Electrophysiological Differences Research Articles

Low Back Pain in Patients with Lumbar Spinal Stenosis-Hemodynamic and electrophysiological study of the lumbar multifidus muscles.

Introduction Several studies have demonstrated improvement in low back pain (LBP) after decompression surgery for lower extremity symptoms in lumbar spinal stenosis (LSS); however, the influence of neuropathic disorders on LBP is uncertain. Aim of this study is to identify the features of motion-induced and walking-induced LBP in patients with LSS and to assess whether neuropathic LBP develops. Methods In total, 234 patients with LSS including L4/5 lesion were asked to identify their LBP. Subjects were classified into three groups: walking-induced LBP that aggravated during walking (W group), motion-induced LBP that aggravated during sitting up (M group), and no LBP (N group). Cross-sectional areas of the dural sac, lumbar multifidus, and the erector spinae were measured. Intramuscular oxygenation was evaluated with near-infrared spectrophotometer. Surface electromyography (EMG) and mechanomyography (MMG) were performed on the lumbar multifidus. Morphological, hemodynamic, and electrophysiological differences in the onset of LBP were evaluated. Results The prevalence of W, M, and control groups was 31.2%, 32.1%, 36.8%, respectively. Concordance between the laterality of LBP and leg symptoms including pain and numbness was 86.3% in the W group and 47.0% in the M group. Dural sac area was lower in the W group than in the M and control groups. In the hemodynamic evaluation, the oxygenated hemoglobin level was significantly lower in the W group than in the M and N groups. In electrophysiological evaluation of lumbar multifidus, the mean power frequency in EMG was significantly higher in the W group than in the N group. Amplitude in MMG was significantly lower in the W group than in the N group. Conclusions Neurologic disturbance in patients with LSS may be attributed to “neuropathic LBP.” Neuropathic multifidus disorder plays a role in walking-induced LBP.

Electrophysiological Difference in Obstructive Sleep Apnea with and without REM sleep Behavior Disorder: Cardiopulmonary Coupling Analysis

Objectives: Although rapid eye movement behavior disorder (RBD) and obstructive sleep apnea syndrome (OSA) have different pathophysiology, RBD patients with OSA appeared to have more stable sleep compared to patients with OSA and to verify it by cardiopulmonary coupling (CPC) method. Methods: The polysomnography (PSG) data of 138 subjects with OSA (AHI ≥ 15), RBD with OSA (AHI ≥ 15), RBD, normal control (N=32, 26, 29, 51, respectively) were collected. For conducting case control study between RBD with OSA and patients with OSA only, a total of 32 OSA controls, matched for age, AHI and BMI were recruited. CPC parameters were obtained using CPC analyzer in Rem Logic. Sleep spectrogram by CPC analyses revealed the percentage of stable tidal volume [high-frequency coupling (HFC), 0.1–0.4 Hz] and fluctuation tidal volume [lowfrequency coupling (LFC), 0.01 Hz to 0.1 Hz)] during sleep. Results: Although there was no significant Apnea-Hypopnea index (AHI) difference between RBD with OSA and OSA group (AHI 29.1 ± 15.6/hr vs. 34.1 ± 18.9, p=0.332), there was significant difference in CPC measurements. In RBD-OSA group showed lower LFC (35.9 ± 16.8 vs. 49.7 ± 21.3, p=0.010) than OSA group. Unlike higher AHI in RBD with OSA than RBD group (29.1 ± 15.6/hr vs. 3.2 ± 1.6, p<0.001), there was no significant difference in CPC study. Both OSA group and RBD with OSA group showed higher LFC (OSA vs. normal: 49.7 ± 21.3 vs. 28.4 ± 13.3, p<0.001, RBD with OSA vs. normal: 35.9 ± 16.8 vs. 28.4 ± 13.2 p=0.035) and lower HFC (OSA vs. normal: 37.5 ± 20.0 vs. 56.2 ± 16.2, p<0.001, RBD with OSA vs. normal: 46.8 ± 20.8 vs. 56.2 ± 16.2, p=0.031) when compared with normal control group, respectively. Conclusions: In terms of autonomic-respiratory interaction, RBD with OSA showed similar CPC profile (higher LFC and lower HFC than normal) to OSA group but less severe than pure OSA group. It suggests that RBD may have a protective effect on OSA.

