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Bilateral Lesions (bilateral + lesion)
Selected AbstractsBilateral lesion in the lateral columns and complete urinary retention: Association with the spinal cord descending pathway for micturitionNEUROUROLOGY AND URODYNAMICS, Issue 4 2005Akiyuki Hiraga [source] Roles of the auditory cortex in discrimination learning by ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2006Kentaro Ono Abstract We investigated the roles of the auditory cortex in sound discrimination learning in Wistar rats. Absolute pitch or relative pitch can be used as discrimination cues in sound frequency discrimination. To clarify this, rats were trained to discriminate between rewarded (S+) and unrewarded (S,) test stimuli (S+ frequency > S, frequency). After learning was acquired by rats, performance was tested in a new test in which S+ frequency was constant but S+ frequency < S, frequency, or S+ frequency > S, frequency but both frequencies were increased. If the discrimination cue of the first test was preserved in the new test, performance following change of testing procedures was expected to remain high. The measured performance suggested that rats used relative pitch in half octave discrimination (difference between S+ and S, frequencies, 0.5 octave), and absolute pitch in octave discrimination (difference between S+ and S, frequencies, 1.0 octave). Bilateral lesions in the auditory cortex had almost no effect on performance before procedure change. Furthermore, performance following procedure change was not affected by lesions in the auditory cortex when the discrimination cue was preserved. However, performance was impaired by lesions in the auditory cortex when a new discrimination cue was used following procedure change. Lesions in the auditory cortex also impaired multimodal discrimination between sound and sound plus light. The present findings suggest that the auditory cortex plays a role as a sensory interface of the higher cortices required for flexible learning and multimodal discrimination. [source] GABAA receptors signal bidirectional reward transmission from the ventral tegmental area to the tegmental pedunculopontine nucleus as a function of opiate stateEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2004Steven R. Laviolette Abstract The brainstem tegmental pedunculopontine nucleus (TPP) is involved in reward signalling and is functionally and anatomically linked to the VTA. We examined the possible role of the TPP as a reward transmission output for GABAA receptors in the VTA in rats not previously exposed to opiates vs. rats that were chronically exposed to and in withdrawal from opiates or in rats that had recovered from chronic opiate exposure. Bilateral lesions of the TPP blocked the rewarding effects of a GABAA antagonist but not the rewarding effects of a GABAA receptor agonist in rats previously unexposed to opiates. This functional pattern was reversed in rats that were dependent on opiates and in withdrawal. However, once rats had recovered from chronic opiate exposure the functional parameters of VTA GABAA receptor reward signalling reverted to the pattern observed in animals that had not been exposed to opiates. These findings suggest that GABAA receptors in the VTA can regulate differential reward signalling through separate neural systems during the transition from a drug-naive to a drug-dependent and withdrawn state. [source] Locus Coeruleus Norepinephrine Regulates the Surge of Prolactin During OestrusJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2005R. E. Szawka Abstract A secondary surge of prolactin has been recently characterised on the afternoon of oestrus. Because the noradrenergic nucleus locus coeruleus participates in the genesis of the pro-oestrous and steroid-induced surges of prolactin, the aim of the present study was to investigate the importance of locus coeruleus norepinephrine in the generation of the prolactin surge of oestrus. For this purpose, we initially re-evaluated the profile of prolactin secretion during the oestrous cycle to verify whether this surge of prolactin was physiological and specific to the day of oestrus. Thereafter, the following were evaluated: (i) the effect of locus coeruleus lesion on the secondary surge of prolactin and on norepinephrine concentration in the medial preoptic area (MPOA), medial basal hypothalamus (MBH) and paraventricular nucleus (PVN) during the day of oestrus and (ii) locus coeruleus neurones activity during the same day by Fos immunoreactivity. Locus coeruleus lesion completely blocked the prolactin surge of oestrus in all rats studied and also significantly reduced norepinephrine concentration in the MPOA, MBH and PVN during the day of oestrus. The number of double-labelled tyrosine hydroxylase/Fos immunoreactive neurones in locus coeruleus was significantly higher at 14.00 h of oestrus, suggesting an increase