scholarly journals Edited Magnetic Resonance Spectroscopy Detects an Age-Related Decline in Nonhuman Primate Brain GABA Levels

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Xuanzi He ◽  
Bang-Bon Koo ◽  
Ronald J. Killiany
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Posterior Cingulate Cortex ◽  
Resonance Spectroscopy ◽  
Gamma Aminobutyric Acid ◽  
Gaba Level ◽  
Inhibitory Neurotransmitter ◽  
Independent Variables ◽  
Age Related ◽  
The Brain

Recent research had shown a correlation between aging and decreasing Gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the brain. However, how GABA level varies with age in the medial portion of the brain has not yet been studied. The purpose of this study was to investigate the GABA level variation with age focusing on the posterior cingulate cortex, which is the “core hub” of the default mode network. In this study, 14 monkeys between 4 and 21 years were recruited, and MEGA-PRESS MRS was performed to measure GABA levels, in order to explore a potential link between aging and GABA. Our results showed that a correlation between age and GABA+/Creatine ratio was at the edge of significance (r=-0.523,p=0.081). There was also a near-significant trend between gray matter/white matter ratio and the GABA+/Creatine ratio (r=-0.518,p=0.0848). Meanwhile, the correlation between age and grey matter showed no significance (r=-0.028,p=0.93). Therefore, age and gray matter/white matter ratio account for different part ofR-squared (adjustedR-squared = 0.5187) as independent variables for predicting GABA levels. AdjustedR-squared is about 0.5 for two independent variables. These findings suggest that there is internal neurochemical variation of GABA levels in the nonhuman primates associated with normal aging and structural brain decline.

scholarly journals GABA levels in ventral visual cortex decline with age and are associated with neural distinctiveness

2019 ◽  
Author(s):  
Jordan D. Chamberlain ◽  
Holly Gagnon ◽  
Poortata Lalwani ◽  
Kaitlin E. Cassady ◽  
Molly Simmonite ◽  
...  
Keyword(s):  
Older Adults ◽  
Visual Cortex ◽  
Magnetic Resonance ◽  
Aminobutyric Acid ◽  
Resonance Spectroscopy ◽  
Gamma Aminobutyric Acid ◽  
Younger Adults ◽  
Inhibitory Neurotransmitter ◽  
Neural Representations ◽  
Age Related

AbstractAge-related neural dedifferentiation – reduced distinctiveness of neural representations in the aging brain– has been associated with age-related declines in cognitive abilities. But why does neural distinctiveness decline with age? Based on prior work in non-human primates, we hypothesized that the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) declines with age and is associated with neural dedifferentiation. To test this hypothesis, we used magnetic resonance spectroscopy (MRS) to measure GABA and functional MRI (fMRI) to measure neural distinctiveness in the ventral visual cortex in a set of older and younger participants. Relative to younger adults, older adults exhibited lower GABA levels and less distinct activation patterns for faces and houses in the ventral visual cortex. Furthermore, individual differences in GABA within older adults predicted individual differences in neural distinctiveness even after controlling for gray matter volume and age. These results provide novel support for the view that age-related reductions of GABA contribute to age-related reductions in neural distinctiveness (i.e., neural dedifferentiation) in the human ventral visual cortex.Significance StatementNeural representations in the ventral visual cortex are less distinguishable in older compared to younger humans, and this neural dedifferentiation is associated with age-related cognitive deficits. Animal models suggest that reductions in the inhibitory neurotransmitter gamma aminobutyric acid (GABA) may play a role. To investigate this hypothesis, we combined functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS) in a study of the human ventral visual cortex. We observed reduced distinctiveness of neural patterns and reduced GABA levels in older compared to younger adults. Furthermore, older adults with higher GABA levels tended to have more distinctive neural representations. These findings suggest that reduced GABA levels contribute to age-related declines in neural distinctiveness in the human ventral visual cortex.

