Default Mode Network and: hyper-connectivity, hypo-connectivity, interconnectivity and intraconnectivity

What is Hypoconnectivity in the brain?

Early and pronounced social-visual circuit hypoconnectivity is a key underlying neurobiological feature describing GeoPref ASD and may be critical for future social-communicative development and represent new treatment targets for early intervention in these individuals.

What is the meaning of Hyperconnectivity?

Hyperconnectivity is a state of unified communications (UC) in which the traffic-handling capacity and bandwidth of a network always exceed the demand. The number of communications pathways and nodes is much greater than the number of subscribers.

How is functional connectivity measured?

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Functional connectivity can be assessed with resting-state functional MRI (rs-fMRI), which measure the blood oxygenation level-dependent signal when subjects are positioned in the scanner in an awake-state without performing any particular task.

What is the default mode network in the brain?

Thus, the default mode network is a group of brain regions that seem to show lower levels of activity when we are engaged in a particular task such as paying attention, but higher levels of activity when we are awake and not involved in any specific mental exercise.

What is a functional network?

Functional networks, i.e. networks representing the interactions between the elements of a complex system and reconstructed from the observed elements’ dynamics, are becoming a fundamental tool to unravel the structures created by the movement of information in systems like the human brain.

What does negative connectivity mean?

Since the very inception of R-fMRI, negative functional connectivity (NFC) has been reported (Biswal et al., 1995). NFC refers to spontaneous BOLD signals in two brain regions that have a negative Pearson cross-correlation coefficient; sometimes it is also called an anticorrelation.

What are the three brain networks?

The three brain networks that are connected and work together that are essential to learning are the recognition, strategic, and affective networks.

What is structural connectivity?

Structural connectivity is defined as the existence of white matter tracts physically interconnecting brain regions and is typically measured in vivo in humans using diffusion weighted imaging.

What is structural and functional connectivity?

Structural connectivity indicates the part of the landscape that is actually connected through e.g. corridors. In contrast, functional connectivity includes species specific aspects and their interaction with landscape structures. Thus, functional connectivity is actual connectivity from a species’ perspective.

What is structural connectivity in brain?

Structural connectivity refers to the anatomical organization of the brain by means of fiber tracts. … Functional connectivity refers to statistical dependence between time series of electro-physiological activity and (de)oxygenated blood levels in distinct regions of the brain.

What is functional brain connectivity?

On a general note, functional connectivity is defined as the statistical relationships between cerebral signals over time and thus potentially allows conclusions to be made regarding the functional interactions between two or more brain regions.

What is the function of the default mode network?

The brain’s default network is a set of regions more active during passive tasks than tasks demanding focused external attention. One hypothesis is that the default network contributes to internal modes of cognition used when remembering, thinking about the future, and mind wandering.

Is the amygdala part of the default mode network?

6–9). These regions include the hippocampus, amygdala, anterior cingulate, ventromedial prefrontal cortex, and dorsal medial prefrontal cortex and fall within the anterior portion of the DMN.

What is EEG connectivity?

Connectivity analyses in M/EEG traditionally include the examination for changes in coherence between sources or sensors. Coherence can be defined as the covariation in amplitude and phase between two signals and quantifies the linear correlation between two time series, and this on the frequency domain (Bowyer, 2016).

Can EEG measure functional connectivity?

For EEG we find a significant connectivity-phenotype relationship with IQ. The actual spatial patterns of functional connectivity are quite different between fMRI and source-space EEG. However, within EEG we observe clusters of functional connectivity that are consistent across frequency bands.

What is imaginary coherence?

One of these new measures, the Imaginary Part of Coherency (ICOH), proposed by Nolte in 2004 [18], is aimed at eliminating all sources of extraneous coherence that are a consequence of instantaneous activity. What is left, the Imaginary Part, captures true source interactions at a given time lag.