JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2001
Sang Hoon Lee MD
The purpose of our study was to assess the accuracy of inversion recovery,fast spin-echo (IR-FSE) imaging for the evaluation of chondromalacia of the patella. Eighty-six patients were included, they underwent magnetic resonance (MR) examination and subsequent knee arthroscopy. Medial and lateral facets of the patella were evaluated separately. Axial images were obtained by using IR-FSE (TR/TE/TI = 3000/25/150 msec; echo train length, 8; 4-mm thickness; 12-cm field of view; 512 × 256 matrix; two, number of excitations) with a 1.5-T MR machine. MR interpretation of chondromalacia was made on the basis of the arthroscopic grading system. Of a total of 172 facets graded, arthroscopy revealed chondromalacia in 14 facets with various grades (G0, 158; G1, 1; G2, 3; G3, 6; G4, 4). Sensitivity, specificity, and accuracy in the chondromalacia grades were 57.1%, 93.0%, and 90.1%, respectively. There was one false-negative case (G4) and 11 false-positive cases (G1, eight; G2, two; G3, one). Sensitivity and specificity corrected by one grade difference were improved to 85.7% and 98.1%, respectively. When cartilage changes were grouped into early (corresponding to grade 1 and 2) and advanced (grade 3 and 4) diseases, sensitivity and specificity of the early and advanced diseases were 75% and 94% and 80% and 99%, respectively. IR-FSE imaging of the knee revealed high specificity but low sensitivity for the evaluation of chondromalacia of the patella. J. Magn. Reson. Imaging 2001;13:412,416. © 2001 Wiley-Liss, Inc. [source]

Calcium-binding protein immunoreactivity characterizes the auditory system of Gekko gecko

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 17 2010
Kai Yan
Abstract A transverse section through the nucleus laminaris and nucleus magnocellularis in Gekko gecko, labeled with an antibody against calretinin (red), with anti-parvalbumin double label (green). Both parvalbumin and calretinin immunoreactivity characterized the auditory nerve fibers above the nucleus laminaris in the nucleus magnocellularis. The red calretinin positive axons of the bitufted nucleus laminaris neurons run ventrally towards the olivary nuclei. Medial is to the right. The Journal of Comparative Neurology, Volume 518, Number 17, pages 3409,3426. [source]

Difference in the Length of the Medial and Lateral Metacarpal and Metatarsal Condyles in Calves and Cows , A Post-Mortem Study

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2007
S. Nacambo
Summary Measurements were taken in the metacarpal and metatarsal bones in 42 calves and 10 dairy cows post-mortem to determine whether there are anatomical differences in bone length. Manual and digital measurements of various bone length parameters were taken. There was a significant difference in the mean length of the condyles of the metacarpal and the metatarsal bones in calves and cows, the lateral condyle being longer than the medial. In all but one metatarsal bone (98.8%), the lateral condyle was longer than the medial. In the metacarpal bones, the lateral condyle was longer in only 52.4% of the bones, in 21.2%, they had the same length and in 27.4% the medial condyle was longer. These intrinsic anatomical differences can help distinguish between the left and right metacarpal and metatarsal bones, for instance, in anatomical and archaeological studies. Knowledge of these differences might be useful for studies on digit function and on the possible predisposition of cattle to claw diseases in the lateral claws of the hind limbs. [source]

Central bone marrow lesions in symptomatic knee osteoarthritis and their relationship to anterior cruciate ligament tears and cartilage loss

ARTHRITIS & RHEUMATISM, Issue 1 2008
Gabriela Hernández-Molina
Objective Medial and lateral compartment bone marrow lesions (BMLs) have been tied to cartilage loss. We undertook this study to assess 2 types of BMLs in the central region of the knee (type 1 BMLs, which are related anatomically to anterior cruciate ligament [ACL]/posterior cruciate ligament [PCL] insertions, and type 2 BMLs, which encompass both the central region and either the medial or the lateral compartment) and determine their relationship to cartilage loss and ACL tears. Methods Magnetic resonance imaging (MRI) of the knee was performed at baseline and at followup (15 and/or 30 months) in 258 subjects with symptomatic osteoarthritis (OA). At baseline, we assessed ACL tears and central BMLs located at or between the tibial spines or adjacent to the femoral notch. Cartilage loss was present if the score in any region of the tibiofemoral joint increased by ,1 units at the last available followup, using a modified Whole-Organ MRI Score. We used logistic regression adjusted for alignment, body mass index, Kellgren/Lawrence score, sex, and age. Results One hundred thirty-nine knees (53.8%) had central BMLs, of which 129 had type 1 BMLs (96 abutted the ACL and had no coexistent type 2 features) and 25 had type 2 BMLs (often overlapped with type 1). Type 1 lesions were associated with ACL tears (odds ratio [OR] 5.9, 95% confidence interval [95% CI] 2.2,16.2) but not with cartilage loss (OR 1.6, 95% CI 0.8,3.1), while medial type 2 BMLs were related to medial cartilage loss (OR 6.1, 95% CI 1.0,35.2). Conclusion Central BMLs that abutted the ACL were highly prevalent and strongly related to ACL pathology, suggesting a role of enthesopathy in OA. Only BMLs with medial extension were related to ipsilateral cartilage loss. [source]

Visualization of stochastic Ca2+ signals in the formed somites during the early segmentation period in intact, normally developing zebrafish embryos

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 7 2009
Christina F. Leung
Localized Ca2+ signals were consistently visualized in the formed somites of intact zebrafish embryos during the early segmentation period. Unlike the regular process of somitogenesis, these signals were stochastic in nature with respect to time and location. They did, however, occur predominantly at the medial and lateral boundaries within the formed somites. Embryos were treated with modulators of [Ca2+]i to explore the signal generation mechanism and possible developmental function of the stochastic transients. Blocking elements in the phosphoinositol pathway eliminated the stochastic signals but had no obvious effect, stochastic or otherwise, on the formed somites. Such treatments did, however, result in the subsequently formed somites being longer in the mediolateral dimension. Targeted uncaging of buffer (diazo-2) or Ca2+ (NP-ethyleneglycoltetraacetic acid [EGTA]) in the presomitic mesoderm, resulted in a regular mediolateral lengthening and shortening, respectively, of subsequently formed somites. These data suggest a requirement for IP3 receptor-mediated Ca2+ release during convergence cell movements in the presomitic mesoderm, which appears to have a distinct function from that of the IP3 receptor-mediated stochastic Ca2+ signaling in the formed somites. [source]