At the Atrioventricular Crossroads: Dual Pathway Electrophysiology in the Atrioventricular Node and its Underlying Heterogeneities.

The atrioventricular node (AVN) is a complex structure that performs a variety of functions in the heart. The AVN is primarily an electrical gatekeeper between the atria and ventricles and introduces a delay between atrial and ventricular excitation, allowing for efficient ventricular filling. The AVN is composed of several compartments that safely transmit electrical excitation from the atria to the ventricles via the fast or slow pathways. There are many electrophysiological differences between these pathways, including conduction time and electrical refractoriness, that increase the predisposition of the atrioventricular junction to arrhythmias such as atrioventricular nodal re-entrant tachycardia. These varied electrophysiological characteristics of the fast and slow pathways stem from their unique structural and molecular composition (tissue and cellular geometry, ion channels and gap junctions). This review summarises the structural and molecular heterogeneities of the human AVN and how they result in electrophysiological variations and arrhythmias.

Species-Dependent Mechanisms of Cardiac Arrhythmia: A Cellular Focus.

Although ventricular arrhythmia remains a leading cause of morbidity and mortality, available antiarrhythmic drugs have limited efficacy. Disappointing progress in the development of novel, clinically relevant antiarrhythmic agents may partly be attributed to discrepancies between humans and animal models used in preclinical testing. However, such differences are at present difficult to predict, requiring improved understanding of arrhythmia mechanisms across species. To this end, we presently review interspecies similarities and differences in fundamental cardiomyocyte electrophysiology and current understanding of the mechanisms underlying the generation of afterdepolarizations and reentry. We specifically highlight patent shortcomings in small rodents to reproduce cellular and tissue-level arrhythmia substrate believed to be critical in human ventricle. Despite greater ease of translation from larger animal models, discrepancies remain and interpretation can be complicated by incomplete knowledge of human ventricular physiology due to low availability of explanted tissue. We therefore point to the benefits of mathematical modeling as a translational bridge to understanding and treating human arrhythmia.

A behavioural and electrophysiological investigation of the effect of bilingualism on aging and cognitive control

Given previous, but inconsistent, findings of language group differences on cognitive control tasks the current investigation examined whether such differences could be demonstrated in a sample of older bilingual adults. Monolingual and bilingual older adults performed three cognitive control tasks that have previously been used in the literature (i.e., Stroop, Simon and flanker tasks) while brain electrophysiological recordings took place. Both behavioural (response time and accuracy) and event-related brain potentials (ERPs; N2 and P3 amplitude and latency) were compared across the two language groups. Processing differences between monolinguals and bilinguals were identified for each task, although the locus differed across the tasks. Language group differences were most clear in the Stroop task, with bilinguals showing superior performance both behaviourally and electrophysiologically. In contrast, for the Simon and flanker tasks there were electrophysiological differences indicating language group processing differences at the level of conflict monitoring (Simon task only) and stimulus categorization (Simon and flanker tasks), but no behavioural differences. These findings support suggestions that these three tasks that are often used to examine executive control processes show little convergent validity; however, there are clear language group differences for each task that are suggestive of superior performance for bilinguals, with behavioural differences emerging only in the linguistic Stroop task. Furthermore, it is clear that behavioural measures alone do not capture the language group effects in their entirety, and perhaps processing differences between language groups are more marked in a sample of older adults who are experiencing age-related cognitive changes than in younger adults who are at the peak of their cognitive capacity.

The vigilance-avoidance model of avoidant recognition: An ERP study under threat priming.

