Bölüm & Birim & Kişi

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A breakthrough in neuroscience needs a "Nebulous Cartesian System" Oscillations, quantum dynamics and chaos in the brain and vegetative system
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2007-04) Güntekin, Bahar; BAŞAR, EROL; TR142226; TR204666
The Cartesian System is a fundamental conceptual and analytical framework related and interwoven with the concept and applications of Newtonian Dynamics. In order to analyze quantum processes physicist moved to a Probabilistic Cartesian System in which the causality principle became a probabilistic one. This means the trajectories of particles (obeying quantum rules) can be described only with the concept of cloudy wave packets. The approach to the brain-body-mind problem requires more than the prerequisite of modem physics and quantum dynamics. In the analysis of the brain-body-mind construct we have to include uncertain causalities and consequently multiple uncertain causalities. These multiple causalities originate from (1) nonlinear properties of the vegetative system (e.g. irregularities in biochemical transmitters, cardiac output, turbulences in the vascular system, respiratory apnea, nonlinear oscillatory interactions in peristalsis); (2) nonlinear behavior of the neuronal electricity (e.g. chaotic behavior measured by EEG), (3) genetic modulations, and (4) additional to these physiological entities nonlinear properties of physical processes in the body. The brain shows deterministic chaos with a correlation dimension of approx. D-2=6, the smooth muscles approx. D-2=3. According to these facts we propose a hyper-probabilistic approach or a hyper-probabilistic Cartesian System to describe and analyze the processes in the brain-body-mind system. If we add aspects as our sentiments, emotions and creativity to this construct, better said to this already hyper-probabilistic construct, this "New Cartesian System" is more than hyper-probabilistic, it is a nebulous system, we can predict the future only in a nebulous way; however, despite this chain of reasoning we can still provide predictions on brain-body-mind incorporations. We tentatively assume that the processes or mechanisms of the brain-body-mind system can be analyzed and predicted similar to the metaphor of '' finding the walking path in a cloudy or foggy day". This is meant by stating "The Nebulous Cartesian System" (NCS). Descartes, at his time undertaking his genius step, did not possess the knowledge of today's physiology and modem physics; we think that the time has come to consider such a New Cartesian System. To deal with this, we propose the utilization of the Heisenberg S-Matrix and a modified version of the Feynman Diagrams which we call "Brain Feynman Diagrams". Another metaphor to consider within the oscillatory approach of the NCS is the "string theory". We also emphasize that fundamental steps should be undertaken in order to create the own dynamical framework of the brain-body-mind incorporation; suggestions or metaphors from physics and mathematics are useful; however, the grammar of the brains intrinsic language must be understood with the help of a new biologically founded, adaptive-probabilistic Cartesian system. This new Cartesian System will undergo mutations and transcend to the philosophy of Henri Bergson in parallel to the Evolution theory of Charles Darwin to open gateways for approaching the brain-body-mind problem. (c) 2006 Published by Elsevier B.V.
A review of brain oscillations in cognitive disorders and the role of neurotransmitters
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2008-10-15) Güntekin, Bahar; BAŞAR, EROL; TR142226; TR204666
The analysis of the functional correlates of "brain oscillations" has become an important branch of neuroscience. Although research on the functional correlates of brain oscillation has progressed to a high level, studies on cognitive disorders are rare and mainly limited to schizophrenia patients. The present review includes the results of the changes in brain oscillations in patients with Alzheimer's, schizophrenia, bipolar disorders, mild cognitive impairment, attention-deficit hyperactivity disorder (ADHD), alcoholism and those with genetic disorders. Furthermore, the effects of pharmaca and the influence of neurotransmitters in patients with cognitive disorders are also reviewed. Following the review, a short synopsis is given related to the analysis of brain oscillations. (c) 2008 Elsevier B.V. All rights reserved.
