Increased "Default Mode" Activity in Adolescents Prenatally Exposed to Cocaine

Biomedical Imaging Technology Center, Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, 101 Woodruff Circle, Atlanta, GA 30322, USA.
Human Brain Mapping (Impact Factor: 5.97). 05/2011; 32(5):759-70. DOI: 10.1002/hbm.21059
Source: PubMed


Prenatal cocaine exposure (PCE) is associated with attention/arousal dysregulation and possible inefficiencies in some cognitive functions. However, the neurobiological bases of these teratogenic effects have not been well characterized. Because activities in the default mode network (DMN) reflect intrinsic brain functions that are closely associated with arousal regulation and cognition, alterations in the DMN could underlie cognitive effects related to PCE. With resting-state and task activation functional magnetic resonance imaging (fMRI), this study investigated the possible PCE related changes in functional brain connectivity and brain activation in the DMN. In the resting state, the PCE group was found to have stronger functional connectivity in the DMN, as compared to the nonexposed controls. During a working memory task with emotional distracters, the PCE group exhibited less deactivation in the DMN and their fMRI signal was more increased by emotional arousal. These data revealed additional neural effects related to PCE, and consistent with previous findings, indicate that PCE may affect behavior and functioning by increasing baseline arousal and altering the excitatory/inhibitory balancing mechanisms involved in cognitive resource allocation.

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Available from: Stephan B Hamann
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    • "Findings in healthy neonates and children show that frontal gyrus is one of the fastest growing regions of GM growth during this time (Gilmore et al., 2012). These anterior brain regions are integral to multiple developing brain networks that are fundamentally involved in essential cognitive functions including attention, perception, memory , inhibition, as well as development of default mode network activity (Gao et al., 2009; Lin et al., 2008; Yap et al., 2011). Our data represent only a single time point embedded within this rapidly changing period, and do not shed light on whether the cocaine-related GM and CSF differences may be normalized by an accelerated postnatal pace of growth. "
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    • "Interestingly, based on previous studies (Buckner, 2012; Buckner et al., 2008; Greicius et al., 2003, 2004; He et al., 2013; Liu et al., 2013; Song et al., 2013), the aforementioned regions are the key regions of the default mode network. The default mode network is engaged when individuals are not focused on the outside world, and it is involved in many neurophysiological processes of cognitive and emotional function, such as episodic memory and emotional regulation (Buckner et al., 2008; Greicius et al., 2004; Li et al., 2011b; Raichle et al., 2001). The PCC/Pcu is located in the posterior midline of brain and is a central hub that plays a significant role in the default mode network (Buckner et al., 2009). "
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