Accelerating Structural Degeneration in Temporal Regions and Their Effects on Cognition in Aging of MCI Patients

2019 ◽  
Vol 30 (1) ◽  
pp. 326-338
Author(s):  
Xin Li ◽  
Jianan Xia ◽  
Chao Ma ◽  
Kewei Chen ◽  
Kai Xu ◽  
...  
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Brain Structure ◽  
Gray Matter Volume ◽  
Imaging Data ◽  
Memory And Attention ◽  
Age Related ◽  
Preclinical Ad ◽  
Brain Imaging Data ◽  
The Brain

Abstract Age is the major risk factor for Alzheimer’s disease (AD) and for mild cognitive impairment (MCI). However, there is limited evidence about MCI-specific aging-related simultaneous changes of the brain structure and their impact on cognition. We analyzed the brain imaging data from 269 subjects (97 MCI patients and 172 cognitively normal [CN] elderly) using voxel-based morphometry and tract-based spatial statistics procedures to explore the special structural pattern during aging. We found that the patients with MCI showed accelerated age-related reductions in gray matter volume in the left planum temporale, thalamus, and posterior cingulate gyrus. The similar age×group interaction effect was found in the fractional anisotropy of the bilateral parahippocampal cingulum white matter tract, which connects the temporal regions. Importantly, the age-related temporal gray matter and white matter alterations were more significantly related to performance in memory and attention tasks in MCI patients. The accelerated degeneration patterns in the brain structure provide evidence for different neural mechanisms underlying aging in MCI patients. Temporal structural degeneration may serve as a potential imaging marker for distinguishing the progression of the preclinical AD stage from normal aging.

scholarly journals Herbal Remedies and Their Possible Effect on the GABAergic System and Sleep

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 530
Author(s):  
Oliviero Bruni ◽  
Luigi Ferini-Strambi ◽  
Elena Giacomoni ◽  
Paolo Pellegrino
Keyword(s):  
Gaba Receptors ◽  
Herbal Medicines ◽  
Well Being ◽  
Herbal Remedies ◽  
Gamma Aminobutyric Acid ◽  
Systematic Analysis ◽  
Inhibitory Neurotransmitter ◽  
Alternative Medicines ◽  
Molecular Components ◽  
The Brain

Sleep is an essential component of physical and emotional well-being, and lack, or disruption, of sleep due to insomnia is a highly prevalent problem. The interest in complementary and alternative medicines for treating or preventing insomnia has increased recently. Centuries-old herbal treatments, popular for their safety and effectiveness, include valerian, passionflower, lemon balm, lavender, and Californian poppy. These herbal medicines have been shown to reduce sleep latency and increase subjective and objective measures of sleep quality. Research into their molecular components revealed that their sedative and sleep-promoting properties rely on interactions with various neurotransmitter systems in the brain. Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter that plays a major role in controlling different vigilance states. GABA receptors are the targets of many pharmacological treatments for insomnia, such as benzodiazepines. Here, we perform a systematic analysis of studies assessing the mechanisms of action of various herbal medicines on different subtypes of GABA receptors in the context of sleep control. Currently available evidence suggests that herbal extracts may exert some of their hypnotic and anxiolytic activity through interacting with GABA receptors and modulating GABAergic signaling in the brain, but their mechanism of action in the treatment of insomnia is not completely understood.

Aging, cognition, and the brain: effects of age-related variation in white matter integrity on neuropsychological function

2018 ◽  
Vol 23 (7) ◽  
pp. 831-839 ◽  
Author(s):  
Yang-Teng Fan ◽  
Ya-Wen Fang ◽  
Ya-Ping Chen ◽  
Eric D. Leshikar ◽  
Ching-Po Lin ◽  
...  
Keyword(s):  
White Matter ◽  
White Matter Integrity ◽  
Neuropsychological Function ◽  
Related Variation ◽  
Age Related ◽  
The Brain

MR Brain Image Segmentation to Detect White Matter, Gray Matter, and Cerebro Spinal Fluid Using TLBO Algorithm