Our study examined attachment-related electrophysiological differences in recognition using event-related potentials (ERPs) measured during a study-test paradigm after threat priming. We identified ERP correlates of recognition by comparing the ERPs of attachment-related positive and negative images between avoidant and secure attachment orientations. Our results revealed that the distribution of early old/new effects was broader in avoidant individuals than in secure individuals, and an early parietal old/new effect was observed in avoidant individuals, which reflected their implicit memory. The late old/new effect was found only in secure individuals when evoked by negative pictures, and was not observed in avoidant individuals. The results suggest that avoidant individuals adopt the "vigilance-avoidance" dual-process model to recognize both positive and negative attachment-related stimuli and carry out preferential familiarity matching at the automatic level and avoidant retrieval at the controlled-processing level.

The Influence of Gestational Diabetes on Neurodevelopment of Children in the First Two Years of Life: A Prospective Study.

ObjectiveAnalyze the relation of gestational diabetes and maternal blood glucose levels to early cognitive functions in the first two years of life.MethodsIn a prospective Singaporean birth cohort study, pregnant women were screened for gestational diabetes at 26–28 weeks gestation using a 75-g oral glucose tolerance test. Four hundred and seventy three children (n = 74 and n = 399 born to mothers with and without gestational diabetes respectively) underwent neurocognitive assessments at 6, 18, and/or 24 month, including electrophysiology during an attentional task and behavioral measures of attention, memory and cognition.ResultsGestational diabetes is related to left hemisphere EPmax amplitude differences (oddball versus standard) at both six (P = 0.039) and eighteen months (P = 0.039), with mean amplitudes suggesting offspring of mothers with gestational diabetes exhibit greater neuronal activity to standard stimuli and less to oddball stimuli. Associations between 2-hour maternal glucose levels and the difference in EPmax amplitude were marginal at 6 months [adjusted β = -0.19 (95% CI: -0.42 to +0.04) μV, P = 0.100] and significant at 18 months [adjusted β = -0.27 (95% CI: -0.49 to -0.06) μV, P = 0.014], and the EPmax amplitude difference (oddball-standard) associated with the Bayley Scales of Infant and toddler Development-III cognitive score at 24 months [β = 0.598 (95% CI: 0.158 to 1.038), P = 0.008].ConclusionGestational diabetes and maternal blood glucose levels are associated with offspring neuronal activity during an attentional task at both six and eighteen months. Such electrophysiological differences are likely functionally important, having been previously linked to attention problems later in life.

Sex hormonal regulation of cardiac ion channels in drug-induced QT syndromes.

Female sex is an independent risk factor for development of torsade de pointes (TdP) arrhythmias not only in congenital long QT syndromes but also in acquired long QT syndromes. Clinical and experimental evidences suggest that the gender differences may be due to, at least in part, gender differences in regulation of rate-corrected QT (QTC) interval between men and women. In adult women, both QTC interval and arrhythmic risks in TdP alter cyclically during menstrual cycle, suggesting a critical role of female sex hormones in cardiac repolarization process. These gender differences in fundamental cardiac electrophysiology result from variable ion channel expression and diverse sex hormonal regulation via long term genomic and acute non-genomic actions, and sex differences in drug responses and metabolisms. In particular, non-genomic actions of testosterone and progesterone on cardiac ion channels are likely to contribute to the gender differences in cardiac repolarization processes. This review summarizes current knowledge on sex hormonal regulation of cardiac ion channels which contribute to cardiac repolarization processes and its implication for gender differences in drug-induced long QT syndromes.

Validity of the small swine model for human electrical safety risks.

Small swine are the most common model now used for electrical safety studies. Because of the significant anatomical and electrophysiological differences and the effect of animal size on the ventricular fibrillation (VF) threshold, there are concerns that these differences may exaggerate the risks of electrical devices to humans. We chose, as an illustrative and relevant example, swine studies of the TASER® conducted electrical weapon (CEW) as it has numerous published VF studies. We reviewed the published electrical swine safety studies for CEWs and compared them to finite element modeling studies, electrical safety standards, and epidemiological experience from field usage. We also compared the body weights of the swine to those of law enforcement arrest-related deaths. Studies of small swine exaggerate the risks of CEWs to humans. This conclusion may be extrapolated to suggest that the use of small swine for electrical safety studies should be questioned in general.

