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Publications (10 of 23) Show all publications
Mårtensson, J., Lätt, J., Åhs, F., Fredriksson, M., Söderlund, H., Schiöth, H. B., . . . Nilsson, M. (2018). Diffusion tensor imaging and tractography of the white matter in normal aging: The rate-of-change differs between segments within tracts. Magnetic Resonance Imaging, 45, 113-119, Article ID S0730-725X(17)30059-0.
Open this publication in new window or tab >>Diffusion tensor imaging and tractography of the white matter in normal aging: The rate-of-change differs between segments within tracts
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2018 (English)In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 45, p. 113-119, article id S0730-725X(17)30059-0Article in journal (Refereed) Published
Abstract [en]

Knowledge concerning the normal aging of cerebral white matter will improve our understanding of abnormal changes in neurodegenerative diseases. The microstructural basis of white matter maturation and aging can be investigated using diffusion tensor imaging (DTI). Generally, diffusion anisotropy increases during childhood and adolescence followed by a decline in middle age. However, this process is subject to spatial variations between tracts. The aim of this study was to investigate to what extent age-related variations also occur within tracts. DTI parameters were compared between segments of two white matter tracts, the cingulate bundle (CB) and the inferior fronto-occipital fasciculus (IFO), in 257 healthy individuals between 13 and 84years of age. Segments of the CB and the IFO were extracted and parameters for each segment were averaged across the hemispheres. The data was analysed as a function of age. Results show that age-related changes differ both between and within individual tracts. Different age trajectories were observed in all segments of the analysed tracts for all DTI parameters. In conclusion, aging does not affect white matter tracts uniformly but is regionally specific; both between and within white matter tracts.

Keywords
Tractography, Inferior fronto-occipital fasciculus, Cingulum, Aging, White matter degeneration, White matter tract
National Category
Medical and Health Sciences Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-319599 (URN)10.1016/j.mri.2017.03.007 (DOI)000417772500015 ()28359912 (PubMedID)
Available from: 2017-04-06 Created: 2017-04-06 Last updated: 2019-03-15Bibliographically approved
Persson, J., Stening, E., Nordin, K. & Söderlund, H. (2018). Predicting episodic and spatial memory performance from hippocampal resting-state functional connectivity: Evidence for an anterior-posterior division of function. Hippocampus, 28(1), 53-66
Open this publication in new window or tab >>Predicting episodic and spatial memory performance from hippocampal resting-state functional connectivity: Evidence for an anterior-posterior division of function
2018 (English)In: Hippocampus, ISSN 1050-9631, E-ISSN 1098-1063, Vol. 28, no 1, p. 53-66Article in journal (Refereed) Published
Abstract [en]

fMRI studies have identified distinct resting-state functional connectivity (RSFC) networks associated with the anterior and posterior hippocampus. However, the functional relevance of these two networks is still largely unknown. Hippocampal lesion studies and task-related fMRI point to a role for the anterior hippocampus in non-spatial episodic memory and the posterior hippocampus in spatial memory. We used Relevance Vector Regression (RVR), a machine-learning method that enables predictions of continuous outcome measures from multivariate patterns of brain imaging data, to test the hypothesis that patterns of whole-brain RSFC associated with the anterior hippocampus predict episodic memory performance, while patterns of whole-brain RSFC associated with the posterior hippocampus predict spatial memory performance. Magnetic resonance imaging (MRI) and memory assessment took place at two separate occasions. The anterior and posterior RSFC largely corresponded with previous findings, and showed no effect of laterality. Supporting the hypothesis, RVR produced accurate predictions of episodic performance from anterior, but not posterior, RSFC, and accurate predictions of spatial performance from posterior, but not anterior, RSFC. In contrast, a univariate approach could not predict performance from resting-state connectivity. This supports a functional dissociation between the anterior and posterior hippocampus, and indicates a multivariate relationship between intrinsic functional networks and cognitive performance within specific domains, that is relatively stable over time.

