Hippocampal serotonin depletion facilitates place learning concurrent with an increase in CA1 high frequency theta activity expression in the rat

Gutiérrez-Guzmán, Blanca Erika; Hernández-Pérez, J. Jesús; González-Burgos, Ignacio; Feria‐Velasco, Alfredo; Medina, R Rodriguez; Guevara, Miguel Ángel; López-Vázquez, Miguel Ángel; Olvera‐Cortés, María Esther

doi:10.1016/j.ejphar.2010.11.014

Cited by 27 publications

(11 citation statements)

References 64 publications

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“…In an animal study, Gutiérrez-Guzmán et al (2011) produced 5-HT hippocampal depletion through lesions to the cingulate bundle, fimbria, and fornix of rats. The hippocampal 5-HT depletion facilitated place learning accuracy.…”

Section: The Role Of 5-ht In Working Spatial and Episodic Memorymentioning

confidence: 99%

Neurobiology of Anorexia Nervosa: Serotonin Dysfunctions Link Self-Starvation with Body Image Disturbances through an Impaired Body Memory

Riva

2016

Front. Hum. Neurosci.

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The etiology of anorexia nervosa (AN) is still unclear, despite that it is a critical and potentially mortal illness. A recent neurobiological model considers AN as the outcome of dysfunctions in the neuronal processes related to appetite and emotionality (Kaye et al., 2009, 2013). However, this model still is not able to answer a critical question: What is behind body image disturbances (BIDs) in AN? The article starts its analysis from reviewing some of the studies exploring the effects of the serotonin systems in memory (episodic, working, and spatial) and its dysfunctions. The review suggests that serotonin disturbances may: (a) facilitate the encoding of third person (allocentric) episodic memories; (b) facilitate the consolidation of emotional episodic memories (e.g., teasing), if preceded by repeated stress; (c) reduce voluntary inhibition of mnestic contents; (d) impair allocentric spatial memory. If we discuss these results within the interpretative frame suggested by the “Allocentric Lock Hypothesis” (Riva, 2012, 2014), we can hypothesize that altered serotoninergic activity in AN patients: (i) improves their ability to store and consolidate negative autobiographical memories, including those of their body, in allocentric perspective; (ii) impairs their ability to trigger voluntary inhibition of the previously stored negative memory of the body; (iii) impairs their capacity to retrieve/update allocentric information. Taken together, these points suggest a possible link between serotonin dysfunctions, memory impairments and BIDs: the impossibility of updating a disturbed body memory using real time experiential data—I'm locked to a wrong body stored in long term memory—pushes AN patients to control body weight and shape even when underweight.

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Section: The Role Of 5-ht In Working Spatial and Episodic Memorymentioning

confidence: 99%

Neurobiology of Anorexia Nervosa: Serotonin Dysfunctions Link Self-Starvation with Body Image Disturbances through an Impaired Body Memory

Riva

2016

Front. Hum. Neurosci.

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“…Humans and rodents have developed a number of strategies to do so, with great importance of place and response learning (Tolman et al, 1946; Maguire et al, 1998; Hartley et al, 2003; Collett and Graham, 2004; Etchamendy and Bohbot, 2007; Liu et al, 2011). Place learning is a hippocampus-dependent navigation strategy, characterized by the use of environmental information incorporated into a cognitive map to locate a destination (O'Keefe et al, 1975; Morris et al, 1982; Eichenbaum et al, 1990; Dupret et al, 2010; Gutierrez-Guzman et al, 2011). It is described to be flexible since it does not rely on the starting position of the subject.…”

Section: Introductionmentioning

confidence: 99%

Hippocampus-dependent place learning enables spatial flexibility in C57BL6/N mice

Kleinknecht¹,

Bedenk²,

Kaltwasser³

et al. 2012

Front. Behav. Neurosci.

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Spatial navigation is a fundamental capability necessary in everyday life to locate food, social partners, and shelter. It results from two very different strategies: (1) place learning which enables for flexible way finding and (2) response learning that leads to a more rigid “route following.” Despite the importance of knockout techniques that are only available in mice, little is known about mice' flexibility in spatial navigation tasks. Here we demonstrate for C57BL6/N mice in a water-cross maze (WCM) that only place learning enables spatial flexibility and relearning of a platform position, whereas response learning does not. This capability depends on an intact hippocampal formation, since hippocampus lesions by ibotenic acid (IA) disrupted relearning. In vivo manganese-enhanced magnetic resonance imaging revealed a volume loss of ≥60% of the hippocampus as a critical threshold for relearning impairments. In particular the changes in the left ventral hippocampus were indicative of relearning deficits. In summary, our findings establish the importance of hippocampus-dependent place learning for spatial flexibility and provide a first systematic analysis on spatial flexibility in mice.

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“…The authors had previously shown (Gutiérrez-Guzmán et al, 2011) that the effect of serotonergic (5-HT) denervation of the hippocampus was the opposite to that at SUM; that is, it produced a facilitation of spatial learning, associated with high frequency theta. Based on the established link between theta and memory processing (Buzsáki, 2002; Hasselmo et al, 2002; Vertes, 2005), the authors proposed that manipulations that enhance theta activity, such as blocking 5-HT actions on the septum/hippocampus, promote learning, whereas those that disrupt theta (e.g., removing 5-HT input to SUM) impair learning/memory (Olvera-Cortés et al, 2013).…”

Section: Sum: Role In Learning and Memorymentioning

confidence: 99%

Major diencephalic inputs to the hippocampus

Vertes

2015

Progress in Brain Research

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The hippocampus receives two major external inputs from the diencephalon, that is, from the supramammillary nucleus (SUM) and nucleus reuniens (RE) of the midline thalamus. These two afferents systems project to separate, nonoverlapping, regions of the hippocampus. Specifically, the SUM distributes to the dentate gyrus (DG) and to CA2 of the dorsal and ventral hippocampus, whereas RE projects to CA1 of the dorsal and ventral hippocampus and to the subiculum. SUM and RE fibers to the hippocampus participate in common as well as in separate functions. Both systems would appear to amplify signals from other sources to their respective hippocampal targets. SUM amplifies signals from the entorhinal cortex (EC) to DG, whereas RE may amplify them from CA3 (and EC) to CA1 of the hippocampus. This “amplification” may serve to promote the transfer, encoding, and possibly storage of information from EC to DG and from CA3 and EC to CA1. Regarding their unique actions on the hippocampus, the SUM is a vital part of an ascending brainstem to hippocampal system generating the theta rhythm of the hippocampus, whereas RE importantly routes information from the medial prefrontal cortex to the hippocampus to thereby mediate functions involving both structures. In summary, although, to date, SUM and RE afferents to the hippocampus have not been extensively explored, the SUM and RE exert a profound influence on the hippocampus in processes of learning and memory.

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Hippocampal serotonin depletion facilitates place learning concurrent with an increase in CA1 high frequency theta activity expression in the rat

Cited by 27 publications

References 64 publications

Neurobiology of Anorexia Nervosa: Serotonin Dysfunctions Link Self-Starvation with Body Image Disturbances through an Impaired Body Memory

Neurobiology of Anorexia Nervosa: Serotonin Dysfunctions Link Self-Starvation with Body Image Disturbances through an Impaired Body Memory

Hippocampus-dependent place learning enables spatial flexibility in C57BL6/N mice

Major diencephalic inputs to the hippocampus

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