Journal Article

Functional connectivity and alterations in baseline brain state in humans

Martuzzi, Roberto, Qiu, Maolin, Rajeevan, Nallakkandi, Constable, R. Todd, Ramani, Ramachandran

2010

Overview

This work examines the influence of changes in baseline activity on the intrinsic functional connectivity fMRI (fc-fMRI) in humans. Baseline brain activity was altered by inducing anesthesia (sevoflurane end-tidal concentration 1%) in human volunteers and fc-fMRI maps between the pre-anesthetized and anesthetized conditions were compared across different brain networks. We particularly focused on low-level sensory areas (primary somatosensory, visual, and auditory cortices), the thalamus, and pain (insula), memory (hippocampus) circuits, and the default mode network (DMN), the latter three to examine higher-order brain regions. The results indicate that, while fc-fMRI patterns did not significantly differ (p<0.005; 20-voxel cluster threshold) in sensory cortex and in the DMN between the pre- and anesthetized conditions, fc-fMRI in high-order cognitive regions (i.e. memory and pain circuits) was significantly altered by anesthesia. These findings provide further evidence that fc-fMRI reflects intrinsic brain properties, while also demonstrating that 0.5 MAC sevoflurane anesthesia preferentially modulates higher-order connections.

• Publisher: Elsevier Inc,Elsevier Limited
• Subject: Adult / Anesthesia / Anesthetics, Inhalation / Brain / Brain - physiology / Brain Mapping / Consciousness / Default mode network / Female / Functional connectivity / Functional magnetic resonance imaging / Hippocampus / Humans / Hypotheses / Image Processing, Computer-Assisted / Insula / Low-sensory areas / Magnetic Resonance Imaging / Male / Methyl Ethers / Nerve Net - anatomy & histology / Nerve Net - physiology / Neural Pathways - anatomy & histology / Neural Pathways - physiology / Pain - physiopathology / Pain - psychology / Sevoflurane / Studies / Thalamus / Young Adult