scholarly journals Afferent connections of the thalamic nucleus reuniens in the mouse

2019 ◽  
Vol 528 (7) ◽  
pp. 1189-1202 ◽  
Author(s):  
Niklas Scheel ◽  
Peer Wulff ◽  
Johanne G. Mooij‐van Malsen
Keyword(s):  
Thalamic Nucleus ◽  
Nucleus Reuniens ◽  
Afferent Connections

scholarly journals Prefrontal projections to the thalamic nucleus reuniens mediate fear extinction

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Karthik R. Ramanathan ◽  
Jingji Jin ◽  
Thomas F. Giustino ◽  
Martin R. Payne ◽  
Stephen Maren
Keyword(s):  
Thalamic Nucleus ◽  
Fear Extinction ◽  
Nucleus Reuniens

scholarly journals Nucleus reuniens is required for encoding and retrieving precise, hippocampal-dependent contextual fear memories in rats

2018 ◽  
Author(s):  
Karthik R. Ramanathan ◽  
Reed L. Ressler ◽  
Jingji Jin ◽  
Stephen Maren
Keyword(s):  
Prefrontal Cortex ◽  
Spatial Memory ◽  
Fear Conditioning ◽  
Medial Prefrontal Cortex ◽  
Thalamic Nucleus ◽  
Nmda Receptor Antagonist ◽  
Pavlovian Fear Conditioning ◽  
Contextual Memory ◽  
Nucleus Reuniens ◽  
Contextual Fear

AbstractThe nucleus reuniens (RE) is a ventral midline thalamic nucleus that interconnects the medial prefrontal cortex (mPFC) and hippocampus (HPC). Considerable data indicate that HPC-mPFC circuits are involved in contextual and spatial memory; however, it is not clear whether the RE mediates the acquisition or retrieval of these memories. To examine this question, we inactivated the RE with muscimol before either the acquisition or retrieval of Pavlovian fear conditioning in rats; freezing served as the index of fear. We found that RE inactivation before conditioning impaired the acquisition of contextual freezing, whereas inactivation of the RE prior to retrieval testing increased the generalization of freezing to a novel context; inactivation of the RE did not affect either the acquisition or expression of auditory fear conditioning. Interestingly, contextual conditioning impairments were absent when retrieval testing was also conducted after RE inactivation. Contextual memories acquired under RE inactivation were hippocampal-independent, insofar as contextual freezing in rats conditioned under RE inactivation was insensitive to intra-hippocampal infusions of the NMDA receptor antagonist, D,L-amino-5-phosophonovaleric acid (APV). Together, these data reveal that the RE supports hippocampal-dependent encoding of precise contextual memories that allow discrimination of dangerous from safe contexts. When the RE is inactive, however, alternate neural systems acquire an impoverished contextual memory that is only expressed when the RE is offline.SIGNIFICANCE STATEMENTThe midline thalamic nucleus reuniens (RE) coordinates communication between the hippocampus and medial prefrontal cortex, brain areas critical for contextual and spatial memory. Here we show that temporary pharmacological inactivation of RE impairs the acquisition and precision of contextual fear memories after Pavlovian fear conditioning in rats. However, inactivating the RE prior to retrieval testing restored contextual memory in rats conditioned after RE inactivation. Critically, we show that imprecise contextual memories acquired under RE inactivation are learned independently of the hippocampus. These data reveal that the RE is required for hippocampal-dependent encoding of precise contextual memories to support the discrimination of safe and dangerous contexts.

scholarly journals Hippocampal CA1 pyramidal cells do not receive monosynaptic input from thalamic nucleus reuniens

2021 ◽  
Author(s):  
Lilya Andrianova ◽  
Erica S Brady ◽  
Gabriella Margetts-Smith ◽  
Shivali Kohli ◽  
Chris J McBain ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Thalamic Nucleus ◽  
Critical Role ◽  
Pyramidal Cells ◽  
Brain Regions ◽  
Thalamic Nuclei ◽  
Nucleus Reuniens ◽  
Ca1 Pyramidal Cells ◽  
Local Inhibition ◽  
The Many

Midline thalamic nuclei play a critical role in cognitive functions such as memory, decision-making and spatial navigation, by facilitating communication between the many brain regions involved in these processes. One canonical feature of thalamic interactions with the cortex or hippocampus appears to be that the thalamus receives input from, and projects to, excitatory neurons. Thalamic nucleus reuniens (NRe) is located on the midline and is viewed primarily as a relay from prefrontal cortex to hippocampal and entorhinal areas, although these connections are poorly defined at the cellular and synaptic level. Using electrophysiology and monosynaptic circuit-tracing, we found that pyramidal cells in CA1 receive no direct input from NRe. This contrasts starkly with prefrontal cortex, subiculum and entorhinal cortex, and indicates that NRe inputs to CA1 primarily drive local inhibition and not excitation they do in the other regions. The NRe to CA1 projection is thus a unique thalamic projection and as such is raising important questions about the function of NRe-mediated prefrontal control of the hippocampus.

scholarly journals Efferent and Afferent Connections of the Supratrigeminal Neurons Conveying Orofacial Muscle Proprioception in Rats

2021 ◽  
Author(s):  
Atsushi Yoshida ◽  
Misaki Inoue ◽  
Fumihiko Sato ◽  
Yayoi Morita ◽  
Yumi Tsutsumi ◽  
...  
Keyword(s):  
Reticular Formation ◽  
Lateral Hypothalamus ◽  
Thalamic Nucleus ◽  
Reticular Nucleus ◽  
Amygdaloid Nucleus ◽  
Central Projection ◽  
Medullary Reticular Formation ◽  
Trigeminal Motor Nucleus ◽  
Afferent Connections ◽  
Proprioceptive Sensation

Abstract The supratrigeminal nucleus (Su5) is a key structure for controlling jaw-movements since it receives proprioceptive sensation from jaw-closing muscle spindles (JCMSs) and sends projection to the trigeminal motor nucleus (Mo5). However, the central projection and regulation of JCMS proprioceptive sensation have not been fully understood. Therefore, we aimed to reveal the efferents and afferents of the Su5 by means of neuronal tract tracings. Anterograde tracer injections into the Su5 revealed that the Su5 sent contralateral projections (or bilateral projections with a contralateral predominance) to the Su5, basilar pontine nuclei, pontine reticular nucleus, deep mesencephalic nucleus, superior colliculus, caudo-ventromedial edge of ventral posteromedial thalamic nucleus, parafascicular thalamic nucleus, zona incerta, and lateral hypothalamus, and ipsilateral projections (or bilateral projections with an ipsilateral predominance) to the intertrigeminal region, trigeminal oral subnucleus, dorsal medullary reticular formation, and hypoglossal nucleus as well as the Mo5. Retrograde tracer injections into the Su5 demonstrated that the Su5 received bilateral projections with a contralateral predominance (or contralateral projections) from the primary and secondary somatosensory cortices, granular insular cortex and Su5, and ipsilateral projections (or bilateral projections with an ipsilateral predominance) from the dorsal peduncular cortex, bed nuclei of stria terminalis, central amygdaloid nucleus, lateral hypothalamus, parasubthalamic nucleus, trigeminal mesencephalic nucleus, parabrachial nucleus, juxtatrigeminal region, trigeminal oral and caudal subnuclei, and dorsal medullary reticular formation. These findings suggest that the Su5 receiving JCMS proprioceptive sensation has efferent and afferent connections with multiple brain regions, which are involved in emotional and autonomic functions as well as orofacial motor functions.

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