scholarly journals Neuronal Graphs: A Graph Theory Primer for Microscopic, Functional Networks of Neurons Recorded by Calcium Imaging

2021 ◽  
Vol 15 ◽  
Author(s):  
Carl J. Nelson ◽  
Stephen Bonner
Keyword(s):  
Graph Theory ◽  
Fluorescence Microscopy ◽  
Calcium Imaging ◽  
Neural Mechanisms ◽  
Fmri Data ◽  
Functional Networks ◽  
Large Bank ◽  
Fundamental Structure ◽  
Formal Study ◽  
The Brain

Connected networks are a fundamental structure of neurobiology. Understanding these networks will help us elucidate the neural mechanisms of computation. Mathematically speaking these networks are “graphs”—structures containing objects that are connected. In neuroscience, the objects could be regions of the brain, e.g., fMRI data, or be individual neurons, e.g., calcium imaging with fluorescence microscopy. The formal study of graphs, graph theory, can provide neuroscientists with a large bank of algorithms for exploring networks. Graph theory has already been applied in a variety of ways to fMRI data but, more recently, has begun to be applied at the scales of neurons, e.g., from functional calcium imaging. In this primer we explain the basics of graph theory and relate them to features of microscopic functional networks of neurons from calcium imaging—neuronal graphs. We explore recent examples of graph theory applied to calcium imaging and we highlight some areas where researchers new to the field could go awry.

scholarly journals Graph-theory based parcellation of functional subunits in the brain from resting-state fMRI data

NeuroImage ◽  
2010 ◽  
Vol 50 (3) ◽  
pp. 1027-1035 ◽  
Author(s):  
X. Shen ◽  
X. Papademetris ◽  
R.T. Constable
Keyword(s):  
Graph Theory ◽  
Resting State ◽  
Resting State Fmri ◽  
Fmri Data ◽  
The Brain

Neural Mechanisms of Memory Enhancement and Impairment Induced by Visual Statistical Learning

2020 ◽  
Vol 32 (9) ◽  
pp. 1749-1763
Author(s):  
Sachio Otsuka ◽  
Jun Saiki
Keyword(s):  
Statistical Learning ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
Neural Mechanisms ◽  
Fmri Data ◽  
Precentral Gyrus ◽  
Memory Enhancement ◽  
Visual Statistical Learning ◽  
Mechanisms Of Memory ◽  
The Brain

Prior research has reported that the medial temporal, parietal, and frontal brain regions are associated with visual statistical learning (VSL). However, the neural mechanisms involved in both memory enhancement and impairment induced by VSL remain unknown. In this study, we examined this issue using event-related fMRI. fMRI data from the familiarization scan showed a difference in the activation level of the superior frontal gyrus (SFG) between structured triplets, where three objects appeared in the same order, and pseudorandom triplets. More importantly, the precentral gyrus and paracentral lobule responded more strongly to Old Turkic letters inserted into the structured triplets than to those inserted into the random triplets, at the end of the familiarization scan. Furthermore, fMRI data from the recognition memory test scan, where participants were asked to decide whether the objects or letters shown were old (presented during familiarization scan) or new, indicated that the middle frontal gyrus and SFG responded more strongly to objects from the structured triplets than to those from the random triplets, which overlapped with the brain regions associated with VSL. In contrast, the response of the lingual gyrus, superior temporal gyrus, and cuneus was weaker to letters inserted into the structured triplets than to those inserted into the random triplets, which did not overlap with the brain regions associated with observing the letters during the familiarization scan. These findings suggest that different brain regions are involved in memory enhancement and impairment induced by VSL.

Functional Anatomy of Intensity Aspects of Attention

2003 ◽  
Vol 14 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Walter Sturm
Keyword(s):  
Right Hemisphere ◽  
Functional Anatomy ◽  
Fmri Data ◽  
Functional Networks ◽  
Top Down ◽  
Stimulus Modality ◽  
Spatial Orienting ◽  
Phasic Alertness ◽  
Co Activation ◽  
Attention System

Abstract: Behavioral and PET/fMRI-data are presented to delineate the functional networks subserving alertness, sustained attention, and vigilance as different aspects of attention intensity. The data suggest that a mostly right-hemisphere frontal, parietal, thalamic, and brainstem network plays an important role in the regulation of attention intensity, irrespective of stimulus modality. Under conditions of phasic alertness there is less right frontal activation reflecting a diminished need for top-down regulation with phasic extrinsic stimulation. Furthermore, a high overlap between the functional networks for alerting and spatial orienting of attention is demonstrated. These findings support the hypothesis of a co-activation of the posterior attention system involved in spatial orienting by the anterior alerting network. Possible implications of these findings for the therapy of neglect are proposed.

