Format
Sort by
Items per page

Send to

Choose Destination

Search results

Items: 1 to 20 of 40

1.
Elife. 2018 Jul 2;7. pii: e35718. doi: 10.7554/eLife.35718.

Assessing reliability in neuroimaging research through intra-class effect decomposition (ICED).

Author information

1
Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
2
Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin, Germany.
3
Clinic and Policlinic for Psychiatry and Psychotherapy, University Clinic Hamburg-Eppendorf, Hamburg, Germany.
4
Wayne State University, Detroit, United States.

Abstract

Magnetic resonance imaging has become an indispensable tool for studying associations of structural and functional properties of the brain with behavior in humans. However, generally recognized standards for assessing and reporting the reliability of these techniques are still lacking. Here, we introduce a new approach for assessing and reporting reliability, termed intra-class effect decomposition (ICED). ICED uses structural equation modeling of data from a repeated-measures design to decompose reliability into orthogonal sources of measurement error that are associated with different characteristics of the measurements, for example, session, day, or scanning site. This allows researchers to describe the magnitude of different error components, make inferences about error sources, and inform them in planning future studies. We apply ICED to published measurements of myelin content and resting state functional connectivity. These examples illustrate how longitudinal data can be leveraged separately or conjointly with cross-sectional data to obtain more precise estimates of reliability.

KEYWORDS:

G theory; coefficient of variation; human; individual differences; intra-class correlation; neuroscience; reliability; structural equation modeling

2.
Front Psychiatry. 2018 Mar 12;9:76. doi: 10.3389/fpsyt.2018.00076. eCollection 2018.

Functional Magnetic Resonance Spectroscopy: The "New" MRS for Cognitive Neuroscience and Psychiatry Research.

Author information

1
Department of Psychiatry and Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, MI, United States.
2
Department of Psychology, Wayne State University, Detroit, MI, United States.
3
Institute of Gerontology, Wayne State University, Detroit, MI, United States.
4
Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.

Abstract

Proton magnetic resonance spectroscopy (1H MRS) is a well-established technique for quantifying the brain regional biochemistry in vivo. In most studies, however, the 1H MRS is acquired during rest with little to no constraint on behavior. Measured metabolite levels, therefore, reflect steady-state concentrations whose associations with behavior and cognition are unclear. With the recent advances in MR technology-higher-field MR systems, robust acquisition techniques and sophisticated quantification methods-1H MRS is now experiencing a resurgence. It is sensitive to task-related and pathology-relevant regional dynamic changes in neurotransmitters, including the most ubiquitous among them, glutamate. Moreover, high temporal resolution approaches allow tracking glutamate modulations at a time scale of under a minute during perceptual, motor, and cognitive tasks. The observed task-related changes in brain glutamate are consistent with new metabolic steady states reflecting the neural output driven by shifts in the local excitatory and inhibitory balance on local circuits. Unlike blood oxygen level differences-base functional MRI, this form of in vivo MRS, also known as functional MRS (1H fMRS), yields a more direct measure of behaviorally relevant neural activity and is considerably less sensitive to vascular changes. 1H fMRS enables noninvasive investigations of task-related glutamate changes that are relevant to normal and impaired cognitive performance, and psychiatric disorders. By targeting brain glutamate, this approach taps into putative neural correlates of synaptic plasticity. This review provides a concise survey of recent technological advancements that lay the foundation for the successful use of 1H fMRS in cognitive neuroscience and neuropsychiatry, including a review of seminal 1H fMRS studies, and the discussion of biological significance of task-related changes in glutamate modulation. We conclude with a discussion of the promises, limitations, and outstanding challenges of this new tool in the armamentarium of cognitive neuroscience and psychiatry research.

KEYWORDS:

1H MRS; MRI; aging; cognition; glutamate; plasticity; schizophrenia

3.
Neuroimage. 2018 May 15;172:21-30. doi: 10.1016/j.neuroimage.2018.01.032. Epub 2018 Jan 28.

Fluid intelligence and gross structural properties of the cerebral cortex in middle-aged and older adults: A multi-occasion longitudinal study.

Author information

1
School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.
2
Department of Psychology, Humboldt University, Berlin, Germany; Max Planck Institute for Human Development, Berlin, Germany.
3
Institute of Gerontology, Wayne State University, Detroit, MI, USA; Department of Psychology, Wayne State University, Detroit, MI, USA; Max Planck Institute for Human Development, Berlin, Germany. Electronic address: nraz@wayne.edu.

Abstract

According to Parieto-Frontal Integration Theory (P-FIT, Jung and Haier, 2007), individual differences in a circumscribed set of brain regions account for variations in general intelligence (g). The components of g, fluid (Gf) and crystallized (Gc) reasoning, exhibit distinct trajectories of age-related change. Because the brain also ages differentially, we hypothesized that age-related cognitive and neural changes would be coupled. In a sample of healthy middle-aged and older adults, we examined changes in Gf (operationalized by Cattell Culture Fair Test) and Gc (indexed by two vocabulary tests) as well as in structural properties of 19 brain regions. We fitted linear mixed models to the data collected on 73 healthy adults who participated in baseline assessment, with 43 returning for at least one follow-up, and 16 of them contributing four repeated assessments over seven years. We observed age differences as well as longitudinal decline in Gf, contrasted to a lack of age differences and stability in Gc. Cortical thickness and cortical volume exhibited significant age differences and longitudinal declines, which were accelerated in P-FIT regions. Gf (but not Gc) was associated with cortical thickness, but no such relationship was found for cortical volume. Uniformity of cognitive change (lack of reliable individual differences) precluded examination of the coupling between cognitive and brain changes. Cortical shrinkage was greater in high-Gc individuals, whereas in participants with higher Gf cortical volume slower volume shrinkage was observed.

