Hippocampal projections to the anterior olfactory nucleus differentially convey spatiotemporal information during episodic odour memory

Aqrabawi, Afif J; Kim, Jun Chul

doi:10.1038/s41467-018-05131-6

Cited by 82 publications

(58 citation statements)

References 53 publications

(56 reference statements)

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“…However, such projections are not equally distributed along the anterior-posterior tract. For example, pyramidal neurons from the ventral hippocampus project massively to medial anterior olfactory nucleus, while dorsal innervate increasingly more lateral positions 100 . We showed recently that OB theta oscillations drive dorsal hippocampus gamma amplitude during long-term social memory retrieval.…”

Section: Discussionmentioning

confidence: 99%

Pro-neurogenic effect of fluoxetine in the olfactory bulb is concomitant to improvements in social memory and depressive-like behavior of socially isolated mice

Medeiros

et al. 2020

Transl Psychiatry

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Although loneliness is a human experience, it can be estimated in laboratory animals deprived from physical contact with conspecifics. Rodents under social isolation (SI) tend to develop emotional distress and cognitive impairment. However, it is still to be determined whether those conditions present a common neural mechanism. Here, we conducted a series of behavioral, morphological, and neurochemical analyses in adult mice that underwent to 1 week of SI. We observed that SI mice display a depressive-like state that can be prevented by enriched environment, and the antidepressants fluoxetine (FLX) and desipramine (DES). Interestingly, chronic administration of FLX, but not DES, was able to counteract the deleterious effect of SI on social memory. We also analyzed cell proliferation, neurogenesis, and astrogenesis after the treatment with antidepressants. Our results showed that the olfactory bulb (OB) was the neurogenic niche with the highest increase in neurogenesis after the treatment with FLX. Considering that after FLX treatment social memory was rescued and depressive-like behavior decreased, we propose neurogenesis in the OB as a possible mechanism to unify the FLX ability to counteract the deleterious effect of SI.

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Section: Discussionmentioning

confidence: 99%

Pro-neurogenic effect of fluoxetine in the olfactory bulb is concomitant to improvements in social memory and depressive-like behavior of socially isolated mice

Medeiros

et al. 2020

Transl Psychiatry

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“…The nerve nuclei with strong antigenic affinity for JEV include the early AO nucleus and the late hippocampal CA2 region. Both the AO and hippocampal CA2 have anatomical and odor-information transmission connections [22]. Early olfactory dysfunction in Parkinson’s patients and Lewy corpuscles, a typical lesion in the brain, first appeared in the neurons of the AO nucleus.…”

Section: Discussionmentioning

confidence: 99%

Precise Localization and Dynamic Distribution of Japanese Encephalitis Virus in the Brain Nuclei of Infected Mice