QEEG and LORETA in Teenagers With Conduct Disorder and Psychopathic Traits.

Few studies have investigated the impact of the psychopathic traits on the EEG of teenagers with conduct disorder (CD). To date, there is no other research studying low-resolution brain electromagnetic tomography (LORETA) technique using quantitative EEG (QEEG) analysis in adolescents with CD and psychopathic traits. To find electrophysiological differences specifically related to the psychopathic traits. The current investigation compares the QEEG and the current source density measures between adolescents with CD and psychopathic traits and adolescents with CD without psychopathic traits. The resting EEG activity and LORETA for the EEG fast spectral bands were evaluated in 42 teenagers with CD, 25 with and 17 without psychopathic traits according to the Antisocial Process Screening Device. All adolescents were assessed using the DSM-IV-TR criteria. The EEG visual inspection characteristics and the use of frequency domain quantitative analysis techniques (narrow band spectral parameters) are described. QEEG analysis showed a pattern of beta activity excess on the bilateral frontal-temporal regions and decreases of alpha band power on the left central-temporal and right frontal-central-temporal regions in the psychopathic traits group. Current source density calculated at 17.18 Hz showed an increase within fronto-temporo-striatal regions in the psychopathic relative to the nonpsychopathic traits group. These findings indicate that QEEG analysis and techniques of source localization may reveal differences in brain electrical activity among teenagers with CD and psychopathic traits, which was not obvious to visual inspection. Taken together, these results suggest that abnormalities in a fronto-temporo-striatal network play a relevant role in the neurobiological basis of psychopathic behavior.

Differences between mesial and neocortical magnetic-resonance-imaging-negative temporal lobe epilepsy.

The aim of this study was to assess clinical and electrophysiological differences within a group of patients with magnetic-resonance-imaging-negative temporal lobe epilepsy (MRI-negative TLE) according to seizure onset zone (SOZ) localization in invasive EEG (IEEG). According to SOZ localization in IEEG, 20 patients with MRI-negative TLE were divided into either having mesial SOZ-mesial MRI-negative TLE or neocortical SOZ-neocortical MRI-negative TLE. We evaluated for differences between these groups in demographic data, localization of interictal epileptiform discharges (IEDs), and the ictal onset pattern in semiinvasive EEG and in ictal semiology. Thirteen of the 20 patients (65%) had mesial MRI-negative TLE and 7 of the 20 patients (35%) had neocortical MRI-negative TLE. The differences between mesial MRI-negative TLE and neocortical MRI-negative TLE were identified in the distribution of IEDs and in the ictal onset pattern in semiinvasive EEG. The patients with neocortical MRI-negative TLE tended to have more IEDs localized outside the anterotemporal region (p=0.031) and more seizures without clear lateralization of ictal activity (p=0.044). No other differences regarding demographic data, seizure semiology, surgical outcome, or histopathological findings were found. According to the localization of the SOZ, MRI-negative TLE had two subgroups: mesial MRI-negative TLE and neocortical MRI-negative TLE. The groups could be partially distinguished by an analysis of their noninvasive data (distribution of IEDs and lateralization of ictal activity). This differentiation might have an impact on the surgical approach.

