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Title: Mechanism of taurine as a neuroprotector.
Creator: Wu, Heng, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: Taurine is one of the most abundant amino acids in mammals and several functions of taurine have been reported. One important function of taurine is its neuroprotection against the glutamate-induced neuronal damage. It was shown that the glutamate-induced neurotoxicity is caused by overexcitation of glutamate receptors and intracellular calcium, [Ca2+]i, elevation. In this dissertation, the mechanism underlying the action of taurine as a neuroprotector was investigated. It was found that...
Show moreTaurine is one of the most abundant amino acids in mammals and several functions of taurine have been reported. One important function of taurine is its neuroprotection against the glutamate-induced neuronal damage. It was shown that the glutamate-induced neurotoxicity is caused by overexcitation of glutamate receptors and intracellular calcium, [Ca2+]i, elevation. In this dissertation, the mechanism underlying the action of taurine as a neuroprotector was investigated. It was found that taurine protected neurons against glutamate or Bay K 8644-induced neurotoxicity only at the concentration that inhibits the calcium influx induced by those two compounds. Furthermore, taurine couldn't protect neurons against sodium nitroprusside, a NO free radical donor, induced neurotoxicity. These results indicate that taurine exerts its neuroprotection by reducing the glutamate-induced [Ca2+]i elevation. Besides necrosis, apoptosis is another major way that glutamate induces neuronal cell death. The effect of taurine on the glutamate-induced apoptosis was investigated. It was found that taurine prevented the glutamate-induced DNA fragmentation, indicating taurine prevents the glutamate-induced apoptosis. We found that anti-apoptotic proteins (BCL-2 and BCL-X) were down-regulated by glutamate treatment and this down-regulation was prevented by taurine. No difference in pro-apoptotic proteins (BAX and BAD) was found. It was found that the down-regulation of BCL-2 and BCL-X was through calpain-mediated proteolysis, and taurine may exert its anti-apoptotic function by preventing the activation of calpain, which is due to the prevention of [Ca2+]i elevation. Furthermore, it was found that pre-treatment with taurine inhibited the glutamate-induced calcium influx through L-, P/Q-, N-type voltage-gated calcium channels and NMDA receptor. Surprisingly, taurine had no effect on calcium influx through the NMDA receptor when neurons were treated with NMDA in Mg 2+-free medium. The effect of taurine is unlikely through GABA A, or glycine receptors, since bicuculline and picrotoxin (GABA A receptor antagonists), and strychnine (glycine receptor antagonist), failed to block taurine's inhibitory effect on the glutamate-induced calcium influx. Since taurine was found to prevent the glutamate-induced membrane depolarization, we propose that taurine protects neurons against the glutamate excitotoxicity by preventing the glutamate-induced membrane depolarization, probably through the opening of chloride channels, therefore preventing the glutamate-induced calcium influx and the downstream events.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12183
Subject Headings: Biology, Neuroscience
Format: Document (PDF)

Title: Instability and pattern formation in the human brain during complex sensorimotor and auditory tasks as revealed by magnetoencephalography.
Creator: Holroyd, Tom, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: Following Kelso et al. (1991a; 1992), Wallenstein et al. (1995), Tuller et al. (1994), and Case et al. (1995); see also Fuchs et al. (1992), the experiments described in this research all used a dynamical methodology designed to produce a coherent brain state and then lead that brain state through a spontaneous reorganization via the influence of a parametric change. Magnetoencephalographic (MEG) recordings made during the spontaneous behavioral and perceptual transitions were analyzed by...
Show moreFollowing Kelso et al. (1991a; 1992), Wallenstein et al. (1995), Tuller et al. (1994), and Case et al. (1995); see also Fuchs et al. (1992), the experiments described in this research all used a dynamical methodology designed to produce a coherent brain state and then lead that brain state through a spontaneous reorganization via the influence of a parametric change. Magnetoencephalographic (MEG) recordings made during the spontaneous behavioral and perceptual transitions were analyzed by decomposition of the brain's high-dimensional magnetic field into a few task-relevant components. The analysis showed that the dynamics of the MEG signal, including the reorganization which occured as a result of the parametric manipulation, could be accounted for by the dynamics of the individual components. This supports the idea that the task requirements in each case placed the brain into a (relatively) low-dimensional state through the cooperative interactions among the many neuronal elements involved in the task. The experiments included two coordination experiments in which subjects were required to produce index finger flexions in time to an auditory metronome in an anti-phase pattern while the metronome rate was increased. Increases in the variability of both the behavior and the motor-associated magnetic field components prior to the transition to an in-phase pattern support the hypothesis that a dynamic instability mechanism exists for pattern formation and change during those tasks. In the third experiment a perceptual instability was explored by systematically scaling a parameter known to influence categorization of speech stimuli: biasing the transition created stimuli that were perceived in two different ways. The design of the experiment allowed the investigation of neural correlates of the physical properties of the stimuli, perceptual invariance, bistability, and perceptual reorganization. Analysis of the MEG signals suggests that presentation of a bistable stimulus places the brain into a highly sensitive, unstable state that can be influenced by ongoing activity.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/12522
Subject Headings: Biology, Neuroscience
Format: Document (PDF)

