Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on July 17, 2009. Major professor: Dr. Robert Szlavik. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degrees [of] Master of Science in Engineering, with specialization in Biomedical Engineering, Bachelor's of Science in Electrical Engineering." "June 2009." Includes bibliographical references (p. 22).

Thesis (Ph.D.)--Biomedical Engineering, Georgia Institute of Technology, 2007. / Committee Chair: Potter, Steve; Committee Member: Butera, Robert; Committee Member: DeWeerth, Stephen; Committee Member: Schumacher, Eric; Committee Member: Wenner, Pete.

Thesis (M.A.)--Ball State University, 2009. / Title from PDF t.p. (viewed on July 12, 2010). Research paper (M.A.), 3 hrs. Includes bibliographical references (p. 42-43).

Wing-Keung Sim. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 109-114). / Abstracts in English and Chinese. / Abstract --- p.2 / 摘要 --- p.3 / Acknowledgements --- p.4 / Contents --- p.5 / List of Figures --- p.8 / List of Tables --- p.9 / Introductions --- p.10 / Chapter 1.1 --- Motivation & Aims --- p.10 / Chapter 1.2 --- Contributions --- p.11 / Chapter 1.3 --- Structure of Thesis --- p.11 / Electrophysiological Spike Discrimination --- p.13 / Chapter 2.1 --- Introduction --- p.13 / Chapter 2.2 --- Cellular Physiology --- p.13 / Chapter 2.2.1 --- Action Potential --- p.13 / Chapter 2.2.2 --- Recording of Spikes Activities --- p.15 / Chapter 2.2.3 --- Demultiplexing of Multi-Neuron Recordings --- p.17 / Chapter 2.3 --- Application of Clustering for Mixed Spikes Train Separation --- p.17 / Chapter 2.3.1 --- Design Principles for Spike Discrimination Procedures --- p.17 / Chapter 2.3.2 --- Clustering Analysis --- p.18 / Chapter 2.3.3 --- Comparison of Clustering Techniques --- p.19 / Chapter 2.4 --- Literature Review --- p.19 / Chapter 2.4.1 --- Template Spike Matching --- p.19 / Chapter 2.4.2 --- Reduced Feature Matching --- p.20 / Chapter 2.4.3 --- Artificial Neural Networks --- p.21 / Chapter 2.4.4 --- Hardware Implementation --- p.21 / Chapter 2.5 --- Summary --- p.22 / Correlation of Perceived Headphone Sound Quality with Physical Parameters --- p.23 / Chapter 3.1 --- Introduction --- p.23 / Chapter 3.2 --- Sound Quality Evaluation --- p.23 / Chapter 3.3 --- Headphone Characterization --- p.26 / Chapter 3.3.1 --- Frequency Response --- p.26 / Chapter 3.3.2 --- Harmonic Distortion --- p.26 / Chapter 3.3.3 --- Voice-Coil Driver Parameters --- p.27 / Chapter 3.4 --- Statistical Correlation Measurement --- p.29 / Chapter 3.4.1 --- Correlation Coefficient --- p.29 / Chapter 3.4.2 --- t Test for Correlation Coefficients --- p.30 / Chapter 3.5 --- Summary --- p.31 / Algorithms --- p.32 / Chapter 4.1 --- Introduction --- p.32 / Chapter 4.2 --- Principal Component Analysis --- p.32 / Chapter 4.2.1 --- Dimensionality Reduction --- p.32 / Chapter 4.2.2 --- PCA Transformation --- p.33 / Chapter 4.2.3 --- PCA Implementation --- p.36 / Chapter 4.3 --- Traditional Clustering Methods --- p.37 / Chapter 4.3.1 --- Online Template Matching (TM) --- p.37 / Chapter 4.3.2 --- Online Template Matching Implementation --- p.40 / Chapter 4.3.3 --- K-Means Clustering --- p.41 / Chapter 4.3.4 --- K-Means Clustering Implementation --- p.44 / Chapter 4.4 --- Unsupervised Neural Learning --- p.45 / Chapter 4.4.1 --- Neural Network Basics --- p.45 / Chapter 4.4.2 --- Artificial Neural Network Model --- p.46 / Chapter 4.4.3 --- Simple Competitive Learning (SCL) --- p.47 / Chapter 4.4.4 --- SCL Implementation --- p.49 / Chapter 4.4.5 --- Adaptive Resonance Theory Network (ART). --- p.50 / Chapter 4.4.6 --- ART2 Implementation --- p.53 / Chapter 4.6 --- Summary --- p.55 / Experimental Design --- p.57 / Chapter 5.1 --- Introduction --- p.57 / Chapter 5.2 --- Electrophysiological Spike Discrimination --- p.57 / Chapter 5.2.1 --- Experimental Design --- p.57 / Chapter 5.2.2 --- Extracellular Recordings --- p.58 / Chapter 5.2.3 --- PCA Feature Extraction --- p.59 / Chapter 5.2.4 --- Clustering Analysis --- p.59 / Chapter 5.3 --- Correlation of Headphone Sound Quality with physical Parameters --- p.61 / Chapter 5.3.1 --- Experimental Design --- p.61 / Chapter 5.3.2 --- Frequency Response Clustering --- p.62 / Chapter 5.3.3 --- Additional Parameters Measurement --- p.68 / Chapter 5.3.4 --- Listening Tests --- p.68 / Chapter 5.3.5 --- Confirmation Test --- p.69 / Chapter 5.4 --- Summary --- p.70 / Results --- p.71 / Chapter 6.1 --- Introduction --- p.71 / Chapter 6.2 --- Electrophysiological Spike Discrimination: A Comparison of Methods --- p.71 / Chapter 6.2.1 --- Clustering Labeled Spike Data --- p.72 / Chapter 6.2.2 --- Clustering of Unlabeled Data --- p.78 / Chapter 6.2.3 --- Remarks --- p.84 / Chapter 6.3 --- Headphone Sound Quality Control --- p.89 / Chapter 6.3.1 --- Headphones Frequency Response Clustering --- p.89 / Chapter 6.3.2 --- Listening Tests --- p.90 / Chapter 6.3.3 --- Correlation with Measured Parameters --- p.90 / Chapter 6.3.4 --- Confirmation Listening Test --- p.92 / Chapter 6.4 --- Summary --- p.93 / Conclusions --- p.97 / Chapter 7.1 --- Future Work --- p.98 / Chapter 7.1.1 --- Clustering Analysis --- p.98 / Chapter 7.1.2 --- Potential Applications of Clustering Analysis --- p.99 / Chapter 7.2 --- Closing Remarks --- p.100 / Appendix --- p.101 / Chapter A.1 --- Tables of Experimental Results: (Spike Discrimination) --- p.101 / Chapter A.2 --- Tables of Experimental Results: (Headphones Measurement) --- p.104 / Bibliography --- p.109 / Publications --- p.114