Brain oscillations are highly influenced by gender differences
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2007-09) Güntekin, Bahar; BAŞAR, EROL; TR204666; TR142226
There are few studies describing gender differences in event related oscillations (EROS). In the present report we demonstrate that gender differences are apparent in EROS even during simple visual stimulation, possibly activating very basic sensory networks. The data of 32 (16 males) healthy subjects were recorded from thirteen different scalp locations (F-3, F-4, C-z, C-3, C-4, T-3, T-4, T-5, T-6, P-3, P-4, O-1, O-2). Analysis was performed in the delta (0.5-3.5 Hz), theta (5-8.5 Hz), alpha (9-13 Hz), beta (15-24 Hz), and gamma (28-48 Hz) frequency ranges. The results showed that the maximum peak-to-peak delta response amplitudes for women were significantly higher than for men over occipital, parietal, central and temporal electrode locations. There were also differentiations in the beta and gamma oscillatory responses. These gender differences were most pronounced over the electrode Site O-2, that is, over primary visual areas. It is suggested that this study might serve as a standard to investigate gender differences in electrophysiology. (c) 2007 Elsevier B.V All rights reserved.
Brain Oscillations Differentiate the Picture of One's Own Grandmother
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2007-04) Özgören, Murat; Öniz, Adile; Schmiedt, Christina; Başar-Eroğlu, Canan; BAŞAR, EROL; TR142226; TR143075; TR59951; TR186954
The present report introduces, as a first study, the concept and methods of oscillatory brain dynamics to analyze well-known (familiar) and unfamiliar face processing in the 800 ms following a face presentation. We analyzed event-related oscillations in young, healthy subjects (N=26) by using three types of stimulation: (1) a simple light signal, (2) the picture of the face of an anonymous elderly lady and (3) the picture of the subjects' own grandmother. We found a number of significant peak to peak amplitude measures in all frequency bands in the time period of 0-500 ms, allowing a differentiation between perception of the subjects' own grandmother, the unknown elderly face and the light stimulation. The results showed increased event-related oscillatory responses elicited by the unknown face compared to the known grandmother a) in the theta responses (4-8 Hz) at T-6 (46%), b) in the gamma (28-48 Hz) responses at C-z (22%) and C-3 (38%) and c) in the beta responses at F-4 (46%), C-z (47%) and P-3 (105%). In contrast, the subjects' own grandmother elicited 20% increased fast theta (6-8 Hz) oscillations at F-4 compared to the unknown face. Delta responses dissociated face from simple light processing, as reflected in the observation of approx. 50% higher amplitudes at the occipital compared to the frontal locations during face perception. We conclude that the described multiple brain oscillations clearly differentiate the known and unknown faces with varied degrees of selective-responsiveness in a short time window between 0 and 800 ms. Furthermore, the results are in conceptual accordance with the "selectively distributed processing" hypothesis. (c) 2006 Published by Elsevier B.V.
Brain Oscillations Evoked by the Face of a Loved Person
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2008-06-12) Schmiedt-Fehr, Christina; Öniz, Adile; Başar Eroğlu, Canan; BAŞAR, EROL; TR59951; TR142226
Previous studies have shown a close interrelation between emotional processing and memory processes using facial stimuli and applying the concept of oscillatory brain dynamics. Amending prior findings the influence of neural correlates related to the emotional state termed "romantic love" was investigated. Specifically, the effect of feelings of love on face perception was of interest. Pictures of a "loved person" were presented to female subjects and the elicited responses were compared with responses to pictures showing faces of a "known and appreciated person" or an "unknown person" during EEG recordings (n=20 females). As a control condition light stimulation was employed. The sequence of faces shown was presented in random and block-design. EEG data was analyzed considering maximum amplitudes and topographical differences within the conventional frequency bands of delta, theta, alpha, beta and gamma. Differences between light and face stimuli were found in the delta and theta bands and differences between the face types and the two designs were found in the delta band. The delta response to the picture of the "loved person" showed significantly higher amplitude values, not only in comparison with the "unknown person", but also with the picture of the "appreciated person". Frontal lobes appear to react to different types of facial stimuli with specific increases in delta responses. The difference between the response to the "loved person" and of the "known and appreciated person" reflects the component of the emotion denoted as love. The findings and their interpretations are discussed within the framework of event-related oscillations and complex stimulus processing emphasizing the concept of dynamic localization. (C) 2008 Published by Elsevier B.V.