Title: Dynamics of human sensorimotor coordination: From behavior to brain activity.
Creator: Chen, Yanqing, Florida Atlantic University, Ding, Mingzhou, Kelso, J. A. Scott
Abstract/Description: The dynamics of human sensorimotor coordination are studied at behavioral and neural levels through temporal synchronization and syncopation tasks. In experiment 1, subjects synchronized their finger movements (in-phase) with a metronome at 2.0Hz and 1.25Hz for 1200 cycles. Fluctuations of timing errors were analyzed through correlation, power spectrum analyses and Maximum Likelihood Estimation (MLE). Results indicated that the synchronization error time series was characterized by a 1/falpha...
Show moreThe dynamics of human sensorimotor coordination are studied at behavioral and neural levels through temporal synchronization and syncopation tasks. In experiment 1, subjects synchronized their finger movements (in-phase) with a metronome at 2.0Hz and 1.25Hz for 1200 cycles. Fluctuations of timing errors were analyzed through correlation, power spectrum analyses and Maximum Likelihood Estimation (MLE). Results indicated that the synchronization error time series was characterized by a 1/falpha type of long memory process with alpha = 0.5. Previous timing models based upon motor program or simple "central clock" ideas were reviewed to show that they could not explain such long range correlations in the synchronization task. To explore the possible cognitive origins of long range correlation, experiment 2 required subjects to synchronize (on the beat) or syncopate (off the beat) to a metronome at 1Hz using different cognitive strategies. Timing fluctuations were again found to be 1/f alpha type, with alpha = 0.5 in synchronization and alpha = 0.8 in syncopation. When subjects employed a synchronization strategy to successfully syncopate, timing fluctuations shifted toward 1/f 0.5 type. This experiment indicated that the scaling exponent in timing fluctuations was related to task requirements and specific coordination strategies. Further, they suggest that the sources of such long memory originated from higher level cognitive processing in the human brain. Experiment 3 analyzed magnetoencephalography (MEG) data associated with synchronization and syncopation tasks. Brain oscillations at alpha (8--14Hz), beta (15--20Hz) and gamma (35--40Hz) frequency ranges were shown to correlate with different aspects of the coordination behavior. Specifically, through power and coherence analyses, alpha activity was linked to sensorimotor integration and "binding", beta activity was related to task requirements (synchronization or syncopation), and gamma activity was related to movement kinematics (trajectory). These results supported the idea that the 1/f alpha type of timing fluctuations originated from collective neural activities in the brain acting on multiple time scales.
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Date Issued: 2000
PURL: http://purl.flvc.org/fcla/dt/12649
Subject Headings: Sensorimotor integration, Cognitive neuroscience
Format: Document (PDF)

Title: Molecular and cellular events associated with damage to rat retinal ganglion cells: Effects of brain-derived neurotrophic factor on fast axonal transport and neuronal apoptosis.
Creator: Wodarczyk, Linda, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: The survival of rat retinal ganglion cells (RGCs) after axotomy has been shown to be enhanced by Brain Derived Neurotrophic Factor (BDNF). It was, therefore, of interest to determine whether previously observed changes in the differential regulation of fast axonally transported proteins (FTPs) occur in rat RGCs during the early response to axotomy or whether such changes are obviated by the action of BDNF at the cell body level. It was of further interest to determine whether these...
Show moreThe survival of rat retinal ganglion cells (RGCs) after axotomy has been shown to be enhanced by Brain Derived Neurotrophic Factor (BDNF). It was, therefore, of interest to determine whether previously observed changes in the differential regulation of fast axonally transported proteins (FTPs) occur in rat RGCs during the early response to axotomy or whether such changes are obviated by the action of BDNF at the cell body level. It was of further interest to determine whether these regeneration-associated changes are sustained during the period of BDNF-enhanced cell survival. It was found that, within 2 days of injury and BDNF injection, rat RGCs initiate a growth-like cellular response that includes the differential synthesis and transport of the same profile of FTPs found to be induced in axotomized animals following injection of a saline control solution. Thus, supplementation of rat RGCs with BDNF does not obviate the changes required to reinstate active cellular regrowth. It is, therefore, unlikely that the loss of a trophic factor, such as BDNF, is the signal for axotomy-induced changes. Although a single injection of BDNF at the time of injury prolongs cell survival to at least 5 days, it is not sufficient to sustain the elevation in FTPs. This result indicates that the regulatory mechanisms that promote cell growth are distinct and separate from those that promote cell survival. This study extended beyond the above findings to affirm that apoptosis of axotomized rat RGCs is mediated by the activation of the cysteine protease, caspase-3. Such activation was demonstrated within 12 hours of axotomy and appeared to become increasingly prevalent in a central to peripheral gradient, as might be anticipated by the loss of glial derived neurotrophic support. Such activation was completely prevented by intraocular injection of BDNF, indicating that BDNF acts upstream of caspase-3 to prevent the proteolytic cascade that leads to apoptosis.
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Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/12586
Subject Headings: Biology, Neuroscience, Biology, Cell
Format: Document (PDF)

