Growth Hormone–Releasing Hormone Effects on Brain γ-Aminobutyric Acid Levels in Mild Cognitive Impairment and Healthy Aging

Friedman, Seth D.; Baker, Laura D.; Borson, Soo; Jensen, J. Eric; Barsness, Suzanne; Craft, Suzanne; Merriam, George R.; Otto, Randolph K.; Novotny, Edward J.; Vitiello, Michael V.

doi:10.1001/jamaneurol.2013.1425

Cited by 38 publications

(31 citation statements)

References 52 publications

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“…Furthermore, concentrations of the primary excitatory neurotransmitter, glutamate (Glu), were also shown to be lower in posterior cingulate cortex (PCC) of AD patients, either when measured alone or as a combined measure of glutamate + glutamine (Glx) (Antuono et al, 2001; Fayed et al, 2011; Rupsingh et al, 2011). However, previous MRS studies found no difference in Glu or Glx levels between MCI and HCS (Fayed et al, 2011; Friedman et al, 2013; Rupsingh et al, 2011). Recently, the combination of Cho to Cr, Glx to Cr, and NAA to Cr ratios in the PCC (and precuneus) was successfully used to differentiate carriers from noncarriers of a fully penetrant, familial early-onset AD (presenilin-1 gene) mutation at different disease stages (Londono et al, 2013).…”

Section: Introductionmentioning

confidence: 66%

Posterior cingulate γ-aminobutyric acid and glutamate/glutamine are reduced in amnestic mild cognitive impairment and are unrelated to amyloid deposition and apolipoprotein E genotype

Riese

Gietl

Zölch

et al. 2015

Neurobiology of Aging

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The biomarker potential of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) for the in vivo characterization of preclinical stages in Alzheimer’s disease has not yet been explored. We measured GABA, glutamate + glutamine (Glx), and N-acetyl-aspartate (NAA) levels by single-voxel MEGA-PRESS magnetic resonance spectroscopy in the posterior cingulate cortex of 21 elderly subjects and 15 patients with amnestic mild cognitive impairment. Participants underwent Pittsburgh Compound B positron emission tomography, apolipoprotein E (APOE) genotyping, and neuropsychological examination. GABA, Glx, and NAA levels were significantly lower in patients. NAA was lower in Pittsburgh Compound B-positive subjects and APOE ε4 allele carriers. GABA, Glx, and NAA levels were positively correlated to CERAD word learning scores. Reductions in GABA, Glx, and NAA levels may serve as metabolic biomarkers for cognitive impairment in amnestic mild cognitive impairment. Because GABA and Glx do not seem to reflect amyloid β deposition or APOE genotype, they are less likely biomarker candidates for preclinical Alzheimer’s disease.

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Section: Introductionmentioning

confidence: 66%

Posterior cingulate γ-aminobutyric acid and glutamate/glutamine are reduced in amnestic mild cognitive impairment and are unrelated to amyloid deposition and apolipoprotein E genotype

Riese

Gietl

Zölch

et al. 2015

Neurobiology of Aging

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“…Importantly, GABA responsiveness assessed with MRS has already been linked to plasticity responses such as learning mechanisms in the human motor cortex [37,38]. On the other side, basal posteriomedial GABA concentrations seems to be decreased in aging [18] and in amnestic mild cognitive impairment [17] as well as it proved sensitive enough to detect pharmacological interventions in the latter condition [63].…”

Section: Discussionmentioning

confidence: 99%

Neurochemical Modulation in Posteromedial Default-mode Network Cortex Induced by Transcranial Magnetic Stimulation

et al. 2015

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“…Using our previously published methods, every J-resolved spectral extraction (64 in total) within the 67 Hz bandwith was fitted with LCModel and its theoretically-correct template, which is optimized GAMMA-simulated J-resolved basis sets modeled for 2.89 T (Friedman et al, 2013; Henry et al, 2011; Jensen et al, 2009). All spectral data were modeled for 2.89 T field strength (123.05 MHz) to match that of our TRIO scanner.…”

Section: Methodsmentioning

confidence: 99%

Dorsal anterior cingulate glutamate is associated with engagement of the default mode network during exposure to smoking cues

Janes

Betts

Jensen

et al. 2016

Drug and Alcohol Dependence

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Background When exposed to smoking cues, nicotine dependent individuals activate brain regions overlapping with the default mode network (DMN), a network of regions involved in internally-focused cognition. The salience network (SN), which includes the dorsal anterior cingulate cortex (dACC), is thought to interact with the DMN and aids in directing attention toward salient internal or external stimuli. One possibility is that neurochemical variation in SN regions such as the dACC impact DMN reactivity to personally relevant stimuli such as smoking cues. This is consistent with emerging evidence suggesting an association between midline cortical glutamate (Glu) and activity in brain regions overlapping with the DMN. Methods In 18 nicotine-dependent individuals, we assessed the relationship between DMN activation to smoking relative to neutral cues using functional magnetic resonance imaging and dACC Glu as measured by magnetic resonance spectroscopy. This association also was tested in a replication sample of 14 nicotine-dependent participants. Results Not only was the DMN significantly less suppressed during smoking cue exposure, but also there was a positive association between DMN reactivity to smoking relative to neutral cues and dACC Glu (r = 0.56, p < 0.02). This finding was confirmed in the independent replication cohort (r = 0.64, p < 0.02). Conclusions The current findings confirm that the DMN is less suppressed when smokers view smoking relative to neutral cues, suggesting that smoking cues engage self-relevant processing. Furthermore, these results indicate that dACC Glu is associated with enhanced DMN engagement when nicotine-dependent individuals are exposed to self-relevant smoking cues.

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Growth Hormone–Releasing Hormone Effects on Brain γ-Aminobutyric Acid Levels in Mild Cognitive Impairment and Healthy Aging

Cited by 38 publications

References 52 publications

Posterior cingulate γ-aminobutyric acid and glutamate/glutamine are reduced in amnestic mild cognitive impairment and are unrelated to amyloid deposition and apolipoprotein E genotype

Posterior cingulate γ-aminobutyric acid and glutamate/glutamine are reduced in amnestic mild cognitive impairment and are unrelated to amyloid deposition and apolipoprotein E genotype

Neurochemical Modulation in Posteromedial Default-mode Network Cortex Induced by Transcranial Magnetic Stimulation

Dorsal anterior cingulate glutamate is associated with engagement of the default mode network during exposure to smoking cues

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