Regional analysis of hippocampal activation during memory encoding and retrieval: fMRI study

Greicius, Michael D.; Krasnow, Ben; Boyett-Anderson, Jesse M.; Eliez, Stéphan; Schatzberg, Alan F.; Reiss, Allan L.; Menon, Vinod

doi:10.1002/hipo.10064

Cited by 203 publications

(154 citation statements)

References 44 publications

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“…It should be kept in mind that technical factors may differentially influence fMRI and voxel-based volumetric measures for anterior vs. posterior portions of human hippocampus. fMRI susceptibility artefact and signal drop-out may affect the anterior medial temporal lobe more than posterior medial temporal lobe 82 (although protocols exist to correct this 83 ). In addition, posterior hippocampus is approximately half the cross-sectional area than the larger anterior hippocampal head, such that activated cluster size and degree of post-acquisition spatial smoothing may influence statistical effects differentially along the long-axis.…”

Section: Spatial Processing In Primatesmentioning

confidence: 99%

Functional organization of the hippocampal longitudinal axis

Witter²,

et al. 2014

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The precise functional role of the hippocampus remains a topic of much debate. According to a dominant view, the dorsal/posterior hippocampus is implicated in memory and spatial navigation and the ventral/anterior hippocampus mediates anxietyrelated behaviours. However, this 'dichotomy view' may need revision. Gene expression studies demonstrate multiple functional domains along the hippocampal long axis, which often exhibit sharply demarcated borders. By contrast, anatomical studies and electrophysiological recordings in rodents suggest that the long-axis is organized along a gradient. Together, these observations suggest a model in which functional long-axis gradients are superimposed on discrete functional domains. This model provides a potential framework to explain and test the multiple functions ascribed to the hippocampus.The hippocampus is a medial temporal lobe structure critically involved in episodic memory and spatial navigation [1][2][3][4][5][6][7] . Its long, curved form is present across all mammalian orders and runs along a dorsal (septal) to ventral (temporal) axis in rodents, corresponding to a posteriorto-anterior axis in humans (FIG. 1a-b). The same basic intrinsic circuitry is maintained throughout the long axis and across species (FIG. 1c). Despite this conserved intrinsic circuitry, the dorsal and ventral portions have different connectivities with cortical and subcortical areas, and this has long posed a question as to whether the hippocampus is functionally uniform along this axis. Here we review cross-species data that show how the seemingly disparate functions ascribed to the hippocampus can be accommodated by a model in which different functional properties exist along the longitudinal axis.The severe memory impairment suffered by patient H.M. following bilateral hippocampal resection 1 led to intensive study 8 of patients and animal models with hippocampal damage, with an ensuing characterisation of hippocampal function in terms of declarative memory 2 , encompassing both episodic and semantic memory. At the same time, however, evidence emerged for a hippocampal role in spatial memory, based on the discovery of hippocampal 'place cells' 9,10 and the demonstration that hippocampal lesions impair spatial memory 4 . Both the declarative memory hypothesis 11 and the spatial mapping hypothesis 12 of hippocampal function proposed a unitary model in which the entire hippocampus is dedicated

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Section: Spatial Processing In Primatesmentioning

confidence: 99%

Functional organization of the hippocampal longitudinal axis

Witter²,

et al. 2014

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“…In light of the debate about gradations of functions along the anterior-posterior axis of hippocampus (Lepage et al, 1998;Greicius et al, 2003;Poppenk et al, 2013;Strange et al, 2014), we tested for systematic variations of activity along this axis during the three phases of the WM task. For this purpose, the average activity of all voxels within hippocampus was calculated at all y-coordinates ranging from anterior to posterior (y ϭ Ϫ8 to Ϫ38) with a 2 mm resolution.…”

Section: Hippocampusmentioning

confidence: 99%

“…The auditory cortex was partitioned into two ROIs (HG and PT). Also, given the debate about the differential function of anterior and posterior hippocampus (Lepage et al, 1998;Greicius et al, 2003), we divided the hippocampus ROI into anterior and posterior parts. From the frontal region, we chose IFG.…”

Section: Functional Connectivity Analysismentioning

confidence: 99%

A Brain System for Auditory Working Memory

Joseph²,

et al. 2016

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The brain basis for auditory working memory, the process of actively maintaining sounds in memory over short periods of time, is controversial. Using functional magnetic resonance imaging in human participants, we demonstrate that the maintenance of single tones in memory is associated with activation in auditory cortex. In addition, sustained activation was observed in hippocampus and inferior frontal gyrus. Multivoxel pattern analysis showed that patterns of activity in auditory cortex and left inferior frontal gyrus distinguished the tone that was maintained in memory. Functional connectivity during maintenance was demonstrated between auditory cortex and both the hippocampus and inferior frontal cortex. The data support a system for auditory working memory based on the maintenance of sound-specific representations in auditory cortex by projections from higher-order areas, including the hippocampus and frontal cortex.

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“…We extracted the time activity curve using a sphere ROI with radius 6 mm centered around the peak coordinate for the bilateral posterior cingulate gyrus of 2/-51/27 (x/y/z) according to the study by Greicius et al (2003) (Greicius et al, 2003b). For bilateral hippocampus we used an ROI centered around Talairach-Tournoux coordinates (-)31/-12/-16 (x/y/z) covering the anterior aspect of the hippocampus ROIO used by a previous study (Greicius et al, 2003a). To include only grey matter areas into the ROIs, we masked the sphere ROIs by the grey matter map derived from the respective anatomical MRI scan in the MNI space using automatic segmentation based on a hidden Markov random field model and expectation maximization (Zhang et al, 2001).…”

Section: Regions Of Interestmentioning

confidence: 99%

White matter microstructure underlying default mode network connectivity in the human brain

Teipel¹,

Bokde²,

Meindl³

et al. 2010

NeuroImage

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White matter microstructure underlying default mode network connectivity in the human brain, NeuroImage (2009), doi:10.1016/j.neuroimage.2009.10.067 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 AbstractResting state functional magnetic resonance imaging (fMRI) reveals a distinct network of correlated brain function representing a default mode state of the human brain. The underlying structural basis of this functional connectivity pattern is still widely unexplored.We combined fractional anisotropy measures of fiber tract integrity derived from diffusion tensor imaging (DTI) and resting state fMRI data obtained at 3 Tesla from 20 healthy elderly subjects (56 to 83 years of age) to determine white matter microstructure underlying default mode connectivity. We hypothesized that the functional connectivity between the posterior cingulate and hippocampus from resting state fMRI data would be associated with the white matter microstructure in the cingulate bundle and fiber tracts connecting posterior cingulate gyrus with lateral temporal lobes, medial temporal lobes and precuneus. This was demonstrated at the p < 0.001 level using a voxel-based multivariate analysis of covariance (MANCOVA) approach. In addition, we used a data driven technique of joint independent component analysis (ICA) that uncovers spatial pattern that are linked across modalities. It revealed a pattern of white matter tracts including cingulate bundle and associated fiber tracts resembling the findings from the hypothesis-driven analysis and was linked to the pattern of default mode network (DMN) connectivity in the resting state fMRI data. Our findings support the notion that the functional connectivity between the posterior cingulate and hippocampus and the functional connectivity across the entire DMN is based on distinct pattern of anatomical connectivity within the cerebral white matter.

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Regional analysis of hippocampal activation during memory encoding and retrieval: fMRI study

Cited by 203 publications

References 44 publications

Functional organization of the hippocampal longitudinal axis

Functional organization of the hippocampal longitudinal axis

A Brain System for Auditory Working Memory

White matter microstructure underlying default mode network connectivity in the human brain

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