Deficits in functional connectivity of hippocampal and frontal lobe circuits after traumatic axonal injury

Carlos D. Marquez De La Plata, Juanita Garces, Ehsan Shokri Kojori, Jack Grinnan, Kamini Krishnan, Rajesh Pidikiti, Jeffrey Spence, Michael D. Devous, Carol Moore, Rodderick McColl, Christopher Madden, Ramon Diaz-Arrastia

Research output: Contribution to journalArticlepeer-review

106 Scopus citations


Objective: To examine the functional connectivity of hippocampal and selected frontal lobe circuits in patients with traumatic axonal injury (TAI). Design: Observational study. Setting: An inpatient traumatic brain injury unit. Imaging and neurocognitive assessments were conducted in an outpatient research facility. Participants: Twenty-five consecutive patients with brain injuries consistent with TAI and acute subcortical white matter abnormalities were studied as well as 16 healthy volunteers of similar age and sex. Interventions: Echo-planar and high-resolution T1-weighted images were acquired using 3-T scanners. Regions of interest (ROI) were drawn bilaterally for the hippocampus, anterior cingulate cortex (ACC), and dorsolateral prefrontal cortex and were used to extract time series data. Blood oxygenation level-dependent data from each ROI were used as reference functions for correlating with all other brain voxels. Interhemispheric functional connectivity was assessed for each participant by correlating homologous regions using a Pearson correlation coefficient. Patient functional and neurocognitive outcomes were assessed approximately 6 months after injury. Main Outcome Measures: Interhemispheric functional connectivity, spatial patterns of functional connectivity, and associations of connectivity measures with functional and neurocognitive outcomes. Results: Patients showed significantly lower interhemispheric functional connectivity for the hippocampus and ACC. Controls demonstrated stronger and more focused functional connectivity for the hippocampi and ACC, and a more focused recruitment of the default mode network for the dorsolateral prefrontal cortex ROI. The interhemispheric functional connectivity for the hippocampus was correlated with delayed recall of verbal information. Conclusions: Traumatic axonal injury may affect interhemispheric neural activity, as patients with TAI show disrupted interhemispheric functional connectivity. More careful investigation of interhemispheric connectivity is warranted, as it demonstrated a modest association with outcome in chronic TBI.

Original languageEnglish (US)
Pages (from-to)74-84
Number of pages11
JournalArchives of neurology
Issue number1
StatePublished - Jan 2011

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Clinical Neurology


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