Browsing by Subject "Cerebellum"

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Open Access
Connections of the dentate nucleus with the amygdala: Experimental rat and human 3-tesla tractography study
(Mary Ann Liebert, Inc. Publishers, 2022-12-13) Çavdar, S.; Güneş, Y. C.; Algın, Oktay
Background: The role of the cerebellum in motor function is well recognized. However, its role in higher nervous system activities such as cognition, emotion, endocrine, and autonomic activities is less known. The present study aims to show direct dento-amygdala projections using a biotinylated dextran amine (BDA) tracer in rats and 3-tesla (T) high-resolution diffusion tensor imaging (DTI)-based tractography in humans. Materials and Methods: The BDA tracer was pressure injected into the dentate nucleus of the cerebellum of Wistar albino rats. Labeled cells and axons were documented. High-resolution 3-T tractography data were obtained from the Human Connectome Project database. Dento-amygdala tracts were analyzed using diffusion spectrum imaging (DSI) Studio software. Results: The experimental study showed bilateral projections between the dentate nucleus and the central and basal nuclei and ipsilateral projections between lateral nuclei of the amygdala. The fibers from the dentate nucleus reached the amygdala through the superior cerebellar peduncle (SCP), and the contralateral fibers crossed in the decussation of SCP at the midbrain. The dento-amygdala results of the experimental study corresponded with the 3-T tractography findings on humans. Additionally, DTI findings showed that most of the dentate fibers passed through the hypothalamus before reaching the amygdala, and the amygdalae of the two sides are connected through the anterior commissure. Discussion: The 3-T DTI data of adult humans showed both direct dento-amygdala and indirect dento-hypothalamo-amygdala projections. Thus, this may indicate cerebellar contribution in modulation of emotional and autonomic functions. Furthermore, this can explain the emotional and cognitive deficits that occur in patients with cerebellar or SCP damage.
Open Access
Musical mirror-symmetrical movement tasks: comparison of rhythm versus melody-playing
(Lippincott Williams and Wilkins, 2020) Tokgöz, S.; Aydoğdu, D.; İlhan, B.; Şahin, Y.; Bariseri, N.; Öztürkler, B. M.; Çukur, Tolga
Bimanual mirror-symmetrical movement (MSM) is relatively easy to control movement. Different MSM tasks may have different activations and interhemispheric interactions. The purpose of this study is to compare anatomo-physiological features such as hemispheric activations and dominance of two different MSMs, namely melody-playing and rhythm. We examined functional MRI (fMRI) recordings in a group of fifteen right-handed pianists performing two separate tasks: bimanual rhythm and bimanual melody-playing on two different keyboards with standard key order for right hand and reversed for left hand, which allows homolog fingers’ movements. Activations and laterality indices on fMRI were examined. The results show that significant cerebellar activations (especially in anterior cerebellum) in both groups. Significant primary sensorimotor cortical activations are observed in the melody-playing group. While there are also bilaterally symmetric activations, and laterality indices suggest overall lateralization towards the left hemisphere in both groups. Activations in the left fronto-parietal cortex, left putamen and left thalamus in conjunction with right cerebellar activations suggest that the left cortico-thalamo-cerebellar loop may be a dominant loop. Dynamic causal modeling (DCM) indicates the presence of causal influences from the left to the right cerebral cortex. In conclusion, melody-playing with bimanual MSM is a complex in-phase task and may help activate the bilateral cortical areas, and left hemisphere is dominant according to laterality indices and DCM results. On the other hand, bimanual rhythm is a simpler in-phase task and may help activate subcortical areas, which might be independent of the voluntary cortical task.
Open Access
Neuro-ophthalmologic findings in humans with quadrupedal locomotion
(2012) Sarac O.; Gulsuner, S.; Yildiz-Tasci, Y.; Ozcelik, T.; Kansu, T.
Purpose: To report the neuro-ophthalmologic findings in four patients from the same family with cerebellar ataxia, mental retardation, and dysequilibrium syndrome (CAMRQ)2 associated with quadrupedal locomotion. Method: A case series. Results: All four patients carry the private missense mutation, WDR81 p.P856L. The brain Magnetic Resonance Imaging (MRI) of these patients revealed morphological abnormalities including mild hypoplasia of the corpus callosum, and atrophy of superior, middle, and inferior peduncles of the cerebellum. All patients had down-beat nystagmus, while two male patients additionally had bilateral temporal disc pallor along with ring-shaped macular atrophy. Conclusions: The neuro-ophthalmic examination in CAMRQ2 revealed downbeat nystagmus in all patients, and temporal disc pallor and macular atrophy in two patients. It remains to be determined whether these findings are consistent in other forms of CAMRQ with mutations in VLDLR or CA8. © 2012 Informa Healthcare USA, Inc.
Open Access
SOX1 antibodies are markers of paraneoplastic Lambert-Eaton myasthenic syndrome
(Lippincott Williams & Wilkins, 2008) Sabater, L.; Titulaer, M.; Saiz, A.; Verschuuren, J.; Güre, A. O.; Graus, F.
BACKGROUND/OBJECTIVE: We reported that 43% of patients with Lambert-Eaton myasthenic syndrome (LEMS) and small cell lung cancer (SCLC) had an antibody called anti-glial nuclear antibody (AGNA), defined by the immunoreaction with the nuclei of the Bergmann glia of the cerebellum. This study was undertaken to identify the antigen recognized by AGNA and to confirm the association with paraneoplastic LEMS in a larger series. METHODS: We probed a fetal brain cDNA library with AGNA-positive sera. The presence of antibodies against the isolated antigen was detected by immunoblot of phage plaques from two positive clones. We studied 105 patients with LEMS (55 with SCLC), 50 with paraneoplastic neurologic syndromes, SCLC, and Hu antibodies, and 50 with only SCLC. RESULTS: Probing of the fetal brain expression library with AGNA sera resulted in the isolation of SOX1, a highly immunogenic tumor antigen in SCLC. IgG eluted from SOX1 clones produced the same cerebellar immunoreactivity as of AGNA sera. SOX1 antibodies were present in 64% of patients with LEMS and SCLC but in none of the 50 with idiopathic LEMS (p < 0.0001). Compared with paraneoplastic LEMS, the frequency of SOX1 antibodies was significantly lower in patients with Hu antibodies (32%, p = 0.002) and in those with only SCLC (22%). CONCLUSIONS: SOX1 is the antigen recognized by anti-glial nuclear antibody-positive sera. The detection of SOX1 antibodies in patients with Lambert-Eaton myasthenic syndrome (LEMS) predicts the presence of small cell lung cancer and may be used to follow more closely those LEMS patients with no evidence of cancer at the initial workup.