PT  - JOURNAL ARTICLE
AU  - Anzar Abbas
AU  - Michaël Belloy
AU  - Amrit Kashyap
AU  - Jacob Billings
AU  - Maysam Nezafati
AU  - Shella Keilholz
TI  - Quasi-periodic patterns contribute to functional connectivity in the brain
AID  - 10.1101/323162
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 323162
4099  - http://biorxiv.org/content/early/2018/05/16/323162.short
4100  - http://biorxiv.org/content/early/2018/05/16/323162.full
AB  - Functional connectivity is widely used to study the coordination of activity between brain regions over time. Functional connectivity in the default mode and task positive networks is particularly important for normal brain function. However, the processes that give rise to functional connectivity in the brain are not fully understood. It has been postulated that low-frequency neural activity plays a key role in establishing the functional architecture of the brain. Quasi-periodic patterns (QPPs) are a reliably observable form of low-frequency neural activity that involve the default mode and task positive networks. Here, QPPs from resting-state and working memory task-performing individuals were acquired. The spatial pattern and the temporal frequency of the QPPs between the two groups was compared and their contribution to functional connectivity in the brain was measured. In task-performing individuals, the spatial pattern of the QPP changes, particularly in task-relevant regions; and the QPP tends to occur with greater strength and frequency. Differences in the QPPs between the two groups could partially account for the variance in functional connectivity between resting-state and task-performing individuals. The QPPs contribute strongly to connectivity in the default mode and task positive networks and to the degree of anti-correlation seen between the two networks. Many of the connections affected by QPPs are also disrupted during several neurological disorders. These findings help towards understanding the dynamic neural processes that give rise to functional connectivity in the brain and how they may be disrupted during disease.