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Medial Part (medial + part)
Selected AbstractsEarly onset of deafening-induced song deterioration and differential requirements of the pallial-basal ganglia vocal pathwayEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2008Haruhito Horita Abstract Similar to humans, songbirds rely on auditory feedback to maintain the acoustic and sequence structure of adult learned vocalizations. When songbirds are deafened, the learned features of song, such as syllable structure and sequencing, eventually deteriorate. However, the time-course and initial phases of song deterioration have not been well studied, particularly in the most commonly studied songbird, the zebra finch. Here, we observed previously uncharacterized subtle but significant changes to learned song within a few days following deafening. Syllable structure became detectably noisier and silent intervals between song motifs increased. Although song motif sequences remained stable at 2 weeks, as previously reported, pronounced changes occurred in longer stretches of song bout sequences. These included deletions of syllables between song motifs, changes in the frequency at which specific chunks of song were produced and stuttering for birds that had some repetitions of syllables before deafening. Changes in syllable structure and song bout sequence occurred at different rates, indicating different mechanisms for their deterioration. The changes in syllable structure required an intact lateral part but not the medial part of the pallial-basal ganglia vocal pathway, whereas changes in the song bout sequence did not require lateral or medial portions of the pathway. These findings indicate that deafening-induced song changes in zebra finches can be detected rapidly after deafening, that acoustic and sequence changes can occur independently, and that, within this time period, the pallial-basal ganglia vocal pathway controls the acoustic structure changes but not the song bout sequence changes. [source] Olfactory metamorphosis in the Coastal Giant Salamander (Dicamptodon tenebrosus)JOURNAL OF MORPHOLOGY, Issue 1 2005Jeremy T. Stuelpnagel Abstract This study examined the gross morphology and ultrastructure of the olfactory organ of larvae, neotenic adults, and terrestrial adults of the Coastal Giant Salamander (Dicamptodon tenebrosus). The olfactory organ of all aquatic animals (larvae and neotenes) is similar in structure, forming a tube extending from the external naris to the choana. A nonsensory vestibule leads into the main olfactory cavity. The epithelium of the main olfactory cavity is thrown into a series of transverse valleys and ridges, with at least six dorsal and nine ventral valleys lined with olfactory epithelium, and separated by ridges of respiratory epithelium. The ridges enlarge with growth, forming large flaps extending into the lumen in neotenes. The vomeronasal organ is a diverticulum off the ventrolateral side of the main olfactory cavity. In terrestrial animals, by contrast, the vestibule has been lost. The main olfactory cavity has become much broader and dorsoventrally compressed. The prominent transverse ridges are lost, although small diagonal ridges of respiratory epithelium are found in the lateral region of the ventral olfactory epithelium. The posterior and posteromedial wall of the main olfactory cavity is composed of respiratory epithelium, in contrast to the olfactory epithelium found here in aquatic forms. The vomeronasal organ remains similar to that in large larvae, but is now connected to the mouth by a groove that extends back through the choana onto the palate. Bowman's glands are present in the main olfactory cavity at all stages, but are most abundant and best developed in terrestrial adults. They are lacking in the lateral olfactory epithelium of the main olfactory cavity. At the ultrastructural level, in aquatic animals receptor cells of the main olfactory cavity can have cilia, short microvilli, a mix of the two, or long microvilli. Supporting cells are of two types: secretory supporting cells with small, electron-dense secretory granules, and ciliated supporting cells. Receptor cells of the vomeronasal organ are exclusively microvillar, but supporting cells are secretory or ciliated, as in the main olfactory cavity. After metamorphosis two distinct types of sensory epithelium occur in the main olfactory cavity. The predominant epithelium, covering most of the roof and the medial part of the floor, is characterized by supporting cells with large, electron-lucent vesicles. The epithelium on the lateral floor of the main olfactory cavity, by contrast, resembles that of aquatic animals. Both types have both microvillar and ciliated receptor cells. No important changes are noted in cell types of the vomeronasal organ after metamorphosis. A literature survey suggests that some features of the metamorphic changes described