Wnt11r is required for cranial neural crest migration

DEVELOPMENTAL DYNAMICS, Issue 11 2008
Helen K. Matthews
Abstract wnt11r is a recently identified member of the Wnt family of genes, which has been proposed to be the true Xenopus homologue to the mammalian wnt11 gene. In this study we have examined the role of wnt11r on neural crest development. Expression analysis of wnt11r and comparison with the neural crest marker snail2 and the noncanonical Wnt, wnt11, shows wnt11r is expressed at the medial or neural plate side of the neural crest while wnt11 is expressed at the lateral or epidermal side. Injection of wnt11r morpholino leads to strong inhibition of neural crest migration with no effect on neural crest induction or maintenance. This effect can be rescued by co-injection of Wnt11r but not by Wnt11 mRNA, demonstrating the specificity of the loss of function treatment. Finally, neural crest graft experiments show that wnt11r is required in a non,cell-autonomous manner to control neural crest migration. Developmental Dynamics 237:3404,3409, 2008. © 2008 Wiley-Liss, Inc. [source]

Ontogeny of tyrosine hydroxylase mRNA expression in mid- and forebrain: Neuromeric pattern and novel positive regions

DEVELOPMENTAL DYNAMICS, Issue 3 2005
Faustino Marín
Abstract Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of catecholamines and, thus, critical in determining the catecholaminergic phenotype. In this study, we have examined the expression of TH mRNA by in situ hybridization in the embryonic mouse forebrain and midbrain and have mapped its localization according to the neuromeric pattern. We find that early in embryonic development, 10 to 12 days post coitum (dpc), TH mRNA is expressed in ample continuous regions of the neuroepithelium, extending across several neuromeres. However, from 12.5 dpc onward, the expression becomes restricted to discrete regions, which correspond to the dopaminergic nuclei (A8 to A15). In addition to these nuclei previously described, TH mRNA is also observed in regions that do not express this enzyme according to immunohistochemical studies. This difference in relation to protein expression pattern is consequent with the known posttranscriptional regulation of TH expression. The most representative example of a novel positive region is the conspicuous mRNA expression in both medial and lateral ganglionic eminences. This result agrees with reports describing the capacity of striatal stem cells (that is, located at the lateral ganglionic eminence) to become dopaminergic in vitro. Other regions include the isthmic mantle layer and the early floor plate of the midbrain,caudal forebrain. On the whole, the expression map we have obtained opens new perspectives for evolutionary/comparative studies, as well as for therapeutic approaches looking for potentially dopaminergic cells. Developmental Dynamics 234:709,717, 2005. © 2005 Wiley-Liss, Inc. [source]

Intrastriatal administration of human immunodeficiency virus-1 glycoprotein 120 reduces glial cell-line derived neurotrophic factor levels and causes apoptosis in the substantia nigra

DEVELOPMENTAL NEUROBIOLOGY, Issue 12 2006
Rachel L. Nosheny
Abstract Uninfected neurons of the substantia nigra (SN) degenerate in human immunodeficiency virus (HIV)-positive patients through an unknown etiology. The HIV envelope glycoprotein 120 (gp120) causes apoptotic neuronal cell death in the rodent striatum, but its primary neurotoxic mechanism is still under investigation. Previous studies have shown that gp120 causes neurotoxicity in the rat striatum by reducing brain-derived neurotrophic factor (BDNF). Because glial cell line-derived neurotrophic factor (GDNF) and BDNF are neurotrophic factors crucial for the survival of dopaminergic neurons of the SN, we investigated whether gp120 reduces GDNF and BDNF levels concomitantly to induce apoptosis. Rats received a microinjection of gp120 or vehicle into the striatum and were sacrificed at various time intervals. GDNF but not BDNF immunoreactivity was decreased in the SN by 4 days in gp120-treated rats. In these animals, a significant increase in the number of caspase-3- positive neurons, both tyrosine hydroxylase (TH)-positive and -negative, was observed. Analysis of TH immunoreactivity revealed fewer TH-positive neurons and fibers in a medial and lateral portion of cell group A9 of the SN, an area that projects to the striatum, suggesting that gp120 induces retrograde degeneration of nigrostriatal neurons. We propose that dysfunction of the nigrostriatal dopaminergic system associated with HIV may be caused by a reduction of neurotrophic factor expression by gp120. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source]

Estimation of Global Left Ventricular Function from the Velocity of Longitudinal Shortening

ECHOCARDIOGRAPHY, Issue 3 2002
Dragos Vinereanu M.D., E.C., Ph.D.
Aims: To determine if global ventricular function can be assessed from the long-axis contraction of the left ventricle, we compared pulsed-wave Doppler myocardial imaging of mitral annular motion to radionuclide ventriculography. Methods and Results: We studied 51 patients (56 ± 10 years, 11 women) with a radionuclide ejection fraction of 52 ± 13% (15%,70%). Peak systolic velocities of medial and lateral mitral annular motion correlated with ejection fraction (0.55 and 0.54, respectively; P < 0.001), as did the time-velocity integrals (0.57 and 0.58, respectively; P < 0.001). Correlations were higher in normal ventricles (0.62,0.69) than in patients with previous myocardial infarction (0.39,0.64). Patients with anterior myocardial infarction had the lowest correlations (0.39,0.46). The best differentiation of normal (, 50%) from abnormal (< 50%) ejection fraction was provided by peak systolic velocity , 8 cm/sec for the medial (sensitivity 80%, specificity 89%) or lateral (sensitivity 80%, specificity 92%) mitral annulus. Conclusion: Global left ventricular function can be estimated by recording mitral annular velocity. The implementation of a cutoff limit of 8 cm/sec gave a simple guide for differentiating between normal and abnormal left ventricular systolic function that might be useful clinically in patients without regional wall-motion abnormalities. However, in patients with important segmental wall-motion abnormalities during systole, left ventricular longitudinal shortening is an imperfect surrogate for ejection fraction. [source]