Title: Neural substrates of movement and music: An fMRI approach.
Creator: Nair, Dinesh G., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: In this dissertation, we examined the neural correlates of motor coordination and music perception using a set of four fMRI experiments. The neural correlates of goal-directed action were examined in a group of healthy adults in experiment I using execution and imagery of a unimanual and a bimanual finger-sequencing task. Similar neural networks were engaged for execution and imagination of movement sequences. Interestingly, we also found that the sensorimotor cortical and cerebellar areas...
Show moreIn this dissertation, we examined the neural correlates of motor coordination and music perception using a set of four fMRI experiments. The neural correlates of goal-directed action were examined in a group of healthy adults in experiment I using execution and imagery of a unimanual and a bimanual finger-sequencing task. Similar neural networks were engaged for execution and imagination of movement sequences. Interestingly, we also found that the sensorimotor cortical and cerebellar areas are functionally decoupled from the task network when people imagine but do not actually execute sequential actions. In experiment 2, we used the same finger-sequencing paradigm to study recovery of function during recovery from stroke. It was observed that the wide spread neural activity during the initial session became more localized during the last session. In addition, using imagery tasks, we showed that hemiplegic patients retained the ability to activate neural pathways that are normally involved in executing goal-directed action sequences, despite the loss of ability to actually execute movements. In experiment 3, we examined brain activity when musicians and non-musicians listened to expressive and mechanical versions of a musical piece. The expressive performance activated the limbic areas more than the mechanical version in both groups of subjects suggesting perception of affect. The pattern of neural activity was also dictated by their experience and familiarity with the piece of music. In addition, we found activation of language related areas when musicians listened to the expressive version suggesting shared neural resources for language and music. The neural basis of sensorimotor coordination and timing in Parkinson's disease was investigated in the last experiment, using a synchronization-syncopation task and the continuation paradigm. Different neural areas subserved timing during the two different modes of coordination. However, these differences persisted during their respective continuation phases. In order to compensate for the functional deficiency in Parkinson's disease, patients recruited functionally segregated circuits that connect the striatum and association areas of the parietal, premotor and prefrontal cortices.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/12082
Subject Headings: Biology, Neuroscience, Psychology, Cognitive
Format: Document (PDF)

Title: Regulation of L-glutamic acid decarboxylase by post-translational modifications.
Creator: Sha, Di, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: In the central nervous system (CNS), the rate-limiting step in GABA synthesis is the reaction catalyzed by L-glutamic acid decarboxylase (GAD). Alternations in the level of GABA or GAD have been linked to various neurological disorders. Mammalian species express two isoforms of GAD, namely, GAD65 and GAD67, referring to GAD with a molecular weight of 65 kDa and 67 kDa, respectively. Numerous studies have been done to elucidate the mechanisms that control the regulation of GAD at the level of...
Show moreIn the central nervous system (CNS), the rate-limiting step in GABA synthesis is the reaction catalyzed by L-glutamic acid decarboxylase (GAD). Alternations in the level of GABA or GAD have been linked to various neurological disorders. Mammalian species express two isoforms of GAD, namely, GAD65 and GAD67, referring to GAD with a molecular weight of 65 kDa and 67 kDa, respectively. Numerous studies have been done to elucidate the mechanisms that control the regulation of GAD at the level of gene expression, protein synthesis, saturation of co-factor, pyridoxal 5'-phosphate (PLP), and post-translational modification. Our previous studies had demonstrated the presence of the truncated form of human brain L-glutamic decarboxylase 65 (tGAD65) in vivo as well as in vitro and found that tGAD65 was more active than the full-length GAD65 (fGAD65). In addition, the recombinant human brain GAD67 has been found to be specifically cleaved at two specific sites, one at arginine 70 and another at arginine 90, to produce two truncated forms of GAD 67 (tGAD67). It seems that the formation of tGAD is catalyzed by specific proteases instead of a random degradation. Furthermore, it has been found that GAD65 is regulated by the Ca2+-free form of calmodulin (apoCaM). My research focus is to elucidate the regulation of GABA biosynthesis through regulation of its synthesizing enzyme, especially GAD67, by protein phosphorylation, proteolytic cleavage and apoCaM. Experiments presented here have been conducted to demonstrate the molecular cloning, expression, and purification of human brain tGAD67. The purified protein was further characterized by kinetic studies and phosphorylation studies. Truncated forms of hGAD67 were much less active than the full-length form. Both truncated enzymes are also phosphorylated by protein kinase A (PKA) as is full-length hGAD67. A deletion of 1-70 aa from the N-terminal results in additional protein kinase C (PKC) phosphorylation. Several phosphopeptides and possible phosphorylation sites are suggested by matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis. Furthermore, evidence of mu-calpain, not m-calpain, as the protease responsible for GAD cleavage in vivo as well as in vitro is presented. In addition, evidence on the effect of ApoCaM on GAD67 activity, phosphporylation and proteolytic cleavage by mu-calpain is discussed. Finally, an overall model of GAD regulation by a variety of mechanisms including protein phosphorylation, mu-calpain proteolytic cleavage and apoCaM is proposed.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12170
Subject Headings: Biology, Neuroscience, Chemistry, Biochemistry
Format: Document (PDF)

