EphA7 expression identifies a unique neuronal compartment in the rat striatum

Prior studies have identified two anatomically and neurochemically distinct cellular compartments within the mammalian striatum, termed striosomes and matrix, which express μ‐opioid receptors (μOR) and EphA4, respectively. Here we identify and characterize an additional compartment in the rat striatum composed of neurons that express EphA7. In situ hybridization and immunohistochemical data indicate that neurons expressing EphA7 mRNA and protein are arranged in a banded “matrisome‐like” pattern confined to the matrix in the dorsal striatum. Within the ventral striatum, EphA7‐positive (+) neurons have a less organized mosaic pattern that partially overlaps areas expressing μOR. Immunolabeling data demonstrate that EphA7⁺ striatofugal axons form distinct fascicles leaving the striatum. Within the globus pallidus, EphA7⁺ axons terminate primarily within ventromedial areas of the nucleus and along its striatal border. EphA7⁺ axons avoid regions containing dopamine neurons within the substantia nigra and preferentially innervate areas near the rostral and caudal margins of the nucleus. Within both nuclei, EphA7⁺ axons have similar but more restricted terminal fields than the entire population of EphA4⁺ matrix axons, indicating that EphA7⁺ axons comprise a subpopulation of matrix axons. Ligand binding data demonstrate that ephrin‐A5 selectively binds areas of the striatum, globus pallidus, and substantia nigra containing EphA7⁺ neurons and axons, but not areas expressing only EphA4. Our findings demonstrate that EphA7 expression identifies a novel “matrisome” compartment within the matrix that binds ephrin‐A5 and possesses unique axonal projections. Our findings also suggest that EphA7 and ephrin‐A5 may participate in the formation of this matrisome subcompartment and its striatofugal projections. J. Comp. Neurol. 521:2663–2679, 2013. © 2013 Wiley Periodicals, Inc.     

Confocal laser scanning microscopy and ultrastructural study of VGLUT2 thalamic input to striatal projection neurons in rats

We examined thalamic input to striatum in rats using immunolabeling for the vesicular glutamate transporter (VGLUT2). Double immunofluorescence viewed with confocal laser scanning microscopy (CLSM) revealed that VGLUT2+ terminals are distinct from VGLUT1+ terminals. CLSM of Phaseolus vulgaris‐leucoagglutinin (PHAL)‐labeled cortical or thalamic terminals revealed that VGLUT2 is rare in corticostriatal terminals but nearly always present in thalamostriatal terminals. Electron microscopy revealed that VGLUT2+ terminals made up 39.4% of excitatory terminals in striatum (with VGLUT1+ corticostriatal terminals constituting the rest), and 66.8% of VGLUT2+ terminals synapsed on spines and the remainder on dendrites. VGLUT2+ axospinous terminals had a mean diameter of 0.624 μm, while VGLUT2+ axodendritic terminals a mean diameter of 0.698 μm. In tissue in which we simultaneously immunolabeled thalamostriatal terminals for VGLUT2 and striatal neurons for D1 (with about half of spines immunolabeled for D1), 54.6% of VGLUT2+ terminals targeted D1+ spines (i.e., direct pathway striatal neurons), and 37.3% of D1+ spines received VGLUT2+ synaptic contacts. By contrast, 45.4% of VGLUT2+ terminals targeted D1‐negative spines (i.e., indirect pathway striatal neurons), and only 25.8% of D1‐negative spines received VGLUT2+ synaptic contacts. Similarly, among VGLUT2+ axodendritic synaptic terminals, 59.1% contacted D1+ dendrites, and 40.9% contacted D1‐negative dendrites. VGLUT2+ terminals on D1+ spines and dendrites tended to be slightly smaller than those on D1‐negative spines and dendrites. Thus, thalamostriatal terminals contact both direct and indirect pathway striatal neurons, with a slight preference for direct. These results are consistent with physiological studies indicating slightly different effects of thalamic input on the two types of striatal projection neurons. J. Comp. Neurol., 521:1354–1377, 2013. © 2012 Wiley Periodicals, Inc.     