Keywords
episodic memory, hippocampus, machine learning, resting state, spatial memory
National Category
Psychology
Identifiers
urn:nbn:se:uu:diva-331607 (URN)10.1002/hipo.22807 (DOI)000418452700006 ()29028135 (Scopus ID)
Funder
Swedish Research Council, 2009-2035
Available from: 2017-10-16 Created: 2017-10-16 Last updated: 2018-01-18Bibliographically approved
Nordin, K., Persson, J., Stening, E., Herlitz, A., Larsson, E.-M. & Söderlund, H. (2018). Structural whole-brain covariance of the anterior and posterior hippocampus: Associations with age and memory. Hippocampus, 28(2), 151-163
Open this publication in new window or tab >>Structural whole-brain covariance of the anterior and posterior hippocampus: Associations with age and memory
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2018 (English)In: Hippocampus, ISSN 1050-9631, E-ISSN 1098-1063, Vol. 28, no 2, p. 151-163Article in journal (Refereed) Published
Abstract [en]

The hippocampus (HC) interacts with distributed brain regions to support memory and shows significant volume reductions in aging, but little is known about age effects on hippocampal whole-brain structural covariance. It is also unclear whether the anterior and posterior HC show similar or distinct patterns of whole-brain covariance and to what extent these are related to memory functions organized along the hippocampal longitudinal axis. Using the multivariate approach partial least squares, we assessed structural whole-brain covariance of the HC in addition to regional volume, in young, middle-aged and older adults (n = 221), and assessed associations with episodic and spatial memory. Based on findings of sex differences in both memory and brain aging, we further considered sex as a potential modulating factor of age effects. There were two main covariance patterns: one capturing common anterior and posterior covariance, and one differentiating the two regions by capturing anterior-specific covariance only. These patterns were differentially related to associative memory while unrelated to measures of single-item memory and spatial memory. Although patterns were qualitatively comparable across age groups, participants' expression of both patterns decreased with age, independently of sex. The results suggest that the organization of hippocampal structural whole-brain covariance remains stable across age, but that the integrity of these networks decreases as the brain undergoes age-related alterations.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
aging, episodic memory, longitudinal axis, sex, spatial memory
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-335505 (URN)10.1002/hipo.22817 (DOI)000422974700008 ()29171897 (PubMedID)
Funder
Swedish Research Council, 2009-2035Swedish Research Council, 2011-1943
Available from: 2017-12-06 Created: 2017-12-06 Last updated: 2019-06-28Bibliographically approved
Hellmer, K., Söderlund, H. & Gredebäck, G. (2018). The eye of the retriever: Developing episodic memory mechanisms in preverbal infants assessed through pupil dilation. Developmental Science, 21(2), Article ID e12520.
Open this publication in new window or tab >>The eye of the retriever: Developing episodic memory mechanisms in preverbal infants assessed through pupil dilation
2018 (English)In: Developmental Science, ISSN 1363-755X, E-ISSN 1467-7687, Vol. 21, no 2, article id e12520Article in journal (Refereed) Published
Abstract [en]

Studying memory in infants can be challenging, as they cannot express their subjective recollection verbally. In this study we use a novel method with which we can assess episodic recognition memory through pupillometry, using identical procedures and stimuli for infants and adults. In three experiments of 4- and 7-month-old infants, and adults we show that the adult pupillary response is larger to previously seen than to never seen items (old/new effect). Pupil dilations index subjective memory experience in adults, producing distinct pupil dilations to items judged as remembered, familiar, and new, regardless of actual previous exposure (Experiment 1). Seven-month-old infants demonstrate a clear pupillary old/new effect, very similar to that of adults (Experiment 2), whereas 4-month-olds do not demonstrate such an effect (Experiment 3). Our findings suggest that the mnemonic mechanisms that serve infants' and adults' episodic recognition memory are more similar than previously asserted: they are not fully developed at 4 months of age but that there is contiguity in human episodic memory development from 7 months of age.

National Category
Psychology
Identifiers
urn:nbn:se:uu:diva-309034 (URN)10.1111/desc.12520 (DOI)000427006200003 ()27981704 (PubMedID)
Funder
Knut and Alice Wallenberg Foundation
Available from: 2016-12-01 Created: 2016-12-01 Last updated: 2018-05-09Bibliographically approved
Nordin, K., Herlitz, A., Larsson, E.-M. & Söderlund, H. (2017). Overlapping effects of age on associative memory and the anterior hippocampus from middle to older age. Behavioural Brain Research, 317, 350-359
Open this publication in new window or tab >>Overlapping effects of age on associative memory and the anterior hippocampus from middle to older age
2017 (English)In: Behavioural Brain Research, ISSN 0166-4328, E-ISSN 1872-7549, Vol. 317, p. 350-359Article in journal (Refereed) Published
Abstract [en]

The anterior hippocampus has been implicated in associative memory, and along with hippocampal volume, this type of memory declines with age. However, few cross-sectional studies include middle-aged samples, making it unclear at what point these age-related changes occur. In addition, although men and women have been shown to differ in associative memory and rates of age-related hippocampal atrophy, sex-differences in aging are rarely studied. To address these issues, we assessed memory for word-pairs, hippocampal volume and activation during encoding and retrieval, across middle-aged (n=39) and older (n=44) participants, specifically in relation to sex. Older adults showed significantly poorer associative memory compared to middle-aged adults, paralleled by smaller anterior hippocampi and less activation during successful retrieval. The age-by-sex interaction observed in memory performance was also mirrored in the volume and activation of the hippocampus, indicating more pronounced age-effects in men as compared to women. These results indicate a specific role of the anterior hippocampus in verbal associative memory and suggest they both decline between middle-age and older age.