ChangQin

Han

Gao

et al. 2020

Preprint

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22Japanese encephalitis virus (JEV) is a pathogen that causes severe vector-borne 23 zoonotic diseases, thereby posing a serious threat to human health. Although JEV is 24 potentially neurotropic, its pathogenesis and distribution in the host have not been 25 fully elucidated. In this study, an infected mouse model was established using a 26 highly virulent P3 strain of JEV. Immunohistochemistry and in situ hybridization, 27 combined with anatomical imaging of the mouse brain, were used to dynamically 28 localize the virus and construct three-dimensional (3D) images. Consequently, onset 29 of mild clinical symptoms occurred in some mice at 84h post JEV infection, while 30 most mice displayed typical neurological symptoms at 144h post infection. Moreover, 31 brain pathology revealed typical changes associated with non-suppurative 32 encephalitis, which lasted up to 192h. The earliest detection of viral antigen was 33 achieved at 72h post infection, in the thalamus and medulla oblongata. At 144h post 34 infection, the positive viral antigen signals were mainly distributed in the cerebral 35 cortex, olfactory area, basal ganglia, thalamus, and brainstem regions in mice. At 36 192h post infection, the antigen signals gradually decreased, and the localization of 37JEV tended to concentrate in the cerebrum and thalamus, while no viral antigen was 38 detected in the brain at 504h post infection. In this model, the viral antigen was first 39 expressed in the reticular thalamic nucleus (Rt), at a consistent concentration. The 40 expression of the viral antigen in the hippocampal CA2 region, the anterior olfactory 41 nucleus, and the deep mesencephalic nucleus was high and persistent. The 3D images 42 showed that viral signals were mostly concentrated in the parietal cortex, occipital 3 / 28 43 lobe, and hippocampus, near the mid-sagittal plane. In the early stages of infection in 44 mice, a large number of viral antigens were detected in denatured and necrotic 45 neurons, suggesting that JEV directly causes neuronal damage. From the time of its 46 entry, JEV is widely distributed in the central nervous system thereby causing 47 extensive damage. 48Author summary 49 There are many theories regarding the mechanism of entry of the Japanese 50 encephalitis virus (JEV) into the nervous system. The inflammation cascade effect, 51 resulting from the virus entering the central nervous system (CNS), is a major cause 52 of brain injury in JEV patients. In this study, we found that the earliest point at which 53 viral antigen was detected in the brain tissues following peripheral infection of JEV 54 was at 72h. The virus was located in the nerve nuclei of the thalamus and medulla 55 oblongata and, subsequently, viral antigens were found in the anterior olfactory 56 nucleus. At 96h post infection, the virus was extensively distributed in the brain 57 tissue, and at 144h-192h the viral antigen was widely distributed and highly 58 concentrated. The viral concentration detected in the ventromedial thalamic nucleus 59 (VM), d...

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“…Information carried by time-cells, may be conveyed to outside the hippocampus, through e.g. polysynaptic and direct projections to the OB 62 and olfactory cortex 26 or monosynaptic projections to the medial prefrontal cortex which is involved in learning the DNMS task 34 and exhibits similar temporal codes 15 . Sequence expansion during learning implies increased information sent out to such areas, which may be important for active memory retention or rule learning during the training process.…”

Section: Links To Working Memorymentioning

confidence: 99%

“…cells that respond to specific odors) are thought to be involved in various learning processes 19,[21][22][23] . Hippocampal networks receive olfactory information through the lateral entorhinal cortex 24,25 and project back to olfactory cortex 26 , rendering them a crucial element in odor-discrimination 19,27 , odor-rule learning 28 or odor-sequence memory 29 .…”

Section: Introductionmentioning

confidence: 99%

Emergence of stable sensory and dynamic temporal representations in the hippocampus during working memory

Taxidis

Pnevmatikakis

Mylavarapu

et al. 2018

Preprint

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Hippocampal networks form maps of experience through spiking sequences that encode sensory cues, space or time. But whether distinct rules govern the emergence, stability and plasticity of externally driven and internallygenerated representations remains unclear. Using two-photon calcium imaging, we recorded CA1 pyramidal populations across multiple days, while mice learned and performed an olfactory, delayed, working-memory task. We observed anatomically intermixed spiking sequences, comprised of 'odor-cells' encoding olfactory cues, followed by 'time-cells' encoding odor-specific delay time-points. Odor-cells were reliably activated across trials and retained stable fields over days and different delays. In contrast, time-cells exhibited sparse, unreliable activation and labile fields that remapped over days and extended delays. Moreover, the number of odor-cells remained stable, whereas time-cells increased over days during learning of the task, but not during passive exposure. Therefore, multi-modal representations with distinct learning-related dynamics and stability can co-exist in CA1, likely driven by different neurophysiological and plasticity mechanisms.

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Hippocampal projections to the anterior olfactory nucleus differentially convey spatiotemporal information during episodic odour memory

Cited by 82 publications

References 53 publications

Pro-neurogenic effect of fluoxetine in the olfactory bulb is concomitant to improvements in social memory and depressive-like behavior of socially isolated mice

Pro-neurogenic effect of fluoxetine in the olfactory bulb is concomitant to improvements in social memory and depressive-like behavior of socially isolated mice

Precise Localization and Dynamic Distribution of Japanese Encephalitis Virus in the Brain Nuclei of Infected Mice

Emergence of stable sensory and dynamic temporal representations in the hippocampus during working memory

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