Functional networks of the brain: from connectivity restoration to dynamic integration

2020 ◽  
Author(s):  
Aleksandr E. Hramov ◽  
Nikita S. Frolov ◽  
Vladimir A. Maksimenko ◽  
Semen A. Kurkin ◽  
Viktor B. Kazantsev ◽  
...  
Keyword(s):  
Functional Networks ◽  
Connectivity Restoration ◽  
Dynamic Integration ◽  
The Brain

Functional networks of the brain: from connectivity restoration to dynamic integration

2020 ◽  
Author(s):  
Aleksandr E. Hramov ◽  
Nikita S. Frolov ◽  
Vladimir A. Maksimenko ◽  
Semen A. Kurkin ◽  
Viktor B. Kazantsev ◽  
...  
Keyword(s):  
Functional Networks ◽  
Connectivity Restoration ◽  
Dynamic Integration ◽  
The Brain

scholarly journals Antagonism between brain regions relevant for cognitive control and emotional memory facilitates the generation of humorous ideas

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Florian Bitsch ◽  
Philipp Berger ◽  
Andreas Fink ◽  
Arne Nagels ◽  
Benjamin Straube ◽  
...  
Keyword(s):  
Cognitive Control ◽  
Positive Emotions ◽  
Emotional Memory ◽  
Brain Regions ◽  
Neural Mechanisms ◽  
Functional Magnetic Resonance ◽  
Frontal Brain ◽  
Successful Resolution ◽  
Neural Underpinnings ◽  
The Brain

AbstractThe ability to generate humor gives rise to positive emotions and thus facilitate the successful resolution of adversity. Although there is consensus that inhibitory processes might be related to broaden the way of thinking, the neural underpinnings of these mechanisms are largely unknown. Here, we use functional Magnetic Resonance Imaging, a humorous alternative uses task and a stroop task, to investigate the brain mechanisms underlying the emergence of humorous ideas in 24 subjects. Neuroimaging results indicate that greater cognitive control abilities are associated with increased activation in the amygdala, the hippocampus and the superior and medial frontal gyrus during the generation of humorous ideas. Examining the neural mechanisms more closely shows that the hypoactivation of frontal brain regions is associated with an hyperactivation in the amygdala and vice versa. This antagonistic connectivity is concurrently linked with an increased number of humorous ideas and enhanced amygdala responses during the task. Our data therefore suggests that a neural antagonism previously related to the emergence and regulation of negative affective responses, is linked with the generation of emotionally positive ideas and may represent an important neural pathway supporting mental health.

scholarly journals Effects of a Motor Imagery Task on Functional Brain Network Community Structure in Older Adults: Data from the Brain Networks and Mobility Function (B-NET) Study

2021 ◽  
Vol 11 (1) ◽  
pp. 118
Author(s):  
Blake R. Neyland ◽  
Christina E. Hugenschmidt ◽  
Robert G. Lyday ◽  
Jonathan H. Burdette ◽  
Laura D. Baker ◽  
...  
Keyword(s):  
Older Adults ◽  
Graph Theory ◽  
Community Structure ◽  
Resting State ◽  
Brain Networks ◽  
Brain Network ◽  
Functional Brain ◽  
Network Community ◽  
Functional Brain Networks ◽  
The Brain

Elucidating the neural correlates of mobility is critical given the increasing population of older adults and age-associated mobility disability. In the current study, we applied graph theory to cross-sectional data to characterize functional brain networks generated from functional magnetic resonance imaging data both at rest and during a motor imagery (MI) task. Our MI task is derived from the Mobility Assessment Tool–short form (MAT-sf), which predicts performance on a 400 m walk, and the Short Physical Performance Battery (SPPB). Participants (n = 157) were from the Brain Networks and Mobility (B-NET) Study (mean age = 76.1 ± 4.3; % female = 55.4; % African American = 8.3; mean years of education = 15.7 ± 2.5). We used community structure analyses to partition functional brain networks into communities, or subnetworks, of highly interconnected regions. Global brain network community structure decreased during the MI task when compared to the resting state. We also examined the community structure of the default mode network (DMN), sensorimotor network (SMN), and the dorsal attention network (DAN) across the study population. The DMN and SMN exhibited a task-driven decline in consistency across the group when comparing the MI task to the resting state. The DAN, however, displayed an increase in consistency during the MI task. To our knowledge, this is the first study to use graph theory and network community structure to characterize the effects of a MI task, such as the MAT-sf, on overall brain network organization in older adults.

Neural Mechanisms of Negative Symptoms

1989 ◽  
Vol 155 (S7) ◽  
pp. 93-98 ◽  
Author(s):  
Nancy C. Andreasen
Keyword(s):  
Frontal Cortex ◽  
Negative Symptoms ◽  
Neural Mechanism ◽  
Brain Regions ◽  
Brain Dysfunction ◽  
Neural Mechanisms ◽  
Dementia Praecox ◽  
Intellectual Abilities ◽  
The Brain ◽  
Psychic Mechanisms

When Kraepelin originally defined and described dementia praecox, he assumed that it was due to some type of neural mechanism. He hypothesised that abnormalities could occur in a variety of brain regions, including the prefrontal, auditory, and language regions of the cortex. Many members of his department, including Alzheimer and Nissl, were actively involved in the search for the neuropathological lesions that would characterise schizophrenia. Although Kraepelin did not use the term ‘negative symptoms', he describes them comprehensively and states explicitly that he believes the symptoms of schizophrenia can be explained in terms of brain dysfunction:“If it should be confirmed that the disease attacks by preference the frontal areas of the brain, the central convolutions and central lobes, this distribution would in a certain measure agree with our present views about the site of the psychic mechanisms which are principally injured by the disease. On various grounds, it is easy to believe that the frontal cortex, which is specially well developed in man, stands in closer relation to his higher intellectual abilities, and these are the faculties which in our patients invariably suffer profound loss in contrast to memory and acquired ability.” Kraepelin (1919, p. 219)

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