Keywords
Aging, Episodic memory, Event-related activation, fMRI, Sex, Voxel-based morphometry
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-305754 (URN)10.1016/j.bbr.2016.10.002 (DOI)000389086700038 ()27713000 (PubMedID)
Funder
Swedish Research Council, VR 2011-1943
Available from: 2016-10-21 Created: 2016-10-21 Last updated: 2018-04-17Bibliographically approved
Stening, E., Persson, J., Eriksson, E., Wahlund, L.-O., Zetterberg, H. & Söderlund, H. (2017). Specific patterns of whole-brain structural covariance of the anterior and posterior hippocampus in young APOE ε4 carriers. Behavioural Brain Research, 326, 256-264
Open this publication in new window or tab >>Specific patterns of whole-brain structural covariance of the anterior and posterior hippocampus in young APOE ε4 carriers
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2017 (English)In: Behavioural Brain Research, ISSN 0166-4328, E-ISSN 1872-7549, Vol. 326, p. 256-264Article in journal (Refereed) Published
Abstract [en]

Apolipoprotein E (APOE) ε4 has been associated with smaller hippocampal volumes in healthy aging, while findings in young adults are inconclusive. Previous studies have mostly used univariate methods, and without considering potential anterior/posterior differences. Here, we used a multivariate method, partial least squares, and assessed whole-brain structural covariance of the anterior (aHC) and posterior (pHC) hippocampus in young adults (n = 97) as a function of APOE ε4 status and sex. Two significant patterns emerged: 1) specific structural covariance of the aHC with frontal regions, temporal and occipital areas in APOE ε4 women, whereas the volume of both the aHC and pHC in all other groups co-varied with frontal, parietal and cerebellar areas; and 2) opposite structural covariance of the pHC in ε4 carriers compared to the aHC in non-carriers, with the pHC of ε4 carriers covarying with parietal and frontal areas, and the aHC of ε4 non-carriers covarying with motor areas and the middle frontal gyrus. APOE ε4 has in young adults been associated with better episodic and spatial memory, functions involving the aHC and pHC, respectively. We found no associations between structural covariance and performance, suggesting that other factors underlie the performance differences seen between carriers and non-carriers. Our findings indicate that APOE ε4 carriers and non-carriers differ in hippocampal organization and that there are differences as a function of sex and hippocampal segment. They stress the need to consider the hippocampus as a heterogeneous structure, and highlight the benefits of multivariate methods in assessing group differences in the brain.

Keywords
APOE ε4, hippocampus, structural covariance, young adults, partial least squares, memory
National Category
Psychology
Identifiers
urn:nbn:se:uu:diva-317322 (URN)10.1016/j.bbr.2017.03.013 (DOI)000401678300028 ()28284953 (PubMedID)
Funder
Swedish Research Council, 2009-2035
Available from: 2017-03-13 Created: 2017-03-13 Last updated: 2017-07-06Bibliographically approved
Stening, E., Persson, J., Eriksson, E., Wahlund, L.-O., Zetterberg, H. & Söderlund, H. (2016). Apolipoprotein E ϵ4 is positively related to spatial performance but unrelated to hippocampal volume in healthy young adults. Behavioural Brain Research, 299, 11-18
Open this publication in new window or tab >>Apolipoprotein E ϵ4 is positively related to spatial performance but unrelated to hippocampal volume in healthy young adults
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2016 (English)In: Behavioural Brain Research, ISSN 0166-4328, E-ISSN 1872-7549, Vol. 299, p. 11-18Article in journal (Refereed) Published
Abstract [en]

The apolipoprotein E (APOE) ϵ4 allele is known to be a major genetic risk factor for Alzheimer's disease (AD). It has been linked to especially episodic memory decline and hippocampal atrophy in both healthy and demented elderly populations. In young adults, ϵ4 carriers have shown better performance in episodic memory compared to non-carriers. Spatial memory, however, has not been thoroughly assessed in relation to APOE in spite of its dependence on the hippocampus. In this study, we assessed the effect of APOE genotype on a variety of spatial and episodic memory tasks as well as hippocampal volume assessed through manual tracing in a sample of young adults (N=123). We also assessed whether potential effects were modulated by sex. The presence of one or more ϵ4 alleles had positive effects on spatial function and memory and object location memory, but no effect on word recognition. Men were superior to women in spatial function and memory but there were no sex differences in the other tasks. In spite of APOE ϵ4 carriers having superior performance in several memory tasks, no difference was found as a function of APOE genotype in hippocampal volume. To our knowledge, this study is the first to show that APOE ϵ4 has a positive effect on spatial ability in young adults.

