Article

Effects of Prenatal Alcohol Exposure on Brain Activation During an Arithmetic Task: An fMRI Study

Department of Biomedical Engineering, Emory University School of Medicine, Atlanta, GA, USA.
Alcoholism Clinical and Experimental Research (Impact Factor: 3.31). 09/2009; 33(11):1901-8. DOI: 10.1111/j.1530-0277.2009.01028.x
Source: PubMed

ABSTRACT While behavioral studies have established that prenatal alcohol exposure (PAE) can result in diminished arithmetic processing capability, the underlying neural correlates of this deficit are still unclear. The aim of the present study was to use functional magnetic resonance imaging to determine the effect of PAE on neuronal activation during a subtraction task.
Participants were young adults from a low socio-economic status population who were identified prenatally; the sample consisted of healthy unexposed controls (n = 17) and PAE who were subdivided based on the presence (n = 19) or absence of physical dysmorphic signs (n = 18). Multiple regression analysis was used to determine extent of activation and percent signal change during arithmetic processing, using a letter-matching task as the baseline. Region of interest analysis of activation was performed in the native space and normalized for each individual to compensate for the considerable variability in head size observed in the alcohol-exposed population.
An exposure-dependent response was observed in task performance and neuronal activation. Dysmorphic PAE individuals showed significantly lower task-related performance and activation in regions known to be associated with arithmetic processing, including left superior and right inferior parietal regions and medial frontal gyrus, while the nondysmorphic PAE group was generally intermediate but not significantly different from the control group in task performance and activation.
Results indicate that there is a range of effects of PAE on arithmetic processing and that the severity of this deficit may be dependent on degree of impairment demonstrated by the exposed individual. Evidence of physical dysmorphia may be indicative of functional damage to regions associated with arithmetic calculation, resulting in markedly impaired neuronal recruitment.

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    • "In an arithmetic task-based fMRI experiment under IRB approval , 44 participants were scanned in 3T Siemens Trio scanner (Santhanam et al., 2009) at the Biomedical Imaging Technology Center of Emory University. They were all young adults (age 20– 26) who were from 3 groups including unexposed healthy controls (16 subjects), exposure with the absence of dysmorphic signs (14 subjects) and exposure with presence of dysmorphic signs (14 subjects) (Santhanam et al., 2009). The task was presented in blocks, and the total scan included 102 time points (the first 2 points are ignored). "
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    • "In regards to directly assessing brain-behavior relationships , functional magnetic resonance imaging (fMRI) studies show significantly lower activation during mental arithmetic tasks in the parietal and frontal regions in PAE [Santhanam et al., 2009]. Similarly, math performance has been related to white matter fractional anisotropy in those with PAE [Lebel et al., 2010]. "
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    • "For instance, a slight change to the size or location of an ROI might dramatically alter its structural and/or functional connectivity profiles [Li et al., 2010b, 2012; Zhu et al., 2011, 2012]. (4) It is very challenging to identify accurate ROIs in PCE affected brains as the brain architecture might have been altered during neurodevelopment [Chen et al., 2011; Coles et al., 2011; Li et al., 2008, 2011; Santhanam et al., 2009, 2011]. "
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