Title: Spatiotemporal dynamics of the human brain associated with transitions in coordination timing.
Creator: Wallenstein, Gene Vincent, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: Recent studies have demonstrated that the strategy an individual uses to synchronize motor behavior (e.g. finger flexions) with externally delivered, periodic stimuli depends, in part, on the stimulus presentation rate (Mates, Muller, Radil, and Poppel, 1994; Engstrom, Kelso, and Holroyd, 1995). At rates slower than approximately 0.5 Hz, subjects typically exhibit a reactive-type coordination pattern where the response follows the stimulus by an order of magnitude consistent with typical...
Show moreRecent studies have demonstrated that the strategy an individual uses to synchronize motor behavior (e.g. finger flexions) with externally delivered, periodic stimuli depends, in part, on the stimulus presentation rate (Mates, Muller, Radil, and Poppel, 1994; Engstrom, Kelso, and Holroyd, 1995). At rates slower than approximately 0.5 Hz, subjects typically exhibit a reactive-type coordination pattern where the response follows the stimulus by an order of magnitude consistent with typical response times (i.e. 150-250 milliseconds). At faster rates, however, subjects typically anticipate the impending stimulus in order to synchronize movement with it. In the present study, scalp electroencephalographic (EEG) signals (61 channels) were recorded during a sensorimotor task designed to investigate transitions from one coordination mode to another. We found that subjects exhibited a spontaneous transition from reactive to anticipatory behavior as the stimulus presentation rate increased past some critical frequency. A spatiotemporal analysis of the EEG signals accompanying this task revealed: (1) a widespread frequency component in the EEG matching that of both the stimulus and movement; (2) peak spectral power density over central and antero-central regions in both men and women during reactive behavior; (3) an additional bilaterally distributed frontal component at the most anterior portion of the scalp in men during anticipatory behavior; (4) an additional left fronto-central component which extended posteriorly toward antero-central regions in women during anticipatory behavior; (5) fluctuation enhancement in both the EEG spectral power density and the time lag ($\tau$) between the movement and stimulus accompanying the transition from reactive to anticipatory behavior; (6) that the spectral power density patterns obtained in the primary experimental condition (REACTIVE) were more similar in terms of their spatial distribution with a control condition in which subjects were asked to produce rhythmic movements without benefit of an external stimulus (MOTOR-ONLY) than with a control condition in which subjects passively watched a periodic visual stimulus (STIMULUS-ONLY); (7) that the spectral power density patterns obtained during reactive behavior in the primary experimental condition were more similar spatially to the MOTOR-ONLY condition than du ring anticipatory behavior; and finally (8) that the spectral power density patterns obtained during the experimental condition are not completely accounted for in terms of purely motor- or stimulus-related components. These results are discussed within a common framework of pattern formation instigated by dynamic instabilities in the human brain and behavior.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/12436
Subject Headings: Biology, Neuroscience, Psychology, Psychobiology
Format: Document (PDF)

Title: Statistical analysis of dynamic interdependence patterns in the cortex.
Creator: Truccolo-Filho, Wilson A., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: This dissertation is an investigation of the sources of commonly observed event-related transients in statistical measures of interdependence: variance, cross-correlation, power spectrum density and coherence spectrum density time functions. These measures are often employed in the analysis of spatio-temporal interdependence patterns in neural activity. In order to understand the phenomenon, the origins of the variability of event-related responses are revisited. The time series of single...
Show moreThis dissertation is an investigation of the sources of commonly observed event-related transients in statistical measures of interdependence: variance, cross-correlation, power spectrum density and coherence spectrum density time functions. These measures are often employed in the analysis of spatio-temporal interdependence patterns in neural activity. In order to understand the phenomenon, the origins of the variability of event-related responses are revisited. The time series of single trial cortical event-related potentials typically have a random appearance, and their trial-to-trial variability is commonly explained by the classic signal-plus-noise model, in which random ongoing background noise activity is linearly combined with a stereotyped evoked response. Here, we demonstrate that more realistic models, challenging both the linear superposition and the trial-to-trial stationarity of the event-related responses, can account for such event-related transients. In particular, two effects are considered: the nonlinear gain modulation in neural networks coupled through sigmoid functions and the trial-to-trial variability in amplitude and latency of the event phase-locked responses. An extensive analysis and characterization of both effects in interdependence measures is carried out through both analytical and numerical simulations in Chapter 2. Chapter 3 presents the outcome of testing the predicted effects on UP data recorded from implanted intracortical electrodes in monkeys performing a visuo-motor pattern discrimination task. Overall, the results point to a large contribution of the trial-to-trial variability of event phase-locked responses on the observed event-related transient in statistical interdependence measures. Because variability of the event-related responses is commonly ignored, event-related modulations in power spectral density, cross-correlation, and spectral coherence are often attributed to dynamic changes in functional connectivity within and among neural populations. It becomes then crucial the separation or removal of the trial-to-trial amplitude and latency variability effect from the statistical measures. In order to achieve this goal, the reconstruction of the single trial event phase-locked potentials is required. In Chapter 4, we approach this problem from a Bayesian inference perspective. The posterior probability density is derived for a specified number of event phase-locked components using data from single or multiple sensors. The Maximum A Posteriori solution is used to obtain the phase-locked component waveforms and their single trial parameters. The outcome is a further and definitive support for predominance of the effect of the nonstationarity of the phase-locked responses on the statistical quantities. Based on the theoretical and experimental analysis conducted in Chapters 2, 3 and 4, a framework for the statistical analysis of dynamic spatio-temporal interdependence patterns in Local Field Potential data is articulated.
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Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/11975
Subject Headings: Biology, Biostatistics, Biology, Neuroscience
Format: Document (PDF)