Extracellular potentials due to firing of action potentials are computed around cortical neurons and populations of cortical neurons. These extracellular potentials are calculated as a sum of contributions from ionic currents passing through the cell membrane at various locations using Maxwell's equations in the quasi-static limit. These transmembrane currents are found from simulations of anatomically reconstructed cortical neurons implemented as multi-compartmental models in the simulation tool NEURON. Extracellular signatures of action potentials of single neurons are calculated both in the immediate vicinity of the neuron somas and along vertical axes. For the neuronal populations only vertical axis distributions are considered. The vertical-axis calculations were performed to investigate the contributions of action potential firing to laminar-electrode recordings. Results for high-pass (750 - 3000 Hz) filtered potentials are also given to mimic multi-unit activity (MUA) recordings. Extracellular traces from single neurons and populations (both synchronous and asynchronous) of neurons are shown for three different neuron types: layer 3 pyramid, layer 4 stellate and layer 5 pyramid cell. The layer 3 cell shows a 'closed-field' configuration, while the layer 5 pyramid demonstrates an 'open-field' appearance for singe neuron simulations which is less apparent in population simulations. The layer 4 stellate cell seems to fall somewhere in between the open- and closed-field scenarios. Comparing single neuron and synchronous populations, the amplitudes of the extracellular traces increase as population radii increase, though the shapes are generally similar. Asynchronous populations produce small amplitudes due to a time convolution of various neuron contributions. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005

Thesis--Copenhagen University. / Summary in Danish. Bibliography: p. 153-161.