Assessment of Acute Right Ventricular Dysfunction Induced by Right Coronary Artery Occlusion Using Echocardiographic Atrioventricular Plane Displacement

ECHOCARDIOGRAPHY, Issue 6 2000
Alpesh R. Shah M.D.
Right ventricular (RV) systolic function analysis by echocardiography has traditionally required RV endocardial border definition with subsequent tracing and is often inaccurate or impossible in technically poor studies. The atrioventricular plane displacement (AVPD) method attempts to use the descent of the tricuspid annular ring, a reflection of the longitudinal shortening of the right ventricle, as a surrogate marker for RV systolic function. We hypothesized that RV ischemia induced during right coronary artery occlusion proximal to the major right ventricular branches would result in severe right ventricular systolic dysfunction detectable by the AVPD method. During this pilot study, seven patients undergoing elective proximal RCA angioplasty had echocardiographic measurement of RV AVPD performed at baseline (i.e., immediately prior to RCA balloon inflation), during the last 30 seconds of first RCA balloon inflation, and at 1 minute after balloon deflation (recovery). Lateral and medial RV AVPD were significantly reduced from baseline values during intracoronary balloon inflation. (Lateral: 2.45 cm ± 0.22 vs 1.77 cm ± 0.13, P < 0.001; medial: 1.46 cm ± 0.37 vs 1.28 cm ± 0.32, P < 0.05). Additionally, lateral and medial RV AVPD significantly returned towards baseline values during recovery. (Lateral: 2.39 cm ± 0.20, P < 0.001; medial: 1.58 cm ± 0.27, P = 0.01). At baseline, all lateral RV AVPD values were > 2.0 cm, whereas during balloon inflation all were < 2.0 cm. No such clear distinction was found in medial RV AVPD values. Proximal RCA angioplasty is associated with a significant reduction in lateral and medial RV AVPD. Thus RV AVPD may serve as a marker for RV systolic dysfunction. [source]

Facial emotion recognition impairment in chronic temporal lobe epilepsy

EPILEPSIA, Issue 6 2009
Stefano Meletti
Summary Purpose:, To evaluate facial emotion recognition (FER) in a cohort of 176 patients with chronic temporal lobe epilepsy (TLE). Methods:, FER was tested by matching facial expressions with the verbal labels for the following basic emotions: happiness, sadness, fear, disgust, and anger. Emotion recognition performances were analyzed in medial (n = 140) and lateral (n = 36) TLE groups. Fifty healthy subjects served as controls. The clinical and neuroradiologic variables potentially affecting the ability to recognize facial expressions were taken into account. Results:, The medial TLE (MTLE) group showed impaired FER (86% correct recognition) compared to both the lateral TLE patients (FER = 93.5%) and the controls (FER = 96.4%), with 42% of MTLE patients recording rates of FER that were lower [by at least 2 standard deviations (SDs)] than the control mean. The MTLE group was impaired compared to the healthy controls in the recognition of all basic facial expressions except happiness. The patients with bilateral MTLE were the most severely impaired, followed by the right and then the left MTLE patients. FER was not affected by type of lesion, number of antiepileptic drugs (AEDs), aura semiology, or gender. Conversely, the early onset of seizures/epilepsy was related to FER deficits. These deficits were already established in young adulthood, with no evidence of progression in older MTLE patients. Conclusion:, These results on a large cohort of TLE patients demonstrate that emotion recognition deficits are common in MTLE patients and widespread across negative emotions. We confirm that early onset seizures with right or bilateral medial temporal dysfunction lead to severe deficits in recognizing facial expressions of emotions. [source]

Characterization of Neuronal Migration Disorders in Neocortical Structures: Loss or Preservation of Inhibitory Interneurons?

EPILEPSIA, Issue 7 2000
Petra Schwarz
Summary: Purpose: Neuronal migration disorders (NMD) are often associated with therapy-resistant epilepsy. In human cerebral cortex, this hyperexcitability has been correlated with a loss of inhibitory interneurons. We used a rat model of focal cortical NMD (microgyria) to determine whether the expression of epileptiform activity in this model coincides with a decrease in inhibitory interneurons. Methods: In 2- to 4-month-old rats, the density of interneurons immunoreactive for ,-aminobutyric acid (GABA), cal-bindin, and parvalbumin was determined in fronto-parietal cortex in nine 200-,m-wide sectors located up to 2.5 mm lateral and 2.0 mm medial from the lesion center in primary parietal cortex (Par 1). Quantitative measurements in homotopic areas of age-matched sham-operated rats served as controls. Results: The freeze lesion performed in newborn rat cortex resulted in adult rats with a microgyrus extending in a rostro-caudal direction from frontal to occipital cortex. The density of GABA- and parvalbumin-positive neurons in fronto-parietal cortex was not significantly different between lesioned and control animals. Only the density of calbindin-immunoreactive neurons located 1.0 mm lateral and 0.5 mm medial from the lesion was significantly (Student t test, p > 0.05) larger in freeze-lesioned rats (5.817 ± 562 and 6,400 ± 795 cells per mm3, respectively; n = 12) compared with measurements in homotopic regions in Parl cortex of controls (4,507 ± 281 and 4,061 ± 319 cells per mm3, respectively; n = 5). Conclusions: The previously reported widespread functional changes in this model of cortical NMD are not related to a general loss of inhibitory interneurons. Other factors, such as a decrease in GABA receptor density, modifications in GABAA receptor subunit composition, or alterations in the excitatory network, e.g., an increase in the density of calbindin-immunoreactive pyramidal cells, more likely contribute to the global disinhibition and widespread expression of pathophysiological activity in this model of cortical NMD. [source]