KEYWORDS:

Aging; Brain; Brain volume; Cognitive aging; Cortical thickness; Frontal; Intelligence; MRI; Parietal; Temporal

PMID:
29360573
PMCID:
PMC5910236
[Available on 2019-05-15]
DOI:
10.1016/j.neuroimage.2018.01.032
Icon for Elsevier Science
4.
Hum Brain Mapp. 2018 Feb;39(2):916-931. doi: 10.1002/hbm.23891. Epub 2017 Nov 23.

Optimization and validation of automated hippocampal subfield segmentation across the lifespan.

Author information

1
Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
2
Division of Psychology, University of Stirling, Stirling, United Kingdom.
3
Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
4
Department of Psychology & Institute of Gerontology, Wayne State University, Detroit, Michigan, USA.
5
Department of Psychiatry and Psychotherapy, University Clinic Hamburg-Eppendorf, Hamburg, Germany.
6
Max Planck Centre for Computational Psychiatry and Ageing Research, London, United Kingdom.
7
European University Institute, San Domenico di Fiesole, Fiesole, Italy.

Abstract

Automated segmentation of hippocampal (HC) subfields from magnetic resonance imaging (MRI) is gaining popularity, but automated procedures that afford high speed and reproducibility have yet to be extensively validated against the standard, manual morphometry. We evaluated the concurrent validity of an automated method for hippocampal subfields segmentation (automated segmentation of hippocampal subfields, ASHS; Yushkevich et al., ) using a customized atlas of the HC body, with manual morphometry as a standard. We built a series of customized atlases comprising the entorhinal cortex (ERC) and subfields of the HC body from manually segmented images, and evaluated the correspondence of automated segmentations with manual morphometry. In samples with age ranges of 6-24 and 62-79 years, 20 participants each, we obtained validity coefficients (intraclass correlations, ICC) and spatial overlap measures (dice similarity coefficient) that varied substantially across subfields. Anterior and posterior HC body evidenced the greatest discrepancies between automated and manual segmentations. Adding anterior and posterior slices for atlas creation and truncating automated output to the ranges manually defined by multiple neuroanatomical landmarks substantially improved the validity of automated segmentation, yielding ICC above 0.90 for all subfields and alleviating systematic bias. We cross-validated the developed atlas on an independent sample of 30 healthy adults (age 31-84) and obtained good to excellent agreement: ICC (2) = 0.70-0.92. Thus, with described customization steps implemented by experts trained in MRI neuroanatomy, ASHS shows excellent concurrent validity, and can become a promising method for studying age-related changes in HC subfield volumes.

KEYWORDS:

MRI; aging; development; hippocampus; morphometry; validation; volume

PMID:
29171108
PMCID:
PMC5861710
[Available on 2019-02-01]
DOI:
10.1002/hbm.23891
Icon for Wiley
5.
Neurobiol Aging. 2017 Nov;59:135-143. doi: 10.1016/j.neurobiolaging.2017.08.003. Epub 2017 Aug 10.

Associations between dynamic functional connectivity and age, metabolic risk, and cognitive performance.

Author information

1
Department of Psychology, Wayne State University, Detroit, MI, USA; Institute of Gerontology, Wayne State University, Detroit, MI, USA.
2
School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.
3
Department of Psychology, Wayne State University, Detroit, MI, USA; Institute of Gerontology, Wayne State University, Detroit, MI, USA. Electronic address: damoiseaux@wayne.edu.

Abstract

Advanced age is associated with reduced within-network functional connectivity, particularly within the default mode network. Most studies to date have examined age differences in functional connectivity via static indices that are computed over the entire blood-oxygen-level dependent time series. Little is known about the effects of age on short-term temporal dynamics of functional connectivity. Here, we examined age differences in dynamic connectivity as well as associations between connectivity, metabolic risk, and cognitive performance in healthy adults (N = 168; age, 18-83 years). A sliding-window k-means clustering approach was used to assess dynamic connectivity from resting-state functional magnetic resonance imaging data. Three out of 8 dynamic connectivity profiles were associated with age. Furthermore, metabolic risk was associated with the relative amount of time allocated to 2 of these profiles. Finally, the relative amount of time allocated to a dynamic connectivity profile marked by heightened connectivity between default mode and medial temporal regions was positively associated with executive functions. Thus, dynamic connectivity analyses can enrich understanding of age-related differences beyond what is revealed by static analyses.

KEYWORDS:

Cognitive aging; Default network; Executive function; Functional connectivity; Resting-state fMRI

PMID:
28882422
PMCID:
PMC5679403
[Available on 2018-11-01]
DOI:
10.1016/j.neurobiolaging.2017.08.003
[Indexed for MEDLINE]
Icon for Elsevier Science
6.
Gerontology. 2018;64(1):49-57. doi: 10.1159/000479508. Epub 2017 Sep 1.

Pathways to Brain Aging and Their Modifiers: Free-Radical-Induced Energetic and Neural Decline in Senescence (FRIENDS) Model - A Mini-Review.

