Functional Frontostriatal Deficits in Pediatric
PTSD-Go-NoGo Task.

Introduction

Subjects with PTSD have problems sustaining attention, likely due to hyperarousal. Studies measuring sustained attention and response inhibition with the Go-NoGo task have shown frontal lobe involvement in suppression of inappropriate behavioral responses. The neural correlates of this process is not fully understood.

We investigated the functional neuroanatomical correlates of attention and response inhibition in adolescents with history of interpersonal trauma and PTSD symptoms.

Method

Six girls (aged 11-15) with a history of trauma (sexual/physical abuse and violence) and 7 age-matched control girls (aged 10-22 years) underwent a 3T fMRI scan during a Go/No-Go response inhibition task.

Result

Controls vs. PTSD: Controls show significantly greater activation than PTSD group in left ventral striatum extending to bilateral caudate and right inferior frontal regions.

PTSD vs. Controls: PTSD group show greater activation than controls in left insula and bilateral nuclei of brainstem/midbrain including thalamus/hypothalamus.

Conclusions

Subjects with PTSD respond to requirements for increased attention and response inhibition with increased activity in areas related to autonomic arousal, but not with increased activation of frontal and striatal regions.

Consistent with the findings in the control group, the ventral prefrontal cortex has previously been implicated in response-inhibition.Failure to normally activate frontal lobe regions, such as the medial prefrontal cortex, also has been reported in adults with PTSD when exposed to traumatic pictures and stories.

A significant portion of the striatal activation seen in controls versus PTSD subjects was located in the ventral striatum, with a maximum peak in the left nucleus accumbens. This region is believed to be important in associating neutral stimuli with positive reward.

Increased pontine/brainstem/midbrain activation observed in the PTSD group versus controls may indicate increased autonomic arousal during the the Go/NoGo task.

Our finding of increased left insula activation in PTSD replicates recent studies showing increased activation of the left anterior insula in adults with combat-related PTSD when exposed to combat-related words compared to negative words in the Emotional Counting Stroop task. Thus, increased insular activation in the PTSD group may reflect the increased levels of anxiety found in pediatric PTSD populations.

Mackenzie K, Carrion V, Garrett A, Menon V, Saltzman K, Pageler N, Reiss A. "Functional Frontostriatal Deficits in Pediatric PTSD-Go-NoGo Task." Presented at 49th Annual Meeting of the American Academy of Child and Adolescent Psychiatry, San Francisco, CA, October 22-27, 2002.