Uterine torsion diagnosed in a mare at 515 days' gestation

EQUINE VETERINARY EDUCATION, Issue 10 2010
C. López
Summary A pregnant mare with a history of prolonged gestation (,515 days) and suspected diagnosis of fetal mummification was examined. Rectal palpation revealed that the left broad ligament of the uterus was dorsal and medial to the right uterine ligament and it was not possible to observe the cervix during vaginal examination. Transabdominal ultrasound revealed fluid in the uterus, fetal membranes and the uterine walls defined and thickened. Free fluid was not seen in the peritoneal cavity. Laboratory tests (blood cell count and clinical chemistry) were normal. Based on clinical history, physical examination and ultrasound findings, a chronic uterine torsion with fetal death was diagnosed and the mare was subjected to exploratory celiotomy. The uterus was strongly adhered to the peritoneum of the ventral abdominal wall and there were multiple adhesions to the colon. Hysterotomy was performed to remove the fetus and to permit repositioning of the uterus. When the fetus was removed, a large devitalised grey tissue area of the right ventral uterine horn was observed. Multiple adhesions prevented a rescue hysterectomy and euthanasia of the patient was performed. During the necropsy, a 180° cranial cervix clockwise uterine torsion was observed. This rare case of uterine torsion appears to be the most chronic case reported in the equine literature. [source]

Longitudinal development of equine conformation from weanling to age 3 years in the Thoroughbred

EQUINE VETERINARY JOURNAL, Issue 7 2004
T. M. ANDERSON
Summary Reasons for performing study: There is little information available to define conformational changes with age using an objective but practical method of recording specific body measurements. Objective: To analyse conformation objectively in a population of racing Thoroughbreds and describe the changes from weanling to age 3 years. Methods: Annual photographs were taken over 4 years and conformation measurements made from photographs using specific reference points marked on the horses. Results: Correlation analysis revealed highly significant, moderate to strong relationships between long bone lengths and wither height for all ages. All long bone lengths showed moderate to strong relationships with each other for all ages. The front and rear pastern angles were significantly correlated with the angle of the dorsal surface of the front and rear hooves, respectively, for all. Wither height, croup height and length of neck topline, neck bottomline, scapula, humerus, radius and femur increased significantly from age 0,1 year and age 1,2 years. Hoof lengths (medial and lateral, right and left) grew significantly between the ages of 0 and 1 and 1 and 2 years, but decreased in length between age 2 and 3 years. Horses became more offset in the right limb between weanling and age 3 years, but the offset ratios did not change with age on the left limb. The angle of the scapula (I), shoulder and radiometacarpus significantly increased between all age groups (became more upright). The angle of the dorsal surface of the hooves (both front and hind) decreased significantly from ages 0 to 1 and 1 to 2 years, but showed no significant difference between ages 2 and 3 years. Conclusions: A strong relationship between long bone lengths and wither height for all ages supports the theory that horses are proportional. Longitudinal bone growth in the distal limb increased only 5,7% from weanling to age 3 years and is presumably completed prior to the yearling year. Several growth measures increased from ages 0 to 1 and 1 to 2 years, but did not increase from age 2,3 years; indicating that growth rate either showed or reached a plateau at this time. Potential relevance: This study provides objective information regarding conformation and skeletal growth in the Thoroughbred which can be utilised for selection and recognition of significant conformational abnormalities. [source]

MRI verified STN stimulation site , gait improvement and clinical outcome

EUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2010
E. L. Johnsen
Background:, Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is effective in alleviating Parkinson's disease (PD) symptoms (tremor, rigidity and bradykinesia) and may improve gait and postural impairment associated with the disease. However, improvement of gait is not always as predictable as the clinical outcome. This may relate to the type of gait impairment or localization of the active DBS contact. Methods:, The active contact was visualized on peri-operative magnetic resonance imaging in 22 patients with idiopathic PD, consecutively treated with bilateral STN DBS. Stimulation site was grouped as either in the dorsal/ventral STN or medial/lateral hereof and anterior/posterior STN or medial/lateral hereof. The localization was compared with relative improvement of clinical outcome (UPDRS-III). In 10 patients, quantitative gait analyses were performed, and the improvement in gait performance was compared with stimulation site in the STN. Results:, Of 44 active contacts, 77% were inside the nucleus, 23% were medial hereof. Stimulation of the dorsal half improved UPDRS-III significantly more than ventral STN DBS (P = 0.02). However, there were no differences between anterior and posterior stimulation in the dorsal STN. Step velocity and length improved significantly more with dorsal stimulation compared with ventral stimulation (P = 0.03 and P = 0.02). Balance during gait was also more improved with dorsal stimulation compared with ventral stimulation. Conclusions:, Deep brain stimulation of the dorsal STN is superior to stimulation of the ventral STN. Possible different effects of stimulation inside the nucleus underline the need for exact knowledge of the active stimulation site position to target the most effective area. [source]

A direct main olfactory bulb projection to the ,vomeronasal' amygdala in female mice selectively responds to volatile pheromones from males