here are characteristic of all salamanders, while others appear unique to D. tenebrosus. J. Morphol. © 2005 Wiley-Liss, Inc. [source] Co-existence of ununited anconeal process and fragmented medial coronoid process of the ulna in the dogJOURNAL OF SMALL ANIMAL PRACTICE, Issue 2 2006A. Meyer-Lindenberg Objectives: To determine the incidence of fragmented medial coronoid process of the ulna in dogs with ununited anconeal process. The efficacy of presurgical radiography to diagnose the co-existence of these diseases was also investigated. Methods: One hundred and fifty-five joints from 137 dogs with ununited anconeal process were included in the study. For the radiographic examinations, an extended mediolateral projection and a craniolateral-caudomedial oblique projection of each elbow joint were taken before surgery. Inspection of the medial part of the joint was carried out either by arthrotomy or arthroscopy. Results: Seventy-two per cent of the dogs were German shepherd dogs. In 25 joints (16 per cent) a fragmented medial coronoid process was diagnosed and removed via arthrotomy or arthroscopy. The co-existence of a fragmented medial coronoid process was diagnosed correctly in only 13 cases (52 per cent) by radiography. In five of these cases with advanced osteoarthritis, the fragment was directly visible because of its dislocation. Compared with published information, the occurrence of ununited anconeal process with fragmented medial coronoid process is noted more frequently in the present study. Clinical Significance: It can be summarised that if ununited anconeal process is present, it is not usually possible to clearly identify fragmented medial coronoid process by radiography. Therefore, it is important to be able to inspect the medial aspect of the joint concerned during surgery. [source] Gender-related changes in the avian vasotocin system during ontogenyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2001Aleksandr Jurkevich Abstract The arginine vasotocin (AVT) system of the avian brain includes a sexually dimorphic part that extends from the caudal part of preoptic region through the medial part of the bed nucleus of stria terminalis (BSTm) to the lateral septum. It is composed of the parvocellular neurons located in the BSTm and the dense innervation of the medial preoptic region and lateral septum. In this part of the brain, AVT expression is stronger in males than in females in a few bird species investigated to date. This review focuses on the ontogeny of sexual differences in the vasotocinergic system of two gallinaceous species, domestic chicken and Japanese quail, and on the role of gonadal hormones in organizing during development and maintaining in adulthood these differences. Parvocellular AVT neurons become discernible in the BSTm of males and females during the second half of embryonic development. These cells undergo a profound and irreversible sexual differentiation during ontogenetic development. Recent findings demonstrate a dual role of estrogens in the organization and activation of sex differences in the AVT system. During the embryonic period of ontogeny, estrogens differentiate the AVT system in a sexually dimorphic manner in parallel with the differentiation of sexual behavior, while in adulthood estrogens, locally produced from testosterone in the male brain, activate AVT synthesis in the BSTm. The sexually dimorphic part of the AVT system is sensitive to a number of abiotic factors such as light, temperature, and water availability. It is suggested that sex dimorphic vasotocinergic systems could be implicated in processes of social recognition in various behavioral contexts. Microsc. Res. Tech. 55:27,36, 2001. © 2001 Wiley-Liss, Inc. [source] Perfusion in free breast reconstruction flap zones assessed with positron emission tomographyMICROSURGERY, Issue 6 2010Aleksi Schrey M.D. The aim of this pilot study was to determine the postoperative blood perfusion (BFPET) and perfusion heterogeneity (BFPET HG) in free microvascular breast reconstruction flap zones with positron emission tomography (PET). Regional BFPET and BFPET HG of the adipose tissue in medial, central, and lateral parts of 13 free flaps were assessed on the first postoperative morning with PET using oxygen-15-labeled water ([15O]H2O) in 12 patients undergoing breast reconstruction with a deep inferior epigastric perforator (DIEP) or a transverse rectus abdominis muscle (TRAM) flap. The mean BFPET values did not differ between DIEP and TRAM flaps (P = 0.791). The mean BFPET values were higher in zone III compared with zone I (P = 0.024). During follow-up, fat necrosis was identified in three patients in the medial part (zone II) of the flap. However, the adipose tissue BFPET assessed on the first postoperative day from all zones of the flap using PET with radiowater was normal. The BFPET HG was higher in the control side (i.e., in the healthy breast tissue) compared