Author information

1
Institute of Gerontology, Wayne State University, Detroit, MI, USA.

Abstract

In this mini-review, we survey the extant literature on brain aging, with the emphasis on longitudinal studies of neuroanatomy, including regional brain volumes and white matter microstructure. We assess the impact of vascular, metabolic, and inflammatory risk factors on the trajectories of change in regional brain volumes and white matter properties, as well as the relationships between neuroanatomical and physiological changes and their influence on cognitive performance. We examine these findings in the context of current biological theories of aging and propose the means of integrating noninvasive measures - spectroscopic indices of brain energy metabolism and regional iron deposits - as valuable proxies for elucidating the basic neurobiology of human brain aging. In a brief summary of the recent findings pertaining to age-related changes in the brain structure and their impact on cognition, we discuss the role of vascular, metabolic, and inflammatory risk factors in shaping the trajectories of change. Drawing on the extant biological theories of aging and mindful of the brain's role as a disproportionately voracious energy consumer in mammals, we emphasize the importance of the fundamental bioenergetic mechanisms as drivers of age-related changes in brain structure and function. We sketch out a model that builds on the conceptualization of aging as an expression of cumulative cellular damage inflicted by reactive oxygen species and ensuing declines in energy metabolism. We outline the ways and means of adapting this model, Free-Radical-Induced Energetic and Neural Decline in Senescence (FRIENDS), to human aging and testing it within the constraints of noninvasive neuroimaging.

KEYWORDS:

Brain energy metabolism; Longitudinal studies; Magnetic resonance imaging; Magnetic resonance spectroscopy; Mitochondria; Myelin; Neuropil; Reactive oxygen species; White matter

PMID:
28858861
PMCID:
PMC5828941
[Available on 2019-01-01]
DOI:
10.1159/000479508
Free full text
Icon for S. Karger AG, Basel, Switzerland
7.
Psychol Aging. 2017 Aug;32(5):489-505. doi: 10.1037/pag0000185.

The role of stimulus complexity and salience in memory for face-name associations in healthy adults: Friend or foe?

Author information

1
Department of Psychology, Wayne State University.
2
Department of Psychological Sciences, University of Missouri.
3
Institute of Gerontology, Wayne State University.

Abstract

The associative deficit hypothesis (ADH) posits that age-related differences in recognition of associations are disproportionately larger than age differences in item recognition because of age-related difficulty in binding and retrieval of two or more pieces of information in a memory episode. This proposition rests on the observation of disproportionately greater age differences in memory for associations than in recognition of individual items. Although ADH has been supported in experiments with verbal and nonverbal stimuli, the effects of task or stimulus characteristics on its generalizability remain unclear. In a series of experiments, we examined how salience and variability of face stimuli presented in face-name pairs affect age differences in recognition of items and associations. We found that a disproportionate age-related deficit in the recognition of face-name associations emerges when face stimuli are more complex, salient, variable, and distinctive, but not when standardized faces appear within minimal visual context. These findings indicate that age-related associative memory deficits may stem at least in part from age differences in use of stimulus characteristics for contextual support. (PsycINFO Database Record.

PMID:
28816475
PMCID:
PMC5592275
DOI:
10.1037/pag0000185
[Indexed for MEDLINE]
Free PMC Article
Icon for American Psychological Association Icon for PubMed Central
8.
Neurobiol Aging. 2017 Nov;59:22-29. doi: 10.1016/j.neurobiolaging.2017.07.003. Epub 2017 Jul 18.

Incident risk and progression of cerebral microbleeds in healthy adults: a multi-occasion longitudinal study.

Author information

1
Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA. Electronic address: adaugher@illinois.edu.
2
Department of Psychology and Institute of Gerontology, Wayne State University, Detroit, MI, USA; Max Planck Institute for Human Development, Berlin, Germany.

Abstract

Decline in cerebrovascular health complicates brain aging, and development of cerebral microbleeds (CMBs) is one of its prominent indicators. In a large sample of healthy adults (N = 251, age 18-78 years at baseline, 70% women), the contributions of chronological age and vascular health indicators to the risk of developing a CMB, as well as the change in CMB size and iron content, were examined in a prospective 8-year longitudinal study using susceptibility weighted imaging. Twenty-six persons (10.4%), most of whom were 40 years of age or older, had at least 1 CMB during the study. Older age was associated with greater risk for developing a CMB (odds ratio 1.03). Elevation of combined metabolic syndrome indicators (b = 0.15, p = 0.001) conferred additional risk (odds ratio 1.02). High body mass index exacerbated the risk associated with poor vascular health (b = 0.75, p < 0.001) and frequent exercise mitigated it (b = -0.46, p = 0.03). CMBs persisted over time, yet their volume decreased (mean change = -0.32, p < 0.05), whereas their relative iron content remained stable (mean change = -0.14, p = 0.05). We conclude that although developing a CMB is unlikely during normal aging, risk increases with declining vascular health, which is modifiable via behavioral and pharmaceutical intervention.

KEYWORDS:

Aging; Inflammation; Latent variable modeling; Metabolic syndrome; Susceptibility weighted imaging

PMID:
28800410
PMCID:
PMC5612885
[Available on 2018-11-01]
DOI:
10.1016/j.neurobiolaging.2017.07.003
[Indexed for MEDLINE]
Icon for Elsevier Science
9.
AJNR Am J Neuroradiol. 2017 Aug;38(8):1617-1622. doi: 10.3174/ajnr.A5219. Epub 2017 May 25.

Jugular Anomalies in Multiple Sclerosis Are Associated with Increased Collateral Venous Flow.