Keywords
APOE epsilon 4; Spatial memory; Episodic memory; Hippocampus; Manual tracing; Young adults
National Category
Psychology
Identifiers
urn:nbn:se:uu:diva-269688 (URN)10.1016/j.bbr.2015.11.006 (DOI)000368565000003 ()26581118 (PubMedID)
External cooperation:
Funder
Swedish Research Council, 2009-2035
Available from: 2015-12-17 Created: 2015-12-17 Last updated: 2017-12-01
Persson, J. & Söderlund, H. (2015). Hippocampal hemispheric and long-axis differentiation of stimulus content during episodic memory encoding and retrieval: An activation likelihood estimation meta-analysis. Hippocampus, 25(12), 1614-1631
Open this publication in new window or tab >>Hippocampal hemispheric and long-axis differentiation of stimulus content during episodic memory encoding and retrieval: An activation likelihood estimation meta-analysis
2015 (English)In: Hippocampus, ISSN 1050-9631, E-ISSN 1098-1063, Vol. 25, no 12, p. 1614-1631Article in journal (Refereed) Published
Abstract [en]

While there is ample evidence that the hippocampus is functionally heterogeneous along its longitudinal axis, there is still no consensus regarding its exact organization. Whereas spatial memory tasks frequently engage the posterior hippocampus, the regions engaged during episodic memory are more varying and may depend on the specific nature of the stimuli. Here, we investigate the effect of stimulus content on the location of hippocampal recruitment during episodic memory encoding and retrieval of pictorial and verbal material with a meta-analysis approach, using activation likelihood estimation and restricting the analysis to the hippocampus. Verbal material was associated with left-lateralized anterior activation, compared to pictorial material that recruited a more posterior aspect of the hippocampus, primarily within the right hemisphere. This effect held for encoding of both single items and item-item associations but was less clear during retrieval. The findings lend further support to a functional subdivision of the hippocampus along its longitudinal axis and indicate that the content of episodic memories is one factor that determines the location of hippocampal recruitment.

Keywords
meta-analysis; hippocampus; episodic memory; spatial memory; activation likelihood estimation; encoding; retrieval
National Category
Psychology
Identifiers
urn:nbn:se:uu:diva-259778 (URN)10.1002/hipo.22482 (DOI)000368281700012 ()26108671 (PubMedID)
Available from: 2015-08-11 Created: 2015-08-11 Last updated: 2017-12-04Bibliographically approved
Hellmer, K., Gredebäck, G. & Söderlund, H. (2015). Pupil Size and Recognition Memory in Infants and Adults. In: : . Paper presented at SRCD, Society for Research in Child Development, Philadelphia, USA. March 2015..
Open this publication in new window or tab >>Pupil Size and Recognition Memory in Infants and Adults
2015 (English)Conference paper, Oral presentation only (Other academic)
National Category
Psychology
Identifiers
urn:nbn:se:uu:diva-284531 (URN)
Conference
SRCD, Society for Research in Child Development, Philadelphia, USA. March 2015.
Available from: 2016-04-18 Created: 2016-04-18 Last updated: 2017-01-25
Palombo, D., Alain, C., Söderlund, H., Khuu, W. & Levine, B. (2015). Severely deficient autobiographical memory (SDAM) in healthy adults: a new mnemonic syndrome. Neuropsychologia, 72, 105-118
Open this publication in new window or tab >>Severely deficient autobiographical memory (SDAM) in healthy adults: a new mnemonic syndrome
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2015 (English)In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 72, p. 105-118Article in journal (Refereed) Published
National Category
Psychology
Identifiers
urn:nbn:se:uu:diva-249405 (URN)10.1016/j.neuropsychologia.2015.04.012 (DOI)000355882300012 ()25892594 (PubMedID)
Available from: 2015-04-13 Created: 2015-04-13 Last updated: 2017-12-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4671-7181

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