with the flap (P = 0.042). The BFPET HG was lower in zone III than in zone I (P = 0.03) and in zone II (P < 0.001). In this pilot study, PET was used for the first time for studying the adipose tissue perfusion in different zones in free flaps in a clinical setup, finding that the mean BFPET values did not differ between DIEP and TRAM flaps, and that zone II was sometimes not as well perfused as zone III supporting revisited zone division. © 2010 Wiley-Liss, Inc. Microsurgery 30:430,436, 2010. [source] The excitatory thalamo-"cortical" projection within the song control system of zebra finches is formed by calbindin-expressing neuronsTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 6 2007Raphael Pinaud Abstract The learning and production of vocalizations in songbirds are controlled by a system of interconnected brain nuclei organized into a direct vocal motor pathway and an anterior forebrain (pallium-basal ganglia-thalamo-pallial) loop. Here we show that the thalamo-pallial ("thalamo-cortical") projection (from the medial part of the dorsolateral thalamic nucleus to the lateral magnocellular nucleus of the anterior nidopallium,DLM to LMAN) within the anterior forebrain loop is composed of cells positive for the calcium-binding protein calbindin. We show that the vast majority of cells within DLM express calbindin, based both on immunocytochemistry (ICC) for calbindin protein and in situ hybridization for calb mRNA. Using a combination of tract-tracing and ICC we show that the neurons that participate in the DLM-to-LMAN projection are calbindin-positive. We also demonstrate that DLM is devoid of cells expressing mRNA for the GABAergic marker zGAD65. This observation confirms that the calbindin-expressing cells in DLM are not GABAergic, in accordance with previous electrophysiological data indicating that the DLM-to-LMAN projection is excitatory. Furthermore, we use ICC to determine the trajectory of the fibers within the DLM-to-LMAN projection, and to demonstrate a sex difference in calbindin expression levels in the fibers of the DLM-to-LMAN projection. Our findings provide a clear-cut neurochemical signature for a critical projection in the songbird vocal control pathways that enable song learning. J. Comp. Neurol. 504:601,618, 2007. © 2007 Wiley-Liss, Inc. [source] Neurokinin B-producing projection neurons in the lateral stripe of the striatum and cell clusters of the accumbens nucleus in the ratTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 2 2004Ligang Zhou Abstract Neurons producing preprotachykinin B (PPTB), the precursor of neurokinin B, constitute 5% of neurons in the dorsal striatum and project to the substantia innominata (SI) selectively. In the ventral striatum, PPTB-producing neurons are collected mainly in the lateral stripe of the striatum (LSS) and cell clusters of the accumbens nucleus (Acb). In the present study, we first examined the distribution of PPTB-immunoreactive neurons in rat ventral striatum and found that a large part of the PPTB-immunoreactive cell clusters was continuous to the LSS, but a smaller part was not. Thus, we divided the PPTB-immunoreactive cell clusters into the LSS-associated and non-LSS-associated ones. We next investigated the projection targets of the PPTB-producing ventral striatal neurons by combining immunofluorescence labeling and retrograde tracing. After injection of Fluoro-Gold into the basal component of the SI (SIb) and medial part of the interstitial nucleus of posterior limb of the anterior commissure, many PPTB-immunoreactive neurons were retrogradely labeled in the LSS-associated cell clusters and LSS, respectively. When the injection site included the ventral part of the sublenticular component of the SI(SIsl), retrogradely labeled neurons showed PPTB-immunoreactivity frequently in non-LSS-associated cell clusters. Furthermore, these PPTB-immunoreactive projections were confirmed by the double-fluorescence method after anterograde tracer injection into the ventral striatum containing the cell clusters. Since the dorsalmost part of the SIsl is known to receive strong inputs from PPTB-producing dorsal striatal neurons, the present results indicate that PPTB-producing ventral striatal neurons project to basal forebrain target regions in parallel with dorsal striatal neurons without significant convergence. J. Comp. Neurol. 