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Loss of resting-state posterior cingulate flexibility is associated with memory disturbance in left temporal lobe epilepsy.

Douw L, Leveroni CL, Tanaka N, Emerton BC, Cole AC, Reinsberger C, Stufflebeam SM - PLoS ONE (2015)

Bottom Line: Lower PCC flexibility, particularly in the contralateral (i.e. right) hemisphere, was found in memory-disturbed LTLE patients, who had up to 22% less flexible connectivity.No significant group differences were found with respect to hippocampal flexibility, stationary connectivity during both rs-fMRI and t-fMRI, or flexibility during t-fMRI.This study indicates that the dynamics of resting-state connectivity are associated with cognitive status of LTLE patients, rather than stationary connectivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States of America; Department of Radiology, Harvard Medical School, Boston, MA, United States of America; Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.

ABSTRACT
The association between cognition and resting-state fMRI (rs-fMRI) has been the focus of many recent studies, most of which use stationary connectivity. The dynamics or flexibility of connectivity, however, may be seminal for understanding cognitive functioning. In temporal lobe epilepsy (TLE), stationary connectomic correlates of impaired memory have been reported mainly for the hippocampus and posterior cingulate cortex (PCC). We therefore investigate resting-state and task-based hippocampal and PCC flexibility in addition to stationary connectivity in left TLE (LTLE) patients. Sixteen LTLE patients were analyzed with respect to rs-fMRI and task-based fMRI (t-fMRI), and underwent clinical neuropsychological testing. Flexibility of connectivity was calculated using a sliding-window approach by determining the standard deviation of Fisher-transformed Pearson correlation coefficients over all windows. Stationary connectivity was also calculated. Disturbed memory was operationalized as having at least one memory subtest score equal to or below the 5th percentile compared to normative data. Lower PCC flexibility, particularly in the contralateral (i.e. right) hemisphere, was found in memory-disturbed LTLE patients, who had up to 22% less flexible connectivity. No significant group differences were found with respect to hippocampal flexibility, stationary connectivity during both rs-fMRI and t-fMRI, or flexibility during t-fMRI. Contralateral resting-state PCC flexibility was able to classify all but one patient with respect to their memory status (94% accuracy). Flexibility of the PCC during rest relates to memory functioning in LTLE patients. Loss of flexible connectivity to the rest of the brain originating from the PCC, particularly contralateral to the seizure focus, is able to discern memory disturbed patients from their preserved counterparts. This study indicates that the dynamics of resting-state connectivity are associated with cognitive status of LTLE patients, rather than stationary connectivity.

No MeSH data available.


Related in: MedlinePlus

Memory and cPCC flexibility.Scatterplot of contralateral posterior cingulate cortex (cPCC) flexibility and memory. Patients with memory disturbance had decreased cPCC flexibility compared to memory preserved patients (p < 0.01). Dotted line indicates a threshold of 0.234, which separates memory preserved and disturbed patients, apart from patient 8 in Table 1 (indicated in red in this figure).
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pone.0131209.g002: Memory and cPCC flexibility.Scatterplot of contralateral posterior cingulate cortex (cPCC) flexibility and memory. Patients with memory disturbance had decreased cPCC flexibility compared to memory preserved patients (p < 0.01). Dotted line indicates a threshold of 0.234, which separates memory preserved and disturbed patients, apart from patient 8 in Table 1 (indicated in red in this figure).

Mentions: Hippocampal flexibility did not differ between patients with and without memory disturbance (iHC p = 0.958, contralateral p = 0.635). In contrast, cPCC flexibility was significantly lower in patients with disturbed memory compared to patients with preserved memory functioning after correction for multiple comparisons (Fig 2; p = 0.003), while the same result was trending in the iPCC (p = 0.093). Flexibility was significantly correlated between the iPCC and cPCC (Tau = 0.550, p = 0.003), further pointing towards a bilateral pattern, instead of an effect specific to the contralateral PCC.


