcoming actions. Despite intensive studies over the last 50 years, the role of corticocortical connections in motor control and the principles whereby selected cortical networks are recruited by different task demands remain elusive. Furthermore, the synaptic integration of different cortical signals, their modulation by transthalamic loops, and the effects of conduction delays remain challenging questions that must be tackled to understand the dynamical aspects of parietofrontal operations. In this article, we evaluate results from nonhuman primate and selected rodent experiments to offer a viewpoint on how corticocortical systems contribute to learning and producing skilled actions. Addressing this subject is not only of scientific interest but also essential for interpreting the devastating consequences for motor control of lesions at different nodes of this integrated circuit. In humans, the study of corticocortical motor networks is currently based on MRI-related methods, such as resting-state connectivity and diffusion tract-tracing, which both need to be contrasted with histological studies in nonhuman primates.

The Crossed Projection to the Striatum in Two Species of Monkey and in Humans: Behavioral and Evolutionary Significance

The corpus callosum establishes the anatomical continuity between the 2 hemispheres and coordinates their activity. Using histological tracing, single axon reconstructions, and diffusion tractography, we describe a callosal projection to n caudatus and putamen in monkeys and humans. In both species, the origin of this projection is more restricted than that of the ipsilateral projection. In monkeys, it consists of thin axons (0.4-0.6 µm), appropriate for spatial and temporal dispersion of subliminal inputs. For prefrontal cortex, contralateral minus ipsilateral delays to striatum calculated from axon diameters and conduction distance are <2 ms in the monkey and, by extrapolation, <4 ms in humans. This delay corresponds to the performance in Poffenberger's paradigm, a classical attempt to estimate central conduction delays, with a neuropsychological task. In both species, callosal cortico-striatal projections originate from prefrontal, premotor, and motor areas. In humans, we discovered a new projection originating from superior parietal lobule, supramarginal, and superior temporal gyrus, regions engaged in language processing. This projection crosses in the isthmus the lesion of which was reported to dissociate syntax and prosody. The projection might originate from an overproduction of callosal projections in development, differentially pruned depending on species.

Water and hexane in an ionic liquid: computational evidence of association under high pressure

Dissolving water and hexane in an ionic liquid, our simulations clearly show association between them at high pressures.

Reaching-related Neurons in Superior Parietal Area 5: Influence of the Target Visibility

Reaching movements require the integration of both somatic and visual information. These signals can have different relevance, depending on whether reaches are performed toward visual or memorized targets. We tested the hypothesis that under such conditions, therefore depending on target visibility, posterior parietal neurons integrate differently somatic and visual signals. Monkeys were trained to execute both types of reaches from different hand resting positions and in total darkness. Neural activity was recorded in Area 5 (PE) and analyzed by focusing on the preparatory epoch, that is, before movement initiation. Many neurons were influenced by the initial hand position, and most of them were further modulated by the target visibility. For the same starting position, we found a prevalence of neurons with activity that differed depending on whether hand movement was performed toward memorized or visual targets. This result suggests that posterior parietal cortex integrates available signals in a flexible way based on contextual demands.

Silver-Doped Calcium Phosphate Bone Cements with Antibacterial Properties

Calcium phosphate bone cements (CPCs) with antibacterial properties are demanded for clinical applications. In this study, we demonstrated the use of a relatively simple processing route based on preparation of silver-doped CPCs (CPCs-Ag) through the preparation of solid dispersed active powder phase. Real-time monitoring of structural transformations and kinetics of several CPCs-Ag formulations (Ag = 0 wt %, 0.6 wt % and 1.0 wt %) was performed by the Energy Dispersive X-ray Diffraction technique. The partial conversion of β-tricalcium phosphate (TCP) phase into the dicalcium phosphate dihydrate (DCPD) took place in all the investigated cement systems. In the pristine cement powders, Ag in its metallic form was found, whereas for CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, CaAg(PO₃)₃ was detected and Ag (met.) was no longer present. The CPC-Ag 0 wt % cement exhibited a compressive strength of 6.5 ± 1.0 MPa, whereas for the doped cements (CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt %) the reduced values of the compressive strength 4.0 ± 1.0 and 1.5 ± 1.0 MPa, respectively, were detected. Silver-ion release from CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, measured by the Atomic Emission Spectroscopy, corresponds to the average values of 25 µg/L and 43 µg/L, respectively, rising a plateau after 15 days. The results of the antibacterial test proved the inhibitory effect towards pathogenic Escherichia coli for both CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, better performances being observed for the cement with a higher Ag-content.

Pressure-induced mesoscopic disorder in protic ionic liquids: first computational study

The application of high pressure to protic ionic liquids with short alkyl chains induces a progressive homogenization of the structure.

