Topographical and laminar distribution of cortical input to the monkey entorhinal cortex

Mohedano-Moriano, Alicia; Pro-Sistiaga, Palma; Arroyo-Jiménez, M.M.; Artacho‐Pérula, Emilio; Insausti, A.M.; Marcos, Pilar; Cebada‐Sánchez, Sandra; Martínez-Ruiz, J.; Muñoz, Mónica; Blaizot, Xavier; Martı́nez-Marcos, Alino; Amaral, David G.; Insausti, Ricardo

doi:10.1111/j.1469-7580.2007.00764.x

Cited by 75 publications

(68 citation statements)

References 26 publications

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“…In the present experiment, subjects were not submitted to any systematic memory task before sleep. Our results demonstrate that even under these conditions, slow oscillation is associated with consistent responses in the parahippocampal gyrus, a major relay area between the hippocampus and neocortex (22).…”

Section: Comparison With Earlier Positron Emission Tomography and Fmrmentioning

confidence: 84%

Spontaneous neural activity during human slow wave sleep

Dang‐Vu

Schabus

Desseilles

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

377

272

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Slow wave sleep (SWS) is associated with spontaneous brain oscillations that are thought to participate in sleep homeostasis and to support the processing of information related to the experiences of the previous awake period. At the cellular level, during SWS, a slow oscillation (<1 Hz) synchronizes firing patterns in large neuronal populations and is reflected on electroencephalography (EEG) recordings as large-amplitude, low-frequency waves. By using simultaneous EEG and event-related functional magnetic resonance imaging (fMRI), we characterized the transient changes in brain activity consistently associated with slow waves (>140 V) and delta waves (75-140 V) during SWS in 14 non-sleep-deprived normal human volunteers. Significant increases in activity were associated with these waves in several cortical areas, including the inferior frontal, medial prefrontal, precuneus, and posterior cingulate areas. Compared with baseline activity, slow waves are associated with significant activity in the parahippocampal gyrus, cerebellum, and brainstem, whereas delta waves are related to frontal responses. No decrease in activity was observed. This study demonstrates that SWS is not a state of brain quiescence, but rather is an active state during which brain activity is consistently synchronized to the slow oscillation in specific cerebral regions. The partial overlap between the response pattern related to SWS waves and the waking default mode network is consistent with the fascinating hypothesis that brain responses synchronized by the slow oscillation restore microwake-like activity patterns that facilitate neuronal interactions.fMRI ͉ neuroimaging ͉ sleep physiology ͉ slow oscillation D uring the deepest stage of nonrapid eye movement (NREM) sleep, also referred to as slow wave sleep (SWS) in humans (stage 3-4 of sleep), spontaneous brain activity is organized by specific physiological rhythms, the neural correlates of which have been described in animals (1). Unit recordings have shown that neuronal activity during SWS is characterized by a fundamental oscillation of membrane potential. This so-called ''slow oscillation'' (Ͻ1 Hz) is recorded in all major types of neocortical neurons during SWS and is composed of a depolarizing phase, associated with important neuronal firing (''up state''), followed by a hyperpolarizing phase during which cortical neurons remain silent for a few hundred milliseconds (''down state'') (2, 3). The slow oscillation occurs synchronously in large neuronal populations in such a way that it can be reflected on electroencephalography (EEG) recordings as large-amplitude, low-frequency waves (4).Delta rhythm (1-4 Hz) is another characteristic oscillation of NREM sleep. The neural underpinnings of delta rhythm remain uncertain, however. In the dorsal thalamus, a clock-like delta rhythm is generated by the interplay of two intrinsic membrane currents, although another delta rhythm survives complete thalamectomy, suggesting a cortical origin (1).In humans, a slow oscillation was identified on s...

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Section: Comparison With Earlier Positron Emission Tomography and Fmrmentioning

confidence: 84%

Spontaneous neural activity during human slow wave sleep

Dang‐Vu

Schabus

Desseilles

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

377

272

View full text Add to dashboard Cite

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“…However, studies in nonhuman primates suggest that the strongest PFC projections to the ERC and PRC arise in the orbitofrontal cortex (11)(12)(13). In contrast, structural connectivity between DLPFC/VLPFC and the MTL is light (10)(11)(12)(13). Therefore, the question whether prefrontal areas that show encoding-related activity patterns are connected with the ERC and PRC is particularly relevant in humans.…”

mentioning

confidence: 80%

“…Activity patterns that reflect successful encoding in functional MRI (fMRI) studies are most frequently observed in the ventrolateral and dorsolateral PFC (VLPFC and DLPFC, respectively) (6, 7). However, studies in nonhuman primates suggest that the strongest PFC projections to the ERC and PRC arise in the orbitofrontal cortex (11)(12)(13). In contrast, structural connectivity between DLPFC/VLPFC and the MTL is light (10)(11)(12)(13).…”

mentioning

confidence: 94%

Fiber density between rhinal cortex and activated ventrolateral prefrontal regions predicts episodic memory performance in humans