Author information

1
From The MRI Institute for Biomedical Research (S.K.S., D.T.U., J.J., E.M.H.), Detroit, Michigan sethisea@gmail.com.
2
Institute of Gerontology (A.M.D., N.R.).
3
Department of Physics and Earth Sciences (G.G.), University of Ferrara, Ferrara, Italy.
4
From The MRI Institute for Biomedical Research (S.K.S., D.T.U., J.J., E.M.H.), Detroit, Michigan.
5
Departments of Psychology (N.R.).
6
Radiology (E.M.H.), Wayne State University, Detroit, Michigan.

Abstract

BACKGROUND AND PURPOSE:

To date, research on extracranial venous collaterals has been focused on structure, with relatively little attention paid to hemodynamics. We addressed this limitation by quantitatively comparing collateral flow in patients with multiple sclerosis and healthy controls by using phase-contrast MR imaging. We hypothesize that patients with MS with structurally anomalous internal jugular veins will have elevated collateral venous flow compared with healthy controls.

MATERIALS AND METHODS:

The sample consisted of 276 patients with MS and 106 healthy controls. We used MRV to classify internal jugular veins as stenotic and nonstenotic based on an absolute cross-sectional area threshold in 276 patients with MS and 60 healthy controls; 46 healthy controls lacked this imaging. Individual and total vessel flows were quantified by using phase-contrast MR imaging on all patients. Veins were classified by extracranial drainage type: internal jugular veins (I), paraspinal (II), and superficial (III). Differences among healthy controls, patients with MS, nonstenotic patients, and stenotic subgroups in total venous flow by vessel type were evaluated in a general linear model for statistical analysis.

RESULTS:

In the MS group, 153 patients (55%) evidenced stenosis, whereas 12 (20%) healthy controls were classified as stenotic (P < .001). Compared with healthy controls, the MS group showed lower type I flow and increased type II flow. Stenosis was associated with reduced flow in the type I vessels [F(1272) = 68; P < .001]. The stenotic MS group had increased flow in the type II vessels compared with the nonstenotic MS group [F(1272) = 67; P < .001].

CONCLUSIONS:

Compared with healthy controls, patients with MS exhibit reduced venous flow in the main extracerebral drainage vein (internal jugular vein). In contrast, flow in the paraspinal venous collaterals is elevated in patients with MS and exacerbated by venous stenosis. Collateral drainage may be a compensatory response to internal jugular vein flow reduction.

PMID:
28546249
PMCID:
PMC5557656
DOI:
10.3174/ajnr.A5219
[Indexed for MEDLINE]
Free PMC Article
Icon for HighWire Icon for PubMed Central
10.
Brain Struct Funct. 2017 Aug;222(6):2919-2920. doi: 10.1007/s00429-017-1398-y.

Erratum to: Age differences in arterial and venous extra-cerebral blood flow in healthy adults: contributions of vascular risk factors and genetic variants.

Author information

1
Institute of Gerontology, Wayne State University, 87 E Ferry St. 226 Knapp Bldg., Detroit, MI, 48202, USA. nraz@wayne.edu.
2
Department of Psychology, Wayne State University, 5057 Woodward Ave., Detroit, MI, 48202, USA. nraz@wayne.edu.
3
Institute of Gerontology, Wayne State University, 87 E Ferry St. 226 Knapp Bldg., Detroit, MI, 48202, USA.
4
Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, 405 N Matthews Ave., Urbana, IL, 61801, USA.
5
The MRI Institute of Biomedical Research, 440 E Ferry St., Detroit, MI, 48202, USA.
6
Department of Psychiatry and Behavioral Sciences, Wayne State University, 3990 John R, Detroit, MI, 48201, USA.
7
Department of Radiology, Wayne State University, 3990 John R, Detroit, MI, 48201, USA.
11.
Brain Struct Funct. 2017 Aug;222(6):2641-2653. doi: 10.1007/s00429-016-1362-2. Epub 2017 Jan 24.

Age differences in arterial and venous extra-cerebral blood flow in healthy adults: contributions of vascular risk factors and genetic variants.

Author information

1
Institute of Gerontology, Wayne State University, 87 E Ferry St. 226 Knapp Bldg., Detroit, MI, 48202, USA. nraz@wayne.edu.
2
Department of Psychology, Wayne State University, 5057 Woodward Ave., Detroit, MI, 48202, USA. nraz@wayne.edu.
3
Institute of Gerontology, Wayne State University, 87 E Ferry St. 226 Knapp Bldg., Detroit, MI, 48202, USA.
4
Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, 405 N Matthews Ave., Urbana, IL, 61801, USA.
5
The MRI Institute of Biomedical Research, 440 E Ferry St., Detroit, MI, 48202, USA.
6
Department of Psychiatry and Behavioral Sciences, Wayne State University, 3990 John R, Detroit, MI, 48201, USA.
7
Department of Radiology, Wayne State University, 3990 John R, Detroit, MI, 48201, USA.

Abstract

Sufficient cerebral blood flow (CBF) and venous drainage are critical for normal brain function, and their alterations can affect brain aging. However, to date, most studies focused on arterial CBF (inflow) with little attention paid to the age differences in venous outflow. We measured extra-cerebral arterial and venous blood flow rates with phase-contrast MRI and assessed the influence of vascular risk factors and genetic polymorphisms (ACE insertion/deletion, COMT val158met, and APOEε4) in 73 adults (age 18-74 years). Advanced age, elevated vascular risk, ACE Deletion, and COMT met alleles were linked to lower in- and outflow, with no effects of APOE ε4 noted. Lower age-related CBF rate was unrelated to brain volume and was observed only in val homozygotes of COMTval158met. Thus, in a disease-free population, age differences in CBF may be notable only in persons with high vascular risk and carriers of genetic variants associated with vasoconstriction and lower dopamine availability. It remains to be established if treatments targeting alleviation of the mutable factors can improve the course of cerebrovascular aging in spite of the immutable genetic influence.