Title: Devising a novel protocol to study 5-hydroxymethylcytosine's role in the consolidation of a methamphatamine [sic] associated contextual memory.
Creator: Odom, John David., Harriet L. Wilkes Honors College
Abstract/Description: DNA methylation, the addition of a methyl group to the 5' position of DNA cytosines (5mC), is generally associated with transcriptional repression during early embryo formation ; however, in the adult brain, it is dynamically regulated and plays an important role in the formation and maintenance of memory. Very recently, it has been hypothesized that DNA hydroxymethylation, the addition of a hydroxyl group to methylated cytosines (5mC), serves as an intermediate in the DNA demethylation...
Show moreDNA methylation, the addition of a methyl group to the 5' position of DNA cytosines (5mC), is generally associated with transcriptional repression during early embryo formation ; however, in the adult brain, it is dynamically regulated and plays an important role in the formation and maintenance of memory. Very recently, it has been hypothesized that DNA hydroxymethylation, the addition of a hydroxyl group to methylated cytosines (5mC), serves as an intermediate in the DNA demethylation pathway. GIven its recent discovery, the role of DNA hydroxymethylation in memory has not yet been explored. In this study, we developed an immunofluorescent triple labeling protocol in order to begin examining the involvement of 5mC and 5hmC in neurons activated by consolidation of a contextual memory associated with methamphetamine in the brain's reward center, the nucleus accumbens.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3359318
Subject Headings: Memory, Physiological aspects, Cognitive neuroscience, DNA, Methylation
Format: Document (PDF)

Title: On the Nature of Neural Causality in Large-Scale Brain Networks: Foundations, Modeling and Nonlinear Neurodynamics.
Creator: Mannino, Michael, Bressler, Steven L., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: We examine the nature of causality as it exists within large-scale brain networks by first providing a rigorous conceptual analysis of probabilistic causality as distinct from deterministic causality. We then use information-theoretic methods, including the linear autoregressive modeling technique of Wiener-Granger causality (WGC), and Shannonian transfer entropy (TE), to explore and recover causal relations between two neural masses. Time series data were generated by Stefanescu-Jirsa 3D...
Show moreWe examine the nature of causality as it exists within large-scale brain networks by first providing a rigorous conceptual analysis of probabilistic causality as distinct from deterministic causality. We then use information-theoretic methods, including the linear autoregressive modeling technique of Wiener-Granger causality (WGC), and Shannonian transfer entropy (TE), to explore and recover causal relations between two neural masses. Time series data were generated by Stefanescu-Jirsa 3D model of two coupled network nodes in The Virtual Brain (TVB), a novel neuroinformatics platform used to model resting state large-scale networks with neural mass models. We then extended this analysis to three nodes to investigate the equivalence of a concept in probabilistic causality known as ‘screening off’ with a method of statistical ablation known as conditional Granger causality. Finally, we review some of the empirical and theoretical work of nonlinear neurodynamics of Walter Freeman, as well as metastable coordination dynamics and investigate what impact they have had on consciousness research.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013164
Subject Headings: Neuroinformatics, Consciousness--Research, Computational neuroscience
Format: Document (PDF)

Title: Analysis of nucleus reuniens cell behavior during hippocampal theta rhythm.
Creator: Morales, George J., Florida Atlantic University, Morgera, Salvatore D., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Coherence estimates have been used to determine the presence of functional coupling between two signals. While direct projections from the nucleus reuniens (RE) to the hippocampus formation in the rat have been discovered, little is known about the possible functional influence of the RE on the hippocampus. This investigation makes use of MATLAB to create a set of specialized algorithms to investigate coherence function estimates between RE cell activity and hippocampal EEG. In addition,...
Show moreCoherence estimates have been used to determine the presence of functional coupling between two signals. While direct projections from the nucleus reuniens (RE) to the hippocampus formation in the rat have been discovered, little is known about the possible functional influence of the RE on the hippocampus. This investigation makes use of MATLAB to create a set of specialized algorithms to investigate coherence function estimates between RE cell activity and hippocampal EEG. In addition, error prevention considerations as well as shortcomings in current data acquisition software that ultimately lead to the necessity for additional software analysis tools are also discussed. An investigation into RE cell behavior requires the calculation of cell activity spike rates as well as the identification of action potential bursting phenomena. Isolation of individual cell activity, from a population recording channel, is needed in order to prevent erroneous effects associated with using unresolved multi-neuron recordings. Changes in spike rate activity and frequency of bursting occurrences are calculated as a means of gauging RE unit response to the presence of a stimulus (e.g., tail pinch). The relationship of RE units on hippocampal EEG by analysis of coherence function estimates between RE units and hippocampal EEG, as well as evaluated RE unit behavior in terms of changes in unit spike rate and bursting activity are established.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/13383
Subject Headings: Hippocampus (Brain), Electroencephalography, Neurosciences, Theta rhythm, Memory
Format: Document (PDF)

Title: Perception of facial affect: A functional magnetic resonance imaging study of adolescents and adults with and without nonverbal learning disabilities.
Creator: Vallabha, Taube Lubart, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: Individuals with nonverbal learning disabilities (NLD) have an impaired ability to interpret facial expressions of emotion (FEE), the consequences of which can include progressively debilitating socioemotional disturbances. Thus, it is important to determine how the neuroanatomical structures underlying the perception of FEE in people with NLD differ from the normal population. To this end, functional magnetic resonance imaging was used to compare brain activation patterns in male and female...
Show moreIndividuals with nonverbal learning disabilities (NLD) have an impaired ability to interpret facial expressions of emotion (FEE), the consequences of which can include progressively debilitating socioemotional disturbances. Thus, it is important to determine how the neuroanatomical structures underlying the perception of FEE in people with NLD differ from the normal population. To this end, functional magnetic resonance imaging was used to compare brain activation patterns in male and female adolescent subjects and male adult subjects with and without NLD. The subjects were presented with FEE at low and high intensities while they performed a gender decision task. Subjects with NLD displayed less activation in limbic areas responsible for processing emotion in the normal population. The NLD subjects exhibited more activity than controls in the orbital gyrus, inferior, middle and superior frontal gyri, fusiform and superior temporal gyri, insula, striatum and inferior and superior parietal lobules. Several of these structures participate in language function: as individuals with NLD have superior verbal abilities, it is probable that this population relies on their linguistic strengths to compensate for their nonverbal weaknesses whilst processing FEE. Additionally, because of an impaired capacity for attention to and discrimination of visual details, the NLD subjects showed more active responses for low intensity FEE in comparison to controls. This may have led to a failure of regions such as the middle and superior frontal and superior temporal gyri to habituate or sensitize appropriately to emotionally salient visual stimuli. In comparison with the normal population, people with NLD utilize different neural structures when processing FEE, in accordance with the strengths and deficits associated with the NLD syndrome.
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Date Issued: 2003
PURL: http://purl.flvc.org/fau/fd/FADT12051
Subject Headings: Biology, Neuroscience, Education, Special, Psychology, Cognitive
Format: Document (PDF)

