scholarly journals Intact renewal after extinction of conditioned suppression with lesions of either the retrosplenial cortex or dorsal hippocampus

2017 ◽  
Vol 320 ◽  
pp. 143-153 ◽  
Author(s):  
Travis P. Todd ◽  
Matthew Y. Jiang ◽  
Nicole E. DeAngeli ◽  
David J. Bucci
Keyword(s):  
Conditioned Suppression ◽  
Dorsal Hippocampus ◽  
Retrosplenial Cortex

scholarly journals Robust information routing by dorsal subiculum neurons

2021 ◽  
Vol 7 (11) ◽  
pp. eabf1913
Author(s):  
Takuma Kitanishi ◽  
Ryoko Umaba ◽  
Kenji Mizuseki
Keyword(s):  
Nucleus Accumbens ◽  
Large Scale ◽  
Dorsal Hippocampus ◽  
Retrosplenial Cortex ◽  
Projection Neurons ◽  
Target Region ◽  
Ca1 Neurons ◽  
Axonal Projections ◽  
Output Structure ◽  
Hippocampal Ca1

The dorsal hippocampus conveys various information associated with spatial navigation; however, how the information is distributed to multiple downstream areas remains unknown. We investigated this by identifying axonal projections using optogenetics during large-scale recordings from the rat subiculum, the major hippocampal output structure. Subicular neurons demonstrated a noise-resistant representation of place, speed, and trajectory, which was as accurate as or even more accurate than that of hippocampal CA1 neurons. Speed- and trajectory-dependent firings were most prominent in neurons projecting to the retrosplenial cortex and nucleus accumbens, respectively. Place-related firing was uniformly observed in neurons targeting the retrosplenial cortex, nucleus accumbens, anteroventral thalamus, and medial mammillary body. Theta oscillations and sharp-wave/ripples tightly controlled the firing of projection neurons in a target region–specific manner. In conclusion, the dorsal subiculum robustly routes diverse navigation-associated information to downstream areas.

scholarly journals Long-range inhibitory intersection of a retrosplenial thalamocortical circuit by apical tuft-targeting CA1 neurons

2018 ◽  
Author(s):  
Naoki Yamawaki ◽  
Xiaojian Li ◽  
Laurie Lambot ◽  
Lynn Y. Ren ◽  
Jelena Radulovic ◽  
...  
Keyword(s):  
Long Range ◽  
Pyramidal Neurons ◽  
Dorsal Hippocampus ◽  
Retrosplenial Cortex ◽  
Molecular Profile ◽  
Thalamic Nuclei ◽  
Cellular Mechanisms ◽  
Ca1 Neurons ◽  
Apical Tuft ◽  
Anterior Thalamic Nuclei

AbstractDorsal hippocampus, retrosplenial cortex (RSC), and anterior thalamic nuclei (ATN) interact to mediate diverse cognitive functions, but the cellular basis for these interactions is unclear. We hypothesized a long-range circuit converging in layer 1 (L1) of RSC, based on the pathway anatomy of GABAergic CA1 retrosplenial-projecting (CA1-RP) neurons and thalamo-restrosplenial projections from ATN. We find that CA1→RSC projections stem from GABAergic neurons with a distinct morphology, electrophysiology, and molecular profile, likely corresponding to recently described Ntng1-expressing hippocampal interneurons. CA1-RP neurons monosynaptically inhibit L5 pyramidal neurons, principal outputs of RSC, via potent GABAergic synapses onto apical tuft dendrites in L1. These inhibitory inputs align precisely with L1-targeting thalamocortical excitatory inputs from ATN, particularly the anteroventral nucleus, forming a convergent circuit whereby CA1 inhibition can intercept ATN excitation to co-regulate RSC activity. Excitatory axons from subiculum, in contrast, innervate proximal dendrites in deeper layers. Short-term synaptic plasticity differs at each connection. Chemogenetically abrogating inhibitory CA1→RSC or excitatory ATN→RSC connections oppositely affects the encoding of contextual fear memory. Collectively, our findings identify multiple cellular mechanisms underlying hippocampo-thalamo-retrosplenial interactions, establishing CA1 RSC-projecting neurons as a distinct class with long-range axons that target apical tuft dendrites, and delineating an unusual cortical circuit in the RSC specialized for integrating long-range inhibition and thalamocortical excitation.

scholarly journals Hippocampal efferents to retrosplenial cortex and lateral septum are required for memory acquisition

2020 ◽  
Author(s):  
Ashley N Opalka ◽  
Dong V Wang
Keyword(s):  
Dorsal Hippocampus ◽  
Memory Performance ◽  
Critical Role ◽  
Selective Inhibition ◽  
Brain Regions ◽  
Retrosplenial Cortex ◽  
Contextual Fear Conditioning ◽  
Lateral Septum ◽  
Contextual Fear ◽  
Memory Acquisition

AbstractLearning and memory involves a large neural network of many brain regions, including the notable hippocampus along with the retrosplenial cortex (RSC) and lateral septum (LS). Previous studies have established that the dorsal hippocampus (dHPC) plays a critical role during the acquisition and expression of episodic memories. However, the role of downstream circuitry from the dHPC, including the dHPC-to-RSC and dHPC-to-LS pathways, has come under scrutiny only recently. Here, we employed an optogenetic approach with contextual fear conditioning in mice to determine whether the above two pathways are involved in acquisition and expression of contextual fear memory. We found that a selective inhibition of the dHPC neuronal terminals in either the RSC or LS during acquisition impaired subsequent memory performance, suggesting that both the dHPC-to-RSC and dHPC-to-LS pathways play a critical role in memory acquisition. We also selectively inhibited the two dHPC efferent pathways during memory expression and found a differential effect on memory performance. These results indicate the intricacies of memory processing and that hippocampal efferents to cortical and subcortical regions may be differentially involved in aspects of physiological and cognitive memory processes.

scholarly journals Reduced renewal of conditioned suppression following lesions of the dorsal hippocampus in male rats.

