Regulation of hippocampal mossy fiber-CA3 synapse function by a Bcl11b/C1ql2/Nrxn3(25b+) pathway.

The transcription factor Bcl11b has been linked to neurodevelopmental and neuropsychiatric disorders associated with synaptic dysfunction. Bcl11b is highly expressed in dentate gyrus granule neurons and is required for the structural and functional integrity of mossy fiber-CA3 synapses. The underlying molecular mechanisms, however, remained unclear.

Hippocampal-medial entorhinal circuit is differently organized along the dorsoventral axis in rodents.

The general understanding of hippocampal circuits is that the hippocampus and the entorhinal cortex (EC) are topographically connected through parallel identical circuits along the dorsoventral axis. Our anterograde tracing and in vitro electrophysiology data, however, show a markedly different dorsoventral organization of the hippocampal projection to the medial EC (MEC). While dorsal hippocampal projections are confined to the dorsal MEC, ventral hippocampal projections innervate both dorsal and ventral MEC.

Apples and oranges in the basket of a clinical model for exercise addiction: Rebuttal to Brevers et al. (2022).

This note is a reply to Brevers et al.'s (2022) the commentary. We first explain that the commentary's title is in discord with the theoretical implications of the Expanded Interactional Model of Exercise Addiction (EIMEA; Dinardi et al.

The expanded interactional model of exercise addiction.

Background And Aims: Cited in over 100 articles, the interactional model of exercise addiction (Egorov & Szabo, 2013) forms the theoretical foundation of many studies on the risk of exercise addiction. Still, the inclusion of previously omitted determinants could make it more useful. Therefore, this review presents the expanded version of the original model.

Processing of Hippocampal Network Activity in the Receiver Network of the Medial Entorhinal Cortex Layer V.

The interplay between hippocampus and medial entorhinal cortex (mEC) is of key importance for forming spatial representations. Within the hippocampal-entorhinal loop, the hippocampus receives context-specific signals from layers II/III of the mEC and feeds memory-associated activity back into layer V (LV). The processing of this output signal within the mEC, however, is largely unknown.

Endogenous Bufadienolide, Blood Pressure and Alcohol Withdrawal.

Background And Objective: Previously, it was demonstrated that marinobufagenin (MBG) is implicated in the development of ethanol withdrawal in rats. It has been shown that ethanol withdrawal is associated with a pressor response in the alcoholics. We hypothesized that elevated levels of sodium pump ligand, MBG, would underline the increase in systolic blood pressure during alcohol withdrawal in humans.

Impact of Social Conformity on Ethanol Preference in Wistar Rats.

Introduction: Social conformity is considered a possible promoter of alcohol use disorder in humans. The goal of this study was to explore the impact of conformity as one of the social factors that might contribute to the alcohol preference in a rat model of ethanol intake.

Methods: To model social conformity, 105 Wistar rats were group housed (3 animals per cage) with a different number of rats drinking either 10% ethanol or water during daily drinking sessions.

Clusters of cooperative ion channels enable a membrane-potential-based mechanism for short-term memory.

Across biological systems, cooperativity between proteins enables fast actions, supra-linear responses, and long-lasting molecular switches. In the nervous system, however, the function of cooperative interactions between voltage-dependent ionic channels remains largely unknown. Based on mathematical modeling, we here demonstrate that clusters of strongly cooperative ion channels can plausibly form bistable conductances.

TRPC channels are not required for graded persistent activity in entorhinal cortex neurons.

Adaptive behavior requires the transient storage of information beyond the physical presence of external stimuli. This short-lasting form of memory involves sustained ("persistent") neuronal firing which may be generated by cell-autonomous biophysical properties of neurons or/and neural circuit dynamics. A number of studies from brain slices reports intrinsically generated persistent firing in cortical excitatory neurons following suprathreshold depolarization by intracellular current injection.

Synaptic entrainment of ectopic action potential generation in hippocampal pyramidal neurons.

Key Points: Ectopic action potentials (EAPs) arise at distal locations in axonal fibres and are often associated with neuronal pathologies such as epilepsy or nerve injury, but they also occur during physiological network conditions. This study investigates whether initiation of such EAPs is modulated by subthreshold synaptic activity. Somatic subthreshold potentials invade the axonal compartment to considerable distances (>350 μm), whereas spread of axonal subthreshold potentials to the soma is inefficient.

Persistent sodium current modulates axonal excitability in CA1 pyramidal neurons.

Axonal excitability is an important determinant for the accuracy, direction, and velocity of neuronal signaling. The mechanisms underlying spike generation in the axonal initial segment and transmitter release from presynaptic terminals have been intensely studied and revealed a role for several specific ionic conductances, including the persistent sodium current (I ). Recent evidence indicates that action potentials can also be generated at remote locations along the axonal fiber, giving rise to ectopic action potentials during physiological states (e.

Stability and Function of Hippocampal Mossy Fiber Synapses Depend on .

