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L T Muftuler

Publications and source records attributed to L T Muftuler.

3 recordsLinked to original sources

FMRI study relevant to the Mozart effect: brain areas involved in spatial-temporal reasoning.

Behavioral studies, motivated by columnar cortical model predictions, have given evidence for music causally enhancing spatial-temporal reasoning. A wide range of behavioral experiments showed that listening to a Mozart Sonata (K.448) gave subsequent enhancements. An EEG coherence study gave evidence for a carryover from that Mozart Sonata listening condition to the subsequent spatial-temporal task in specific cortical regions. Here we present fMRI studies comparing cortical blood flow activation by the Mozart Sonata vs. other music. In addition to expected temporal cortex activation, we report dramatic statistically significant differences in activation by the Mozart Sonata (in comparison to Beethoven's Fur Elise and 1930s piano music) in dorsolateral pre-frontal cortex, occipital cortex and cerebellum, all expected to be important for spatial-temporal reasoning. It would be of great interest to explicitly test this expectation. We propose an fMRI study comparing (subject by subject) brain areas activated in music listening conditions and in spatial-temporal tasks.

Acoustic Stimulation↗

Improvement of temporal resolution in fMRI using slice phase encode reordered 3D EPI.

A magnetic resonance imaging (MRI) pulse sequence was developed for acquiring high temporal resolution 3D functional magnetic resonance images (fMRI). The technique uses a 3D-acquisition scheme that increases the SNR per unit time. Compared to the previously developed methods, the proposed one does not sacrifice the spatial resolution or require a reduction in the number of acquired slices. The method was tested on six control subjects using a well-known visual activation task. Statistical analysis of the acquired data showed significant activation in the primary visual cortex of each subject. The proposed acquisition method makes use of the periodicity of the applied stimulus. A given kz plane is scanned sequentially using a modified 3D EPI pulse sequence while the stimulus cycle (SC) is applied. The same SC is repeated for each acquisition of a new kz plane sequence. After data acquisition, temporal reordering is done on the data to obtain the proper 3D image sequence. Since the familiarization of the subject with the activation task is an important aspect that might affect the performance of the method, habituation of the primary visual cortex was tested by applying a similar visual stimulus and acquiring data using standard 2D Echo Planar Imaging (EPI). No habituation was observed within a duration of 7 min 12 sec.

Adult↗

Measurement of AC magnetic field distribution using magnetic resonance imaging.

Electric currents are applied to body in numerous applications in medicine such as electrical impedance tomography, cardiac defibrillation, electrocautery, and physiotherapy. If the magnetic field within a region is measured, the currents generating these fields can be calculated using the curl operator. In this study, magnetic fields generated within a phantom by currents passing through an external wire is measured using a magnetic resonance imaging (MRI) system. A pulse sequence that is originally designed for mapping static magnetic field inhomogeneity is adapted. AC current in the form of a burst sine wave is applied synchronously with the pulse sequence. The frequency of the applied current is in the audio range with an amplitude of 175-mA rms. It is shown that each voxel value of sequential images obtained by the proposed pulse sequence is modulated similar to a single tone broadband frequency modulated (FM) waveform with the ac magnetic field strength determining the modulation index. An algorithm is developed to calculate the ac magnetic field intensity at each voxel using the frequency spectrum of the voxel signal. Experimental results show that the proposed algorithm can be used to calculate ac magnetic field distribution within a conducting sample that is placed in an MRI system.

Algorithms↗