Loss of resting-state posterior cingulate flexibility is associated with memory disturbance in left temporal lobe epilepsy.

Douw L, Leveroni CL, Tanaka N, Emerton BC, Cole AC, Reinsberger C, Stufflebeam SM - PLoS ONE (2015)

Memory and cPCC flexibility.Scatterplot of contralateral posterior cingulate cortex (cPCC) flexibility and memory. Patients with memory disturbance had decreased cPCC flexibility compared to memory preserved patients (p < 0.01). Dotted line indicates a threshold of 0.234, which separates memory preserved and disturbed patients, apart from patient 8 in Table 1 (indicated in red in this figure).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481466&req=5

pone.0131209.g002: Memory and cPCC flexibility.Scatterplot of contralateral posterior cingulate cortex (cPCC) flexibility and memory. Patients with memory disturbance had decreased cPCC flexibility compared to memory preserved patients (p < 0.01). Dotted line indicates a threshold of 0.234, which separates memory preserved and disturbed patients, apart from patient 8 in Table 1 (indicated in red in this figure).
Mentions: Hippocampal flexibility did not differ between patients with and without memory disturbance (iHC p = 0.958, contralateral p = 0.635). In contrast, cPCC flexibility was significantly lower in patients with disturbed memory compared to patients with preserved memory functioning after correction for multiple comparisons (Fig 2; p = 0.003), while the same result was trending in the iPCC (p = 0.093). Flexibility was significantly correlated between the iPCC and cPCC (Tau = 0.550, p = 0.003), further pointing towards a bilateral pattern, instead of an effect specific to the contralateral PCC.

Bottom Line: Lower PCC flexibility, particularly in the contralateral (i.e. right) hemisphere, was found in memory-disturbed LTLE patients, who had up to 22% less flexible connectivity.No significant group differences were found with respect to hippocampal flexibility, stationary connectivity during both rs-fMRI and t-fMRI, or flexibility during t-fMRI.This study indicates that the dynamics of resting-state connectivity are associated with cognitive status of LTLE patients, rather than stationary connectivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States of America; Department of Radiology, Harvard Medical School, Boston, MA, United States of America; Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.

ABSTRACT
The association between cognition and resting-state fMRI (rs-fMRI) has been the focus of many recent studies, most of which use stationary connectivity. The dynamics or flexibility of connectivity, however, may be seminal for understanding cognitive functioning. In temporal lobe epilepsy (TLE), stationary connectomic correlates of impaired memory have been reported mainly for the hippocampus and posterior cingulate cortex (PCC). We therefore investigate resting-state and task-based hippocampal and PCC flexibility in addition to stationary connectivity in left TLE (LTLE) patients. Sixteen LTLE patients were analyzed with respect to rs-fMRI and task-based fMRI (t-fMRI), and underwent clinical neuropsychological testing. Flexibility of connectivity was calculated using a sliding-window approach by determining the standard deviation of Fisher-transformed Pearson correlation coefficients over all windows. Stationary connectivity was also calculated. Disturbed memory was operationalized as having at least one memory subtest score equal to or below the 5th percentile compared to normative data. Lower PCC flexibility, particularly in the contralateral (i.e. right) hemisphere, was found in memory-disturbed LTLE patients, who had up to 22% less flexible connectivity. No significant group differences were found with respect to hippocampal flexibility, stationary connectivity during both rs-fMRI and t-fMRI, or flexibility during t-fMRI. Contralateral resting-state PCC flexibility was able to classify all but one patient with respect to their memory status (94% accuracy). Flexibility of the PCC during rest relates to memory functioning in LTLE patients. Loss of flexible connectivity to the rest of the brain originating from the PCC, particularly contralateral to the seizure focus, is able to discern memory disturbed patients from their preserved counterparts. This study indicates that the dynamics of resting-state connectivity are associated with cognitive status of LTLE patients, rather than stationary connectivity.

No MeSH data available.


Related in: MedlinePlus