Organization and evolution of parieto-frontal processing streams in macaque monkeys and humans

The functional organization of the parieto-frontal system is crucial for understanding cognitive-motor behavior and provides the basis for interpreting the consequences of parietal lesions in humans from a neurobiological perspective. The parieto-frontal connectivity defines some main information streams that, rather than being devoted to restricted functions, underlie a rich behavioral repertoire. Surprisingly, from macaque to humans, evolution has added only a few, new functional streams, increasing however their complexity and encoding power. In fact, the characterization of the conduction times of parietal and frontal areas to different target structures has recently opened a new window on cortical dynamics, suggesting that evolution has amplified the probability of dynamic interactions between the nodes of the network, thanks to communication patterns based on temporally-dispersed conduction delays. This might allow the representation of sensory-motor signals within multiple neural assemblies and reference frames, as to optimize sensory-motor remapping within an action space characterized by different and more complex demands across evolution.

Hydration Phenomena in a Concentrated Aqueous Solution of Ce(NO3)3. X-ray Diffraction and Raman Spectroscopy

The scattering of X-rays from a concentrated Ce(NO3)3 aqueous solution has been measured and analyzed. The experimental correlation function appears to be mainly characterized by the hydration of the cation: peaks at about 2.55 and 4.65 Å. Good agreement with experimental data is achieved through a model in which the Ce(III) ions have a first and a second hydration shell and also the nitrate group is considered hydrated. Complex formation between cation and anion is confirmed by using Raman spectroscopy.

X-Ray Diffraction Study on Hydration and Ion-Pairing in Aqueous ZnSO4 Solution

An X-ray diffraction experiment on a 2.98 molar ZnSO4 aqueous solution has been interpreted in terms of coordination models. The best agreement between model and experimental structure functions was reached when the Zn2+ ion is hydrated in octahedral form, with twelve water molecules in a second hydration shell, bonded by shortened H-bonds to the first hydration shell. The sulfate group is loosely coordinated by 8.2 water molecules. Besides the dominating Zn(H2O)2+ 6 complexes, about 40% [Zn(H2O)5SO4] inner complexes were found to be consistent with the X-ray data. Alternative models of cationic hydration are critically examined and for the sulfate group the independent atom approximation is compared with a spherical molecular description.

An X-ray and NMR Study on Cerium(III) and Magnesium(II) Perchlorate Solutions

Metal-perchlorate solutions have been investigated by the X-ray scattering technique and 35Cl NMR spectroscopy. The aim of this work was to obtain structural information on the complex formation between the Cerium and the Perchlorate group and on the ClO- 4 - H2O interactions. The NMR data, the correlation functions and the analysis of the structure functions agree with the literature information about the Ce - (OClO3)z species present in aqueous solutions. Good agreement with experimental data is achieved through a model in which the Perchlorate ions are bonded as monodentate ligands to the Cerium(III). No complex formation is confirmed for Mg(II). The cations also possess a second coordination shell of water molecules. Some indications have been obtained supporting the presence of ClO- 4 - H2O contacts.

A Comparative X-Ray Diffraction Study of Aqueous MnSO4 and Crystals of MnSO4·5H2O

X-ray single crystal analysis of MnSO4·5H2O shows that the manganese atoms are octahedrally coordinated by oxygen atoms, four of which belong to water molecules and two to sulphate groups.

A model derived from the crystal structure was fitted to the X-ray scattering intensities from aqueous MnSO4. Good agreement with experimental data is achieved using a model in which Mn(H2O)6-z(OSO3)z +2-2z interacts with about ten water molecules and each sulphate ion with about seven water molecules.

On the Structure in Aqueous Superconcentrated Calcium Nitrate

Liquid hydrous calcium nitrate of composition Ca(NO3)2 · 3.5 H2O was investigated by X-ray diffraction. Experimental data were interpreted in terms of geometrical models suggested by the structure of the crystalline hydrates Ca (NO3)2 · 3H2O and Ca(NO3)2 · 4H2O, in which calcium ions are coordinated to nine oxygen atoms, partly coming from water molecules, partly from NO3 -ions.

X-Ray Diffraction and Structural Properties of Aqueous Solutions of Divalent Metal-Chlorides

X-ray diffraction data are reported for aqueous solutions of CaCl2 (6.30 M), CdCl2 (0.87 and 1.26 M) and NiCl2 (1.96 and 3.88 M). The highly concentrated CaCl2 solution shows a medium range order resembling that of the corresponding hydrate crystal. The CdCl2 solutions are characterized by the presence of complexes with chloride ions in the first coordination sphere of the cation. In NiCl2 solutions, a first sphere Ni-Cl coordination can be excluded and the existence of six Ni-H2O nearest neighbour contacts is clearly confirmed. In these solutions no evidence was found for the existence of highly ordered structures; hexa-aquo cations interact with external water molecules and, at the highest concentration, some outer sphere Ni-Cl correlation is possible as due to packing.

Amino acid anions in organic ionic compounds. An ab initio study of selected ion pairs

The combination of amino acids in their deprotonated and thus anionic form with a choline cation gives origin to a new and potentially important class of organic ionic compounds. A series of such neutral ion pairs has been investigated by first principle methods. The results reveal intriguing structural motives as well as regular patterns in the charge distribution and predict a number of vibrational and optical properties that could guide the experimental investigation of these compounds. The replacement of choline with its phosphocholine analogue causes the spontaneous reciprocal neutralization of cations and anions, taking place through the transfer of a proton between the two ions. Systems of this kind, therefore, provide a wide and easily accessible playground to probe the ionic/polar transition in organic systems, while the easy transfer of H(+) among neutral and ionic species points to their potential application as proton conductors. The analysis of the ab initio data highlights similarities as well as discrepancies from the rigid-ions force-field picture and suggests directions for the improvement of empirical models.