Serotonin differentially modulates excitatory and inhibitory synaptic inputs to putative sleep-promoting neurons of the ventrolateral preoptic nucleus

The role of serotonin (5-HT) in sleep-wake regulation has been a subject of intense debate and remains incompletely understood. In the ventrolateral preoptic nucleus (VLPO), the main structure that triggers non-rapid eye movement (NREM) sleep, putative sleep-promoting (PSP) neurons were shown ex vivo to be either inhibited (Type-1) or excited (Type-2) by 5-HT application. To determine the complex action of this neurotransmitter on PSP neurons, we recorded spontaneous and miniature excitatory and inhibitory postsynaptic currents (sEPSCs, sIPSCs, mEPSCs and mIPSCs) in response to bath application of 5-HT. We established in mouse acute VLPO slices that 5-HT reduces spontaneous and miniature EPSC and IPSC frequencies to Type-1 neurons, whereas 5-HT selectively increases sIPSC and mIPSC frequencies to Type-2 VLPO neurons. We further determined that Type-1 neurons display a lower action potential threshold and a smaller soma size than Type-2 neurons. Finally, single-cell RT-PCR designed to identify the 13 serotonergic receptor subtypes revealed the specific mRNA expression of the 5-HT1A,B,D,F receptors by Type-1 neurons. Furthermore, the 5-HT2A-C,4,7 receptors were found to be equivalently expressed by both neuronal types. Altogether, our results establish that the excitatory and inhibitory inputs to Type-1 and Type-2 VLPO PSP neurons are differentially regulated by 5-HT. Electrophysiological, morphological and molecular differences were also identified between these two neuronal types. Our results provide new insights regarding the orchestration of sleep regulation by 5-HT release, and strongly suggest that Type-2 neurons could play a permissive role, whereas Type-1 neurons could have an executive role in sleep induction and maintenance.

The role of the rectum in osmoregulation and the potential effect of renoguanylin on SLC26a6 transport activity in the Gulf toadfish (Opsanus beta).

Teleosts living in seawater continually absorb water across the intestine to compensate for branchial water loss to the environment. The present study reveals that the Gulf toadfish (Opsanus beta) rectum plays a comparable role to the posterior intestine in ion and water absorption. However, the posterior intestine appears to rely more on SLC26a6 (a HCO3 (-)/Cl(-) antiporter) and the rectum appears to rely on NKCC2 (SLC12a1) for the purposes of solute-coupled water absorption. The present study also demonstrates that the rectum responds to renoguanylin (RGN), a member of the guanylin family of peptides that alters the normal osmoregulatory processes of the distal intestine, by inhibited water absorption. RGN decreases rectal water absorption more greatly than in the posterior intestine and leads to net Na(+) and Cl(-) secretion, and a reversal of the absorptive short-circuit current (ISC). It is hypothesized that maintaining a larger fluid volume within the distal segments of intestinal tract facilitates the removal of CaCO3 precipitates and other solids from the intestine. Indeed, the expression of the components of the Cl(-)-secretory response, apical CFTR, and basolateral NKCC1 (SLC12a2), are upregulated in the rectum of the Gulf toadfish after 96 h in 60 ppt, an exposure that increases CaCO3 precipitate formation relative to 35 ppt. Moreover, the downstream intracellular effects of RGN appear to directly inhibit ion absorption by NKCC2 and anion exchange by SLC26a6. Overall, the present findings elucidate key electrophysiological differences between the posterior intestine and rectum of Gulf toadfish and the potent regulatory role renoguanylin plays in osmoregulation.

72. Electrophysiological differences between Early Onset and Late Onset Alzheimer Disease patients

Early Onset Alzheimer Disease (EOAD) and Late Onset Alzheimer Disease (LOAD) share the same pathological features and are considered the same disorder affecting people at different ages, under 65 years for EOAD, over 65 years for LOAD. Whether the different pathological burden could influence also synaptic plasticity mechanisms has never been addressed yet. The aim of our study is to investigate the neurophysiological characteristics of these patients through transcranial magnetic stimulation protocols, comparing with two control groups, respectively old healthy and young healthy age-matched subjects. To verify this hypothesis we evaluated a group of 22 sporadic EOAD and 33 LOAD for plasticity induction of LTP/LTD-like effects using respectively intermittent TBS (iTBS) or continuous TBS (cTBS). Central cholinergic activity was evaluated by means of short afferent inhibition (SAI) protocol. Patients, both EOAD and LOAD, showed an impairment of LTP mechanisms while healthy controls, showed a normal profile of cortical plasticity. SAI protocol results show a positive correlation between SAI dysfunction and aging, reflecting acetylcholine role in aging. The central cholinergic pathway seems to be affected more by age than by the disease process itself. LTP mechanisms are altered in AD patients despite the age, thus representing a reliable marker of disease.

