scholarly journals Topological inference from spontaneous activity structures in FMRI videos with peristence barcodes

2019 ◽  
Author(s):  
Arjuna P.H. Don ◽  
James F. Peters ◽  
Sheela Ramanna ◽  
Arturo Tozzi
Keyword(s):  
Betti Numbers ◽  
Brain Activation ◽  
Blood Oxygen Level Dependent ◽  
Functional Magnetic Resonance ◽  
Blood Oxygen Level ◽  
Activation Patterns ◽  
Video Frames ◽  
Natural Outcome ◽  
Spatio Temporal ◽  
Topology Of Data

AbstractSpatio-temporal brain activities with variable delay detectable in resting-state functional magnetic resonance imaging (rs-fMRI) give rise to highly reproducible structures, termed cortical lag threads, that can propagate from one brain region to another. Using a computational topology of data approach, we found that Betti numbers that are cycle counts and the areas of vortex cycles covering brain activation regions in triangulated rs-fMRI video frames make it possible to track persistent, recurring blood oxygen level dependent (BOLD) signals. Our findings have been codified and visualized in what are known as persistent barcodes. Importantly, a topology of data offers a practical approach in coping with and sidestepping massive noise in neuro data, such as unwanted dark (low intensity) regions in the neighbourhood of non-zero BOLD signals. A natural outcome of a topology of data approach is the tracking of persistent, non-trivial BOLD signals that appear intermittently in a sequence of rs-fMRI video frames. The end result of this tracking of changing lag structures is a persistent barcode, which is a pictograph that offers a convenient visual means of exhibiting, comparing and classifying brain activation patterns.

scholarly journals Shock-like haemodynamic responses induced in the primary visual cortex by moving visual stimuli

2016 ◽  
Vol 13 (125) ◽  
pp. 20160576 ◽  
Author(s):  
T. C. Lacy ◽  
K. M. Aquino ◽  
P. A. Robinson ◽  
M. M. Schira
Keyword(s):  
Signal To Noise Ratio ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen ◽  
Bold Response ◽  
Optimal Conditions ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Blood Oxygen Level ◽  
Signal To Noise ◽  
Spatio Temporal

It is shown that recently discovered haemodynamic waves can form shock-like fronts when driven by stimuli that excite the cortex in a patch that moves faster than the haemodynamic wave velocity. If stimuli are chosen in order to induce shock-like behaviour, the resulting blood oxygen level-dependent (BOLD) response is enhanced, thereby improving the signal to noise ratio of measurements made with functional magnetic resonance imaging. A spatio-temporal haemodynamic model is extended to calculate the BOLD response and determine the main properties of waves induced by moving stimuli. From this, the optimal conditions for stimulating shock-like responses are determined, and ways of inducing these responses in experiments are demonstrated in a pilot study.

scholarly journals The role of the mesolimbic dopamine system in the formation of blood-oxygen-level dependent responses in the medial prefrontal/anterior cingulate cortex during high-frequency stimulation of the rat perforant pathway

2016 ◽  
Vol 36 (12) ◽  
pp. 2177-2193 ◽  
Author(s):  
Cornelia Helbing ◽  
Marta Brocka ◽  
Thomas Scherf ◽  
Michael T Lippert ◽  
Frank Angenstein
Keyword(s):  
Magnetic Resonance Imaging ◽  
Anterior Cingulate Cortex ◽  
Cingulate Cortex ◽  
Blood Oxygen Level Dependent ◽  
Anterior Cingulate ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Blood Oxygen Level

Several human functional magnetic resonance imaging studies point to an activation of the mesolimbic dopamine system during reward, addiction and learning. We previously found activation of the mesolimbic system in response to continuous but not to discontinuous perforant pathway stimulation in an experimental model that we now used to investigate the role of dopamine release for the formation of functional magnetic resonance imaging responses. The two stimulation protocols elicited blood-oxygen-level dependent responses in the medial prefrontal/anterior cingulate cortex and nucleus accumbens. Inhibition of dopamine D1/5 receptors abolished the formation of functional magnetic resonance imaging responses in the medial prefrontal/anterior cingulate cortex during continuous but not during discontinuous pulse stimulations, i.e. only when the mesolimbic system was activated. Direct electrical or optogenetic stimulation of the ventral tegmental area caused strong dopamine release but only electrical stimulation triggered significant blood-oxygen level-dependent responses in the medial prefrontal/anterior cingulate cortex and nucleus accumbens. These functional magnetic resonance imaging responses were not affected by the D1/5 receptor antagonist SCH23390 but reduced by the N-methyl-D-aspartate receptor antagonist MK801. Therefore, glutamatergic ventral tegmental area neurons are already sufficient to trigger blood-oxygen-level dependent responses in the medial prefrontal/anterior cingulate cortex and nucleus accumbens. Although dopamine release alone does not affect blood-oxygen-level dependent responses it can act as a switch, permitting the formation of blood-oxygen-level dependent responses.

