scholarly journals Skipping ahead: A circuit for representing the past, present, and future

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Jennifer C Robinson ◽  
Mark P Brandon
Keyword(s):  
Prefrontal Cortex ◽  
Theta Rhythm ◽  
Medial Septum ◽  
Brain Regions ◽  
Memory System ◽  
Future Scenarios ◽  
Nucleus Reuniens ◽  
The Past ◽  
Temporal Segregation ◽  
Brain Circuit

Envisioning the future is intuitively linked to our ability to remember the past. Within the memory system, substantial work has demonstrated the involvement of the prefrontal cortex and the hippocampus in representing the past and present. Recent data shows that both the prefrontal cortex and the hippocampus encode future trajectories, which are segregated in time by alternating cycles of the theta rhythm. Here, we discuss how information is temporally organized by these brain regions supported by the medial septum, nucleus reuniens, and parahippocampal regions. Finally, we highlight a brain circuit that we predict is essential for the temporal segregation of future scenarios.

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 The Role of the Medial Septum—Associated Networks in Controlling Locomotion and Motivation to Move

2021 ◽  
Vol 15 ◽  
Author(s):  
Petra Mocellin ◽  
Sanja Mikulovic
Keyword(s):  
Theta Rhythm ◽  
Medial Septum ◽  
Brain Regions ◽  
Cell Populations ◽  
Specific Cell ◽  
Diagonal Band ◽  
Open Questions ◽  
Motivational Aspect ◽  
Novel Theory

The Medial Septum and diagonal Band of Broca (MSDB) was initially studied for its role in locomotion. However, the last several decades were focussed on its intriguing function in theta rhythm generation. Early studies relied on electrical stimulation, lesions and pharmacological manipulation, and reported an inconclusive picture regarding the role of the MSDB circuits. Recent studies using more specific methodologies have started to elucidate the differential role of the MSDB’s specific cell populations in controlling both theta rhythm and behaviour. In particular, a novel theory is emerging showing that different MSDB’s cell populations project to different brain regions and control distinct aspects of behaviour. While the majority of these behaviours involve movement, increasing evidence suggests that MSDB-related networks govern the motivational aspect of actions, rather than locomotion per se. Here, we review the literature that links MSDB, theta activity, and locomotion and propose open questions, future directions, and methods that could be employed to elucidate the diverse roles of the MSDB-associated networks.

scholarly journals Cell assemblies in the cortico-hippocampal-reuniens network during slow oscillations

2018 ◽  
Author(s):  
David Angulo-Garcia ◽  
Maëva Ferraris ◽  
Antoine Ghestem ◽  
Lauriane Nallet-Khosrofian ◽  
Christophe Bernard ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Information Exchange ◽  
Brain Regions ◽  
Nucleus Reuniens ◽  
Slow Oscillations ◽  
Neuronal Assemblies ◽  
Up States ◽  
Sequential Activation ◽  
The Stability

AbstractThe nucleus reuniens (NR) is an important anatomical and functional relay between the medial prefrontal cortex (mPFC) and the hippocampus (HPC). Whether the NR controls neuronal assemblies, a hallmark of information exchange between the HPC and mPFC for memory transfer/consolidation, is not known. Using simultaneous LFP and unit recordings in NR, HPC and mPFC in rats during slow oscillations under anesthesia, we identified a reliable sequential activation of NR neurons at the beginning of UP states, which preceded mPFC ones. NR sequences were spatially organized, from dorsal to ventral NR. Chemical inactivation of the NR disrupted mPFC sequences at the onset of UP states as well as HPC sequences present during sharp-wave ripples. We conclude that the NR contributes to the coordination and stabilization of mPFC and HPC neuronal sequences during slow oscillations, possibly via the early activation of its own sequences.Significance StatementNeuronal assemblies are believed to be instrumental to code/encode/store information. They can be recorded in different brain regions, suggesting that widely distributed networks of networks are involved in such information processing. The prefrontal cortex, the hippocampus and the thalamic nucleus reuniens constitute a typical example of a complex network involved in memory consolidation. In this study, we show that spatially organized cells assemblies are recruited in the nucleus reuniens at the UP state onset during slow oscillations. Nucleus reuniens activity appears to be necessary to the stability of prefrontal cortex and hippocampal cell assembly formation during slow oscillations. This result further highlights the role of the Nucleus Reuniens as a functional hub for exchanging and processing memories.