Title: Memory deficits for faces and names in Alzheimer's disease: Investigation with a faces-names Stroop-like task.
Creator: Taft, Janna Renee., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: A prominent deficit in Alzheimer's disease (AD) is a difficulty in recognizing and naming people. Unfamiliar and famous face recognition tasks are sparse in the neuropsychology literature. It was hypothesized that: a deficit in recognition of faces would be found for AD patients, the semantic mismatch condition would result in the longest response latency and least accurate naming, and semantic cues would not facilitate naming for the AD group. Accuracy and reaction time from ten mild AD...
Show moreA prominent deficit in Alzheimer's disease (AD) is a difficulty in recognizing and naming people. Unfamiliar and famous face recognition tasks are sparse in the neuropsychology literature. It was hypothesized that: a deficit in recognition of faces would be found for AD patients, the semantic mismatch condition would result in the longest response latency and least accurate naming, and semantic cues would not facilitate naming for the AD group. Accuracy and reaction time from ten mild AD patients diagnosed by NINCDS-ADRDA criteria and 10 normal controls (matched age, 66--82 years, education & ethnicity) were tested via unfamiliar and famous faces recognition memory tests and famous faces naming tasks with and without semantic interference. Both subject groups were more accurate on the famous face recognition rather than memory for unfamiliar faces, with significant group differences. The Stroop-like face naming task performance was characterized by an increased interference effect, semantic face-name mismatches produced the longest response delays, and less accurate face naming particularly in the AD group. The semantic cues resulted in a decrease in naming accuracy for the AD patients, which may be indicative of their name retrieval deficit. Consistent with existing face-name models, these findings suggest that the deficit in AD is related to semantic naming rather than the perceptual component of face recognition. Furthermore, the ability to correctly name faces even in the presence of interference may prove to be a diagnostic tool that is sensitive to face naming deficits characteristic in cases of brain damage.
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Date Issued: 2003
PURL: http://purl.flvc.org/fau/fd/FADT12061
Subject Headings: Biology, Neuroscience, Psychology, Clinical, Psychology, Cognitive
Format: Document (PDF)

Title: A neuroanatomical investigation of the median raphe nucleus, supramammillary nucleus, and nucleus reuniens: Possible implications for the modulation of the hippocampal EEG.
Creator: McKenna, James Timothy, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: The theta rhythm of the hippocampus, present in area CA1 of Ammon's horn and the dentate gyrus, is thought to serve a role in short-term memory processing. Rhythmically bursting cells of the medial septum projecting to the hippocampus are responsible for pacing theta. Further anatomical investigation of limbic-related circuitry in the rat, particularly connections of the medial septum and hippocampus, will lead to a better understanding of the pathways which influence the hippocampal EEG. Our...
Show moreThe theta rhythm of the hippocampus, present in area CA1 of Ammon's horn and the dentate gyrus, is thought to serve a role in short-term memory processing. Rhythmically bursting cells of the medial septum projecting to the hippocampus are responsible for pacing theta. Further anatomical investigation of limbic-related circuitry in the rat, particularly connections of the medial septum and hippocampus, will lead to a better understanding of the pathways which influence the hippocampal EEG. Our first study examined single and collateral projections from the supramammillary nucleus to the medial septum and hippocampus, employing the retrograde fluorescent tracers FluoroGold and FluoroRuby. The supramammillary nucleus neurons we identified with collateral projections to the medial septum and hippocampus may be directly involved in generation of the theta rhythm. The second study examined single and collateral projections from the median raphe nucleus to the medial septum and hippocampus, employing the retrograde tracers FluoroGold and FluoroRuby. It has been proposed that the median raphe nucleus serves a direct role in desynchronization of the hippocampal EEG, or blockade of theta. The median raphe nucleus neurons we identified with collateral projections to the medial septum and hippocampus may be directly involved in the termination of theta, in turn modulating hippocampal memory processing. The third study examined afferent projections to the nucleus reuniens of the thalamus, employing the retrograde tracer FluoroGold, combined with a primary-antibody immunohistochemical procedure, in order to identify FluoroGold labeled cells by means of bright-field microscopy. RE afferents originate from widespread regions of the brain, providing multi-sensory and limbic input to RE. The fourth study examined efferents of the nucleus reuniens, employing the anterograde tracer PHA-L (Phaseolus vulgaris-leucoagglutinin). RE efferents terminated largely in regions of the telencephalon, and may influence working memory and sensorimotor systems. Investigations have linked the theta rhythm of the hippocampus to memory processing. The activity of the supramammillary nucleus, median raphe nucleus, and nucleus reuniens may influence the hippocampal EEG, particularly theta, and hence hippocampal mnemonic processing, by means of the pathways described in this dissertation.
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Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/11971
Subject Headings: Biology, Anatomy, Biology, Neuroscience, Psychology, Psychobiology
Format: Document (PDF)

