scholarly journals Dual projecting cells linking thalamic and cortical communication routes between the medial prefrontal cortex and hippocampus

2021 ◽  
Author(s):  
Maximilian Schlecht ◽  
Maanasa Jayachandran ◽  
Gabriela E Rasch ◽  
Timothy Alexander Allen
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Entorhinal Cortex ◽  
Lateral Septum ◽  
Anterior Cingulate ◽  
Cell Populations ◽  
Midline Thalamus ◽  
Cholera Toxin Subunit B ◽  
Cornu Ammonis ◽  
Subunit B

The interactions between the medial prefrontal cortex (mPFC) and hippocampus (HC) are critical for memory and decision making and have been specifically implicated in several neurological disorders including schizophrenia, epilepsy, frontotemporal dementia, and Alzheimers disease. The ventral midline thalamus (vmThal), and lateral entorhinal cortex and perirhinal cortex (LEC/PER) constitute major communication pathways that facilitate mPFC-HC interactions in memory. Although vmThal and LEC/PER circuits have been delineated separately we sought to determine whether these two regions share cell-specific inputs that could influence both routes simultaneously. To do this we used a dual fluorescent retrograde tracing approach using cholera toxin subunit-B (CTB-488 and CTB-594) with injections targeting vmThal and the LEC/PER in rats. Retrograde cell body labeling was examined in key regions of interest within the mPFC-HC system including: (1) mPFC, specifically anterior cingulate cortex (ACC), dorsal and ventral prelimbic cortex (dPL, vPL), and infralimbic cortex (IL); (2) medial and lateral septum (MS, LS); (3) subiculum (Sub) along the dorsal-ventral and proximal-distal axes; and (4) LEC and medial entorhinal cortex (MEC). Results showed that dual vmThal-LEC/PER-projecting cell populations are found in MS, vSub, and the shallow layers II/III of LEC and MEC. We did not find any dual projecting cells in mPFC or in the cornu ammonis (CA) subfields of the HC. Thus, mPFC and HC activity is sent to vmThal and LEC/PER via non-overlapping projection cell populations. Importantly, the dual projecting cell populations in MS, vSub, and LEC are in a unique position to simultaneously influence both cortical and thalamic mPFC-HC pathways critical to memory.

scholarly journals Two contrasting mediodorsal thalamic circuits target the medial prefrontal cortex

2021 ◽  
Author(s):  
Polina Lyuboslavsky ◽  
Alena Kizimenko ◽  
Audrey C. Brumback
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Action Potentials ◽  
Brain Slices ◽  
Membrane Resistance ◽  
Channel Activity ◽  
Cholera Toxin Subunit B ◽  
Dendritic Arbors ◽  
Subunit B ◽  
Two Populations

ABSTRACTAt the heart of the prefrontal executive and limbic networks is the mediodorsal thalamus (MD). Despite the importance of MD in a broad range of behaviors and neuropsychiatric disorders, virtually nothing is known about the physiology of neurons in MD. Here, we injected the retrograde tracer cholera toxin subunit B (CTB) into the medial prefrontal cortex (mPFC) of adult (8 – 12 week old) male and female wildtype mice. We prepared acute brain slices and used current clamp electrophysiology to measure and compare the intrinsic properties of the neurons in MD that project to mPFC (MD→mPFC neurons). MD→mPFC neurons are located predominantly in the medial (MD-M) and lateral (MD-L) subnuclei of MD. We found that that MD-M→mPFC neurons have longer membrane time constants, higher membrane resistance, less Hyperpolarization and Cyclic Nucleotide gated (HCN) channel activity, and more readily generate action potentials compared to MD-L→mPFC neurons. Additionally, MD-M→mPFC neurons have larger and more complex dendritic arbors compared to MD-L→mPFC neurons. These data demonstrating that the two populations of MD→mPFC neurons have distinct physiologies and morphologies suggests a differential role in thalamocortical information processing and potentially behavior.

scholarly journals Novel Inferences in a Multidimensional Social Network Use a Grid-like Code

2020 ◽  
Author(s):  
Seongmin A. Park ◽  
Douglas S. Miller ◽  
Erie D. Boorman
Keyword(s):  
Decision Making ◽  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Entorhinal Cortex ◽  
Brain Regions ◽  
Cognitive Map ◽  
General Mechanism ◽  
Temporoparietal Junction ◽  
Flexible Behavior ◽  
Discrete Problems