2021 ◽  
pp. 2150034
Author(s):  
Sandhya Gudise ◽  
Giri Babu Kande ◽  
T. Satya Savithri
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Population Based ◽  
Spinal Fluid ◽  
Brain Image ◽  
Tlbo Algorithm ◽  
Wide Range ◽  
Skull Stripping ◽  
The Brain ◽  
Mr Brain

This paper proposes an advanced and precise technique for the segmentation of Magnetic Resonance Image (MRI) of the brain. Brain MRI segmentation is to be familiar with the anatomical structure, to recognize the deformities, and to distinguish different tissues which help in treatment planning and diagnosis. Nature’s inspired population-based evolutionary algorithms are extremely popular for a wide range of applications due to their best solutions. Teaching Learning Based Optimization (TLBO) is an advanced population-based evolutionary algorithm designed based on Teaching and Learning process of a classroom. TLBO uses common controlling parameters and it won’t require algorithm-specific parameters. TLBO is more appropriate to optimize the real variables which are fuzzy valued, computationally efficient, and does not require parameter tuning. In this work, the pixels of the brain image are automatically grouped into three distinct homogeneous tissues such as White Matter (WM), Gray Matter (GM), and Cerebro Spinal Fluid (CSF) using the TLBO algorithm. The methodology includes skull stripping and filtering in the pre-processing stage. The outcomes for 10 MR brain images acquired by utilizing the proposed strategy proved that the three brain tissues are segmented accurately. The segmentation outputs are compared with the ground truth images and high values are obtained for the measure’s sensitivity, specificity, and segmentation accuracy. Four different approaches, namely Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Bacterial Foraging Algorithm (BFA), and Electromagnetic Optimization (EMO) are likewise implemented to compare with the results of the proposed methodology. From the results, it can be proved that the proposed method performed effectively than the other.

scholarly journals Brain Substrates of Time-Based Prospective Memory Decline in Aging: A Voxel-Based Morphometry and Diffusion Tensor Imaging Study

2020 ◽  
Vol 31 (1) ◽  
pp. 396-409
Author(s):  
Alexandrine Morand ◽  
Shailendra Segobin ◽  
Grégory Lecouvey ◽  
Julie Gonneaud ◽  
Francis Eustache ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Prospective Memory ◽  
Gray Matter ◽  
Diffusion Tensor ◽  
Imaging Study ◽  
Age Related ◽  
Young Subjects ◽  
Anterior Prefrontal Cortex ◽  
And Diffusion

Abstract Time-based prospective memory (TBPM) allows us to remember to perform intended actions at a specific time in the future. TBPM is sensitive to the effects of age, but the neural substrates of this decline are still poorly understood. The aim of the present study was thus to better characterize the brain substrates of the age-related decline in TBPM, focusing on macrostructural gray matter and microstructural white matter integrity. We administered a TBPM task to 22 healthy young (26 ± 5.2 years) and 23 older (63 ± 5.9 years) participants, who also underwent volumetric magnetic resonance imaging and diffusion tensor imaging scans. Neuroimaging analyses revealed lower gray matter volumes in several brain areas in older participants, but these did not correlate with TBPM performance. By contrast, an age-related decline in fractional anisotropy in several white-matter tracts connecting frontal and occipital regions did correlate with TBPM performance, whereas there was no significant correlation in healthy young subjects. According to the literature, these tracts are connected to the anterior prefrontal cortex and the thalamus, 2 structures involved in TBPM. These results confirm the view that a disconnection process occurs in aging and contributes to cognitive decline.

scholarly journals Effects of Temperature on Evoked Electrical Activity and Anoxic Injury in CNS White Matter

1992 ◽  
Vol 12 (6) ◽  
pp. 977-986 ◽  
Author(s):  
Peter K. Stys ◽  
Stephen G. Waxman ◽  
Bruce R. Ransom
Keyword(s):  
White Matter ◽  
Optic Nerve ◽  
Functional Outcome ◽  
Gray Matter ◽  
Functional Recovery ◽  
Temperature Sensitive ◽  
Anoxic Injury ◽  
Intracellular Ca ◽  
Effects Of Temperature ◽  
The Brain