Structural and functional plasticity of synapses are critical neuronal mechanisms underlying learning and memory. While activity-dependent regulation of synaptic strength has been extensively studied, much less is known about the transcriptional control of synapse maintenance and plasticity. Hippocampal mossy fiber (MF) synapses connect dentate granule cells to CA3 pyramidal neurons and are important for spatial memory formation and consolidation.

Marinobufagenin in Urine: A Potential Marker of Predisposition to Ethanol and a Target for Spironolactone.

Background And Objective: Previously it was demonstrated that digitalis-like cardiotonic steroid, marinobufagenin (MBG), is implicated in the development of ethanol addiction in rats. We hypothesized that (i) levels of sodium pump ligand, MBG, would be negatively correlated with the amount of ethanol consumed by rats, and (ii) that spironolactone would oppose the MBG induced ethanol-seeking behavior and blood pressure in rats.

Methods: Voluntary consumption of 9% alcohol (vs.

Downstream effects of hippocampal sharp wave ripple oscillations on medial entorhinal cortex layer V neurons in vitro.

The entorhinal cortex (EC) is a critical component of the medial temporal lobe (MTL) memory system. Local networks within the MTL express a variety of state-dependent network oscillations that are believed to organize neuronal activity during memory formation. The peculiar pattern of sharp wave-ripple complexes (SPW-R) entrains neurons by a very fast oscillation at ∼200 Hz in the hippocampal areas CA3 and CA1 and then propagates through the "output loop" into the EC.

KATP channels modulate intrinsic firing activity of immature entorhinal cortex layer III neurons.

Medial temporal lobe structures are essential for memory formation which is associated with coherent network oscillations. During ontogenesis, these highly organized patterns develop from distinct, less synchronized forms of network activity. This maturation process goes along with marked changes in intrinsic firing patterns of individual neurons.

The exercise paradox: An interactional model for a clearer conceptualization of exercise addiction.

Background And Aims: Exercise addiction receives substantial attention in the field of behavioral addictions. It is a unique form of addiction because in contrast to other addictive disorders it is carried out with major physical-effort and high energy expenditure.

Methods: A critical literature review was performed.

Axon-carrying dendrites convey privileged synaptic input in hippocampal neurons.

Neuronal processing is classically conceptualized as dendritic input, somatic integration, and axonal output. The axon initial segment, the proposed site of action potential generation, usually emanates directly from the soma. However, we found that axons of hippocampal pyramidal cells frequently derive from a basal dendrite rather than from the soma.

Choline-mediated modulation of hippocampal sharp wave-ripple complexes in vitro.

The cholinergic system is critically involved in the modulation of cognitive functions, including learning and memory. Acetylcholine acts through muscarinic (mAChRs) and nicotinic receptors (nAChRs), which are both abundantly expressed in the hippocampus. Previous evidence indicates that choline, the precursor and degradation product of Acetylcholine, can itself activate nAChRs and thereby affects intrinsic and synaptic neuronal functions.

Development of coherent neuronal activity patterns in mammalian cortical networks: common principles and local hetereogeneity.

Many mammals are born in a very immature state and develop their rich repertoire of behavioral and cognitive functions postnatally. This development goes in parallel with changes in the anatomical and functional organization of cortical structures which are involved in most complex activities. The emerging spatiotemporal activity patterns in multi-neuronal cortical networks may indeed form a direct neuronal correlate of systemic functions like perception, sensorimotor integration, decision making or memory formation.

Spontaneous bursting activity in the developing entorhinal cortex.

Periodic spontaneous activity represents an important attribute of the developing nervous system. The entorhinal cortex (EC) is a crucial component of the medial temporal lobe memory system. Yet, little is known about spontaneous activity in the immature EC.

TrkB modulates fear learning and amygdalar synaptic plasticity by specific docking sites.

Understanding the modulation of the neural circuitry of fear is clearly one of the most important aims in neurobiology. Protein phosphorylation in response to external stimuli is considered a major mechanism underlying dynamic changes in neural circuitry. TrkB (Ntrk2) neurotrophin receptor tyrosine kinase potently modulates synaptic plasticity and activates signal transduction pathways mainly through two phosphorylation sites [Y515/Shc site; Y816/PLCgamma (phospholipase Cgamma) site].

Muscarinic control of graded persistent activity in lateral amygdala neurons.

The cholinergic system is crucially involved in several cognitive processes including attention, learning and memory. Muscarinic actions have profound effects on the intrinsic firing pattern of neurons. In principal neurons of the entorhinal cortex (EC), muscarinic receptors activate an intrinsic cation current that causes multiple self-sustained spiking activity, which represents a potential mechanism for transiently sustaining information about novel items.

Mechanism of graded persistent cellular activity of entorhinal cortex layer v neurons.

Working memory is an emergent property of neuronal networks, but its cellular basis remains elusive. Recent data show that principal neurons of the entorhinal cortex display persistent firing at graded firing rates that can be shifted up or down in response to brief excitatory or inhibitory stimuli. Here, we present a model of a potential mechanism for graded firing.