PMID- 16921178
OWN - NLM
STAT- MEDLINE
DCOM- 20061211
LR  - 20220311
IS  - 1460-2156 (Electronic)
IS  - 0006-8950 (Linking)
VI  - 129
IP  - Pt 11
DP  - 2006 Nov
TI  - fMRI revealed neural substrate for reversible working memory dysfunction in 
      subclinical hypothyroidism.
PG  - 2923-30
AB  - Cognitive impairments have been found in thyroid hormone-related diseases (e.g. 
      hyperthyroidism and hypothyroidism) for a long time. However, whether and how 
      subclinical hypothyroidism (SCH) causes any deficits in brain functions, and 
      whether a hormone-replacement treatment is necessary for SCH patients, still 
      remain controversial subjects. In the present study, functional MRI (fMRI) was 
      used to measure brain functions by asking euthyroid subjects, hyperthyroid 
      patients and SCH patients to perform the widely used digit n-back working memory 
      task. After having been treated with l-thyroxine for approximately 6 months, the 
      SCH patients were asked to do the same fMRI experiment. The hypothyroid and SCH 
      patients scored significantly lower in the 2-back task than either the 
      hyperthyroid patients or the euthyroid subjects (P < 0.012). The fMRI showed that 
      a common frontoparietal network, including bilateral middle/inferior frontal gyri 
      (M/IFG), bilateral dorsolateral prefrontal cortex (DLPFC), bilateral premotor 
      areas (PreMA), the supplementary motor area/anterior cingulate cortex (SMA/ACC) 
      and bilateral parietal areas (PA), was activated by the n-back task in all the 
      subjects. Further quantitative analysis showed that the load effect of blood 
      oxygen level-dependent (BOLD) response appeared in all the five regions of 
      interest (ROIs) in the euthyroid and hyperthyroid subjects. In the pre-treatment 
      SCH patients, however, the load effect of BOLD response was only found in the PA 
      and PreMA, but not in other frontal cortex ROIs [general linear model (GLM), F < 
      2.6, P > 0.1]. After an approximately 6 month treatment with LT4, the SCH 
      patients exhibited the same load effects in all five ROIs as the euthyroid 
      subjects (GLM, F > 6, P < 0.05) along with an improvement of performance in 
      n-back task. These results suggest that working memory (but not other memory 
      functions) is impaired in SCH patients, mainly as far as disorders of the 
      frontoparietal network were concerned. Both the memory performance and frontal 
      executive functions were improved after an l-thyroxine-replacement treatment.
FAU - Zhu, De-Fa
AU  - Zhu DF
AD  - Department of Endocrinology, Anhui Geriatric Institute, The First Affiliated 
      Hospital of Anhui Medical University Hefei, Anhui, China.
FAU - Wang, Zhao-Xin
AU  - Wang ZX
FAU - Zhang, Da-Ren
AU  - Zhang DR
FAU - Pan, Zhong-Lin
AU  - Pan ZL
FAU - He, Sheng
AU  - He S
FAU - Hu, Xiao-Ping
AU  - Hu XP
FAU - Chen, Xiang-Chuan
AU  - Chen XC
FAU - Zhou, Jiang-Ning
AU  - Zhou JN
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20060818
PL  - England
TA  - Brain
JT  - Brain : a journal of neurology
JID - 0372537
RN  - 0 (Thyroid Hormones)
RN  - Q51BO43MG4 (Thyroxine)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Brain Mapping/methods
MH  - Female
MH  - Follow-Up Studies
MH  - Frontal Lobe/physiopathology
MH  - Humans
MH  - Hypothyroidism/drug therapy/physiopathology/*psychology
MH  - Magnetic Resonance Imaging/methods
MH  - Male
MH  - Memory Disorders/*etiology/physiopathology
MH  - *Memory, Short-Term
MH  - Mental Recall
MH  - Neuropsychological Tests
MH  - Oxygen/blood
MH  - Psychometrics
MH  - Thyroid Hormones/blood
MH  - Thyroxine/therapeutic use
EDAT- 2006/08/22 09:00
MHDA- 2006/12/12 09:00
CRDT- 2006/08/22 09:00
PHST- 2006/08/22 09:00 [pubmed]
PHST- 2006/12/12 09:00 [medline]
PHST- 2006/08/22 09:00 [entrez]
AID - awl215 [pii]
AID - 10.1093/brain/awl215 [doi]
PST - ppublish
SO  - Brain. 2006 Nov;129(Pt 11):2923-30. doi: 10.1093/brain/awl215. Epub 2006 Aug 18.