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2009
Ningdong Kang
Abstract The main olfactory system, like the accessory olfactory system, responds to pheromones involved in social communication. Whereas pheromones detected by the accessory system are transmitted to the hypothalamus via the medial (,vomeronasal') amygdala, the pathway by which pheromones are detected and transmitted by the main system is not well understood. We examined in female mice whether a direct projection from mitral/tufted (M/T) cells in the main olfactory bulb (MOB) to the medial amygdala exists, and whether medial amygdala-projecting M/T cells are activated by volatile urinary odors from conspecifics or a predator (cat). Simultaneous anterograde tracing using Phaseolus vulgaris leucoagglutinin and Fluoro-Ruby placed in the MOB and accessory olfactory bulb (AOB), respectively, revealed that axons of MOB M/T cells projected to superficial laminae of layer Ia in anterior and posterodorsal subdivisions of the medial amygdala, whereas projection neurons from the AOB sent axons to non-overlapping, deeper layer Ia laminae of the same subdivisions. Placement of the retrograde tracer cholera toxin B into the medial amygdala labeled M/T cells that were concentrated in the ventral MOB. Urinary volatiles from male mice, but not from female conspecifics or cat, induced Fos in medial amygdala-projecting MOB M/T cells of female subjects, suggesting that information about male odors is transmitted directly from the MOB to the ,vomeronasal' amygdala. The presence of a direct MOB-to-medial amygdala pathway in mice and other mammals could enable volatile, opposite-sex pheromones to gain privileged access to diencephalic structures that control mate recognition and reproduction. [source]

The pallial basal ganglia pathway modulates the behaviorally driven gene expression of the motor pathway

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2007
Lubica Kubikova
Abstract The discrete neural network for songbird vocal communication provides an effective system to study neural mechanisms of learned motor behaviors in vertebrates. This system consists of two pathways , a vocal motor pathway used to produce learned vocalizations and a vocal pallial basal ganglia loop used to learn and modify the vocalizations. However, it is not clear how the loop exerts control over the motor pathway. To study the mechanism, we used expression of the neural activity-induced gene ZENK (or egr-1), which shows singing-regulated expression in a social context-dependent manner: high levels in both pathways when singing undirected and low levels in the lateral part of the loop and in the robust nucleus of the arcopallium (RA) of the motor pathway when singing directed to another animal. Here, we show that there are two parallel interactive parts within the pallial basal ganglia loop, lateral and medial, which modulate singing-driven ZENK expression of the motor pathway nuclei RA and HVC, respectively. Within the loop, the striatal and pallial nuclei appear to have opposing roles; the striatal vocal nucleus lateral AreaX is required for high ZENK expression in its downstream nuclei, particularly during undirected singing, while the pallial vocal lateral magnocellular nucleus of the anterior nidopallium is required for lower expression, particularly during directed singing. These results suggest a dynamic molecular interaction between the basal ganglia pathway and the motor pathway during production of a learned motor behavior. [source]

Visualization of corticofugal projections during early cortical development in a ,-GFP-transgenic mouse

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2007
Erin C. Jacobs
Abstract The first postmitotic neurons in the developing neocortex establish the preplate layer. These early-born neurons have a significant influence on the circuitry of the developing cortex. However, the exact timing and trajectory of their projections, between cortical hemispheres and intra- and extra-cortical regions, remain unresolved. Here, we describe the creation of a transgenic mouse using a 1.3 kb golli promoter element of the myelin basic protein gene to target expression of a ,,green fluorescent protein (GFP) fusion protein in the cell bodies and processes of pioneer cortical neurons. During embryonic and early neonatal development, the timing and patterning of process extension from these neurons was examined. Analysis of ,-GFP fluorescent fibers revealed that progression of early labeled projections was interrupted unexpectedly by transient pauses at the corticostriatal and telencephalic,diencephalic boundaries before invading the thalamus just prior to birth. After birth the pioneering projections differentially invaded the thalamus, excluding some nuclei, e.g. medial and lateral geniculate, until postnatal days 10,14. Early labeled projections were also found to cross to the contralateral hemisphere as well as to the superior colliculus. These results indicate that early corticothalamic projections appear to pause before invading specific subcortical regions during development, that there is developmental regulation of innervation of individual thalamic nuclei, and that these early-generated neurons also establish early projections to commissural and subcortical targets. [source]

Dopaminergic regulation of orexin neurons

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2005
Michael Bubser
Abstract Orexin/hypocretin neurons in the lateral hypothalamus and adjacent perifornical area (LH/PFA) innervate midbrain dopamine (DA) neurons that project to corticolimbic sites and subserve psychostimulant-induced locomotor activity. However, it is not known whether dopamine neurons in turn regulate the activity of orexin cells. We examined the ability of dopamine agonists to activate orexin neurons in the rat, as reflected by induction of Fos. The mixed dopamine agonist apomorphine increased Fos expression in orexin cells, with a greater effect on orexin neurons located medial to the fornix. Both the selective D1-like agonist, A-77636, and the D2-like agonist, quinpirole, also induced Fos in orexin cells, suggesting that stimulation of either receptor subtype is sufficient to activate orexin neurons. Consistent with this finding, combined SCH 23390 (D1 antagonist),haloperidol (D2 antagonist) pretreatment blocked apomorphine-induced activation of medial as well as lateral orexin neurons; in contrast, pretreatment with either the D1-like or D2-like antagonists alone did not attenuate apomorphine-induced activation of medial orexin cells. In situ hybridization histochemistry revealed that LH/PFA cells rarely express mRNAs encoding dopamine receptors, suggesting that orexin cells are transsynaptically activated by apomorphine. We therefore lesioned the nucleus accumbens, a site known to regulate orexin cells, but this treatment did not alter apomorphine-elicited activation of medial or lateral orexin neurons. Interestingly, apomorphine failed to activate orexin cells in isoflurane-anaesthetized animals. These data suggest that apomorphine-induced arousal but not accumbens-mediated hyperactivity is required for dopamine to transsynaptically activate orexin neurons. [source]

Genetic ablation of the mammillary bodies in the Foxb1 mutant mouse leads to selective deficit of spatial working memory

