Amir Samii

Prof. Dr. Amir Samii

Department of Neurosurgery, INI-Hannover, 30625 Hannover, Germany

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 March 2013 in BMC Neuroscience
Verified
Journal Article
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GSGerd Schmitz
Gerd Schmitz
BMBahram Mohammadi
Bahram Mohammadi
AHAnke Hammer
Anke Hammer
MHMarcus Heldmann
Marcus Heldmann
ASAmir Samii
Amir Samii
AEAlfred O. Effenberg
Alfred O. Effenberg
Background: Producing sounds by a musical instrument can lead to audiomotor coupling, i.e. the joint activation of the auditory and motor system, even when only one modality is probed. The sonification of otherwise mute movements by sounds based on kinematic parameters of the movement has been shown to improve motor performance and perception of movements.Results: Here we demonstrate in a group of healthy young non-athletes that congruently (sounds match visual movement kinematics) vs. incongruently (no match) sonified breaststroke movements of a human avatar lead to better perceptual judgement of small differences in movement velocity. Moreover, functional magnetic resonance imaging revealed enhanced activity in superior and medial posterior temporal regions including the superior temporal sulcus, known as an important multisensory integration site, as well as the insula bilaterally and the precentral gyrus on the right side. Functional connectivity analysis revealed pronounced connectivity of the STS with the basal ganglia and thalamus as well as frontal motor regions for the congruent stimuli. This was not seen to the same extent for the incongruent stimuli.Conclusions: We conclude that sonification of movements amplifies the activity of the human action observation system including subcortical structures of the motor loop. Sonification may thus be an important method to enhance training and therapy effects in sports science and neurological rehabilitation.

26 September 2008 in Neurosurgical Review
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Journal Article
Closed access
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ASAmir Samii
Amir Samii
VGVenelin Gerganov
Venelin Gerganov
CHChristian Herold
Christian Herold
AGAlireza Gharabaghi
Alireza Gharabaghi
NHNakamasa Hayashi
Nakamasa Hayashi
MSMadjid Samii
Madjid Samii

9 March 2022 in Cancers
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Journal Article
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PRPeter Raab
Peter Raab
RBRouzbeh Banan
Rouzbeh Banan
AAArash Akbarian
Arash Akbarian
MEMajid Esmaeilzadeh
Majid Esmaeilzadeh
MSMadjid Samii
Madjid Samii
RBRoland Brüning
Roland Brüning
We conducted a two-center retrospective survey on standard MRI features including apparent diffusion coefficient mapping (ADC) of diffuse midline gliomas H3 K27M-mutant (DMG) compared to midline glioblastomas H3 K27M-wildtype (midGBM-H3wt). We identified 39 intracranial DMG and 18 midGBM-H3wt tumors. Samples were microscopically re-evaluated for microvascular proliferations and necrosis. Image analysis focused on location, peritumoral edema, degree of contrast enhancement and DWI features. Within DMG, MRI features between tumors with or without histomorphological GBM features were compared. DMG occurred in 15/39 samples from the thalamus (38%), in 23/39 samples from the brainstem (59%) and in 1/39 tumors involving primarily the cerebellum (2%). Edema was present in 3/39 DMG cases (8%) versus 78% in the control (midGBM-H3wt) group (p < 0.001). Contrast enhancement at the tumor rim was detected in 17/39 DMG (44%) versus 67% in control (p = 0.155), and necrosis in 24/39 (62%) versus 89% in control (p = 0.060). Strong contrast enhancement was observed in 15/39 DMG (38%) versus 56% in control (p = 0.262). Apparent diffusion coefficient (ADC) histogram analysis showed significantly higher skewness and kurtosis values in the DMG group compared to the controls (p = 0.0016/p = 0.002). Minimum relative ADC (rADC) values, as well as the 10th and 25th rADC-percentiles, were lower in DMGs with GBM features within the DMG group (p < 0.001/p = 0.012/p = 0.027). In conclusion, DMG cases exhibited markedly less edema than midGBM-H3wt, even if histomorphological malignancy was present. Histologically malignant DMGs and midGBM-H3wt more often displayed strong enhancement, as well as rim enhancement, than DMGs without histomorphological malignancy. DMGs showed higher skewness and kurtosis values on ADC-histogram analysis compared to midGBM-H3wt. Lower minimum rADC values in DMGs indicated malignant histomorphological features, likely representing a more complex tissue microstructure.