Electrophysiological differences between Early Onset and Late Onset Alzheimer Disease Patients

Early Onset Alzheimer Disease (EOAD) and Late Onset Alzheimer Disease (LOAD) share the same pathological features and are considered the same disorder affecting people at different ages, under 65 years for EOAD, over 65 years for LOAD. Whether the different pathological burden could influence also synaptic plasticity mechanisms has never been addressed yet. The aim of our study is to investigate the neurophysiological characteristics of these patients through transcranial magnetic stimulation protocols, comparing with two control groups, respectively old healthy and young healthy age-matched subjects. To verify this hypothesis we evaluated a group of 22 sporadic EOAD and 33 LOAD for plasticity induction of LTP/LTD-like effects using respectively intermittent TBS (iTBS) or continuous TBS (cTBS). Central cholinergic activity was evaluated by means of short afferent inhibition (SAI) protocol. Patients, both EOAD and LOAD, showed an impairment of LTP mechanisms while healthy controls, showed a normal profile of cortical plasticity. SAI protocol results show a positive correlation between SAI dysfunction and aging, reflecting acetylcholine role in aging. The central cholinergic pathway seems to be affected more by age than by the disease process itself. LTP mechanisms are altered in AD patients despite the age, thus representing a reliable marker of disease.

ID 345 – “What”, “When”, “Whether” – The electrophysiological correlates of voluntary action in virtual environment

The study of (Libet, 1985) gave rise to active discussion among scientists over the nature of the will and volition, suggesting that intention to perform voluntary action can be predicted from prior neural activity. (Brass and Haggart, 2008) proposed three different classes of voluntary decisions: ”what” type of action to perform, “when” to act, and “whether” to act or not. Those distinct decisions might involve different neural pathways and anatomical regions, including medial pFC, ACC, preSMA and SMA, PMC, and parietal cortex. In our study, we repeatedly confront participants with the three classes of decisions in a natural, yet still strictly controlled experimental setup, involving navigating a car through a virtual environment. For each participant we acquired high-resolution EEG data with 128-channel Biosemi ActiveTwo system, structural MR brain image (3T Philips), and recorded electrode coordinates with Localite neuro-navigation system. We demonstrate electrophysiological differences in activation of brain regions related to different classes of decisions, in terms of spatial distribution and time-frequency modulation. The event-related modulation of EEG signals, along with subject-specific T1 images, session-specific electrode coordinates, and set of spatial filters are then used to localize decision-relevant neuroanatomical sources distributed over frontal and posterior cortical regions.

Differences in Left Versus Right Ventricular Electrophysiological Properties in Cardiac Dysfunction and Arrhythmogenesis.

A wide range of ion channels, transporters, signaling pathways and tissue structure at a microscopic and macroscopic scale regulate the electrophysiological activity of the heart. Each region of the heart has optimised these properties based on its specific role during the cardiac cycle, leading to well-established differences in electrophysiology, Ca(2+) handling and tissue structure between atria and ventricles and between different layers of the ventricular wall. Similarly, the right ventricle (RV) and left ventricle (LV) have different embryological, structural, metabolic and electrophysiological features, but whether interventricular differences promote differential remodeling leading to arrhythmias is not well understood. In this article, we will summarise the available data on intrinsic differences between LV and RV electrophysiology and indicate how these differences affect cardiac function. Furthermore, we will discuss the differential remodeling of both chambers in pathological conditions and its potential impact on arrhythmogenesis.

