Hyperconnectivity is a fundamental response to neurological disruption.

Area of Science:

• Cognitive and Clinical Neurosciences
• Neuroimaging
• Neurological Disorders

Background:

• Noninvasive methods have significantly advanced the study of brain connectivity.
• Functional magnetic resonance imaging (fMRI) is a key tool for examining neural connectivity.
• Understanding connectivity shifts in neurological disorders is crucial for diagnosis and treatment.

Purpose of the Study:

• To critically review the blood oxygen level dependent functional MRI (BOLD fMRI) literature on neural connectivity changes in neurological disorders.
• To demonstrate that pathology degree predicts shifts in local and large-scale brain network connectivity.
• To investigate hyperconnectivity as a common network response to neurological insult.

Main Methods:

• Systematic review of 1,426 studies on functional brain connectivity in neurological disorders.
• Inclusionary criteria applied, resulting in detailed analysis of 126 selected studies.
• Focus on conditions including multiple sclerosis, traumatic brain injury, mild cognitive impairment, and Alzheimer's disease.

Main Results:

• Increased brain connectivity observed in traumatic brain injury and multiple sclerosis.
• Diminished connectivity observed in mild cognitive impairment and Alzheimer's disease as degeneration progresses.
• Connectivity patterns are linked to the degree of neuropathology.

Conclusions:

• Hyperconnectivity is a common response to neurological disruption, observable across different brain regions.
• Both hyper- and hypoconnectivity can occur after neurological disruption, influenced by various factors.
• These findings have implications for understanding network plasticity in neurological disorders.