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2005
Konstantin Radyushkin
Abstract Mammillary bodies and the mammillothalamic tract are parts of a classic neural circuitry that has been implicated in severe memory disturbances accompanying Korsakoff's syndrome. However, the specific role of mammillary bodies in memory functions remains controversial, often being considered as just an extension of the hippocampal memory system. To study this issue we used mutant mice with a targeted mutation in the transcription factor gene Foxb1. These mice suffer perinatal degeneration of the medial and most of the lateral mammillary nuclei, as well as of the mammillothalamic bundle. Foxb1 mutant mice showed no deficits in such hippocampal-dependent tasks as contextual fear conditioning and social transmission of food preference. They were also not impaired in the spatial reference memory test in the radial arm maze. However, Foxb1 mutants showed deficits in the task for spatial navigation within the Barnes maze. Furthermore, they showed impairments in spatial working memory tasks such as the spontaneous alternation and the working memory test in the radial arm maze. Thus, our behavioural analysis of Foxb1 mutants suggests that the medial mammillary nuclei and mammillothalamic tract play a role in a specific subset of spatial tasks, which require combined use of both spatial and working memory functions. Therefore, the mammillary bodies and the mammillothalamic tract may form an important route through which the working memory circuitry receives spatial information from the hippocampus. [source]

Topographic distribution of direct and hippocampus- mediated entorhinal cortex activity evoked by olfactory tract stimulation

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2004
Vadym Gnatkovsky
Abstract Olfactory information is central for memory-related functions, such as recognition and spatial orientation. To understand the role of olfaction in learning and memory, the distribution and propagation of olfactory tract-driven activity in the parahippocampal region needs to be characterized. We recently demonstrated that repetitive stimulation of the olfactory tract in the isolated guinea pig brain preparation induces an early direct activation of the rostrolateral entorhinal region followed by a delayed response in the medial entorhinal cortex (EC), preceded by the interposed activation of the hippocampus. In the present study we performed a detailed topographic analysis of both the early and the delayed entorhinal responses induced by patterned stimulation of the lateral olfactory tract in the isolated guinea pig brain. Bi-dimensional maps of EC activity recorded at 128 recording sites with 4 × 4 matrix electrodes (410 µm interlead separation) sequentially placed in eight different positions, showed (i) an early (onset at 16.09 ± 1.2 ms) low amplitude potential mediated by the monosynaptic LOT input, followed by (ii) an associative potential in the rostral EC which originates from the piriform cortex (onset at 33.2 ± 2.3 ms), and (iii) a delayed potential dependent on the previous activation of the hippocampus. The sharp component of the delayed response had an onset latency between 52 and 63 ms and was followed by a slow wave. Laminar profile analysis demonstrated that in the caudomedial EC the delayed response was associated with two distinct current sinks located in deep and in superficial layers, whereas in the rostrolateral EC a small-amplitude sink could be detected in the superficial layers exclusively. The present report demonstrates that the output generated by the hippocampal activation is unevenly distributed across different EC subregions and indicates that exclusively the medial and caudal divisions receive a deep-layer input from the hippocampus. In the rostrolateral EC, specific network interactions may be generated by the convergence of the direct olfactory input and the olfaction-driven hippocampal output. [source]

Organization of connections of the basal and accessory basal nuclei in the monkey amygdala

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2000
Eva Bonda
Abstract PLEASE NOTE: Expression of Concern (EJN, 12:11, p4153) The present study investigated the intrinsic connections of the basal and accessory basal nuclei of the Macaca fascicularis monkey by means of the anterograde tracers Phaseolus vulgaris-leucoagglutinin (PHA-L) and biotinylated dextran amine (BDA). Analysis of the intranuclear connections of the basal nucleus indicates that there are five modules: dorsal, intermediate, ventral lateral, ventral medial and periamygdaloid sulcal cortex. The dorsal division projects to the intermediate division. Laterally, the intermediate division projects to the ventral lateral division and dorsal parts of the ventral medial division. Ventrally, the ventral lateral division projects to the ventral medial division and periamygdaloid sulcal cortex, which appears to constitute a medial extension of the basal nucleus onto the cortical surface of the amygdala. Medially, the ventral medial division projects to the intermediate and dorsal divisions. Thus, the connections between these modules form functional microcolumns within the nucleus with distinct patterns of information flow that are dorsal to ventral laterally, lateral to medial ventrally, and ventral to dorsal medially. Observations on the intranuclear connections of the accessory basal nucleus suggest that they are organized into two relatively distinct domains: the dorsal division projects to the ventral division and the ventral division projects primarily to the ventromedial division. Projections to other amygdaloid areas originate in select divisions of the basal and accessory basal nuclei, and are topographically distributed. The organization of intrinsic connections of the basal nuclei correlates with specific amygdalo-cortical connections and suggests that extensive convergence of information takes place within the amygdala, which potentially influences activity at both the temporal and parietal pathways and hippocampal fields. [source]

Conservation and variation in Ubx expression among chelicerates

EVOLUTION AND DEVELOPMENT, Issue 6 2001
Aleksandar Popadi
SUMMARY Chelicerates are an ancient arthropod group with a distinct body plan composed of an anterior (prosoma) and a posterior portion (opisthosoma). The expression of the Hox gene Ultrabithorax (Ubx) has been examined in a single representative of the chelicerates, the spider Cupiennius salei. In spiders, Ubx expression starts in the second opisthosomal segment (O2). Because the first opisthosomal segment (O1) in spiders is greatly reduced relative to other chelicerates, we hypothesized that the observed Ubx expression pattern might be secondarily modified. Shifts in the anterior boundary of the expression of Ubx have been correlated with functional shifts in morphology within malacostracan crustaceans. Thus, the boundary of Ubx expression between chelicerates with different morphologies in their anterior opisthosoma could also be variable. To test this prediction, we examined the expression patterns of Ubx and abdominal-A (collectively referred to as UbdA) in two basal chelicerate lineages, scorpions and xiphosurans (horseshoe crabs), which exhibit variation in the morphology of their anterior opisthosoma. In the scorpion Paruroctonus mesaensis, the anterior border of early expression of UbdA is in a few cells in the medial, posterior region of the O2 segment, with a predominant expression in O3 and posterior. Expression later spreads to encompass the whole O2 segment and a ventral, posterior portion of the O1 segment. In the xiphosuran Limulus polyphemus, early expression of UbdA has an anterior boundary in the segment. Later in development, the anterior boundary moves forward one segment to the chilarial (O1) segment. Thus, the earliest expression boundary of UbdA lies within the second opisthosomal segment in all the chelicerates examined. These results suggest that rather than being derived, the spider UbdA expression in O2 likely reflects the ancestral expression boundary. Changes in the morphology of the first opisthosomal segment are either not associated with changes in UbdA expression or correlate with late developmental changes in UbdA expression. [source]

