Fan cells in layer 2 of lateral entorhinal cortex are critical for episodic-like memory

Vandrey, Brianna; Garden, Derek L. F.; Ambrozova, Veronika; McClure, Christina; Nolan, Matthew F.; Ainge, James A.

doi:10.1101/543777

Cited by 9 publications

(17 citation statements)

References 30 publications

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“…Analysis of performance on the object recognition (OR) task replicated our previously reported effects (Kuruvilla and Ainge, 2017; Vandrey et al, 2020; Wilson et al, 2013a, 2013b). Average discrimination ratios were not significantly different between sham and LEC lesion rats ( F (1,11) = 2.82, p = .061, η normalp 2 = .204; Figure 3(a)).…”

Section: Behavioural Analysis: Experimentssupporting

confidence: 76%

“…However, recent studies using more specific manipulations have demonstrated the existence of segregated functional circuits within the LEC. Leitner et al (2016) showed that reelin and calbindin positive cells in layer 2 of LEC respond differently to odours and Vandrey et al (2020) went on to show that specific inactivation of reelin positive cells in layer 2a of LEC results in impaired object–place–context memory while leaving object–context memory intact. While neither of these studies tested different spatial reference frames, they do demonstrate that LEC as a whole does not act as a functional unit but rather that it is made up of specialised sub-systems that can be functionally segregated.…”

Section: Discussionmentioning

confidence: 99%

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Lateral entorhinal cortex lesions impair both egocentric and allocentric object–place associations

Kuruvilla

Wilson

Ainge

2020

Brain and Neuroscience Advances

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During navigation, landmark processing is critical either for generating an allocentric-based cognitive map or in facilitating egocentric-based strategies. Increasing evidence from manipulation and single-unit recording studies has highlighted the role of the entorhinal cortex in processing landmarks. In particular, the lateral (LEC) and medial (MEC) sub-regions of the entorhinal cortex have been shown to attend to proximal and distal landmarks, respectively. Recent studies have identified a further dissociation in cue processing between the LEC and MEC based on spatial frames of reference. Neurons in the LEC preferentially encode egocentric cues while those in the MEC encode allocentric cues. In this study, we assessed the impact of disrupting the LEC on landmark-based spatial memory in both egocentric and allocentric reference frames. Animals that received excitotoxic lesions of the LEC were significantly impaired, relative to controls, on both egocentric and allocentric versions of an object–place association task. Notably, LEC lesioned animals performed at chance on the egocentric version but above chance on the allocentric version. There was no significant difference in performance between the two groups on an object recognition and spatial T-maze task. Taken together, these results indicate that the LEC plays a role in feature integration more broadly and in specifically processing spatial information within an egocentric reference frame.

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Section: Behavioural Analysis: Experimentssupporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Lateral entorhinal cortex lesions impair both egocentric and allocentric object–place associations

Kuruvilla

Wilson

Ainge

2020

Brain and Neuroscience Advances

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“…The EC has been subdivided into several areas but is now commonly divided into two, the lateral entorhinal cortex (LEC) and the medial entorhinal cortex (MEC) which deviates in both connectivity and function (Witter, Doan et al 2017). The MEC is predominantly involved in spatial processing, whereas the LEC is predominantly involved in object recognition, odor discrimination and episodic memory (Staubli, Ivy et al 1984, Schultz, Sommer et al 2015, Vandrey, Garden et al 2020. In the human, the EC is located in the anterior portion of the medial temporal lobe (Insausti, Munoz-Lopez et al 2017), whereas, in the rat, it forms the ventro-caudal part of the cerebral hemisphere (Insausti, Herrero et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Development of the entorhinal cortex occurs via parallel lamination during neurogenesis