Brain oscillatory responses in patients with bipolar disorder manic episode before and after valproate treatment
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2008-10-15) Özerdem, Ayşegül; Güntekin, Bahar; Tunca, Zeliha; BAŞAR, EROL; TR204666; TR140995; TR142226
Background: GABA/Glutamatergic dysfunction and neural circuits which regulate cognitive processing are involved in the underlying pathology of bipolar disorder. Event related oscillatory neuroelectrical activity reflects integrative brain functioning, different frequency bands representing different cognitive functions. Methods: Event Related Potentials to visual odd-ball paradigm in ten manic/hypomanic medication free, DSM-IV bipolar patients were measured before and after six weeks of valproate monotherapy in comparison to ten sex and age matched healthy controls. Different frequency band responses were obtained by digital filtration of ERPs. Young mania rating scale (YMRS) was used to assess clinical response. Repeated measures ANOVA, Wilcoxon and Mann Whitney U tests were used for statistical analysis. Results: Patients showed significantly higher baseline occipital beta (1830 Hz) (p: 0.014) response than healthy controls. They were devoid of the occipito-frontal alpha (8-13 Hz) dominance presented by the control group. Occipital beta response reduced significantly (p: 0.009) and became similar to controls after treatment. Post-treatment alpha responses were significantly lower than baseline in anterior temporal (p: 0.038) and occipital (p: 0.027) locations. Healthy controls displayed a significantly increased frontal alpha response at the second assessment but the patients did not. Mean YMRS score reduced significantly compared to baseline at the end of six weeks (P: 0.004). Conclusions: Alpha response is the universal operator in the brain. Increased occipital beta response in mania may be compensatory to the dysfunctional alpha operation. its reduction after valproate may be through modulation of glutamatergic and GABAergic mechanisms and indicate medication's corrective effect on the underlying pathogenesis. (c) 2008 Elsevier B.V. All rights reserved.
Decrease of evoked delta, theta and alpha coherences in Alzheimer patients during a visual oddball paradigm
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2008-10-15) Güntekin, Bahar; Saatçı, Ertuğrul; Yener, Görsev; TR143760; TR204666; TR10488
In this study event related coherence of patients with Alzheimer type of dementia (AD) was analyzed by using a visual oddball paradigm as stimuli. A total of 21 mild probable AD subjects (10 untreated, 11 treated) were compared with a group of 19 healthy controls. The members of the groups had their EEG recorded from 12 electrodes by means of a visual oddball paradigm. The evoked coherence was analyzed for delta (1-3.5 Hz), theta (4-7 Hz) and alpha (8-13 Hz) frequency ranges for inter-hemispheric (F(3)-F(4), C(3)-C(4), T(3)-T(4), T(5)-T(6), P(3)-P(4), O(1)-O(2)) and long range intra-hemi spheric (F(3)-P(3), F(4)-P(4), F(3)-T(5), F(4)-T(6), F(3)-O(1), F(4)-O(2)) electrode pairs. The control group showed higher values of evoked coherence in "delta", "theta" and "alpha" bands in the left fronto-parietal electrode pairs in comparison with the untreated AD group (p < 0.01 for all frequency bands). Furthermore, the control group showed higher values of evoked coherence in the left fronto-parietal electrode pair in theta frequency band (p < 0.01) and higher values of evoked coherence in the right fronto-parietal electrode pair in delta band (p < 0.01) when compared to treated AD group. The only significant difference between the treated and untreated AD groups was in the alpha band. The treated AD group showed higher values of evoked coherence at the left fronto-parietal pair in alpha band in comparison to the untreated AD group (p < 0.01). During a working memory process the coherence in the left fronto-parietal electrode pair (F(3)-P(3)) of AD patients is significantly decreased, thus indicating reduced connectivity between frontal and parietal sites. (c) 2008 Elsevier B.V. All rights reserved.