Title: Functional roles of L1-Cam/Neuroglian in the nervous system of Drosophila Melanogaster.
Creator: Kudumala, Sirisha, Godenschwege, Tanja A., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Neuronal cell adhesion molecules of L1 family play a critical role in proper nervous system development. Various mutations on human L1-CAM that lead to severe neurodevelopmental disorders like retardation, spasticity etc. termed under L1 syndrome. The vertebrr their roles in axon pathfinding, neurite extension and cell migration, howeverate L1CAM and its homolog in Drosophila, neuroglian (nrg) have been well studied fo, much less is known about the mechanisms by which they fine tune synaptic...
Show moreNeuronal cell adhesion molecules of L1 family play a critical role in proper nervous system development. Various mutations on human L1-CAM that lead to severe neurodevelopmental disorders like retardation, spasticity etc. termed under L1 syndrome. The vertebrr their roles in axon pathfinding, neurite extension and cell migration, howeverate L1CAM and its homolog in Drosophila, neuroglian (nrg) have been well studied fo, much less is known about the mechanisms by which they fine tune synaptic connectivity to control the development and maintenance of synaptic connections within neuronal circuits. Here we characterized the essential role of nrg in regulating synaptic structure and function in vivo in a well characterized Drosophila central synapse model neuron, the Giant Fiber (GF) system. Previous studies from our lab revealed that the phosphorylation status of the tyrosine in the Ankyrin binding FIGQY motif in the intracellular domain of Nrg iscrucial for synapse formation of the GF to Tergo-Trochanteral Motor neuron (TTMn) synapse in the GF circuit. The present work provided us with novel insights into the role of Nrg-Ank interaction in regulating Nrg function during synapse formation and maintenance. By utilizing a sophisticated Pacman based genomic rescue strategy we have shown that dynamic regulation of the Neuroglian–Ankyrin interaction is required to coordinate transsynaptic development in the GF–TTMn synapse. In contrast, the strength of Ankyrin binding directly controls the balance between synapse formation and maintenance at the NMJ. Human L1 pathological mutations affect different biological processes distinctively and thus their proper characterization in vivo is essential to understand L1CAM function. By utilizing nrg14;P[nrg180ΔFIGQY] mutants that have exclusive synaptic defects and the previously characterized nrg849 allele that affected both GF guidance and synaptic function, we were able to analyze pathological L1CAM missense mutations with respect to their effects on guidance and synapse formation in vivo. We found that the human pathological H210Q, R184Q and Y1070C, but not the E309K and L120V L1CAM mutations affect outside-in signaling via the FIGQY Ankyrin binding domain which is required for synapse formation and not for axon guidance while L1CAM homophilic binding and signaling via the ERM motif is essential for axon guidance in Drosophila.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004131, http://purl.flvc.org/fau/fd/FA00004131
Subject Headings: Cell adhesion molecules, Cellular signal transduction, Cognitive neuroscience, Cognitive neuroscience, Drosophila melanogaster, Molecular neurobiology
Format: Document (PDF)

Title: The Role of Dorsal Anterior Cingulate Cortex in the Motor Control.
Creator: Asemi, Avisa, Bressler, Steven L., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: We sought to better understand human motor control by investigating functional interactions between the Supplementary Motor Area (SMA), dorsal Anterior Cingulate Cortex (dACC), and primary motor cortex (M1) in healthy adolescent participants performing visually coordinated unimanual finger-movement and n-back working memory tasks. We discovered modulation of the SMA by the dACC by analysis of fMRI BOLD time series recorded from the three ROIs (SMA, dACC, and M1) in each participant. Two...
Show moreWe sought to better understand human motor control by investigating functional interactions between the Supplementary Motor Area (SMA), dorsal Anterior Cingulate Cortex (dACC), and primary motor cortex (M1) in healthy adolescent participants performing visually coordinated unimanual finger-movement and n-back working memory tasks. We discovered modulation of the SMA by the dACC by analysis of fMRI BOLD time series recorded from the three ROIs (SMA, dACC, and M1) in each participant. Two measures of functional interaction were used: undirected functional connectivity was measured using the Pearson product-moment correlation coefficient (PMCC), and directed functional connectivity was measured from linear autoregressive (AR) models. In the first project, task-specific modulation of the SMA by the dACC was discovered while subjects performed a coordinated unimanual finger-movement task, in which the finger movement was synchronized with an exogenous visual stimulus. In the second project, modulation of the SMA by the dACC was found to be significantly greater in the finger coordination task than in an n-back working memory, in which the same finger movement signified a motor response indicating a 0-back or 2-back working memory match. We thus demonstrated in the first study that the dACC sends task-specific directed signals to the supplementary motor area, suggesting a role for the dACC in top-down motor control. Finally, the second study revealed that these signals were significantly greater in the coordinated motor task than in the n-back working memory task, suggesting that the modulation of the SMA by the dACC was associated with sustained, continuous motor production and/or motor expectation, rather than with the motor movement itself.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004478
Subject Headings: Brain mapping, Cerebral cortex -- Anatomy, Cognitive neuroscience, Computational neuroscience, Movement sequences, Perceptual motor learning, Sensorimotor integration
Format: Document (PDF)

