| Zugriffsnummer | 32464 |
| Dokumenttyp | Dissertation |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | High-frequency electroencephalography (hf-EEG): Non-invasive detection of spike-related brain activity |
| Autor(in); Institution |
Fedele, Tommaso; 8.2, Biosignale, PTB-Berlin; Elektrotechnik und Informatik, TU-Berlin, Berlin, GERMANY
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| Quelle/Jahr | (2014), 161 S. |
| Dissertationsvermerk | Dissertation, Technische Universität Berlin, 2014 |
| Persistent Identifier | |
| Verlag | Berlin: |
| Zusammenfassung | Brain dynamics generate electric fields, whose projections can be recorded at the Level of the scalp. Electroencephalography (EEG), given its low-cost, portability, and millisecond range temporal resolution, is the more widespread non-invasive technology in use for the investigation and the monitoring of neurophysiological activity. The complex ensemble of ongoing neural electro-chemical interactions relies on action potentials propagation and synaptic transmission in a variety of cortical and subcortical structures. Spatial extension and temporal synchronization of these events define their non-invasive detectability, quantified in terms of Signal-to-Noise Ratio (SNR). In particular, slower potentials belong to larger neural substrates, and express higher SNR, while faster Events are more localized and often buried by noise. For this reason, standard EEG recordings ((100 Hz) mainly reflects mass post-synaptic potentials, which are the input of the neural networks processing, but generally miss correlated spiking activity, representing the net computational output. Recent intracranial EEG recordings revealed that frequencies above 100 Hz convey signals highly informative for application scenarios as movement decoding for BCI, dissociating spatial attention from movement preparation in Motor cortex, and focus localization in neocortical epilepsy. While such novel neurophysiological concepts are advancing rapidly, they are compromised by a progressively decreasing SNR for higher frequencies. Nevertheless, it was shown that bursts in the range of 600 Hz, mimicking spiking activity, can be isolated in somatosensory evoked potential (SEP) non-invasive recordings in healthy humans by means of median nerve stimulation. These fast oscillatory patterns represent an excellent workhorse for the improvement of non-invasive detection of human high-frequency EEG. The aim of this thesis is to analyze the factors hindering the high-frequency neural signatures, systematically breaking down their contribution along the measurement system chain, from the sensor applied to the scalp to the recording system requirements. The detection and characterization of high-frequency EEG components will be pursued by integrating the physiological paradigm of 600 Hz SEP bursts with the recent progress in low-noise amplifier technology, and multivariate data analysis of scalp potential distribution, in order to achieve a novel integrated neurotechnology for the noninvasive monitoring of cortical population spikes. |