Differential patterns of cortical activation as a function of fluid reasoning complexity

HUMAN BRAIN MAPPING, Issue 2 2009
Bernardo Perfetti
Abstract Fluid intelligence (gf) refers to abstract reasoning and problem solving abilities. It is considered a human higher cognitive factor central to general intelligence (g). The regions of the cortex supporting gf have been revealed by recent bioimaging studies and valuable hypothesis on the neural correlates of individual differences have been proposed. However, little is known about the interaction between individual variability in gf and variation in cortical activity following task complexity increase. To further investigate this, two samples of participants (high-IQ, N = 8; low-IQ, N = 10) with significant differences in gf underwent two reasoning (moderate and complex) tasks and a control task adapted from the Raven progressive matrices. Functional magnetic resonance was used and the recorded signal analyzed between and within the groups. The present study revealed two opposite patterns of neural activity variation which were probably a reflection of the overall differences in cognitive resource modulation: when complexity increased, high-IQ subjects showed a signal enhancement in some frontal and parietal regions, whereas low-IQ subjects revealed a decreased activity in the same areas. Moreover, a direct comparison between the groups' activation patterns revealed a greater neural activity in the low-IQ sample when conducting moderate task, with a strong involvement of medial and lateral frontal regions thus suggesting that the recruitment of executive functioning might be different between the groups. This study provides evidence for neural differences in facing reasoning complexity among subjects with different gf level that are mediated by specific patterns of activation of the underlying fronto-parietal network. Hum Brain Mapp, 2009. © 2007 Wiley-Liss, Inc. [source]

Prefrontal cortex activity is reduced in gambling and nongambling substance users during decision-making,

HUMAN BRAIN MAPPING, Issue 12 2007
Jody Tanabe
Abstract Objective: Poor decision-making is a hallmark of addiction, whether to substances or activities. Performance on a widely used test of decision-making, the Iowa Gambling Task (IGT), can discriminate controls from persons with ventral medial frontal lesions, substance-dependence, and pathological gambling. Positron emission tomography (PET) studies indicate that substance-dependent individuals show altered prefrontal activity on the task. Here we adapted the IGT to an fMRI setting to test the hypothesis that defects in ventral medial and prefrontal processing are associated with impaired decisions that involve risk but may differ depending on whether substance dependence is comorbid with gambling problems. Method: 18 controls, 14 substance-dependent individuals (SD), and 16 SD with gambling problems (SDPG) underwent fMRI while performing a modified version of the IGT. Result: Group differences were observed in ventral medial frontal, right frontopolar, and superior frontal cortex during decision-making. Controls showed the greatest activity, followed by SDPG, followed by SD. Conclusion: Our results support a hypothesis that defects in ventral medial frontal processing lead to impaired decisions that involve risk. Reductions in right prefrontal activity during decision-making appear to be modulated by the presence of gambling problems and may reflect impaired working memory, stimulus reward valuation, or cue reactivity in substance-dependent individuals. Hum Brain Mapp, 2007. © 2007 Wiley-Liss, Inc. [source]

Medial temporal lobe activity at recognition increases with the duration of mnemonic delay during an object working memory task

HUMAN BRAIN MAPPING, Issue 11 2007
Marco Picchioni
Abstract Object working memory (WM) engages a disseminated neural network, although the extent to which the length of time that data is held in WM influences regional activity within this network is unclear. We used functional magnetic resonance imaging to study a delayed matching to sample task in 14 healthy subjects, manipulating the duration of mnemonic delay. Across all lengths of delay, successful recognition was associated with the bilateral engagement of the inferior and middle frontal gyri and insula, the medial and inferior temporal, dorsal anterior cingulate and the posterior parietal cortices. As the length of time that data was held in WM increased, activation at recognition increased in the medial temporal, medial occipito-temporal, anterior cingulate and posterior parietal cortices. These results confirm the components of an object WM network required for successful recognition, and suggest that parts of this network, including the medial temporal cortex, are sensitive to the duration of mnemonic delay. Hum Brain Mapp 2007. © 2006 Wiley-Liss, Inc. [source]

A systematic review and quantitative appraisal of fMRI studies of verbal fluency: Role of the left inferior frontal gyrus

HUMAN BRAIN MAPPING, Issue 10 2006
Sergi G. Costafreda
Abstract The left inferior frontal gyrus (LIFG) has consistently been associated with both phonologic and semantic operations in functional neuroimaging studies. Two main theories have proposed a different functional organization in the LIFG for these processes. One theory suggests an anatomic parcellation of phonologic and semantic operations within the LIFG. An alternative theory proposes that both processes are encompassed within a supramodal executive function in a single region in the LIFG. To test these theories, we carried out a systematic review of functional magnetic resonance imaging studies employing phonologic and semantic verbal fluency tasks. Seventeen articles meeting our pre-established criteria were found, consisting of 22 relevant experiments with 197 healthy subjects and a total of 41 peak activations in the LIFG. We determined 95% confidence intervals of the mean location (x, y, and z coordinates) of peaks of blood oxygenation level-dependent (BOLD) responses from published phonologic and semantic verbal fluency studies using the nonparametric technique of bootstrap analysis. Significant differences were revealed in dorsal,ventral (z -coordinate) localizations of the peak BOLD response: phonologic verbal fluency peak BOLD response was significantly more dorsal to the peak associated with semantic verbal fluency (confidence interval of difference: 1.9,17.4 mm). No significant differences were evident in antero,posterior (x -coordinate) or medial,lateral (y -coordinate) positions. The results support distinct dorsal,ventral locations for phonologic and semantic processes within the LIFG. Current limitations to meta-analytic integration of published functional neuroimaging studies are discussed. Hum Brain Mapp, 2006. © 2006 Wiley-Liss, Inc. [source]

