DMN deactivations. Longitudinal comparison of the “default mode” deactivations in adolescents prenatally exposed to cocaine Zhihao Li, Priya Santhanam, Claire Coles, Mary Ellen Lynch, Stephan Hamann, and Xiaoping Hu Biomedical Engineering, Emory University & Georgia Institute of Technology, Atlanta, Georgia, United States, Psychiatry and Behavioral Science, Emory University, Atlanta, Georgia, United States, Psychology, Emory University, Atlanta, Georgia, United States

Introduction Brain structural outcomes in individuals exposed prenatally to cocaine have been reported previously . However, findings from previous studies are limited and need to be replicated . In the present study, an automated method was used to segment the entire brain into various cortical and sub-cortical regions of interest (ROIs). Effects of prenatal cocaine exposure (PCE) on the brain were examined as the volumetric differences between PCE and control participants in these ROIs. Thus, more detailed information about PCE effects on brain structures could be observed. In addition, possible gender difference in PCE effect on brain volume was also investigated. Such gender effect has not been reported in human samples. Methods Two participant groups (control: 11 males and 16 females, PCE: 23 males and 13 females) participated in this study. Participants in both groups were recruited after birth from the same hospital and are similar in demographic variables (e.g., race, age, education, and head circumference). For each participant, T1-weighted images were obtained on a 3.0 Tesla Siemens Magnetom TRIO scanner with an MPRAGE sequence (TR = 2300 ms, TE = 3.02 ms, TI = 1100 ms, Flip Angle = 8°, voxel size = 1×1×1 mm). FreeSurfer was used to automatically segment cortical and sub-cortical ROIs. Volumes of these ROIs were also calculated with FreeSurfer . PASW Statistics (SPSS) 18 was used for statistical analysis. Results A 2 × 2 (group: control, PCE; gender: male, female) ANOVA showed that volumes of sub-cortical grey matter regions, including the caudate, putamen, pallidum, thalamus, amygdala, hippocampus and accumbens area in both hemispheres, were not significantly affected by PCE (no significant effect of group factor). In contrast, gross volumes of the left and right cerebral cortices were significantly reduced by PCE. The same ANOVA of the segmented cortical ROIs indicated that PCE exerted an adverse effect (volume reduction) on a few cortical regions. These regions are shown in Figure 1 (In the left hemisphere, A: Frontal Pole, B: Rostral Middle Frontal Gyrus, C: Precentral Gyrus, D: Inferior Parietal Lobule, E: Precuneus Cortex. In the right hemisphere, F: Caudal Middle Frontal Gyrus, G: Rostral Middle Frontal Gyrus, H: Pars Triangularis, I: Pars Opercularis, J: Medial Orbital Frontal Cortex, K: Caudal Anterior Cingulate Cortex, L: Precuneus Cortex). In addition, a few cortical ROIs exhibited a significant group × gender interaction effect, indicating a gender difference in PCE effect on brain volume. These regions are shown in Figure 2 (In the left hemisphere, A: Supramarginal Gyrus, B: Inferior Parietal Lobule, C: Banks of Superior Temporal Sulcus. In the right hemisphere, D: Inferior Parietal Lobule, E: Superior Frontal Gyrus, F: Precuneus Cortex, G: Temporal Pole). A t-test between the control and PCE groups for each gender showed that all these regions were significantly affected by PCE in the female, but not in the male participants, except for the left supramarginal gyrus which demonstrated no significant PCE effect in both the female and male participants. Discussion and Conclusion Although the PCE and control groups were not generally different in head circumference and cognitive outcomes, the present study suggests that the left and right cerebral cortices are altered by prenatal cocaine exposure. More interestingly, the gender difference in PCE effect suggests that female may be more vulnerable to PCE than male. Thus, the gender factor should be considered in future studies of PCE effects on human brain structures and functions.

BACKGROUNDWhile 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.METHODSParticipants 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.RESULTSAn 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.CONCLUSIONSResults 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.

G. Deshpande, P. Santhanam, Z. Li, G. A. James, C. D. Coles, M. E. Lynch, S. Hamman, and X. P. Hu Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States, Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, United States, Fetal Alcohol Syndrome and Drug Exposure Clinic, Marcus Autism Center, Atlanta, GA, United States, Department of Psychology, Emory University, Atlanta, GA, United States

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text D. H. Kelly, M. E. Lynch, and D. S. Ross, "Improved Sinusoidal Test Charts," J. Opt. Soc. Am. 48, 858_1-859 (1958) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article