The diameter of cortical axons depends both on the area of origin and target

In primates, different cortical areas send axons of different diameters into comparable tracts, notably the corpus callosum (Tomasi S, Caminiti R, Innocenti GM. 2012. Areal differences in diameter and length of corticofugal projections. Cereb Cortex. 22:1463-1472). We now explored if an area also sends axons of different diameters to different targets. We find that the parietal area PEc sends thicker axons to area 4 and 6, and thinner ones to the cingulate region (area 24). Areas 4 and 9, each sends axons of different diameters to the nucleus caudatus, to different levels of the internal capsule, and to the thalamus. The internal capsule receives the thickest axon, followed by thalamus and nucleus caudatus. The 2 areas (4 and 9) differ in the diameter and length of axons to corresponding targets. We calculated how diameter determines conduction velocity of the axons and together with pathway length determines transmission delays between different brain sites. We propose that projections from and within the cerebral cortex consist of a complex system of lines of communication with different geometrical and time computing properties.

Impairment of online control of hand and eye movements in a monkey model of optic ataxia

The parietal mechanisms for online control of hand trajectory were studied by combining single-cell recording and reversible inactivation of superior parietal area 5 (PE/PEc; SPL) of monkeys while these made reaches and saccades to visual targets, when the target position changed unexpectedly. Neural activity was modulated by hand position, speed, and movement direction, and by pre- and/or postsaccadic signals. After bilateral muscimol injection, an increase in the hand reaction- and movement-time toward both the first and second targets was observed. This caused an increase in the time necessary for the trajectory correction, and therefore an elongation of the hand-path toward the first target location. Furthermore, hand trajectories were different in shape than control ones. An elongation of the eye reaction time to both first and second targets was also observed, which could partially explain the deficit of planning and correction of hand movement. These results identify the superior parietal lobule as a crucial node in the online control of hand and eye movement and highlight the role of the eye impairment in the emergence of the reaching disorder so far regarded as the hallmark of optic ataxia.

Areal differences in diameter and length of corticofugal projections

Cortical areas differ in the size and distribution of neuronal cell bodies, density, and distribution of myelinated axons, connections, and functional properties. We find that they also differ in the diameter of long corticofugal axons, with the thickest axons originating from primary motor, somatosensory, and visual areas and the thinnest ones from prefrontal and temporal areas. Since diameter is proportional to axonal conduction velocity, it can be inferred that action potentials issued from the different areas will be relayed to their targets at different speed. Conduction delays also depend on conduction distance. By computing conduction velocity and conduction distances, we found the longest conduction delays for the primary visual and temporal areas and the shortest for the premotor, primary motor, and somatosensory areas, compatible with the available electrophysiological data. These findings seem to establish a new principle in cortical organization relevant to the pathophysiology of neurological or psychiatric illnesses as well as to the speed of information processing in cortical circuits.

Pseudoaneurysm of the hepatic artery and hemobilia: a rare complication of laparoscopic cholecystectomy; clinical case and literature review

Laparoscopic cholecystectomy is the Gold Standard for the treatment of symptomatic cholelithiasis. There is still an increase in the rate of incidence of biliary and vascular injuries with laparoscopy. Hepatic artery pseudoaneurysm is a rare but serious complication associated with laparoscopic cholecystectomy and bile duct injury. The diagnosis may be difficult. Our experience of a case of iatrogenic lesion of the right hepatic artery with the formation of pseudoaneurysm treated by means of embolization of the artery is presented here.

The structure of geminal imidazolium bis(trifluoromethylsulfonyl)amide ionic liquids: a theoretical study of the gas phase ionic complexes

In this work we report molecular mechanics and ab initio calculations on the geminal di-imidazolium bis(trifluoromethylsulfonyl)amide ionic liquid in the gas phase. We report the likely energetically preferred geometries of the ionic complex and its main features in terms of charge distribution, electronic density, structure, and energetics. We find that the gas phase structure of the ionic complex is quite compact and that the alkyl chain connecting the two imidazolium charged rings is strongly bent in order to maximize their electrostatic interactions with the two anions.

[Intestinal perforation by ingested foreign bodies in the digestive tract: an insidious pathology always of interest. Our experience]

The authors want to present five cases (from May 1999 to May 2009) of acute abdomen from perforation of the foreign body introduced with food. They highlight how the accidental ingestion is very common but the perforation is rare. The preoperative diagnosis, in these cases, is always very difficult and the radiological examinations are not always able to resolve the diagnostic doubt with other acute intestinal diseases that are responsible of perforation. Then, the surgery procedure is, necessarily, the only possible diagnostic and therapeutic means. The mortality and the morbidity remain still high first of all for the delay in the diagnosis and the advanced age of patients.