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Disruption of caudate working memory activation in chronic blast-related traumatic brain injury.

Newsome MR, Durgerian S, Mourany L, Scheibel RS, Lowe MJ, Beall EB, Koenig KA, Parsons M, Troyanskaya M, Reece C, Wilde E, Fischer BL, Jones SE, Agarwal R, Levin HS, Rao SM - Neuroimage Clin (2015)

Bottom Line: Blast TBI was also associated with worse performance on the Sternberg Item Recognition Task relative to the other groups, although no other group differences were found on neuropsychological measures of episodic memory, inhibition, and general processing speed.These results could not be attributed to caudate atrophy or the presence of PTSD symptoms.Our results point to a specific vulnerability of the caudate to blast injury.

View Article: PubMed Central - PubMed

Affiliation: Research Service Line, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, USA ; Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX, USA.

ABSTRACT
Mild to moderate traumatic brain injury (TBI) due to blast exposure is frequently diagnosed in veterans returning from the wars in Iraq and Afghanistan. However, it is unclear whether neural damage resulting from blast TBI differs from that found in TBI due to blunt-force trauma (e.g., falls and motor vehicle crashes). Little is also known about the effects of blast TBI on neural networks, particularly over the long term. Because impairment in working memory has been linked to blunt-force TBI, the present functional magnetic resonance imaging (fMRI) study sought to investigate whether brain activation in response to a working memory task would discriminate blunt-force from blast TBI. Twenty-five veterans (mean age = 29.8 years, standard deviation = 6.01 years, 1 female) who incurred TBI due to blast an average of 4.2 years prior to enrollment and 25 civilians (mean age = 27.4 years, standard deviation = 6.68 years, 4 females) with TBI due to blunt-force trauma performed the Sternberg Item Recognition Task while undergoing fMRI. The task involved encoding 1, 3, or 5 items in working memory. A group of 25 veterans (mean age = 29.9 years, standard deviation = 5.53 years, 0 females) and a group of 25 civilians (mean age = 27.3 years, standard deviation = 5.81 years, 0 females) without history of TBI underwent identical imaging procedures and served as controls. Results indicated that the civilian TBI group and both control groups demonstrated a monotonic relationship between working memory set size and activation in the right caudate during encoding, whereas the blast TBI group did not (p < 0.05, corrected for multiple comparisons using False Discovery Rate). Blast TBI was also associated with worse performance on the Sternberg Item Recognition Task relative to the other groups, although no other group differences were found on neuropsychological measures of episodic memory, inhibition, and general processing speed. These results could not be attributed to caudate atrophy or the presence of PTSD symptoms. Our results point to a specific vulnerability of the caudate to blast injury. Changes in activation during the Sternberg Item Recognition Task, and potentially other tasks that recruit the caudate, may serve as biomarkers for blast TBI.

No MeSH data available.


Related in: MedlinePlus

Significant two-way interactions (1–7) between group (control vs. TBI) and set size (1, 3, 5) and significant three-way interactions (8–9) between group (control vs. TBI), set size (1, 3, 5) and military status (military vs. control).
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f0020: Significant two-way interactions (1–7) between group (control vs. TBI) and set size (1, 3, 5) and significant three-way interactions (8–9) between group (control vs. TBI), set size (1, 3, 5) and military status (military vs. control).

Mentions: Seven regions demonstrated significant interaction effects of working memory load and the presence/absence of a TBI (Table 3 and Fig. 4). These included 3 cortical regions (left insula/inferior frontal gyrus, bilateral middle orbital frontal gyrus, and right middle occipital gyrus), 3 subcortical regions (right head/body of the caudate, right tail of the caudate, and left caudate/putamen/pallidum), and the cerebellar vermis. In 5 regions (left insula/inferior frontal gyrus, right head/body of the caudate, right tail of the caudate, left caudate/putamen/pallidum, and cerebellar vermis), the two non-injured control groups demonstrated a monotonic increase in fMRI signal intensity with increasing load; the two TBI groups failed to demonstrate this monotonic increase (Fig. 4). In 2 regions (bilateral middle orbital frontal gyrus, and right middle occipital gyrus), the two control groups demonstrated a decrease in activation (“deactivation”) at SS3; in contrast, the TBI groups did not demonstrate deactivation at SS3 (Fig. 4).


