Trivedi R, Bagga D, Bhattacharya D, Kaur P, Kumar P, Khushu S, Tripathi RP, Singh N (2013). White
matter damage is associated with memory decline in chronic alcoholics: A
quantitative diffusion tensor tractography study. Behavioural Brain Research; 250: 192-198.
10 abstinent chronic alcoholic, 10 demographically equivalent control men
PGI-memory scale (PGIMS) test
Spearman's rank correlation coefficient
Significantly
reduced FA in corpus callosum (CC), fornix (FX), and right hemispheric
arcuate fasciculus (AF), anterior thalamic radiation (ATR), inferior
longitudinal fasciculus (ILF). (where are these regions?)
significant
inverse correlation with memory dysfunction score was observed with
right cingulum, right uncinate fasciculus, right ILF, and left ILF.
Main findings: white matter deficit in these white matter fibers may contribute to underlying dysfunction in memory in alcoholism.
Alcoholism-impaired
effects: cognitive functioning, attention, working memory, speed of
processing, visuospatial abilities, executive functions, impulsivity,
learning, memory and verbal fluency.
The damaging effects
of alcoholism has been focused on the frontal lobes toward the toxicity
of ethanol. Inhibition, categorization, flexibility, deduction of rules,
organization and planning have mostly been found to be impaired in
alcoholism.
Neuroimaging studies have reported an
association between white matter integrity and cognitive performance in
normal aging and alcoholics.
Diffusion tensor tractography
(DTT) offers an overall view of individual fiber bundle in 3D spaces.
It also helps in delineation of specific white matter tracts for
quantitative analysis.
Significance: many studies
have shown brain defects in relation to neurocognitive dysfunction in
alcoholics, but very few have correlated DTI measures and memory
assessment at the same time.
Statistical Analysis: Student's independent t test
was performed to determine the changes in memory dysfunction scores and
DTI measures (FA and MD) among controls and alcoholic groups. In
alcoholic patients as well as healthy controls, Spearman's rank
correlation coefficient was computed to study the relationship between
the white matter tract specific DTI measures and memory dysfunction
scores.
The mesocorticolimbic reward circuit is viewed as
important in encoding maintenance, and retrieval of information. The
mesocorticolimbic reward system consists of several brain regions that
include amygdata, hippocampus, ventral striatum, ventral diencephalon,
and cortical areas such as dorsolateral-prefrontal, orbitofrontal,
temporal pole, subcallosal, and cingulate cortices, parahippocampal
gyri, and the insula.
CNG (cingulum) is a white matter fiber bundle which connects cingulated gyrus with entorhinal cortex. The main function of entorhinal cortex is to relay messages to and from the hippocampus, which is viewed as the epicenter of long-term memory and spatial navigation.
UNC (uncinate fasciculous) is a
ventral associative white matter fiber tract that connects the anterior
temporal lobe with the medial and lateral orbitofrontal cortex. The UNC
has been found to be associated with memory and language impairments in
patients with temporal lobe epilepsy.
CNG (cingulum) is a white matter fiber bundle which connects cingulated gyrus with entorhinal cortex. The main function of entorhinal cortex is to relay messages to and from the hippocampus, which is viewed as the epicenter of long-term memory and spatial navigation.
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