Cocaine administration decreases functional connectivity in human primary visual and motor cortex as detected by functional MRI

Abstract

Functional magnetic resonance imaging (fMRI) was conducted to observe the effects of cocaine administration on the physiological fluctuations of fMRI signal in two brain regions. Seven long‐term cocaine users with an average age of 32 years and 8 years of cocaine use history were recruited for the study. A T2*‐weighted fast echo‐planar imaging (EPI) pulse sequence was employed at 1.5 T to acquire three sets of brain images for each subject under three conditions (at rest, after saline injection, and after cocaine injection [0.57 mg/kg]). Cross‐correlation maps were constructed using the synchronous, low frequency signal from voxel time courses after filtering respiratory, cardiac, and other physiological noise. A quantitative evaluation of the changes in functional connectivity was made using spatial correlation coefficient (SCC) analysis. A marked 50% reduction in SCC values in the region of primary visual cortex and 43% reduction in SCC values in the region of primary motor cortex were observed after cocaine administration. This significant reduction in SCC values in these cortical regions is a reflection of changes in neuronal activity. It is suggested that the observed changes in low frequency components after acute cocaine administration during a resting, no‐task situation may be used as a baseline reference source when assessing the effects of cocaine on task‐driven activation or on mesolimbic dopamine pathways. Magn Reson Med 43:45–51, 2000. © 2000 Wiley‐Liss, Inc.

Characterization of effects of mean arterial blood pressure induced by cocaine and cocaine methiodide on BOLD signals in rat brain

“…Nevertheless, Gollub et al (8) noted that functional activation by visual stimulation, as measured by BOLD contrast, did not change significantly after cocaine administration, although blood flow was decreased by 14% due to cerebrovascular constriction. In a previous work we also demonstrated that acute cocaine administration alters functional synchrony in the visual and motor cortex regions, as observed by fMRI using spontaneous low-frequency component analysis (9).…”

Detecting low‐frequency functional connectivity in fMRI using a self‐organizing map (SOM) algorithm

“…Thus, these fluctuations agree with the concept of functional connectivity: a descriptive measure of spatio-temporal correlations between spatially distinct regions of cerebral cortex [Friston et al, 1993]. Several recent studies have shown decreased low-frequency correlations for patients in pathological states (such as multiple sclerosis [Lowe et al, 2002] or cocaine use [Li et al, 2000]). Accordingly, low-frequency functional connectivity may be important as a potential indicator of regular neuronal activity within the brain.…”

Mobilization of Medial and Lateral Frontal-Striatal Circuits in Cocaine Users and Controls: An Interleaved TMS/BOLD Functional Connectivity Study

“…While the functional connectivity of these circuits in cocainedependent individuals has been measured in a resting state Hu et al, 2015;Li et al, 2000;Tomasi et al, 2010), the goal of this study was to investigate the functional connectivity in these circuits when they were engaged by an external source. The primary results demonstrate that (1) ventral striatal areas responsible for limbic arousal are not as responsive to the same level of medial prefrontal stimulation in cocaine users as controls (consistent with opponent process theory), (2) dorsal striatal areas typically implicated in cognitive control and habit formation have similar response profiles in cocaine users and controls, and (3) the reciprocal relationship between DLPFC stimulation and Brodmann 10 (MPFC) attenuation observed in controls is disrupted in cocaine users.…”