Effects of neurological damage on production of formulaic language

Early studies reported preserved formulaic language in left hemisphere damaged subjects and reduced incidence of formulaic expressions in the conversational speech of stroke patients with right hemispheric damage. Clinical observations suggest a possible role also of subcortical nuclei. This study examined formulaic language in the spontaneous speech of stroke patients with left, right, or subcortical damage. Four subjects were interviewed and their speech samples compared to normal speakers. Raters classified formulaic expressions as speech formulae, fillers, sentence stems, and proper nouns. Results demonstrated that brain damage affected novel and formulaic language competence differently, with a significantly smaller proportion of formulaic expressions in subjects with right or subcortical damage compared to left hemisphere damaged or healthy speakers. These findings converge with previous studies that support the proposal of a right hemisphere/subcortical circuit in the management of formulaic expressions, based on a dual‐process model of language incorporating novel and formulaic language use.     

A left basal ganglia case of dynamic aphasia or impairment of extra-language cognitive processes?

We report the case of OTM who presented with dynamic aphasia following a stroke that occurred in the left basal ganglia. He showed drastically reduced spontaneous speech in the context of well preserved naming, repetition and comprehension skills. OTM was particularly impaired in generating words, sentences and phrases when cued by a stimulus allowing many response options. By contrast, when a single response was strongly suggested by a stimulus, he could generate verbal responses adequately. OTM's non-verbal response generation abilities varied across tasks. He performed in the normal range in a motor movement generation test and he produced as many figures as controls when tested on a figural fluency task. He showed, however, many perseverations on this test. Moreover in a random number generation task he produced more responses that were part of ascending and descending series of numbers. The patient's impairments are interpreted as a consequence of two deficits. The first of these consists of an inability to generate verbal responses particularly in situations of high competition and involves the function of left frontal regions. The second deficit is one of impaired novel thought generation as evidenced by perseverations. This second deficit has been proposed to be a function of basal ganglia damage.     

Starch digestibility modulation significantly improves glycemic variability in type 2 diabetic subjects: A pilot study

Background and aimsIn type 2 diabetes (T2D) patients, the reduction of glycemic variability and postprandial glucose excursions is essential to limit diabetes complications, beyond HbA1c level. This study aimed at determining whether increasing the content of Slowly Digestible Starch (SDS) in T2D patients’ diet could reduce postprandial hyperglycemia and glycemic variability compared with a conventional low-SDS diet.Methods and resultsFor this randomized cross-over pilot study, 8 subjects with T2D consumed a controlled diet for one week, containing starchy products high or low in SDS. Glycemic variability parameters were evaluated using a Continuous Glucose Monitoring System.Glycemic variability was significantly lower during High-SDS diet compared to Low-SDS diet for MAGE (Mean Amplitude of Glycemic Excursions, p < 0.01), SD (Standard Deviation, p < 0.05), and CV (Coefficient of Variation, p < 0.01). The TIR (Time In Range) [140–180 mg/dL[ was significantly higher during High-SDS diet (p < 0.0001) whereas TIRs ≥180 mg/dL were significantly lower during High-SDS diet. Post-meals tAUC (total Area Under the Curve) were significantly lower during High-SDS diet.ConclusionOne week of High-SDS Diet in T2D patients significantly improves glycemic variability and reduces postprandial glycemic excursions. Modulation of starch digestibility in the diet could be used as a simple nutritional tool in T2D patients to improve daily glycemic control.Registration numberin clinicaltrials.gov: NCT 03289494.     

Sanger sequencing versus INNO-LiPA® HBV PreCore assay for routine detection of precore and basal core promoter mutations in hepatitis virus B chronically infected patients

We compared the Sanger sequencing and the commercial INNO-LiPA® HBV assay for the routine detection of precore (PC) and basal core promoter (BCP) mutations of hepatitis B virus in chronically infected patients. The overall agreement rate between assays was 94.2% and 98.8% for the detection of PC and BCP mutations, respectively.     

100例左右两侧基底神经节区出血致卒中后抑郁的对比研究

目的:观察左右两侧基底神经节区病变致脑卒中后抑郁发生情况的侧别间差异。方法:左侧或右侧基底神经节区出血的患者各50例,详细测查其情绪状况。结果:左侧50例合并卒中后抑郁39例,右侧50例合并卒中后抑郁14例,左侧高于右侧,差异有统计学意义。从汉密尔顿抑郁量表得分看,左侧基底神经节出血组的总分集中在26分左右,而右侧基底神经节出血组的总分集中在11分左右,左侧组得分明显高于右侧组。结论:左侧基底神经节损害合并卒中后抑郁发病率高于右侧,左侧基底神经节区出血致抑郁程度重于右侧。