in its activity preceding the prolactin surge that generally occurs at 15.00 h. Therefore, the increase in locus coeruleus activity on the afternoon of oestrus supports the data obtained with bilateral lesion of this nucleus, suggesting a stimulatory role of locus coeruleus norepinephrine in the genesis of the secondary surge of prolactin. [source] Elbow flexion response as another primitive reflexPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 2 2002Kazumasa Sudo MD Abstract In daily clinical practice we noticed that patients with intellectual impairment spontaneously flex the elbow within a few seconds of the forearm being manipulated during routine examination of spasticity of the muscles in the upper extremities. We termed this phenomenon elbow flexion response (EFR), and prospectively studied it in 229 patients who underwent in-hospital rehabilitation following brain damage. Evaluation of each patient included EFR, patient profile, ability to communicate, scores on three parameters from various intelligence tests, scores on seven parameters testing primitive reflexes, and scores on three parameters describing personality. We investigated for relationships among these parameters. Consequently, although EFR rarely have a statistical association with the varied profiles of patients, patients with bilateral lesion or bilateral paresis demonstrated significantly more marked EFR than those with unilateral lesion or unilateral paresis. Patients with involvement of the frontal lobe showed significantly more marked EFR than those without damage in this area. Elbow flexion responses occurred significantly more frequently in relation with lower scores on intelligence and occurred with significantly higher frequency in conjunction with the more marked appearance of conventional primitive reflexes. Therefore, we conclude that EFR have a strong association with intelligence and with the existence of frontal lobe lesion, and their mode of clinical presentation parallels that of primitive reflexes particularly that of the grasp reflex. We propose that EFR could be referred as a variation of the grasp reflex occurring in the more proximal or axial part of the body. [source] 4365: The role of transpupillary thermotherapy in combined treatment of retinoblastomaACTA OPHTHALMOLOGICA, Issue 2010SV SAAKYAN Purpose Retinoblastoma (RB) is one of the most serious ophthalmic pathology in childhood. Treatment options that provide eye preservation include chemotherapy, brachytherapy, external beam radiation, cryotherapy and laser treatment. The aim of our study is to evaluate efficiency of transpupillary thermotherapy (TTT) as a part of combined treatment of RB. Methods Our group consists of 30 RB patients (34 eyes). All patients received systemic chemotherapy (Carboplatin and Vincristine). Tumor thickness before TTT varied from 0.9 to 2.6 mm, tumor base diameter varied from 2 to 10 mm. Seven patients had monolateral RB, others had bilateral lesion. Five patients were treated with brachytherapy before TTT. TTT was performed using infrared diode laser Nidec DC 3300. Exposure time was 60 seconds. Width of laser beam was from 1000 to 2000 nm. TTT power setting varied from 600 to 900 mW. Eleven patients had TTT more then once. Follow-up period after TTT was up to 24 months. Results Control examination after TTT showed good response to the treatment in 27 eyes (79.4%). After TTT we saw hyperpigmented scar on the eye fundus at the place of previous tumor location, on OCT it looked like hyper-reflective stripe replacing all layers of a retina. Seven eyes (20.6%) were resistant to TTT, five of them were successfully treated by additional brachytherapy. Two eyes were enucleated because of uncontrolled tumor growth. Evaluation of metastatic disease in all patients revealed no signs of metastasis at the time of treatment or during follow-up. Conclusion TTT can be used in combined treatment of RB for small multifocal lesions. The method is rather simple and uncomplicated. Patients treated with TTT have better visual prognosis in comparison with brachytherapy. [source] The use of neuroimaging in the diagnosis of mitochondrial diseaseDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 2 2010Seth D. Friedman Abstract Mutations in nuclear and mitochondrial DNA impacting mitochondrial function result in disease manifestations ranging from early death to abnormalities in all major organ systems and to symptoms that can be largely confined to muscle fatigue. The definitive diagnosis of a mitochondrial disorder can be difficult to establish. When the constellation of symptoms is suggestive of mitochondrial disease, neuroimaging features may be diagnostic and suggestive, can help direct further workup, and can help to further characterize the underlying brain abnormalities. Magnetic resonance imaging changes may be nonspecific, such as atrophy (both general and involving specific