Temperature is known to influence the extent of anoxic/ischemic injury in gray matter of the brain. We tested the hypothesis that small changes in temperature during anoxic exposure could affect the degree of functional injury seen in white matter, using the isolated rat optic nerve, a typical CNS white matter tract (Foster et al., 1982). Functional recovery after anoxia was monitored by quantitative assessment of the compound action potential (CAP) area. Small changes in ambient temperature, within a range of 32 to 42°C, mildly affected the CAP of the optic nerve under normoxic conditions. Reducing the temperature to <37°C caused a reversible increase in the CAP area and in the latencies of all three CAP peaks; increasing the temperature to >37°C had opposite effects. Functional recovery of white matter following 60 min of anoxia was strongly influenced by temperature during the period of anoxia. The average recovery of the CAP, relative to control, after 60 min of anoxia administered at 37°C was 35.4 ± 7%; when the temperature was lowered by 2.5°C (i.e., to 34.5°C) for the period of anoxic exposure, the extent of functional recovery improved to 64.6 ± 15% ( p < 0.00001). Lowering the temperature to 32°C during anoxic exposure for 60 min resulted in even greater functional recovery (100.5 ± 14% of the control CAP area). Conversely, if temperature was increased to >37°C during anoxia, the functional outcome worsened, e.g., CAP recovery at 42°C was 8.5 ± 7% ( p < 0.00001). Hypothermia (i.e., 32°C) for 30 min immediately following anoxia at 37°C did not improve the functional outcome. Many processes within the brain are temperature sensitive, including O2 consumption, and it is not clear which of these is most relevant to the observed effects of temperature on recovery of white matter from anoxic injury. Unlike the situation in gray matter, the temperature dependency of anoxic injury cannot be related to reduced release of excitotoxins like glutamate, because neurotransmitters play no role in the pathophysiology of anoxic damage in white matter (Ransom et al., 1990 a). It is more likely that temperature affects the rate of ion transport by the Na+–Ca2+ exchanger, the transporter responsible for intracellular Ca2+ loading during anoxia in white matter, and/or the rate of some destructive intracellular enzymatic mechanism(s) activated by pathological increases in intracellular Ca2+.

scholarly journals White matter disconnection is related to age-related phonological deficits

2019 ◽  
Vol 14 (5) ◽  
pp. 1555-1565 ◽  
Author(s):  
Sara B. W. Troutman ◽  
Michele T. Diaz
Keyword(s):  
White Matter ◽  
Language Production ◽  
Signal Transmission ◽  
Dorsal Stream ◽  
Cognitive Differences ◽  
Age Related ◽  
White Matter Connectivity ◽  
Open Question ◽  
Transmission Failures ◽  
The Brain

Abstract Older adults have more language production difficulties than younger adults but display largely comparable language comprehension abilities. The Transmission Deficit Hypothesis suggests that production difficulties stem from an age-related increase in phonological signal transmission failures, while the semantic system, being more redundant than the phonological system, allows comprehension to be relatively preserved despite signal failures. Though the neural instantiation of the Transmission Deficit Hypothesis remains an open question, white matter represents one important factor to investigate. Metrics indicative of white matter connectivity across the brain, namely, Radial Diffusivity (RD) and Fractional Anisotropy (FA) have also been linked to age-related cognitive differences including naming difficulties. Using a Picture-Word Interference (PWI) task with 18 younger and 19 older healthy adults, we found that, across ages, better picture naming in the presence of phonological distractors was associated with lower RD across dorsal (r = −.35, p = .03), ventral (r = −.34, p = .04), and fronto-striatal (r = −.33, p = .04) tracts, and higher FA along dorsal tracts (r = .43, p = .008). The pattern of lower RD and higher FA, which is thought to reflect better white matter structure, points to the dorsal stream tracts as critical for performance on the PWI task. Moreover, the effects of RD and FA on performance were attenuated by the effect of age, reflecting the shared variance between age and white matter as it relates to language production ability.

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