Emotional Face Expressions are Differentiated With Brain Oscillations
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2007-04) Güntekin, Bahar; BAŞAR, EROL; TR204666; TR142226
The differentiation of "facial expressions" is a process of higher mental activity, which has considerable applications in "psychology of moods and emotions". We applied the approach of event-related oscillations (EROs) to investigate the modulation of electrical manifestations related to emotional expression in EEG recordings of 20 healthy subjects. EROs of "neutral, angry and happy" faces in 13 electrical recordings sites (F-3, F-4, C-z, C-3, C-4, T-3, T-4, T-5, T-6, P-3, P-4, O-1, O-2) were analyzed. Following the recording session, the subjects were asked to express the degree of their emotional involvement (valence and arousal) using the Self-Assessment Manikin ratings. Amplitude frequency characteristics (AFCs) were used to determine the frequencies of interest and the ranges for digital pass-band filtering applied accordingly. Consecutively, peak to peak amplitude measures of oscillatory responses were computed for the selected frequency bands and for the differentiation of the different stimuli. A differentiation between angry and happy facial expressions was observed especially in the alpha (9-13 Hz) and beta (15-24 Hz) frequencies, however, only when selecting stimuli with high mood involvement. Therefore, these frequency bands are the main focus of this report. The amplitudes of the alpha responses upon angry face stimulation were significantly higher than upon presentation of the happy faces at posterior locations. At F3, C, and C3, beta responses upon angry face stimulation were significantly higher in amplitude compared with the happy face stimulation. It is discussed that the frontal theta response is highly increased in comparison to all theta responses also encountered in studies of face recognition: During observation of facial expression, the occipital theta is much higher. We conclude and emphasize that the analysis of brain oscillatory responses distributed over the scalp in combination with subjective ratings of emotional impact of stimuli provide a good basis for analysing the influence of emotional information processing in the brain. In congruence with others, the results support the phylogenetical viewpoint suggesting that angry face stimulations are faster and more ample in responding. Furthermore, frontal, temporal, parietal and occipital lobes seem to be involved in processing of facial expressions, as reflected in an ensemble of different frequency brain oscillatory responses distributed over the scalp. (c) 2006 Published by Elsevier B.V.
Increased frontal phase-locking of event-related theta oscillations in Alzheimer patients treated with cholinesterase inhibitors
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2007-04) Yener, Görsev G.; Güntekin, Bahar; Öniz, Adile; BAŞAR, EROL; TR142226; TR143760; TR59951; TR204666
This is a pilot study describing event-related oscillations in patients with Alzheimer-type dementia (AD). Theta responses of 22 mild probable AD subjects according to NINCDS-ADRDA criteria (11 non-treated, 11 treated by cholinesterase inhibitors), and 20 healthy elderly controls were analyzed by using the conventional visual oddball paradigm. We aimed to compare theta responses of the three groups in a range between 4-7 Hz at the frontal electrodes. At F-3 location, theta responses of healthy subjects were phase locked to stimulation and theta oscillatory responses of non-treated Alzheimer patients showed weaker phase-locking, i.e. average of Z-transformed means of correlation coefficients between single trials was closer to zero. In treated AD patients, phase-locking following target stimulation was two times higher in comparison to the responses of non-treated patients. The results indicate that the phase-locking of theta oscillations at F-3 in the treated patients is as strong as the control subjects. The F-4 theta responses were not statistically significant between the groups. Our findings imply that the theta responses at F3 location are highly unstable in comparison to F4 in non-treated mild AD patients and cholinergic agents may modulate event-related theta oscillatory activities in the frontal regions. (c) 2006 Elsevier B.V. All rights reserved.
Oscillations in "brain-body-mind"-A holistic view including the autonomous system
(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2008-10-15) BAŞAR, EROL; TR142226
Studies related to brain oscillations pervade the neuroscience literature. Functional correlates of oscillations in the delta, theta, alpha, beta and gamma frequency windows are interpreted in several ways. However, only a small number of reports indicate the need for overall interpretations by integrating all type of results. The present essay emphasizes the importance of developing a common overview by considering sensory and cognitive inputs, in studies comparing healthy subjects with subjects with cognitive impairments. By doing this, the present report briefly outlines some general aspects and rules in the study of brain oscillations. The use in clinical studies of drugs mimicking neurotransmitters is also taken into consideration for a more complete analysis. A prominent extension to the study of functional correlates of brain functions is the new emerging results in oscillatory processes in the spinal cord and the autonomous system. By integrating oscillations in all EEG frequency windows, together with oscillations in the spinal cord and the autonomous system, a Gedanken-Model denoted as "globally coupled oscillators" of brain-body-mind incorporation is proposed in order to gain new insights in the dynamics of neural systems. (c) 2008 Elsevier B.V. All rights reserved.

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