The electrophysiological properties of dentate granule cells and hippocampal pyramidal neurons were examined with extracellular and intracellular recording techniques in the hippocampal slice. Intracellular analysis revealed that there may exist two populations of granule cells distinguishable by the presence or absence of non-linear current-voltage (I-V) membrane properties (anomalous rectification, AR). The granule cells exhibiting AR also maintained greater resting membrane potentials and action potential (AP) amplitude values. The membrane input resistance (Rn) and time constant (Tc) measurements were similar between the populations in response to hyperpolarizing current injection, but granule cells displaying AR had significantly higher Rn and Tc values in response to depolarizing pulses. Both groups also responded to maintained depolarizing current injection with repetitive AP discharges; however, this response accommodated. Upon termination of the depolarizing current injection, an afterhyperpolarization (AHP) resulted, the amplitude of which appeared to depend on the duration of the depolarizing pulse and not on the number of APs generated during the pulse. Stimulation of either the lateral (LPP) or medial (MPP) perforant paths evoked a monosynaptic EPSP followed by a depolarizing afterpotential (DAP) and a long afterhyperpolarization (LHP). In contrast, antidromic stimulation elicited a depolarizing-IPSP (D-IPSP) and a LHP. Both the DAP and D-IPSP were reversed by membrane depolarization, whereas, the LHP was inverted by membrane hyperpolarization. In all cases, however, the EPSP could not be inverted. Afterpotentials were associated with an increase in conductance, but the change accompanying the LHP was less than the DAP and D-IPSP. In addition, by reducing the [Ca]₀ and increasing the [Mg]₀, the DAP was attenuated and the LHP eliminated. Similar results were also obtained with the GABAB agonist, baclofen. Paired pulse stimulation of either the LPP or MPP resulted in the potentiation of the intracellular EPSP at condition-test (C-T) intervals less than 100 ms; however, simultaneous extracellular records from the granule cell layer (GCL) illustrated depression of the EPSP. The discrepancy between the extra- and intracellular recordings was shown to be related to the presence of the DAP. In addition, the MPP evoked test EPSP at C-T intervals greater than 150 ms exhibited inhibition regardless of whether it was recorded inside or outside the granule cell and this EPSP depression was partially due to the granule cell LHP. The LPP evoked test EPSP potentiated at all C-T intervals less than 1s when recorded from the outer molecular layer (OML) but was inhibited at both the GCL and intracellular recording sites. These data confirmed that postsynaptic processes contribute to the short-term alterations observed with paired pulse stimulation. The typical inhibition-potentiation-inhibition sequence of the perforant path (PP) evoked population spike (PS) was noted at C-T intervals of 20, 80 and 400 ms, respectively. The inhibition of the PS at 20 ms was abolished with perfusion of the GABA antagonist, bicuculline. In contrast, the PS inhibition at 400ms was unaffected by this treatment but was slightly attenuated by the gKca antagonist TEA. A number of factors appeared to contribute to the potentiation of the PS: 1) reduction in AP threshold; 2) the presence of the DAP; and 3) extrasynaptic events. In addition to the PS data from normal tissue, hippocampal slices from chronically kindled rats exhibited depression of the PS at all C-T intervals tested. This augmentation of inhibition was dependent on the presence of hippocampal afterdischarges but not on motor seizures. Perfusing the kindled slices with either bicuculline or lowered [Cl]₀ did not markedly reverse the enhanced inhibition at C-T intervals which displayed dramatic facilitation in normal slices. Intracellular recordings of granule cells obtained from kindled slices also exhibited an increase in the Rn and Tc. Both the alterations in inhibition and membrane characteristics appear to be localized to.the granule cells, since these changes were not observed in CA1 pyramidal neurons. These data indicate that short-term and long-term alterations in granule cell neuronal excitability are partially due to changes in the postsynaptic membrane. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Includes bibliographies. / by Binseng Wang. / Sc.D.

What changes in our brain when we learn? This is perhaps the most intriguing question of science in this century. In an attempt to learn more about the inner workings of neural circuitry, I studied cultured 2-dimensional networks of neurons on multi-electrode arrays (MEAs). MEAs are ideal tools for studying long-term neural ensemble activity because many individual cells can be studied continuously for months, through electrical stimulation and recording. One of the most prominent patterns of activity observed in these cultures is network-wide spontaneous bursting, during which most of the active electrodes in the culture show elevated firing rates. We view the persistence of spontaneous bursting in vitro as a sign of arrested development due to deafferentation. Substituting distributed electrical stimulation for afferent input transformed the activity in dissociated cultures from bursting to more dispersed spiking, reminiscent of activity in the adult brain. Burst suppression reduced the variability in neural responses making it easier to induce and detect functional plasticity caused by tetanic stimulation. This suggests that spontaneous bursts interfere with the effects of external stimulation and that a burst-free environment leads to more stable connections and predictable effects of tetanization. Moreover, our culture models continuously receive input stimulation in the form of background electrical stimulation, and so better resemble the intact brain than isolated (non-continuously stimulated) cultures. The proportion of GABAergic neurons in the cultures was significantly increased (p<1e-2, paired t-test) after burst-quieting for 2 days, suggesting that burst suppression operated through the homeostatic control of inhibitory neurotransmitter levels. We also studied the role of spontaneous bursts as potential carriers of information in the network by clustering these spatiotemporally diverse bursts. Spontaneous burst clusters were stable over hours and tetanic stimulation significantly reorganized the distribution of the clusters. In summary, this body of work explores the rules of network-level functional plasticity and provides the input (electrical stimulation) output (spatiotemporal patterns) mappings for behavioral studies in embodied hybrid systems. The results of this study may also have clinical implications in the development of sensory prostheses and treatment of diseases of aberrant network activity such as epilepsy.

Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Steve M. Potter; Committee Member: Eric Schumacher; Committee Member: Robert J. Butera; Committee Member: Stephan P. DeWeerth; Committee Member: Thomas D. DeMarse.