ABSTRACTGeneralizing experiences to guide decision making in novel situations is a hallmark of flexible behavior. It has been hypothesized such flexibility depends on a cognitive map of an environment or task, but directly linking the two has proven elusive. Here, we find that discretely sampled abstract relationships between entities in an unseen two-dimensional (2-D) social hierarchy are reconstructed into a unitary 2-D cognitive map in the hippocampus and entorhinal cortex. We further show that humans utilize a grid-like code in several brain regions, including entorhinal cortex and medial prefrontal cortex, for inferred direct trajectories between entities in the reconstructed abstract space during discrete decisions. Moreover, these neural grid-like codes in the entorhinal cortex predict neural decision value computations in the medial prefrontal cortex and temporoparietal junction area during choice. Collectively, these findings show that grid-like codes are used by the human brain to infer novel solutions, even in abstract and discrete problems, and suggest a general mechanism underpinning flexible decision making and generalization.

scholarly journals Nucleus reuniens of the midline thalamus: Link between the medial prefrontal cortex and the hippocampus

2007 ◽  
Vol 71 (6) ◽  
pp. 601-609 ◽  
Author(s):  
Robert P. Vertes ◽  
Walter B. Hoover ◽  
Klara Szigeti-Buck ◽  
Csaba Leranth
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Nucleus Reuniens ◽  
Midline Thalamus

scholarly journals Maternal Separation Modifies the Activity of Social Processing Brain Nuclei Upon Social Novelty Exposure

2021 ◽  
Vol 15 ◽  
Author(s):  
Sara Mejía-Chávez ◽  
Arturo Venebra-Muñoz ◽  
Fabio García-García ◽  
Aleph Alejandro Corona-Morales ◽  
Arturo Enrique Orozco-Vargas
Keyword(s):  
Prefrontal Cortex ◽  
Nucleus Accumbens ◽  
Social Behavior ◽  
Medial Prefrontal Cortex ◽  
Paraventricular Nucleus ◽  
Maternal Separation ◽  
Lateral Septum ◽  
Medial Amygdala ◽  
Physiological Basis ◽  
Brain Nuclei

Maternal separation has been shown to disrupt proper brain development and maturation, having profound consequences on the neuroendocrine systems in charge of the stress response, and has been shown to induce behavioral and cognitive abnormalities. At the behavioral level, maternal separation has been shown to increase offensive play-fighting in juvenile individuals and reduce social interest in adulthood. Since most of the studies that have evaluated the consequences of maternal separation on social behavior have focused on behavioral analysis, there is a need for a further understanding of the neuronal mechanisms underlying the changes in social behavior induced by maternal separation. Therefore, the aim of the present research was to assess the long-term effects of maternal separation on social interaction behavior and to assess the activity of several brain regions involved in the processing of social cues and reward upon social novelty exposure, using c-Fos immunohistochemistry as a marker of neuronal activity. Male Wistar rats were subjected to 4 h maternal separation during the neonatal period, 9:00 h–13:00 h from postnatal day 1 to 21, and exposed to social novelty during adulthood. After social novelty exposure, brains were fixed and coronal sections of the medial amygdala, lateral septum (LS), paraventricular nucleus of the hypothalamus, nucleus accumbens, and medial prefrontal cortex were obtained for c-Fos immunohistochemistry. Maternally separated rats spent less time investigating the novel peer, suggesting that maternal separation reduces social approach motivation. Furthermore, maternal separation reduced the number of c-Fos positive cells of the medial amygdala, paraventricular nucleus of the hypothalamus, LS, nucleus accumbens, and medial prefrontal cortex upon social novelty exposure. These findings suggest that maternal separation can reduce the plastic capacity of several brain nuclei, which constitute a physiological basis for the emergence of behavioral disorders presented later in life reported to be linked to early life adversity.

scholarly journals Neural mechanisms of economic commitment in the human medial prefrontal cortex

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Konstantinos Tsetsos ◽  
Valentin Wyart ◽  
S Paul Shorkey ◽  
Christopher Summerfield
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Neural Mechanisms ◽  
Anterior Cingulate ◽  
Dorsal Anterior Cingulate Cortex ◽  
Financial Return ◽  
Economic Decisions ◽  
Decision Biases ◽  
Stimulus Value ◽  
Over Time

Neurobiologists have studied decisions by offering successive, independent choices between goods or gambles. However, choices often have lasting consequences, as when investing in a house or choosing a partner. Here, humans decided whether to commit (by acceptance or rejection) to prospects that provided sustained financial return. BOLD signals in the rostral medial prefrontal cortex (rmPFC) encoded stimulus value only when acceptance or rejection was deferred into the future, suggesting a role in integrating value signals over time. By contrast, the dorsal anterior cingulate cortex (dACC) encoded stimulus value only when participants rejected (or deferred accepting) a prospect. dACC BOLD signals reflected two decision biases–to defer commitments to later, and to weight potential losses more heavily than gains–that (paradoxically) maximised reward in this task. These findings offer fresh insights into the pressures that shape economic decisions, and the computation of value in the medial prefrontal cortex.

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