2020 ◽  
Vol 134 (5) ◽  
pp. 444-459
Author(s):  
Armin Tavakkoli ◽  
Danielle I. Fournier ◽  
David J. Bucci ◽  
Travis P. Todd
Keyword(s):  
Conditioned Suppression ◽  
Dorsal Hippocampus ◽  
Male Rats

scholarly journals The Impact of Removal of Ovarian Hormones on Cholinergic Muscarinic Receptors: Examining Prepulse Inhibition and Receptor Binding

2020 ◽  
Vol 10 (2) ◽  
pp. 106
Author(s):  
Sarah S. Ch’ng ◽  
Adam J. Walker ◽  
Madeleine McCarthy ◽  
Thien-Kim Le ◽  
Natalie Thomas ◽  
...  
Keyword(s):  
Muscarinic Receptor ◽  
Prepulse Inhibition ◽  
Receptor Binding ◽  
Dorsal Hippocampus ◽  
Ovarian Hormones ◽  
Retrosplenial Cortex ◽  
Female Rats ◽  
Receptor System ◽  
Significant Group ◽  
The Impact

Ovarian hormones, such as estrogens and progesterone, are known to exert beneficial effects on cognition and some psychiatric disorders. The basis of these effects is not fully understood, but may involve altered cholinergic neurotransmission. This study aimed to investigate how a lack of ovarian hormones would impact muscarinic receptor-induced deficits in prepulse inhibition (PPI) and muscarinic receptor density in several brain regions. Adult female rats were either ovariectomized, to remove the source of ovarian hormones, or left intact (sham-operated). PPI is a measure of sensorimotor gating that is typically impaired in schizophrenia patients, and similar deficits can be induced in rats by administering scopolamine, a muscarinic receptor antagonist. Our results revealed no significant effects of ovariectomy on PPI after saline or scopolamine treatment. Autoradiography was performed to measure cholinergic muscarinic receptor binding density using [3H]-pirenzepine, [3H]-AF-DX, and [3H]-4-DAMP, to label M1, M2/M4, and M3 receptors, respectively. We examined the amygdala, caudate putamen, dorsal hippocampus, motor cortex, retrosplenial cortex, and ventromedial hypothalamus. There were no significant group differences in any region for any muscarinic receptor type. These results suggest that removing peripheral ovarian hormones does not influence the cholinergic muscarinic receptor system in the context of PPI or receptor binding density.

Experience Influences Brain Mechanisms of Watching Dance

2011 ◽  
Vol 29 (supplement) ◽  
pp. 352-377 ◽  
Author(s):  
Seon Hee Jang ◽  
Frank E Pollick
Keyword(s):  
Motor Imagery ◽  
Visual Experience ◽  
Primary Motor Cortex ◽  
Action Observation ◽  
Brain Area ◽  
Retrosplenial Cortex ◽  
Imagery Task ◽  
Temporoparietal Junction ◽  
Action Observation Network ◽  
Viewing Experience

The study of dance has been helpful to advance our understanding of how human brain networks of action observation are influenced by experience. However previous studies have not examined the effect of extensive visual experience alone: for example, an art critic or dance fan who has a rich experience of watching dance but negligible experience performing dance. To explore the effect of pure visual experience we performed a single experiment using functional Magnetic Resonance Imaging (fMRI) to compare the neural processing of dance actions in 3 groups: a) 14 ballet dancers, b) 10 experienced viewers, c) 12 novices without any extensive dance or viewing experience. Each of the 36 participants viewed short 2-second displays of ballet derived from motion capture of a professional ballerina. These displays represented the ballerina as only points of light at the major joints. We wished to study the action observation network broadly and thus included two different types of display and two different tasks for participants to perform. The two different displays were: a) brief movies of a ballet action and b) frames from the ballet movies with the points of lights connected by lines to show a ballet posture. The two different tasks were: a) passively observe the display and b) imagine performing the action depicted in the display. The two levels of display and task were combined factorially to produce four experimental conditions (observe movie, observe posture, motor imagery of movie, motor imagery of posture). The set of stimuli used in the experiment are available for download after this paper. A random effects ANOVA was performed on brain activity and an effect of experience was obtained in seven different brain areas including: right Temporoparietal Junction (TPJ), left Retrosplenial Cortex (RSC), right Primary Somatosensory Cortex (S1), bilateral Primary Motor Cortex (M1), right Orbitofrontal Cortex (OFC), right Temporal Pole (TP). The patterns of activation were plotted in each of these areas (TPJ, RSC, S1, M1, OFC, TP) to investigate more closely how the effect of experience changed across these areas. For this analysis, novices were treated as baseline and the relative effect of experience examined in the dancer and experienced viewer groups. Interpretation of these results suggests that both visual and motor experience appear equivalent in producing more extensive early processing of dance actions in early stages of representation (TPJ and RSC) and we hypothesise that this could be due to the involvement of autobiographical memory processes. The pattern of results found for dancers in S1 and M1 suggest that their perception of dance actions are enhanced by embodied processes. For example, the S1 results are consistent with claims that this brain area shows mirror properties. The pattern of results found for the experienced viewers in OFC and TP suggests that their perception of dance actions are enhanced by cognitive processes. For example, involving aspects of social cognition and hedonic processing – the experienced viewers find the motor imagery task more pleasant and have richer connections of dance to social memory. While aspects of our interpretation are speculative the core results clearly show common and distinct aspects of how viewing experience and physical experience shape brain responses to watching dance.

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