480:143,161, 2004. © 2004 Wiley-Liss, Inc. [source] Biomechanics of the Fractured Medial Coronoid Process and the Isolated Anconeal Process in the Canine Elbow JointANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005J. Maierl Introduction:, Elbow dysplasia is one of the most important orthopaedic diseases of the canine elbow joint. The medial coronoid process (MCP) and the anconeal process (AP) are involved with a high incidence. Aims:, The aim of this study was to clarify whether these processes are especially loaded resulting in osteoarthrosis. Material and Methods:, Elbow joints were examined from dogs of various breeds, with a body weight over 20 kg and an age ranging from 1 to 12 years. Only joints without damage to the articular cartilage have been included in this investigation. Articular surfaces have been evaluated macroscopically, subchondral bone density (long-term loading) and split-lines (long-term tensile loading) have been determined. Results:, In the humeral fossa olecrani, there was a distinct impression on the inner side of the lateral compared to the medial epicondyle. In the ulna, the MCP was much greater than the lateral coronoid indicating that the medial process has to support the humeral condyle to a higher extent. Subchondral split lines with a transverse orientation in the fossa olecrani gave evidence of long-term transverse tensile loading in this area. Split lines on the MCP were oriented radially as if the lateral edge was bent downwards. Subchondral bone density in the fossa olecrani was higher towards the lateral epicondyle in comparison to the medial. Furthermore, there was a bone density maximum on the medial part of the humeral condyle opposite of the MCP with its very high density. Discussion:, Gait analyses showed that there is a transverse, medially oriented force of up to 4% bodyweight acting on the paw during midstance. As the carpus is stable when slightly hyperextended during midstance loading there is a long lever arm from the ground up to an assumed rotation centre in the depth of the trochlear notch. The medially directed ground reaction force slightly rotates the forearm inwards causing a bending moment about the elbow joint, which leads to an increased pressure of the AP and the MCP. This bending in addition to sagittal loading is the reason for the high susceptibility of the MCP and AP. [source] Changes of effective connectivity between the lateral and medial parts of the prefrontal cortex during a visual taskEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003Thierry Chaminade Abstract Structural equation modelling was used to study the change of connectivity during a visual task with continuous variation of the attention load. The model was based on areas defined by the haemodynamic responses described elsewhere [Mazoyer, P., Wicker, B. & Fonlupt, P. (2002) A neural network elicited by parametric manipulation of the attention load. Neuroreport, 13, 2331,2334], including occipitotemporal, parietal, temporal and prefrontal (lateral and medial areas) cortices. We have studied stationary- (which does not depend on the attentional load) and attention-related coupling between areas. This allowed the segregation of two subsystems. The first could reflect a system performing the integration step of the visual signal and the second a system participating in response selection. The major finding is the mutual negative influence between the lateral and medial parts of the prefrontal cortex. This negative influence between these two brain regions increased with the attention load. This is interpreted as a modification of the balance between integration and decision processes that are needed for the task to be efficiently completed. [source] Prevention of levodopa-induced dyskinesias by a selective NR1A/2B N -methyl- D -aspartate receptor antagonist in parkinsonian monkeys: Implication of preproenkephalinMOVEMENT DISORDERS, Issue 1 2006Marc Morissette PhD Abstract Enkephalin is reported to play an important role in the pathophysiology of levodopa (LD) -induced dyskinesias. The present study investigated the effect of chronic treatment with a selective NR1A/2B N -methyl- D -aspartate (NMDA) receptor antagonist, CI-1041, on the expression of preproenkephalin-A (PPE-A) in brains of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) -treated monkeys in relation to the development of LD-induced dyskinesias. Four MPTP-monkeys received LD/benserazide alone; they all developed dyskinesias. Four other MPTP-monkeys received LD/benserazide plus CI-1041; only one of them developed mild dyskinesias at the end of the fourth week of treatment. Four normal monkeys and four saline-treated MPTP monkeys were also included. MPTP-treated monkeys had extensive and similar striatal dopamine denervation. An increase of PPE-A mRNA levels assayed by in situ hybridization was observed in the lateral putamen (rostral and caudal) and caudate nucleus (rostral) of saline-treated MPTP monkeys compared to controls, whereas no change or a small increase was observed in their medial parts. Striatal PPE-A mRNA levels remained elevated in LD-treated MPTP monkeys, whereas cotreatment with CI-1041 brought them back to control values. These findings suggest that chronic blockade of striatal NR1A/2B NMDA receptors with CI-1041 normalizes PPE-A mRNA expression and prevents the development of LD-induced dyskinesias in an animal model of Parkinson disease. © 2005 Movement Disorder Society [source] | |||||||||||||