structures, such as cerebellum), more suggestive of particular disorders such as focal and often bilateral lesions confined to deep brain nuclei, or clearly characteristic of a given disorder such as stroke-like lesions that do not respect vascular boundaries in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode (MELAS). White matter hyperintensities with or without associated gray matter involvement may also be observed. Across patients and discrete disease subtypes (e.g., MELAS, Leigh syndrome, etc.), patterns of these features are helpful for diagnosis. However, it is also true that marked variability in expression occurs in all mitochondrial disease subtypes, illustrative of the complexity of the disease process. The present review summarizes the role of neuroimaging in the diagnosis and characterization of patients with suspected mitochondrial disease. © 2010 Wiley-Liss, Inc. Dev Disabil Res Rev 2010;16:129,135. [source] Behavioral discrimination of sexually dimorphic calls by male zebra finches requires an intact vocal motor pathwayDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2001David S. Vicario Abstract Vocal communication between zebra finches includes the exchange of long calls (LCs) as well as song. By using this natural call behavior and quantifying the LCs emitted in response to playbacks of LCs of other birds, we have previously shown that adult male zebra finches have a categorical preference for the LCs of females over those of males. Female LCs are acoustically simpler than male LCs, which include complex acoustic features that are learned during development. Production of these male-typical features requires an intact nucleus RA, the sexually dimorphic source of the main telencephalic projection to brainstem vocal effectors. We have now made bilateral lesions of RA in 17 adult males and tested their discrimination behavior in the call response situation. Lesioned birds continue to call, but lose the male-typical preference for female LCs. The degree of loss is correlated with the extent of RA damage. Further, the simplified LCs of males with RA lesions have a variable duration that is correlated with stimulus features. In effect, the call response behavior of lesioned males becomes like that of females. Apparently, in the absence of RA, the remaining intact structures receive different call information than RA normally does, and/or process it differently. This suggests that the vocal motor nucleus RA could play a role in the transformation of a signal encoding the salience of stimulus parameters into a control signal that modulates the probability and strength of responding. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 109,120, 2001 [source] Effect of auditory cortex lesions on the discrimination of frequency-modulated tones in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2006Natalia Rybalko Abstract The lateralization of functions to individual hemispheres of the mammalian brain remains, with the exception of the human brain, unresolved. The aim of this work was to investigate the ability to discriminate between falling and rising frequency-modulated (FM) stimuli in rats with unilateral or bilateral lesions of the auditory cortex (AC). Using an avoidance conditioning procedure, thirsty rats were trained to drink in the presence of a rising FM tone and to stop drinking when a falling FM tone was presented. Rats with a lesion of the AC were able to learn to discriminate between rising and falling FM tones; however, they performed significantly worse than did control rats. A greater deficit in the ability to discriminate the direction of frequency modulation was observed in rats with a right or bilateral AC lesion. The discrimination performance (DP) in these rats was significantly worse than the DP in rats with a left AC lesion. Animals with a right or bilateral AC lesion improved their DP mainly by recognizing the pitch at the beginning of the stimuli. The lesioning of the AC in trained animals caused a significant decrease in DP, down to chance levels. Retraining resulted in a significant increase in DP in rats with a left AC lesion; animals with a right lesion improved only slightly. The results demonstrate a hemispheric asymmetry of the rat AC in the recognition of FM stimuli and indicate the dominance of the right AC in the discrimination of the direction of frequency modulation. [source] Impairment and recovery on a food foraging task following unilateral vestibular deafferentation in ratsHIPPOCAMPUS, Issue 4 2006Yiwen Zheng Abstract It has been suggested that the vestibular system may contribute to the development of higher cognitive function, especially spatial learning and memory that uses idiothetic cues (e.g., dead reckoning). However, few studies have been done using behavioral tasks that could potentially separate the animals' ability for dead reckoning from piloting. The food foraging task