Kim Maria Cecil PhD, Presenter: Nothing to Disclose

Kim N. Dietrich PhD, MS, Abstract Co-Author: Nothing to Disclose

Caleb M. Adler MD, Abstract Co-Author: Speakers Bureau, AstraZeneca PLC

James C. Eliassen PhD, Abstract Co-Author: Nothing to Disclose

Bruce P Lanphear MD, MPH, Abstract Co-Author: Nothing to Disclose

We examined neuronal activation with functional magnetic resonance imaging (fMRI) during performance of tasks assessing executive functioning in a population of young adults with a documented history of prenatal and childhood lead exposure.

Adult participants (N=33, mean age 21 y, 14 women) of a longitudinal birth cohort studying the effects of lead exposure completed two paradigms: an identical pairs continuous performance task (CPT) and a visual oddball paradigm during fMRI. Using a 3T MR scanner, a T2 weighted gradient EPI sequence was employed for fMRI acquisition. An MDEFT sequence provided a high-resolution whole brain anatomic dataset. Raw EPI data was corrected for Nyquist ghosting and geometrical distortion artifacts. fMRI data was processed using AFNI and SPM software.

For the attention paradigm (CPT), increased mean blood lead levels were associated with decreased activation in posterior portions of the parietal cortex including the bilateral precuneus (BA31) and posterior cingulate (BA31). Decreased activation was also observed in the right insula (BA13), left superior temporal gyrus (BA22) and in the hippocampal complex (BA36). For males, they alone showed decreased activation in several additional brain regions including portions of the frontal cortex, including bilateral superior frontal gyrus (BA 8) and precentral gyrus and lobule (BA 5, 6) and subcortical structures including bilateral thalamus and putamen. For the response inhibition task (visual oddball), increased mean blood lead levels for the group were associated with increased activation for a blue “X” target response within the left inferior frontal (BA 6, 9) and left precentral gyrus (BA 2,3 4).

Impairments of executive function have been linked to lead exposure. This work demonstrated lead associated patterns of brain function in performance of tasks requiring executive functioning. Increased blood lead levels were associated with decreased activation in parietal regions associated with elements of attention. For response inhibition, in order to correctly respond to the appropriate target, the participants with higher childhood blood lead levels required additional activation within the frontal lobe and the precentral gyrus.

This work holds significance by demonstrating how lead exposure during development is associated with damaged and compensatory brain functioning.

Cecil, K, Dietrich, K, Adler, C, Eliassen, J, Lanphear, B, Functional MRI Studies Examining Executive Functioning in Adults with Childhood Lead Exposure.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8012324.html