Neural substrates of tactile object recognition: An fMRI study

HUMAN BRAIN MAPPING, Issue 4 2004
Catherine L. Reed
Abstract A functional magnetic resonance imaging (fMRI) study was conducted during which seven subjects carried out naturalistic tactile object recognition (TOR) of real objects. Activation maps, conjunctions across subjects, were compared between tasks involving TOR of common real objects, palpation of "nonsense" objects, and rest. The tactile tasks involved similar motor and sensory stimulation, allowing higher tactile recognition processes to be isolated. Compared to nonsense object palpation, the most prominent activation evoked by TOR was in secondary somatosensory areas in the parietal operculum (SII) and insula, confirming a modality-specific path for TOR. Prominent activation was also present in medial and lateral secondary motor cortices, but not in primary motor areas, supporting the high level of sensory and motor integration characteristic of object recognition in the tactile modality. Activation in a lateral occipitotemporal area associated previously with visual object recognition may support cross-modal collateral activation. Finally, activation in medial temporal and prefrontal areas may reflect a common final pathway of modality-independent object recognition. This study suggests that TOR involves a complex network including parietal and insular somatosensory association cortices, as well as occipitotemporal visual areas, prefrontal, and medial temporal supramodal areas, and medial and lateral secondary motor cortices. It confirms the involvement of somatosensory association areas in the recognition component of TOR, and the existence of a ventrolateral somatosensory pathway for TOR in intact subjects. It challenges the results of previous studies that emphasize the role of visual cortex rather than somatosensory association cortices in higher-level somatosensory cognition. Hum. Brain Mapping 21:236,246, 2004. © 2004 Wiley-Liss, Inc. [source]

Age-related changes in human meniscal glycosaminoglycans

INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2004
Gareth Blackburn
Introduction With an increased human lifespan, a major challenge is now to ensure a concomitant increase in healthspan. Meniscal damage and degradation are common and are strongly correlated with subsequent osteoarthritis. Indeed, meniscal damage has been identified in about 60% of people over 60. Markers of pathology will facilitate intervention but first require normal age-related changes to be established. Methods Undamaged vascular and avascular regions of medial and lateral human menisci were comminuted and the tissue extracted into 4- m GuHCl and subject to associative CsCl density gradient centrifugation. Aggrecan and the small leucine rich PGs (SLRPs) were isolated and their GAG profiles examined by HPAEC fingerprinting, following enzyme depolymerization, and by an NMR spectroscopy. Results and discussion Analysis of aggrecan and the SLRPs show that there is a complex and dynamic pattern of KS, CS and DS abundance and distribution within human menisci, which changes with age. The abundance of SLRPs is higher in the avascular than vascular tissues, however, this is not reflected in the abundance of aggrecan which is present at similar levels in both tissue regions. The data show no other significant differences between medial and lateral and between vascular and avascular tissue regions. Analysis of the sulfation pattern of CS following digestion by ACII lyase, shows that in both aggrecan and SLRPs the 4-sulfation level falls with age from 20 to 35% in young tissues to 10,20% in older. Subsequent analyses following ABC lyase depolymerization, to include DS, shows very significant change with age from CS + DS 4-sulfation levels of ca. 40,55% in young tissue to ca. 15,30% in older. The difference between these datasets represents the contribution made by 4-sulfated DS. Thus, analysis of the difference suggests that DS makes a decreasing contribution to the CS/DS profile with age. Indeed, this is confirmed by an NMR analysis of these samples. Analysis of the resonances in the region 1.95,2.2 p.p.m. (ref to TSP) allows the estimation of the contribution made by DS, CS and KS. These data show that, in aggrecan, the contribution made by DS chains falls from ca. 10% in younger tissues to ca. 2,4% in older tissues. NMR analysis also shows that KS levels fall with age from ca. 15,20% in younger tissues to 5,10% in older tissues. Analysis of the structure of the KS chains shows chains with a structure similar to that of in articular cartilage but that at all ages there are very low levels of fucosylation (ca. 1,5%). Previous studies of age-related changes in CS/DS and KS structures have shown significant changes in the first 17 years of life, with only modest nonpathological changes after that time. These data from meniscal tissues do not show such a dramatic halting of normal age-related changes. Indeed, the data show gradual age-related changes in DS, CS and KS abundance and structure throughout life. These baseline age-related changes data will now allow the analysis of pathology-related changes. [source]

The distribution, density and three-dimensional histomorphology of Pacinian corpuscles in the foot of the Asian elephant (Elephas maximus) and their potential role in seismic communication

JOURNAL OF ANATOMY, Issue 4 2007
D. M. Bouley
Abstract Both Asian (Elephas maximus) and African (Loxodonta africana) elephants produce low-frequency, high-amplitude rumbles that travel well through the ground as seismic waves, and field studies have shown that elephants may utilize these seismic signals as one form of communication. Unique elephant postures observed in field studies suggest that the elephants use their feet to ,listen' to these seismic signals, but the exact sensory mechanisms used by the elephant have never been characterized. The distribution, morphology and tissue density of Pacinian corpuscles, specialized mechanoreceptors, were studied in a forefoot and hindfoot of Asian elephants. Pacinian corpuscles were located in the dermis and distal digital cushion and were most densely localized to the anterior, posterior, medial and lateral region of each foot, with the highest numbers in the anterior region of the forefoot (52.19%) and the posterior region of the hindfoot (47.09%). Pacinian corpuscles were encapsulated, had a typical lamellar structure and were most often observed in large clusters. Three-dimensional reconstruction through serial sections of the dermis revealed that individual Pacinian corpuscles may be part of a cluster. By studying the distribution and density of these mechanoreceptors, we propose that Pacinian corpuscles are one possible anatomic mechanism used by elephants to detect seismic waves. [source]