requires the animal to continuously monitor and integrate self-movement cues and generate an accurate return path. It has been shown that bilateral vestibular-lesioned rats were impaired on this task. The present study used the same task to further examine the contribution of vestibular information to spatial navigation by comparing unilateral and bilateral lesions and by testing the animals at different time points following the lesion. The results demonstrated that animals with unilateral vestibular deafferentation were impaired in performing the task in the dark at 3 months after the lesion, and this impairment disappeared at 6 months after the lesion. This supports the notion that vestibular information contributes to dead reckoning and suggests possible recovery of function over time after the lesion. Animals with bilateral vestibular deafferentation were not able to be tested on the foraging task because they exhibited behavior distinct from the unilateral-lesioned animals, with significant hesitation in leaving their home cage for as long as 6 months after the lesion. © 2005 Wiley-Liss, Inc. [source] MRI-based evaluation of locus and extent of neurotoxic lesions in monkeys ,HIPPOCAMPUS, Issue 4 2001e Málková Abstract To minimize the variability in the extent of lesions made by injections of the excitotoxin ibotenic acid in rhesus monkeys, we developed and validated an MRI-based method to determine the efficacy of the injections soon after surgery. T2-weighted MR images were obtained 6,11 days after surgery from 17 brain hemispheres of monkeys that had received bilateral lesions of either the hippocampal formation (HF), perirhinal cortex, or parahippocampal cortex. The extent of lesion estimated from the hypersignal that appeared in and outside of the targeted area on these MR images was compared with the extent of damage assessed histologically after survival periods ranging from 120,370 days. Highly significant correlations (r values between 0.85,0.99) were found between these two measures for several regions in the medial temporal lobe. Based on this finding, lack of hypersignal in the targeted area of some Ss was followed by successful reinjection of the neurotoxin to create more complete cell loss prior to the postoperative phase of the study. We also assessed the relationship between a postoperative reduction in HF volume, measured from T1-weighted MR images, and the extent of damage determined histologically in 14 hemispheres of monkeys with bilateral excitotoxic HF lesions. The HF volume decreases sharply after surgery until 40,50 days postoperatively, after which there is only a minor further decrease. Based on this finding, we obtained T1-weighted MR images at least 44 days but in most cases close to 1 year after surgery. A highly significant positive correlation (r = 0.95, P < 0.001) was found between neuronal damage and volume reduction, with nearly complete neuronal damage (96,99%) corresponding to a volume reduction of 68,79%. These MRI-based methods thus provide an accurate in vivo evaluation of the locus and extent of neurotoxic lesions. Application of these methods can ensure that each animal in the experiment is used effectively. Hippocampus 2001;11:361,370. Published 2001 Wiley-Liss, Inc. [source] Ethanol-Induced Conditioned Taste Avoidance: Reward or Aversion?ALCOHOLISM, Issue 3 2009Chuang Liu Background:, Rats avoid intake of a palatable taste cue when paired with all drugs of abuse tested. Evidence suggests that, at least for morphine and cocaine, rats avoid the taste cue because they are anticipating the rewarding properties of the drug. Thus, the suppressive effects of a rewarding sucrose solution and cocaine, but not those of the putatively aversive agent, lithium chloride (LiCl), are exaggerated in drug-sensitive Lewis rats. Likewise, the suppressive effects of sucrose and morphine, but not those of LiCl, are eliminated by bilateral lesions of the gustatory thalamus. Unlike morphine and cocaine, it is less clear whether rewarding or aversive drug properties are responsible for ethanol-induced suppression of intake of a taste cue. The present set of studies tests whether, like cocaine, ethanol-induced suppression of intake of a taste cue also is greater in the drug-sensitive Lewis rats and whether the suppressive effects of the drug are prevented by bilateral lesions of the taste thalamus. Methods:, In Experiment 1, fluid-deprived Lewis and Fischer rats were given 5-minute access to 0.15% saccharin and then injected with saline or a range of doses of ethanol (0.5, 0.75, 1.0, or 1.5 g/kg). There was a total of 6 such pairings. In Experiments 2 and 3, Sprague,Dawley rats received bilateral electrophysiologically guided lesions of the gustatory thalamus. After recovery, suppression of intake of the saccharin cue was evaluated following repeated daily pairings with either a high (1.5 g/kg) or a low (0.75 g/kg) dose of