scholarly journals Social Feedback Modulates Neural Response Associated With Cognitive Bias in Individuals Expressing Anxious Symptoms

2019 ◽  
Vol 3 ◽  
pp. 247054701984864 ◽  
Author(s):  
Khalil Thompson ◽  
Kendrick King ◽  
Eddy Nahmias ◽  
Negar Fani ◽  
Trevor Kvaran ◽  
...  
Keyword(s):  
Social Anxiety ◽  
Blood Oxygen Level Dependent ◽  
Regions Of Interest ◽  
Blood Oxygen ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Social Feedback ◽  
Blood Oxygen Level ◽  
High Anxiety ◽  
Anxiety Group

Background Social anxiety is characterized by a tendency to overestimate the likelihood of negative outcomes and consequences before, during, and after interpersonal interactions with social partners. Recent evidence suggests that a network of brain regions critical for perspective-taking, threat appraisal, and uncertainty resolution may function atypically in those prone to social anxiety. In this study, we used functional magnetic resonance imaging to examine neural activity in specific regions of interest in a sample of young adults who endorsed high or low levels of social anxiety. Methods We recruited 31 college student volunteers (age: 18–28 years), categorized as having high or low anxiety based on their Liebowitz Social Anxiety Scale-Self Report scores. These participants were each scanned while playing the iterated Prisoner’s Dilemma game with three computerized confederates, two of whom they were deceived to believe were human co-players. This study focuses on data collected during play with the presumed humans. Regions of interest were defined for the temporoparietal junction, anterior midcingulate, and dorsomedial prefrontal cortex. Average weighted mean blood-oxygen-level-dependent signals for each subject were extracted and analyzed using mixed design analyses of variance to detect group differences in activation during decision-making, anticipation, and appraisal of round outcomes during the game. Results Behavior analysis revealed that the high-anxiety group was more likely to defect than the low-anxiety group. Neuroimaging analysis showed that the high-anxiety group exhibited elevated blood-oxygen-level-dependent activity relative to the low-anxiety group in all three regions during the social feedback appraisal phase but not during decision-making or the anticipation of interaction outcomes. Conclusions These findings provide evidence that some behaviors linked to cognitive biases associated with social anxiety may be mediated by a network of regions involved in recognizing and processing directed social information. Future investigation of the neural basis of cognition and bias in social anxiety using the prisoner’s dilemma and other economic-exchange tasks is warranted. These tasks appear to be highly effective, functional magnetic resonance imaging-compatible methods of probing altered cognition and behavior associated with anxiety and related conditions.

scholarly journals A comparative study of brain activation patterns associated with sexual arousal between males and females using 3.0-T functional magnetic resonance imaging

Sexual Health ◽  
2014 ◽  
Vol 11 (1) ◽  
pp. 11 ◽  
Author(s):  
Gwang-Won Kim ◽  
Gwang-Woo Jeong
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Gender Difference ◽  
Functional Magnetic Resonance Imaging ◽  
Sexual Arousal ◽  
Brain Activation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Activation Patterns ◽  
3.0 T

Background In contrast to the previous studies using a 1.5-T magnetic resonance imaging system, our study was performed on a higher magnetic field strength, 3.0 T, to gain more valuable information on the functional brain anatomy associated with visual sexual arousal for discriminating the gender difference by increasing the detection power of brain activation. Methods: Twenty-four healthy subjects consisting of 12 males and 12 females underwent functional magnetic resonance imaging examination for this study. Brain activity was measured while viewing erotic videos. Results: The predominant activation areas observed in males as compared with females included the hypothalamus, the globus pallidus, the head of the caudate nucleus, the parahippocampal gyrus, the amygdala and the septal area, whereas the predominant activation in females was observed in the anterior cingulate gyrus and the putamen. Conclusion: Our findings suggest that the brain activation patterns associated with visual sexual arousal are specific to gender. This gender difference in brain activation patterns is more remarkable at higher magnet field (3.0 T) than at 1.5 T.

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