KEYWORDS:

ACE; COMT; Internal carotid artery; Jugular vein; Phase-contrast MRI; Vertebral artery

PMID:
28120105
DOI:
10.1007/s00429-016-1362-2
[Indexed for MEDLINE]
Icon for Springer
12.
Hum Brain Mapp. 2017 Apr;38(4):1780-1790. doi: 10.1002/hbm.23481. Epub 2016 Dec 23.

Test-retest reliability and concurrent validity of in vivo myelin content indices: Myelin water fraction and calibrated T1 w/T2 w image ratio.

Author information

1
Department of Psychiatry and Behavioral Neuroscience, School of Medicine, Wayne State University, Detroit, Michigan.
2
Institute of Gerontology, Wayne State University, Detroit, Michigan.
3
Department of Psychology, Wayne State University, Detroit, Michigan.

Abstract

In an age-heterogeneous sample of healthy adults, we examined test-retest reliability (with and without participant repositioning) of two popular MRI methods of estimating myelin content: modeling the short spin-spin (T2 ) relaxation component of multi-echo imaging data and computing the ratio of T1 -weighted and T2 -weighted images (T1 w/T2 w). Taking the myelin water fraction (MWF) index of myelin content derived from the multi-component T2 relaxation data as a standard, we evaluate the concurrent and differential validity of T1 w/T2 w ratio images. The results revealed high reliability of MWF and T1 w/T2 w ratio. However, we found significant correlations of low to moderate magnitude between MWF and the T1 w/T2 w ratio in only two of six examined regions of the cerebral white matter. Notably, significant correlations of the same or greater magnitude were observed for T1 w/T2 w ratio and the intermediate T2 relaxation time constant, which is believed to reflect differences in the mobility of water between the intracellular and extracellular compartments. We conclude that although both methods are highly reliable and thus well-suited for longitudinal studies, T1 w/T2 w ratio has low criterion validity and may be not an optimal index of subcortical myelin content. Hum Brain Mapp 38:1780-1790, 2017.

KEYWORDS:

MRI; Simpson paradox; T2 relaxation; brain water mobility; white matter

PMID:
28009069
PMCID:
PMC5342928
DOI:
10.1002/hbm.23481
[Indexed for MEDLINE]
Free PMC Article
Icon for Wiley Icon for PubMed Central
13.
Hippocampus. 2017 Jan;27(1):3-11. doi: 10.1002/hipo.22671. Epub 2016 Nov 15.

A harmonized segmentation protocol for hippocampal and parahippocampal subregions: Why do we need one and what are the key goals?

Author information

1
Penn Image Computing and Science Laboratory, Department of Radiology, University of Pennsylvania, Philadelphia, USA.
2
Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Champaign, USA.
3
Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada.
4
Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany.
5
Department of Psychology, Stanford University, Palo Alto, USA.
6
Department of Psychology, San Jose State University, San Jose, USA.
7
Department of Neurobiology and Behavior, University of California Irvine, Irvine, USA.
8
Cerebral Imaging Centre, Douglas Mental Health University Institute, McGill University, Montreal, Canada.
9
Departments of Psychiatry and Biological and Biomedical Engineering, McGill University, Montreal, Canada.
10
Integrated Program in Neuroscience, McGill University, Montreal, Canada.
11
Institute of Neuroscience and Medicine, INM-1, Research Center Jülich, Jülich, Germany.
12
JARA-BRAIN, Jülich-Aachen Research Alliance, Jülich, Germany.
13
C. and O. Vogt Institute for Brain Research, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
14
AA Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Boston, USA.
15
Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
16
Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, USA.
17
LANVIE Laboratory of Neuroimaging of Aging, University of Geneva, Geneva, Switzerland.
18
Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK.
19
Department of Psychiatry and Biobehavioural Sciences, University of California Los Angeles, Los Angeles, USA.
20
INSERM, CNRS, UMR-S975, Institut du Cerveau et de la Moelle Epinière (ICM), Paris, France.
21
Center for Neuroscience, University of California Davis, Davis, USA.
22
Department of Psychology, University of California Davis, Davis, USA.
23
INSERM U1077, Université de Caen Normandie, UMR-S1077, Ecole Pratique des Hautes Etudes, Centre Hospitalier Universitaire de Caen, Caen, France.
24
Human Neuroanatomy Laboratory and C.R.I.B., School of Medicine, University of Castilla-La Mancha, Albacete, Spain.
25
Department of Computer Science, Florida State University, Tallahassee, USA.
26
Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, USA.
27
School of Public Health and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, USA.
28
Department of Biomedical Engineering, University of Alberta, Edmonton, Canada.
29
The Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada.
30
Department of Psychiatry, University of Alberta, Edmonton, Canada.
31
Department of Radiology, University of California, San Francisco, USA.
32
Center for Imaging of Neurodegenerative Diseases, San Francisco VA Medical Center, San Francisco, USA.
33
Psychology Department, Wayne State University, Detroit, USA.
34
Institute of Gerontology, Wayne State University, Detroit, USA.
35
VA Boston Healthcare System, Boston, USA.
36
Department of Radiology, Stanford University, Palo Alto, USA.
37
McGill Centre for Studies in Aging, Faculty of Medicine, McGill University, Montreal, Canada.
38
Department of Psychology, McGill University, Montreal, Canada.
39
Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Canada.
40
Department of Neurosurgery, University of California Los Angeles, Los Angeles, USA.
41
Northwestern University Feinberg School of Medicine, Chicago, USA.
42
Department of Neurology, University of California Irvine, Irvine, USA.
#
Contributed equally