ethanol. Results:, Ethanol-induced suppression of intake of the saccharin conditioned stimulus (CS) did not differ between the drug-sensitive Lewis rats relative to the less-sensitive Fischer rats. Lesions of the taste thalamus, however, prevented the suppressive effect of the 0.75 g/kg dose of the drug, but had no impact on the suppressive effect of the 1.5 g/kg dose of ethanol. Conclusion:, The results suggest that the suppressive effects of ethanol on CS intake are mediated by both rewarding and aversive consequences, varying as a function of dose. [source] Mycoplasma pneumonia: Clinical and radiographic features in 39 childrenPEDIATRICS INTERNATIONAL, Issue 3 2007SHU-CHIANG HSIEH Abstract Background: The purpose of the present paper was to evaluate the clinical and chest radiographic features of pediatric patients with serologically proven Mycoplasma pneumoniae pneumonia (mycoplasma pneumonia). Methods: The clinical records and chest radiographs of 39 consecutive patients (19 male, 20 female; age 3,13 years) with serologically positive IgG and IgM mycoplasma pneumonia were reviewed. Results: More than 90% of patients presented with fever and cough and 48% of patients had leukocyte count >10 000/mm3. A C-reactive protein (CRP) level >0.375 mg/dL was noted in 28 patients (72%). Chest radiographs displayed four different patterns: (i) peribronchial and perivascular interstitial infiltrates (n= 19, 49%); (ii) airspace consolidations (n= 15, 38%); (iii) reticulonodular opacification (n= 3, 8%); and (iv) nodular or mass-like opacification (n= 2, 5%). Bilateral peribronchial perivascular interstitial infiltrations in central and middle lung zones were frequently seen (n= 19, 49%). Other radiological features were bilateral lesions in 51% of patients, pleural effusion in 23%, and hilar lymphadenopathy in 13%. Means of duration for treatment response and hospitalization were 2.5 and 5 days, respectively. Conclusion: There are various radiological features of mycoplasma pneumonia in children. Bilateral peribronchial and perivascular interstitial infiltrates were most frequently seen in the present patients. [source] Benign lesions of the vocal folds: a masqueradeCLINICAL OTOLARYNGOLOGY, Issue 4 2000P.J.P. Poels Objective. The aim of this study is to give an analysis of the nature of benign vocal fold lesions with an indication for microlaryngoscopy that are found in a general ENT clinic. Patients and methods. Retrospectively, pre- and peroperative data from 177 successive patients were examined. Results. The male : female distribution was 1 : 3. Preoperatively, bilateral lesions were found in 53%, changing into 82% at peroperative examination. Nodules, polyps, Reinke's oedema and intracordal lesions,such as sulcus vocalis, vergeture and cysts,were the most frequently found lesions. The intracordale lesions were easily missed at preoperative examination. Half of the patients had occupational voice use. Conclusion. In spite of laryngostroboscopy, the vocal fold lesions could not always be diagnosed correctly. It is recommended to perform a diagnostic microlaryngoscopy in cases of unclear dysphonia and to examine both vocal folds peroperatively. It may be advisable to develop a new terminology for vocal fold lesions, based on their functional behaviour. At this, stroboscopy can be completed by videokymography. [source] Effects of local arteriosclerosis on carotid baroreflex sensitivity and on heart rate and arterial pressure variability in humansCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2006Ola Eiken Summary The study examined whether the alterations in heart rate variability (HRV) and baroreflex sensitivity (BRS) observed in patients with coronary artery disease can also be discerned in otherwise healthy subjects with mild-to-moderate arteriosclerosis in the carotid artery bifurcation. Based on the results of carotid duplex ultrasonography, subjects were designated as either having no arteriosclerotic lesions (n = 18), unilateral (n = 19) or bilateral lesions (n = 18) in the bifurcation. Electrocardiograms were recorded and simultaneous and continuous records of arterial pressure were obtained. Resting HRV was determined by calculating the spectral power density in three frequency bands: 0,0·05 Hz [very low frequency (VLF) band], 0·05,0·15 [low frequency (LF) band] and 0·15,2 Hz (high frequency band), whereas the arterial pressure variability (APV) was determined from spectral power density of the VLF and LF bands. Carotid BRS was evaluated by measuring R-R intervals during application of pulse-synchronous graded pressures (40 to ,65 mmHg) in a neck-chamber device. Analysis of variance revealed no effect of mild-to-moderate carotid arteriosclerosis on the spectral components of HRV and APV or on BRS. It thus appears that mild-to-moderate asymptomatic carotid arteriosclerosis does not affect carotid BRS, APV or HRV at rest. [source] | |||||||||||||