Disruption of caudate working memory activation in chronic blast-related traumatic brain injury.

Newsome MR, Durgerian S, Mourany L, Scheibel RS, Lowe MJ, Beall EB, Koenig KA, Parsons M, Troyanskaya M, Reece C, Wilde E, Fischer BL, Jones SE, Agarwal R, Levin HS, Rao SM - Neuroimage Clin (2015)

Significant two-way interactions (1–7) between group (control vs. TBI) and set size (1, 3, 5) and significant three-way interactions (8–9) between group (control vs. TBI), set size (1, 3, 5) and military status (military vs. control).
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477106&req=5

f0020: Significant two-way interactions (1–7) between group (control vs. TBI) and set size (1, 3, 5) and significant three-way interactions (8–9) between group (control vs. TBI), set size (1, 3, 5) and military status (military vs. control).
Mentions: Seven regions demonstrated significant interaction effects of working memory load and the presence/absence of a TBI (Table 3 and Fig. 4). These included 3 cortical regions (left insula/inferior frontal gyrus, bilateral middle orbital frontal gyrus, and right middle occipital gyrus), 3 subcortical regions (right head/body of the caudate, right tail of the caudate, and left caudate/putamen/pallidum), and the cerebellar vermis. In 5 regions (left insula/inferior frontal gyrus, right head/body of the caudate, right tail of the caudate, left caudate/putamen/pallidum, and cerebellar vermis), the two non-injured control groups demonstrated a monotonic increase in fMRI signal intensity with increasing load; the two TBI groups failed to demonstrate this monotonic increase (Fig. 4). In 2 regions (bilateral middle orbital frontal gyrus, and right middle occipital gyrus), the two control groups demonstrated a decrease in activation (“deactivation”) at SS3; in contrast, the TBI groups did not demonstrate deactivation at SS3 (Fig. 4).

Bottom Line: Blast TBI was also associated with worse performance on the Sternberg Item Recognition Task relative to the other groups, although no other group differences were found on neuropsychological measures of episodic memory, inhibition, and general processing speed.These results could not be attributed to caudate atrophy or the presence of PTSD symptoms.Our results point to a specific vulnerability of the caudate to blast injury.

View Article: PubMed Central - PubMed

Affiliation: Research Service Line, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, USA ; Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX, USA.

ABSTRACT
Mild to moderate traumatic brain injury (TBI) due to blast exposure is frequently diagnosed in veterans returning from the wars in Iraq and Afghanistan. However, it is unclear whether neural damage resulting from blast TBI differs from that found in TBI due to blunt-force trauma (e.g., falls and motor vehicle crashes). Little is also known about the effects of blast TBI on neural networks, particularly over the long term. Because impairment in working memory has been linked to blunt-force TBI, the present functional magnetic resonance imaging (fMRI) study sought to investigate whether brain activation in response to a working memory task would discriminate blunt-force from blast TBI. Twenty-five veterans (mean age = 29.8 years, standard deviation = 6.01 years, 1 female) who incurred TBI due to blast an average of 4.2 years prior to enrollment and 25 civilians (mean age = 27.4 years, standard deviation = 6.68 years, 4 females) with TBI due to blunt-force trauma performed the Sternberg Item Recognition Task while undergoing fMRI. The task involved encoding 1, 3, or 5 items in working memory. A group of 25 veterans (mean age = 29.9 years, standard deviation = 5.53 years, 0 females) and a group of 25 civilians (mean age = 27.3 years, standard deviation = 5.81 years, 0 females) without history of TBI underwent identical imaging procedures and served as controls. Results indicated that the civilian TBI group and both control groups demonstrated a monotonic relationship between working memory set size and activation in the right caudate during encoding, whereas the blast TBI group did not (p < 0.05, corrected for multiple comparisons using False Discovery Rate). Blast TBI was also associated with worse performance on the Sternberg Item Recognition Task relative to the other groups, although no other group differences were found on neuropsychological measures of episodic memory, inhibition, and general processing speed. These results could not be attributed to caudate atrophy or the presence of PTSD symptoms. Our results point to a specific vulnerability of the caudate to blast injury. Changes in activation during the Sternberg Item Recognition Task, and potentially other tasks that recruit the caudate, may serve as biomarkers for blast TBI.

No MeSH data available.


Related in: MedlinePlus