How Iconicity Helps People Learn New Words: Neural Correlates and Individual Differences in Sound-Symbolic Bootstrapping

Sound symbolism is increasingly understood as involving iconicity, or perceptual analogies and cross-modal correspondences between form and meaning, but the search for its functional and neural correlates is ongoing. Here we study how people learn sound-symbolic words, using behavioural, electrophysiological and individual difference measures. Dutch participants learned Japanese ideophones —lexical sound-symbolic words— with a translation of either the real meaning (in which form and meaning show cross-modal correspondences) or the opposite meaning (in which form and meaning show cross-modal clashes). Participants were significantly better at identifying the words they learned in the real condition, correctly remembering the real word pairing 86.7% of the time, but the opposite word pairing only 71.3% of the time. Analysing event-related potentials (ERPs) during the test round showed that ideophones in the real condition elicited a greater P3 component and late positive complex than ideophones in the opposite condition. In a subsequent forced choice task, participants were asked to guess the real translation from two alternatives. They did this with 73.0% accuracy, well above chance level even for words they had encountered in the opposite condition, showing that people are generally sensitive to the sound-symbolic cues in ideophones. Individual difference measures showed that the ERP effect in the test round of the learning task was greater for participants who were more sensitive to sound symbolism in the forced choice task. The main driver of the difference was a lower amplitude of the P3 component in response to ideophones in the opposite condition, suggesting that people who are more sensitive to sound symbolism may have more difficulty to suppress conflicting cross-modal information. The findings provide new evidence that cross-modal correspondences between sound and meaning facilitate word learning, while cross-modal clashes make word learning harder, especially for people who are more sensitive to sound symbolism.

The late and dual origin of cerebrospinal fluid-contacting neurons in the mouse spinal cord.

Considerable progress has been made in understanding the mechanisms that control the production of specialized neuronal types. However, how the timing of differentiation contributes to neuronal diversity in the developing spinal cord is still a pending question. In this study, we show that cerebrospinal fluid-contacting neurons (CSF-cNs), an anatomically discrete cell type of the ependymal area, originate from surprisingly late neurogenic events in the ventral spinal cord. CSF-cNs are identified by the expression of the transcription factors Gata2 and Gata3, and the ionic channels Pkd2l1 and Pkd1l2. Contrasting with Gata2/3(+) V2b interneurons, differentiation of CSF-cNs is independent of Foxn4 and takes place during advanced developmental stages previously assumed to be exclusively gliogenic. CSF-cNs are produced from two distinct dorsoventral regions of the mouse spinal cord. Most CSF-cNs derive from progenitors circumscribed to the late-p2 and the oligodendrogenic (pOL) domains, whereas a second subset of CSF-cNs arises from cells bordering the floor plate. The development of these two subgroups of CSF-cNs is differentially controlled by Pax6, they adopt separate locations around the postnatal central canal and they display electrophysiological differences. Our results highlight that spatiotemporal mechanisms are instrumental in creating neural cell diversity in the ventral spinal cord to produce distinct classes of interneurons, motoneurons, CSF-cNs, glial cells and ependymal cells.

A Novel Eigenvector-based Method to Detect Mild Alzheimer's Disease Using Event-Related Potentials.

Event-related potentials (ERPs) are a physiological measure of cognitive function that have shown diagnostic and prognostic utility in Alzheimer's disease (AD). In this study, we used a novel eigenvector-based technique to better understand brain electrophysiological differences between subjects with mild AD and healthy controls (HC). Using ERPs from 75 subjects with mild AD and 95 HC, we first calculated cognitive task eigenvectors within each subject from three conditions and then calculated second-order eigenvector components to compare the AD group to the HC group. A MANOVA of the three second-level components discriminated between AD and HC multivariately (Wilks' lambda=.4297, p<0.0001, R2 = .5703), and also on each of the three components univariately (all 3 p-values<0.0001). The eigenvector-based technique used in this study accurately discriminated between the mild AD group and HC. As such, this analysis method adds to our understanding of the differences in ERP signal between AD and HC, and could provide a sensitive biomarker for diagnosis and monitoring of AD progression.