Abstract

The advent of high-resolution magnetic resonance imaging (MRI) has enabled in vivo research in a variety of populations and diseases on the structure and function of hippocampal subfields and subdivisions of the parahippocampal gyrus. Because of the many extant and highly discrepant segmentation protocols, comparing results across studies is difficult. To overcome this barrier, the Hippocampal Subfields Group was formed as an international collaboration with the aim of developing a harmonized protocol for manual segmentation of hippocampal and parahippocampal subregions on high-resolution MRI. In this commentary we discuss the goals for this protocol and the associated key challenges involved in its development. These include differences among existing anatomical reference materials, striking the right balance between reliability of measurements and anatomical validity, and the development of a versatile protocol that can be adopted for the study of populations varying in age and health. The commentary outlines these key challenges, as well as the proposed solution of each, with concrete examples from our working plan. Finally, with two examples, we illustrate how the harmonized protocol, once completed, is expected to impact the field by producing measurements that are quantitatively comparable across labs and by facilitating the synthesis of findings across different studies.

KEYWORDS:

MRI; harmonization; hippocampus; parahippocampal gyrus; segmentation

PMID:
27862600
PMCID:
PMC5167633
DOI:
10.1002/hipo.22671
[Indexed for MEDLINE]
Free PMC Article
Icon for Wiley Icon for PubMed Central
14.
Neuroimage. 2017 Feb 1;146:492-506. doi: 10.1016/j.neuroimage.2016.09.044. Epub 2016 Sep 19.

A virtual water maze revisited: Two-year changes in navigation performance and their neural correlates in healthy adults.

Author information

1
Institute of Gerontology, Wayne State University, Detroit, MI, USA; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Champaign, IL, USA. Electronic address: adaugher@illinois.edu.
2
Institute of Gerontology, Wayne State University, Detroit, MI, USA; Department of Psychology, Wayne State University, Detroit, MI, USA.

Abstract

Age-related declines in spatial navigation are associated with deficits in procedural and episodic memory and deterioration of their neural substrates. For the lack of longitudinal evidence, the pace and magnitude of these declines and their neural mediators remain unclear. Here we examined virtual navigation in healthy adults (N=213, age 18-77 years) tested twice, two years apart, with complementary indices of navigation performance (path length and complexity) measured over six learning trials at each occasion. Slopes of skill acquisition curves and longitudinal change therein were estimated in structural equation modeling, together with change in regional brain volumes and iron content (R2* relaxometry). Although performance on the first trial did not differ between occasions separated by two years, the slope of path length improvement over trials was shallower and end-of-session performance worse at follow-up. Advanced age, higher pulse pressure, smaller cerebellar and caudate volumes, and greater caudate iron content were associated with longer search paths, i.e. poorer navigation performance. In contrast, path complexity diminished faster over trials at follow-up, albeit less so in older adults. Improvement in path complexity after two years was predicted by lower baseline hippocampal iron content and larger parahippocampal volume. Thus, navigation path length behaves as an index of perceptual-motor skill that is vulnerable to age-related decline, whereas path complexity may reflect cognitive mapping in episodic memory that improves with repeated testing, although not enough to overcome age-related deficits.

KEYWORDS:

Aging; Brain; Caudate; Hippocampus; Iron; Longitudinal

PMID:
27659539
PMCID:
PMC5322178
DOI:
10.1016/j.neuroimage.2016.09.044
[Indexed for MEDLINE]
Free PMC Article
Icon for Elsevier Science Icon for PubMed Central
15.
Neuroimage. 2016 Dec;143:26-39. doi: 10.1016/j.neuroimage.2016.08.047. Epub 2016 Aug 22.

Adult age differences in subcortical myelin content are consistent with protracted myelination and unrelated to diffusion tensor imaging indices.

Author information

1
Department of Psychiatry & Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, MI, United States; Institute of Gerontology, Wayne State University, Detroit, MI, United States.
2
Department of Psychiatry & Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, MI, United States.
3
Institute of Gerontology, Wayne State University, Detroit, MI, United States; Department of Psychology, Wayne State University, Detroit, MI, United States. Electronic address: nraz@wayne.edu.

Abstract

Post mortem studies suggest protracted myelination of subcortical white matter into the middle age followed by gradual decline in the late adulthood. To date, however, establishing the proposed inverted-U pattern of age-myelin association proved difficult, as the most common method of investigating white matter, diffusion tensor imaging (DTI), usually reveals only linear associations between DTI indices and age among healthy adults. Here we use a novel method of estimating Myelin Water Fraction (MWF) based on modeling the short spin-spin (T2) relaxation component from multi-echo T2 relaxation imaging data and assess subcortical myelin content within six white matter tracts in a sample of healthy adults (N=61, age 18-84 years). Myelin content evidenced a quadratic relationship with age, in accord with the pattern observed postmortem studies. In contrast, DTI-derived indices that are frequently cited as proxies for myelination, fractional anisotropy (FA) and radial diffusivity (RD), exhibited linear or null relationships with age. Furthermore, the magnitude of age differences in MWF varied across the white matter tracts. Myelin content estimated by MWF was unrelated to FA and correlated with RD only in the splenium. These findings are consistent with the notion that myelination continues throughout the young adulthood into the middle age. The results demonstrate that single-tensor DTI cannot serve as a source of specific proxies for myelination of white matter tracts.