A unique role for the hippocampus in recollecting the past and remembering the future

2007 ◽  
Vol 30 (3) ◽  
pp. 319-320
Author(s):  
Valerie A. Carr ◽  
Indre V. Viskontas
Keyword(s):  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Human Evolution ◽  
Brain Region ◽  
Memory System ◽  
Future Event ◽  
Unique Role ◽  
The Past ◽  
The Future ◽  
Episodic Memories

AbstractSuddendorf & Corballis (S&C) argue that episodic memory is the most flexible and recently evolved memory system, and point to the reorganization of prefrontal cortex throughout human evolution as the neuroanatomical substrate. Their approach, however, fails to address the unique role that the hippocampus, a primitive brain region, plays in creating and recalling episodic memories, as well as future event construction.

Evidence for the differential co-localization of neurokinin-1 receptors with 5-HT receptor subtypes in rat forebrain

2011 ◽  
Vol 26 (4) ◽  
pp. 505-515 ◽  
Author(s):  
Sepehr Hafizi ◽  
Florence Serres ◽  
Qi Pei ◽  
Susan Totterdell ◽  
Trevor Sharp
Keyword(s):  
Prefrontal Cortex ◽  
Basolateral Amygdala ◽  
Medial Septum ◽  
Brain Regions ◽  
Common Point ◽  
Receptor Subtypes ◽  
Double Labelling ◽  
Rat Forebrain ◽  
Neurokinin 1 ◽  
High Degree

Studies suggest that like selective 5-hydroxytryptamine (5-HT; serotonin) reuptake inhibitors, antagonists at neurokinin-1 receptors (NK1Rs) may have antidepressant and anxiolytic properties. NK1Rs are present in 5-HT innervated forebrain regions which may provide a common point of interaction between these two transmitter systems. This study aimed to investigate for cellular co-localization between NK1Rs and 5-HT receptor subtypes in mood-related brain regions in the rat forebrain. With experiments using fluorescence immunocytochemistry, double-labelling methods demonstrated a high degree of co-localization between NK1Rs and 5-HT1A receptors in most regions examined. Co-localization was highest in the medial septum (88% NK1R expressing cells were 5-HT1A receptor-positive) and hippocampal regions (e.g. dentate gyrus, 65%), followed by the lateral/basolateral amygdala (35%) and medial prefrontal cortex (31%). In contrast, co-localization between NK1Rs and 5-HT2A receptors was infrequent (< 8%) in most areas examined except for the hippocampus (e.g. CA3, 43%). Overall co-localization between NK1Rs and 5-HT1A receptors was much greater than that between NK1Rs and 5-HT2A receptors. Thus, these experiments demonstrate a high degree of co-localization between NK1Rs and 5-HT1A receptors in cortical and limbic regions of the rat forebrain. These findings suggest a novel site of interaction between NK1R antagonists and the 5-HT system.