Title: Role of activation and sensory stimuli in recovery from lateral hypothalmic damage in the cat.
Creator: Wolgin, David L., Teitelbaum, Philip
Date Issued: 1978-06
PURL: http://purl.flvc.org/fau/228751
Subject Headings: Psychophysiology--Research., Animals, Domestic--Physiology, Neurosciences
Format: Document (PDF)

Title: A BCU scalable sensory acquisition system for EEG embedded applications.
Creator: Fathalla, Sherif S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Electroencephalogram (EEG) Recording has been through a lot of changes and modification since it was first introduced in 1929 due to rising technologies and signal processing advancements. The EEG Data acquisition stage is the first and most valuable component in any EEG recording System, it has the role of gathering and conditioning its input and outputting reliable data to be effectively analyzed and studied by digital signal processors using sophisticated and advanced algorithms which help...
Show moreElectroencephalogram (EEG) Recording has been through a lot of changes and modification since it was first introduced in 1929 due to rising technologies and signal processing advancements. The EEG Data acquisition stage is the first and most valuable component in any EEG recording System, it has the role of gathering and conditioning its input and outputting reliable data to be effectively analyzed and studied by digital signal processors using sophisticated and advanced algorithms which help in numerous medical and consumer applications. We have designed a low noise low power EEG data acquisition system that can be set to act as a standalone mobile EEG data processing unit providing data preprocessing functions; it can also be a very reliable high speed data acquisition interface to an EEG processing unit.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/3164095
Subject Headings: Brain-computer interfaces, Computational neuroscience, Neural networks (Computer science)
Format: Document (PDF)

Title: Functional consequences of top-down anticipatory modulation of primary visual cortex.
Creator: Richter, Craig G., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: It is well established that anticipation of the arrival of an expected stimulus is accompanied by rich ongoing oscillatory neurodynamics, which span and link large areas of cortex. An intriguing possibility is that these dynamic interactions may convey knowledge that is embodied by large-scale neurocognitive networks from higher level regions of multi-model cortex to lower level primary sensory areas. In the current study, using autoregressive spectral analysis, we establish that during the...
Show moreIt is well established that anticipation of the arrival of an expected stimulus is accompanied by rich ongoing oscillatory neurodynamics, which span and link large areas of cortex. An intriguing possibility is that these dynamic interactions may convey knowledge that is embodied by large-scale neurocognitive networks from higher level regions of multi-model cortex to lower level primary sensory areas. In the current study, using autoregressive spectral analysis, we establish that during the anticipatory phase of a visual discrimination task there are rich patterns of coherent interaction between various levels of the ventral visual hierarchy across the frequency spectrum of 8 - 90 Hz. Using spectral Granger causality we determined that a subset of these interactions carry beta frequency (14 - 30 Hz) top-down influences from higher level visual regions V4 and TEO to primary visual cortex. We investigated the functional significance of these top-down interactions by correlating the magnitude of the anticipatory signals with the amplitude of the visual evoked potential that was elicited by stimulus processing. We found that in one third of the extrastriate-striate pairs, tested in three monkeys, the amplitude of the visual evoked response is well predicted by the magnitude of pre-stimulus coherent top-down anticipatory influences. To investigate the dynamics of the coherent and topdown Granger causal interactions, we analyzed the relationship between coherence and top-down Granger causality with stimulus onset asynchrony. This analysis revealed that in an abundance of cases the magnitudes of the coherent interactions and top-down directional influences scaled with the length of time that had elapsed before stimulus onset., Together these results reveal a complex network of coherent and top-down directional interactions that predict the amplitude of early components of the visual evoked potential in primary visual cortex and vary in strength on the basis of the length of the stimulus onset.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/369200
Subject Headings: Cognitive neuroscience, Brain mapping, Visual perception, Testing, Intersensory effects
Format: Document (PDF)

Title: Hominin endocast topography: an analysis using geographic information systems.
Creator: Boas, Melissa., Dorothy F. Schmidt College of Arts and Letters, Department of Anthropology
Abstract/Description: This study examined the topography of prefrontal molds of human endocasts using three-dimensional laser scanning and geographic information systems (GIS) in order to carry out intra-species comparisons. Overall brain topography can indicate when major reorganizational shifts in brain structure happened in our evolutionalry history, and these shifts may indicate major shifts in cognition and behavior. Endocasts are one of the sole sources of information about extinct hominin brains ; they...
Show moreThis study examined the topography of prefrontal molds of human endocasts using three-dimensional laser scanning and geographic information systems (GIS) in order to carry out intra-species comparisons. Overall brain topography can indicate when major reorganizational shifts in brain structure happened in our evolutionalry history, and these shifts may indicate major shifts in cognition and behavior. Endocasts are one of the sole sources of information about extinct hominin brains ; they reproduce details of the brain's external morphology. Analysis of endocast morphology has never been done using GIS methodology. The use of GIS helps to overcome previous obstacles in regards to endocast analysis. Since this methodology is new, this research focuses on only one species, Homo sapiens and the area of focus is narrowed to the frontal lobe, specifically Broca's cap. This area is associated with speech in humans and is therefore of evolutionary significance. The variability in lateralization of this feature was quantified.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3358286
Subject Headings: Human evolution, Brain mapping, Cognitive neuroscience, Geographic information systems
Format: Document (PDF)

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