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Bioinformatics of the Brain

of mostly frontal hub regions. The authors conclude that dsyconnectivity of

brain regions in this disease is a general finding reported by many researchers

and highly connected hub regions display abnormalities.

Functional brain networks in schizophrenia are investigated in [44] to re-

veal localized functional connectivity abnormalities at three different levels:

either in regional connectivity strength or node degrees; edge strengths and

interconnected subnetworks. Abnormalities of the prefrontal cortex (PFC) in

this disease have been reported in various studies.

Structure of hubs in schizophrenia is studied in [45] where the authors re-

port strong evidence for network abnormalities of prefrontal hubs, and moder-

ate evidence for network abnormalities of limbic, temporal, and parietal hubs.

The authors also postulate that a wide range of symptoms of schizophrenia

may be due to abnormalities of brain hubs.

Connectivity impairment between brain network regions in schizophrenia

is investigated in [46] over 72 cerebral regions in 15 healthy subjects and 12

subjects with schizophrenia. Functional connectivity was found to be signifi-

cantly reduced in patients with increased diversity of functional connections.

Functional brain networks were found to have reduced clustering and small-

world properties with fewer number of high-degree hubs in edial parietal,

premotor and cingulate, and right orbitofrontal cortical nodes of functional

networks of affected individuals than normal subjects.

In conclusion, the altered brain network structures in this disease may be

summarized as reduced average path length, the existence of abnormal frontal

hubs, reduced clustering and segregated brain regions with less connections

than normal. These characteristics may prove to be decisive in diagnosing

patients with schizophrenia.

9.7.3

Other Disease Networks

PD is a progressive neurological disorder that affects the nervous system,

characterized by progressive neuronal loss in the brain. As with all other

neurological disorders, alterations of connectome topology in patients with PD

is observed in a number of studies. Changes in connectome in PD is surveyed

in [47] to conclude that it is difficult to have clear-cut conclusions about the

functional connectome changes associated with PD and parkinsonism.

Freezing of gait (FOG) is one of the disturbances developed in patients

with PD. Resting-state fMRI values were investigated in [48] with 28 PD

patients, 15 with FOG and 13 without it, to find that patients with FOG

had reduced functional connectivity across many seeds. The authors conclude

that alterations in the resting state functional connectivity of the opercular

parietal cortex may be one of the substrates of FOG.

Global structural connectome properties in PD using meta-analysis were

investigated in [49] in patients with PD and healthy subjects in to discover

that the clustering coefficient is significantly reduced and characteristic path

length is significantly increased in PD patients compared with the healthy