Liu

Bergmann

Mori

et al. 2021

Preprint

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The entorhinal cortex (EC) is the spatial processing center of the brain and structurally is an interface between the three layered paleocortex and six layered neocortex, known as the periarchicortex. Limited studies indicate peculiarities in the formation of the EC such as early emergence of cells in layers (L) II and late deposition of LIII, as well as divergence in the timing of maturation of cell types in the superficial layers. In this study, we examine developmental events in the entorhinal cortex using an understudied model in neuroanatomy and development, the pig and supplement the research with BrdU labeling in the developing mouse EC. We determine the pig serves as an excellent anatomical model for studying human neurogenesis, given its long gestational length, presence of a moderate sized outer subventricular zone and early cessation of neurogenesis during gestation. Immunohistochemistry identified prominent clusters of OLIG2+ oligoprogenitor-like cells in the superficial layers of the lateral EC (LEC) that are sparser in the medial EC (MEC). These are first detected in the subplate during the early second semester. MRI analyses reveal an acceleration of EC growth at the end of the second trimester. BrdU labeling of the developing MEC, shows the deeper layers form first and prior to the superficial layers, but the LV/VI emerges in parallel and the LII/III emerges later, but also in parallel. We coin this lamination pattern parallel lamination. The early-born Reln+ stellate cells in the superficial layers express the classic LV marker, Bcl11b (Ctip2) and arise from a common progenitor that forms the late deep layer LV neurons. In summary, we characterize the developing EC in a novel animal model and outline in detail the formation of the EC. We further provide insight into how the periarchicortex forms in the brain, which differs remarkably to the inside-out lamination of the neocortex.

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“…Given there are both direct and indirect anatomical pathways between all three of these brain regions (Burwell et al, 1995; Delatour and Witter, 2002; Jay and Witter, 1991), to understand how the network functions more precise network manipulations will be critical. For example, selective deactivation of direct projections from layer II of lateral entorhinal cortex to the DG impaired object-place-context but not object-context associative memory (Vandrey et al, 2020). Therefore, the precise anatomical connections between the brain regions which are critical for the formation of contextual associations may be different.…”

Section: Discussionmentioning

confidence: 99%

Putting objects in context: A prefrontal–hippocampal–perirhinal cortex network

Barker

Warburton

2020

Brain and Neuroscience Advances

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When we encounter an object, we spontaneously form associations between the object and the environment in which it was encountered. These associations can take a number of different forms, which include location and context. A neural circuit between the hippocampus, medial prefrontal cortex and perirhinal cortex is critical for object-location and object-sequence associations; however, how this neural circuit contributes to the formation of object-context associations has not been established. Bilateral lesions were made in the hippocampus, medial prefrontal cortex or perirhinal cortex to examine each region contribution to object-context memory formation. Next, a disconnection lesion approach was used to examine the necessity of functional interactions between the hippocampus and medial prefrontal cortex or perirhinal cortex. Spontaneous tests of preferential exploration were used to assess memory for different types of object-context associations. Bilateral lesion in the hippocampus, medial prefrontal cortex or perirhinal cortex impaired performance in both an object-place-context and an object-context task. Disconnection of the hippocampus from either the medial prefrontal cortex or perirhinal cortex impaired performance in both the object-place-context and object-context task. Interestingly, when object recognition memory was tested with a context switch between encoding and test, performance in the hippocampal and medial prefrontal cortex lesion groups was disrupted and performance in each disconnection group (i.e. hippocampus + medial prefrontal cortex, hippocampus + perirhinal cortex) was significantly impaired. Overall, these experiments establish the importance of the hippocampal-medial prefrontal-perirhinal cortex circuit for the formation of object-context associations.

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Fan cells in layer 2 of lateral entorhinal cortex are critical for episodic-like memory

Cited by 9 publications

References 30 publications

Lateral entorhinal cortex lesions impair both egocentric and allocentric object–place associations

Lateral entorhinal cortex lesions impair both egocentric and allocentric object–place associations

Development of the entorhinal cortex occurs via parallel lamination during neurogenesis

Putting objects in context: A prefrontal–hippocampal–perirhinal cortex network

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