Neuro-Clinical Signatures of Language Impairments: A Theoretical Framework for Function-to-structure Mapping in Clinics

2020 ◽  
Vol 20 (9) ◽  
pp. 800-811 ◽  
Author(s):  
Ferath Kherif ◽  
Sandrine Muller
Keyword(s):  
Brain Mapping ◽  
Theoretical Framework ◽  
Brain Regions ◽  
Language Impairments ◽  
Structure Mapping ◽  
Language Functions ◽  
The Past ◽  
Language Recovery ◽  
The Brain ◽  
Bow Tie

In the past decades, neuroscientists and clinicians have collected a considerable amount of data and drastically increased our knowledge about the mapping of language in the brain. The emerging picture from the accumulated knowledge is that there are complex and combinatorial relationships between language functions and anatomical brain regions. Understanding the underlying principles of this complex mapping is of paramount importance for the identification of the brain signature of language and Neuro-Clinical signatures that explain language impairments and predict language recovery after stroke. We review recent attempts to addresses this question of language-brain mapping. We introduce the different concepts of mapping (from diffeomorphic one-to-one mapping to many-to-many mapping). We build those different forms of mapping to derive a theoretical framework where the current principles of brain architectures including redundancy, degeneracy, pluri-potentiality and bow-tie network are described.

scholarly journals Hippocampal regenerative medicine: neurogenic implications for addiction and mental disorders

2021 ◽  
Author(s):  
Lee Peyton ◽  
Alfredo Oliveros ◽  
Doo-Sup Choi ◽  
Mi-Hyeon Jang
Keyword(s):  
Decision Making ◽  
Prefrontal Cortex ◽  
Executive Function ◽  
General Population ◽  
Mental Disorders ◽  
Psychiatric Illness ◽  
Neural Circuitry ◽  
Brain Regions ◽  
Neuropsychiatric Disease ◽  
Motivated Behavior

AbstractPsychiatric illness is a prevalent and highly debilitating disorder, and more than 50% of the general population in both middle- and high-income countries experience at least one psychiatric disorder at some point in their lives. As we continue to learn how pervasive psychiatric episodes are in society, we must acknowledge that psychiatric disorders are not solely relegated to a small group of predisposed individuals but rather occur in significant portions of all societal groups. Several distinct brain regions have been implicated in neuropsychiatric disease. These brain regions include corticolimbic structures, which regulate executive function and decision making (e.g., the prefrontal cortex), as well as striatal subregions known to control motivated behavior under normal and stressful conditions. Importantly, the corticolimbic neural circuitry includes the hippocampus, a critical brain structure that sends projections to both the cortex and striatum to coordinate learning, memory, and mood. In this review, we will discuss past and recent discoveries of how neurobiological processes in the hippocampus and corticolimbic structures work in concert to control executive function, memory, and mood in the context of mental disorders.

scholarly journals Convergence of heteromodal lexical retrieval in the lateral prefrontal cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander A. Aabedi ◽  
Sofia Kakaizada ◽  
Jacob S. Young ◽  
Jasleen Kaur ◽  
Olivia Wiese ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Picture Naming ◽  
Cognitive Rehabilitation ◽  
Tumor Model ◽  
Brain Regions ◽  
Support Vector ◽  
Lexical Retrieval ◽  
Lateral Prefrontal Cortex ◽  
Lesion Symptom Mapping ◽  
Single Construct

AbstractLexical retrieval requires selecting and retrieving the most appropriate word from the lexicon to express a desired concept. Few studies have probed lexical retrieval with tasks other than picture naming, and when non-picture naming lexical retrieval tasks have been applied, both convergent and divergent results emerged. The presence of a single construct for auditory and visual processes of lexical retrieval would influence cognitive rehabilitation strategies for patients with aphasia. In this study, we perform support vector regression lesion-symptom mapping using a brain tumor model to test the hypothesis that brain regions specifically involved in lexical retrieval from visual and auditory stimuli represent overlapping neural systems. We find that principal components analysis of language tasks revealed multicollinearity between picture naming, auditory naming, and a validated measure of word finding, implying the existence of redundant cognitive constructs. Nonparametric, multivariate lesion-symptom mapping across participants was used to model accuracies on each of the four language tasks. Lesions within overlapping clusters of 8,333 voxels and 21,512 voxels in the left lateral prefrontal cortex (PFC) were predictive of impaired picture naming and auditory naming, respectively. These data indicate a convergence of heteromodal lexical retrieval within the PFC.