12 May 2020 in Neurological Research and Practice
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Journal Article
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BMBahram Mohammadi
Bahram Mohammadi
TMThomas F. Münte
Thomas F. Münte
DCDavid M. Cole
David M. Cole
ASAmir Samii
Amir Samii
MBMelanie Boltzmann
Melanie Boltzmann
JRJascha Rüsseler
Jascha Rüsseler
Background: About 6.2 million adults in Germany cannot read and write properly despite attending school for several years. They are considered to be functional illiterates (FI). Since the ability to read and write is crucial for being employed and socially accepted, we developed a special literacy training to overcome these deficits.Methods: In this study, we investigate training-related changes in intrinsic functional connectivity (iFC) at rest in a group of 20 FI and 20 adult normal readers using resting state functional magnetic resonance imaging (rsfMRI). We used independent component analysis (ICA) to define different networks.Results: Before training, the between group analysis showed increased iFC in FI in a left-fronto-parietal network (LFPN; anterior insula, medial frontal cortex, lateral and frontal parietal regions) and in the Basal Ganglia network (BGN: thalamus, caudate, putamen, pallidum, amygdala, supplementary motor cortex and cingulate gyrus). Furthermore, the Visual Network-1 (VN1; temporal occipital fusiform gyrus, lateral occipital cortex, occipital pole, lingual gyrus, thalamus) showed decreased iFC in FI. After training the FI group showed reversal of the “hyperconnectivity” in middle frontal gyrus and in the frontal orbital cortex and between supramarginal gyrus and the BGN. Furthermore, functional connectivity increased in FI VN1 (lateral occipital cortex, insular cortex). These changes in connectivity correlated with gains in reading speed and spelling accuracy.Conclusions: These findings show that poor reading and writing abilities are associated with abnormalities in iFC in several brain areas subserving cognitive processes important for reading. Intensive literacy training induces changes in the functional connectivity between and within neural networks important for literacy skills.


27 July 2026 in Molecular Biology Reports
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NTNele Teichmann
Nele Teichmann
SSSanthilal Subhash
Santhilal Subhash
MGMario Giordano
Mario Giordano
AAAshraqat Ahmed
Ashraqat Ahmed
RGRobert Geffers
Robert Geffers
SKSouvik Kar
Souvik Kar
Vestibular schwannoma (VS) is a benign tumor growing from Schwann cells of the vestibulocochlear nerve (cranial nerve VIII), accounting for 6–8% of brain tumors. Cystic vestibular schwannoma (cVS) represents 10% of VS cases and is characterized by unpredictable growth and worse surgical outcomes compared to solid VS (sVS). The molecular mechanisms underlying this aggressive phenotype remain poorly understood. In this context, long non-coding RNAs (lncRNAs) are gaining increased interest as biomarkers for early diagnosis and improved clinical management. lncRNAs are RNA molecules that are longer than 200 nucleotides. They are known to regulate gene transcription and participate in chromatin remodeling through various mechanisms. However, their role in cVS is largely unexplored. In this study, we identified cVS-associated lncRNAs using patient-derived samples. Whole transcriptome analysis via RNA sequencing revealed 65 differentially expressed lncRNAs and 308 protein-coding genes (PCGs) between cVS and sVS. From these, we selected the top eight lncRNAs (TENM3-AS1, ADIRF-AS1, PCA3, RP11-108K14.12, RP11-728F11.4, AC132217.4, RP11-43F13.3, and EGFLAM-AS1), each showing significant correlation with more than 20 differentially expressed PCGs. The upregulation of PCA3 and ADIRF-AS1, and the downregulation of EGFLAM-AS1 in cVS, were further validated using qRT-PCR. Here, by transcriptome-wide approach, we demonstrate that lncRNAs are prevalent in cVS disease and are likely to play critical roles in regulating important signaling pathways involved in disease pathogenesis. We believe, that detailed future investigations on this set of identified lncRNAs can provide useful insights into the biology and, ultimately, contribute to biomarker development for this neoplasm.