Schott

Niklas²,

Kaufmann³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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The prefrontal cortex (PFC) is assumed to contribute to goaldirected episodic encoding by exerting cognitive control on medial temporal lobe (MTL) memory processes. However, it is thus far unclear to what extent the contribution of PFC-MTL interactions to memory manifests at a structural anatomical level. We combined functional magnetic resonance imaging and fiber tracking based on diffusion tensor imaging in 28 young, healthy adults to quantify the density of white matter tracts between PFC regions that were activated during the encoding period of a verbal free-recall task and MTL subregions. Across the cohort, the strength of fiber bundles linking activated ventrolateral PFC regions and the rhinal cortex (comprising the peri-and entorhinal cortices) of the MTL correlated positively with free-recall performance. These direct white matter connections provide a basis through which activated regions in the PFC can interact with the MTL and contribute to interindividual differences in human episodic memory.functional MRI | tractography | hippocampus | perirhinal cortex | entorhinal cortex E pisodic memory (1) is the ability to encode, store, and recall events in their spatial and temporal context. Human lesion studies (2, 3) have demonstrated that episodic memory function is critically dependent on the hippocampus and neighboring structures of the medial temporal lobe (MTL), and functional neuroimaging experiments have shown that episodic memory encoding is associated with activations of the MTL and regions of the prefrontal cortex (PFC) (1, 4, 5).During encoding, both MTL and PFC regions show stronger activity for items that are later recalled compared with items that are forgotten [difference because of memory (DM)] (for reviews see refs. 6 and 7). It had long been hypothesized that coactivation of PFC and MTL structures might indicate that both regions cooperate during encoding and that activated PFC regions might be anatomically connected to MTL structures by white matter tracts (8). Via these fiber tracts, PFC regions might exert top-down control on MTL structures (9, 10) that act as gateways to the hippocampus, most notably the entrorhinal and perirhinal cortices (ERC and PRC, respectively, jointly referred to as the rhinal cortex) (7).Although intriguing, the possibility of a direct anatomically based functional interaction between PFC regions and the ERC and PRC during successful encoding is not without doubt. Activity patterns that reflect successful encoding in functional MRI (fMRI) studies are most frequently observed in the ventrolateral and dorsolateral PFC (VLPFC and DLPFC, respectively) (6, 7). However, studies in nonhuman primates suggest that the strongest PFC projections to the ERC and PRC arise in the orbitofrontal cortex (11-13). In contrast, structural connectivity between DLPFC/VLPFC and the MTL is light (10-13). Therefore, the question whether prefrontal areas that show encoding-related activity patterns are connected with the ERC and PRC is particularly relevant in humans.Diffusion tensor im...

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“…Indeed, output connectivity of the primate hippocampus with subcortical areas -including nucleus accumbens 173 -follows a graded topography similar to that in rodents 174 (but note longitudinally restricted vs. distributed hippocampal-amygdala projections in primates and rodents, respectively 107,175 ). Input connectivity from entorhinal cortex to DG also follow a graded mapping that is analogous to that in rats [34][35] , with an anteromedial-posterolateral EC axis corresponding to an anterior-posterior DG termination [176][177][178] . For example, the pattern of connectivity between cingulate cortex and hippocampus in primates is similar to that in rats, in the sense that anterior hippocampus is more strongly connected with anterior regions and medial frontal cortex, and connections with posterior cingulate (including retrosplenial cortex) are stronger with posterior hippocampus [179][180] .…”

Section: Box 1 Is the Rodent Ventral-dorsal Axis Homologous To The Pmentioning

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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Topographical and laminar distribution of cortical input to the monkey entorhinal cortex

Cited by 75 publications

References 26 publications

Spontaneous neural activity during human slow wave sleep

Spontaneous neural activity during human slow wave sleep

Fiber density between rhinal cortex and activated ventrolateral prefrontal regions predicts episodic memory performance in humans

Functional organization of the hippocampal longitudinal axis

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