scholarly journals Comparison of Activation in the Prefrontal Cortex of Native Speakers of Mandarin by Ability of Japanese as a Second Language Using a Novel Speaking Task

Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 412
Author(s):  
Li Cong ◽  
Hideki Miyaguchi ◽  
Chinami Ishizuki
Keyword(s):  
Second Language ◽  
Prefrontal Cortex ◽  
Cognitive Load ◽  
Near Infrared ◽  
Native Speakers ◽  
Brain Activation ◽  
Brain Regions ◽  
Strong Inhibition ◽  
Functional Near Infrared Spectroscopy ◽  
High Level

Evidence shows that second language (L2) learning affects cognitive function. Here in this work, we compared brain activation in native speakers of Mandarin (L1) who speak Japanese (L2) between and within two groups (high and low L2 ability) to determine the effect of L2 ability in L1 and L2 speaking tasks, and to map brain regions involved in both tasks. The brain activation during task performance was determined using prefrontal cortex blood flow as a proxy, measured by functional near-infrared spectroscopy (fNIRS). People with low L2 ability showed much more brain activation when speaking L2 than when speaking L1. People with high L2 ability showed high-level brain activation when speaking either L2 or L1. Almost the same high-level brain activation was observed in both ability groups when speaking L2. The high level of activation in people with high L2 ability when speaking either L2 or L1 suggested strong inhibition of the non-spoken language. A wider area of brain activation in people with low compared with high L2 ability when speaking L2 is considered to be attributed to the cognitive load involved in code-switching L1 to L2 with strong inhibition of L1 and the cognitive load involved in using L2.

A single acute pharmacological dose of γ-hydroxybutyrate modifies multiple gene expression patterns in rat hippocampus and frontal cortex

2010 ◽  
Vol 41 (2) ◽  
pp. 146-160 ◽  
Author(s):  
Véronique Kemmel ◽  
Christian Klein ◽  
Doulaye Dembélé ◽  
Bernard Jost ◽  
Omar Taleb ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Expression Patterns ◽  
Cell Communication ◽  
Alcohol Withdrawal Syndrome ◽  
Brain Regions ◽  
Rat Hippocampus ◽  
Transport Systems ◽  
Cellular Mechanisms ◽  
Biological Regulation ◽  
Nucleotide Binding Sites

γ-Hydroxybutyrate (GHB) is a natural brain neuromodulator that has its own enzymatic machinery for synthesis and degradation, release, and transport systems and several receptors that belong to the G protein-coupled receptor (GPCR) family. Targeting of this system with exogenous GHB is used in therapy to induce sleep and anesthesia and to reduce alcohol withdrawal syndrome. GHB is also popular as a recreational drug for its anxiolytic and mild euphoric effects. However, in both cases, GHB must be administered at high doses in order to maintain GHB concentrations in brain of ∼800–1,000 μM. These high concentrations are thought to be necessary for interactions with low-affinity sites on GABAB receptor, but the molecular targets and cellular mechanisms modulated by GHB remain poorly characterized. Therefore, to provide new insights into the elucidation of GHB mechanisms of action and open new tracks for future investigations, we explored changes of GHB-induced transcriptomes in rat hippocampus and prefrontal cortex by using DNA microarray studies. We demonstrate that a single acute anesthetic dose of 1 g/kg GHB alters a large number of genes, 121 in hippocampus and 53 in prefrontal cortex; 16 genes were modified simultaneously in both brain regions. In terms of molecular functions, the majority of modified genes coded for proteins or nucleotide binding sites. In terms of Gene Ontology (GO) functional categories, the largest groups were involved in metabolic processing for hippocampal genes and in biological regulation for prefrontal cortex genes. The majority of genes modified in both structures were implicated in cell communication processes. Western blot and immunohistochemical studies carried out on eight selected proteins confirmed the microarray findings.

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