KEYWORDS:

Aging; Brain; Fractional Anisotropy; Multi-exponential T(2) relaxation; White Matter

PMID:
27561713
PMCID:
PMC5124541
DOI:
10.1016/j.neuroimage.2016.08.047
[Indexed for MEDLINE]
Free PMC Article
Icon for Elsevier Science Icon for PubMed Central
16.
Neuroimage. 2016 Jun;133:468-476. doi: 10.1016/j.neuroimage.2016.03.047. Epub 2016 Mar 28.

Differential effect of age on posterior and anterior hippocampal functional connectivity.

Author information

1
Institute of Gerontology and Department of Psychology, Wayne State University, Detroit, MI, USA. Electronic address: damoiseaux@wayne.edu.
2
Institute of Gerontology and Department of Psychology, Wayne State University, Detroit, MI, USA.
3
School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.

Abstract

Aging is associated with declines in cognitive performance and multiple changes in the brain, including reduced default mode functional connectivity (FC). However, conflicting results have been reported regarding age differences in FC between hippocampal and default mode regions. This discrepancy may stem from the variation in selection of hippocampal regions. We therefore examined the effect of age on resting state FC of anterior and posterior hippocampal regions in an adult life-span sample. Advanced age was associated with lower FC between the posterior hippocampus and three regions: the posterior cingulate cortex, medial prefrontal cortex, and lateral parietal cortex. In addition, age-related reductions of FC between the left and right posterior hippocampus, and bilaterally along the posterior to anterior hippocampal axis were noted. Age differences in medial prefrontal and inter-hemispheric FC significantly differed between anterior and posterior hippocampus. Older age was associated with lower performance in all cognitive domains, but we observed no associations between FC and cognitive performance after controlling for age. We observed a significant effect of gender and a linear effect of COMT val158met polymorphism on hippocampal FC. Females showed higher FC of anterior and posterior hippocampus and medial prefrontal cortex than males, and the dose of val allele was associated with lower posterior hippocampus - posterior cingulate FC, independent of age. Vascular and metabolic factors showed no significant effects on FC. These results suggest differential age-related reduction in the posterior hippocampal FC compared to the anterior hippocampus, and an age-independent effect of gender and COMT on hippocampal FC.

KEYWORDS:

Aging; COMT val158met; Functional connectivity; Gender; Hippocampus; Vascular risk

PMID:
27034025
PMCID:
PMC4889536
DOI:
10.1016/j.neuroimage.2016.03.047
[Indexed for MEDLINE]
Free PMC Article
Icon for Elsevier Science Icon for PubMed Central
17.
Neuroimage. 2016 Mar;128:11-20. doi: 10.1016/j.neuroimage.2015.12.045. Epub 2015 Dec 30.

Accumulation of iron in the putamen predicts its shrinkage in healthy older adults: A multi-occasion longitudinal study.

Author information

1
Institute of Gerontology, Wayne State University, Detroit, MI, USA. Electronic address: ana.daugherty@wayne.edu.
2
Institute of Gerontology, Wayne State University, Detroit, MI, USA; Psychology Department, Wayne State University, Detroit, MI, USA.

Abstract

Accumulation of non-heme iron is believed to play a major role in neurodegeneration of the basal ganglia. In healthy aging, however, the temporal relationship between change in brain iron content and age-related volume loss is unclear. Here, we present the first long-term longitudinal multi-occasion investigation of changes in iron content and volume in the neostriatum in a sample of healthy middle-aged and older adults (N=32; ages 49-83years at baseline). Iron content, estimated via R2* relaxometry, increased in the putamen, but not the caudate nucleus. In the former, the rate of accumulation was coupled with change in volume. Moreover, greater baseline iron content predicted faster shrinkage and smaller volumes seven years later. Older age partially accounted for individual differences in neostriatal iron content and volume, but vascular risk did not. Thus, brain iron content may be a promising biomarker of impending decline in normal aging.

KEYWORDS:

Aging; Oxidative stress; R2*; Striatum; Susceptibility weighted imaging

PMID:
26746579
PMCID:
PMC4762718
[Available on 2017-03-01]
DOI:
10.1016/j.neuroimage.2015.12.045
[Indexed for MEDLINE]
Free PMC Article
Icon for Elsevier Science Icon for PubMed Central
18.
Neuroimage. 2016 Feb 1;126:15-26. doi: 10.1016/j.neuroimage.2015.11.028. Epub 2015 Nov 14.

Regional brain shrinkage and change in cognitive performance over two years: The bidirectional influences of the brain and cognitive reserve factors.

Author information

1
Department of Psychology, Stockholm University, Sweden; Stockholm Brain Institute, Sweden.
2
Faculty of Psychology and Educational Sciences, University of Geneva, Switzerland; Distance Learning University, Sierre, Switzerland.
3
Institute of Gerontology, Wayne State University, Detroit, USA.
4
Institute of Gerontology, Wayne State University, Detroit, USA; Department of Psychology, Wayne State University, Detroit, USA.
5
Institute of Gerontology, Wayne State University, Detroit, USA; Department of Psychology, Wayne State University, Detroit, USA; Institute of Gerontology, Wayne State University, 87 East Ferry St., Detroit, MI 48201, USA. Electronic address: nraz@wayne.edu.

Abstract

We examined relationships between regional brain shrinkage and changes in cognitive performance, while taking into account the influence of chronological age, vascular risk, Apolipoprotein E variant and socioeconomic status. Regional brain volumes and cognitive performance were assessed in 167 healthy adults (age 19-79 at baseline), 90 of whom returned for the follow-up after two years. Brain volumes were measured in six regions of interest (ROIs): lateral prefrontal cortex (LPFC), prefrontal white matter (PFw), hippocampus (Hc), parahippocampal gyrus (PhG), cerebellar hemispheres (CbH), and primary visual cortex (VC), and cognitive performance was evaluated in three domains: episodic memory (EM), fluid intelligence (Gf), and vocabulary (V). Average volume loss was observed in Hc, PhG and CbH, but reliable individual differences were noted in all examined ROIs. Average positive change was observed in EM and V performance but not in Gf scores, yet only the last evidenced individual differences in change. We observed reciprocal influences among neuroanatomical and cognitive variables. Larger brain volumes at baseline predicted greater individual gains in Gf, but differences in LPFC volume change were in part explained by baseline level of cognitive performance. In one region (PFw), individual change in volume was coupled with change in Gf. Larger initial brain volumes did not predict slower shrinkage. The results underscore the complex role of brain maintenance and cognitive reserve in adult development.

KEYWORDS:

Fluid abilities; Longitudinal; MRI; Memory; Prefrontal cortex; Volume; White matter

PMID:
26584866
PMCID:
PMC4733615
DOI:
10.1016/j.neuroimage.2015.11.028
[Indexed for MEDLINE]
Free PMC Article
Icon for Elsevier Science Icon for PubMed Central
19.
Neuroimage. 2016 May 1;131:193-204. doi: 10.1016/j.neuroimage.2015.10.085. Epub 2015 Nov 3.

White matter and memory in healthy adults: Coupled changes over two years.

Author information

1
Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany. Electronic address: bender@mpib-berlin.mpg.de.
2
Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
3
Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany; Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin, Germany.
4
Institute of Gerontology & Department of Psychology, Wayne State University, Detroit, MI, USA.

Abstract

Numerous cross-sectional studies have used diffusion tensor imaging (DTI) to link age-related differences in white matter (WM) anisotropy and concomitant decrements in cognitive ability. Due to a dearth of longitudinal evidence, the relationship between changes in diffusion properties of WM and cognitive performance remains unclear. Here we examine the relationship between two-year changes in WM organization and cognitive performance in healthy adults (N=96, age range at baseline=18-79 years). We used latent change score models (LCSM) to evaluate changes in age-sensitive cognitive abilities - fluid intelligence and associative memory. WM changes were assessed by fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) in WM regions that are considered part of established memory networks and exhibited individual differences in change. In modeling change, we postulated reciprocal paths between baseline measures and change factors, within and between WM and cognition domains, and accounted for individual differences in baseline age. Although baseline cross-sectional memory performance was positively associated with FA and negatively with RD, longitudinal effects told an altogether different story. Independent of age, longitudinal improvements in associative memory were significantly associated with linear reductions in FA and increases in RD. The present findings demonstrate the sensitivity of DTI-derived indices to changes in the brain and cognition and affirm the importance of longitudinal models for evaluating brain-cognition relations.

KEYWORDS:

Aging; DTI; Episodic memory; Longitudinal; Practice effect

PMID:
26545457
PMCID:
PMC4848116
DOI:
10.1016/j.neuroimage.2015.10.085
[Indexed for MEDLINE]
Free PMC Article
Icon for Elsevier Science Icon for PubMed Central
20.
Neuroimage. 2016 Jan 15;125:74-83. doi: 10.1016/j.neuroimage.2015.10.030. Epub 2015 Oct 19.

Differential aging of cerebral white matter in middle-aged and older adults: A seven-year follow-up.

Author information

1
Center for Lifespan Psychology, Max Planck Institute for Human Development, Germany. Electronic address: bender@mpib-berlin.mpg.de.
2
Department of Psychology, Humboldt University, Max Planck Institute for Human Development, Germany; Center for Lifespan Psychology, Max Planck Institute for Human Development, Germany.
3
Institute of Gerontology & Department of Psychology, Wayne State University, USA.

Abstract

The few extant reports of longitudinal white matter (WM) changes in healthy aging, using diffusion tensor imaging (DTI), reveal substantial differences in change across brain regions and DTI indices. According to the "last-in-first-out" hypothesis of brain aging late-developing WM tracts may be particularly vulnerable to advanced age. To test this hypothesis we compared age-related changes in association, commissural and projection WM fiber regions using a skeletonized, region of interest DTI approach. Using linear mixed effect models, we evaluated the influences of age and vascular risk at baseline on seven-year changes in three indices of WM integrity and organization (axial diffusivity, AD, radial diffusivity, RD, and fractional anisotropy, FA) in healthy middle-aged and older adults (mean age=65.4, SD=9.0years). Association fibers showed the most pronounced declines over time. Advanced age was associated with greater longitudinal changes in RD and FA, independent of fiber type. Furthermore, older age was associated with longitudinal RD increases in late-developing, but not early-developing projection fibers. These findings demonstrate the increased vulnerability of later developing WM regions and support the "last-in-first-out" hypothesis of brain aging.

KEYWORDS:

Age; DTI; Diffusivity; Hypertension; Longitudinal; White matter

PMID:
26481675
PMCID:
PMC4691398
DOI:
10.1016/j.neuroimage.2015.10.030
[Indexed for MEDLINE]
Free PMC Article
Icon for Elsevier Science Icon for PubMed Central

Supplemental Content

Loading ...
Support Center