Modelling Ebola.

This paper is the combination of a review on the problems of data collection and modelling efforts of the recent Ebola epidemics. After a brief review of data availability, the modelling frameworks have been discussed. Both deterministic and stochastic models have been reviewed and supplemented with a short discussion of some problems of parameter estimation.

Multi-scale modeling of altered synaptic plasticity related to Amyloid β effects.

As suggested by Palop and Mucke (2010) pathologically elevated β-amyloid (Aβ) impairs long term potentiation (LTP) and enhances long term depression (LTD) possible underlying mechanisms in Alzheimer's Disease (AD). In the present paper we adopt and further elaborate a phenomenological computational model of bidirectional plasticity based on the calcium control hypothesis of Shouval et al. (2002).

Teaching computational neuroscience.

The problems and beauty of teaching computational neuroscience are discussed by reviewing three new textbooks.

Anxiolytic drugs and altered hippocampal theta rhythms: the quantitative systems pharmacological approach.

The spirit of systems pharmacology was adopted to study the possible mechanisms of anxiolytic drugs on hippocampal electric patterns. The frequency of the hippocampal theta rhythm increases linearly with the intensity of electrical stimulation to the brainstem. The reduction of mean theta frequency in this paradigm predicts the clinical efficacy of anxiolytic drugs.

Localization of single-cell current sources based on extracellular potential patterns: the spike CSD method.

Traditional current source density (tCSD) calculation method calculates neural current source distribution of extracellular (EC) potential patterns, thus providing important neurophysiological information. While the tCSD method is based on physical principles, it adopts some assumptions, which can not hold for single-cell activity. Consequently, tCSD method gives false results for single-cell activity.

Model-based dynamical analysis of functional disconnection in schizophrenia.

Schizophrenia is shown to be associated with impaired interactions in functional macro-networks of the brain. The focus of our study was if there is an impairment of cognitive control of learning during schizophrenia. To investigate this question, we collected fMRI data from a group of stable schizophrenia patients and controls performing an object-location associative learning task in which the learning performance of the patient group was significantly worse.

Parallel computational subunits in dentate granule cells generate multiple place fields.

A fundamental question in understanding neuronal computations is how dendritic events influence the output of the neuron. Different forms of integration of neighbouring and distributed synaptic inputs, isolated dendritic spikes and local regulation of synaptic efficacy suggest that individual dendritic branches may function as independent computational subunits. In the present paper, we study how these local computations influence the output of the neuron.

Distance coding strategies based on the entorhinal grid cell system.

Estimating and keeping track of the distance from salient points of the environment are important constituents of the spatial awareness and navigation. In rodents, the majority of principal cells in the hippocampus are known to be correlated with the position of the animal. However, the lack of topography in the hippocampal cognitive map does not support the assumption that connections between these cells are able to store and recall distances between coded positions.

Impaired associative learning in schizophrenia: behavioral and computational studies.

Associative learning is a central building block of human cognition and in large part depends on mechanisms of synaptic plasticity, memory capacity and fronto-hippocampal interactions. A disorder like schizophrenia is thought to be characterized by altered plasticity, and impaired frontal and hippocampal function. Understanding the expression of this dysfunction through appropriate experimental studies, and understanding the processes that may give rise to impaired behavior through biologically plausible computational models will help clarify the nature of these deficits.

Pharmacological and computational analysis of alpha-subunit preferential GABA(A) positive allosteric modulators on the rat septo-hippocampal activity.

Clinically most active anxiolytic drugs are positive allosteric modulators (PAMs) of GABA(A) receptors, represented by benzodiazepine compounds. Due to their non-selective profile, however, they potently modulate several sup-type specific GABA(A) receptors, contributing to their broad-range side effects. Based on observations in genetically altered mice, however, it has been proposed that anxiolytic action of benzodiazepines is predominantly mediated by GABA(A) alpha2/3 subunit-containing receptors.

Intrinsic and synaptic mechanisms determining the timing of neuron population activity during hippocampal theta oscillation.

Hippocampal theta (3-8 Hz) is a major electrophysiological activity in rodents, which can be found in primates and humans as well. During theta activity, pyramidal cells and different classes of interneurons were shown to discharge at different phases of the extracellular theta. A recent in vitro study has shown that theta-frequency oscillation can be elicited in a hippocampal CA1 slice by the activation of metabotropic glutamate receptors with similar pharmacological and physiological profile that was found in vivo.

From electric patterns to drugs: perspectives of computational neuroscience in drug design.

A novel way of computational modeling by integrating compartmental neural techniques and detailed kinetic description of pharmacological modulation of transmitter-receptor interaction is offered as a method to test the electro-physiological and behavioral effects of potential drugs. Even more, an inverse method is suggested as a method for controlling a neural system to realize a prescribed temporal pattern. Generation and pharamcological modulation of theta rhythm in area CA1 of the hippocampus related to anxiety is analyzed.

Computational neuropharmacology: dynamical approaches in drug discovery.

Computational approaches that adopt dynamical models are widely accepted in basic and clinical neuroscience research as indispensable tools with which to understand normal and pathological neuronal mechanisms. Although computer-aided techniques have been used in pharmaceutical research (e.g.

Hippocampal theta rhythms from a computational perspective: code generation, mood regulation and navigation.

In this paper three computer models are summarized discussing different functions of the cortico-hippocampal system. Mood regulation, rhythm and code generation and navigation are integrated into a coherent conceptual framework around the concepts of structural hierarchy and circular causality. First, a model of spatio-temporal code generation is reviewed in which the hippocampal population theta rhythm plays an important role.

Theta oscillation-coupled dendritic spiking integrates inputs on a long time scale.

Persistent neural activity lasting for seconds after transient stimulation has been observed in several brain areas. This activity has been taken to be indicative of the integration of inputs on long time scales. Passive membrane properties render neural time constants to be on the order of milliseconds.

Model-based source localization of extracellular action potentials.

A new model-based analysis method was set up for revealing information encrypted in extracellular spatial potential patterns of neocortical action potentials. Spikes were measured by extracellular linear multiple microelectrode in vivo cat's primary auditory cortex and were analyzed based on current source density (CSD) distribution models. Validity of the monopole and other point source approximations were tested on the measured potential patterns by numerical fitting.

Computational theories on the function of theta oscillations.

Neural rhythms can be studied in terms of conditions for their generation, or in terms of their functional significance. The theta oscillation is a particularly prominent rhythm, reported to be present in many brain areas, and related to many important cognitive processes. The generating mechanisms of theta have extensively been studied and reviewed elsewhere; here we discuss ideas that have accumulated over the past decades on the computational roles it may subserve.

Theta-modulated feedforward network generates rate and phase coded firing in the entorhino-hippocampal system.

Principal cells of the hippocampus and of its only cortical input region, the entorhinal cortex exhibit place specific activity in the freely moving rat. While entorhinal cells have widely tuned place fields, hippocampal place fields are more localized and determine not only the rate but also the timing of place cell spikes. Several models have successfully attempted to explain this fine tuning making use of intrahippocampal attractor network dynamics provided by the recurrent collaterals of hippocampal area CA3.

Properties of a random attachment growing network.

In this study we introduce and analyze the statistical structural properties of a model of growing networks which may be relevant to social networks. At each step a new node is added which selects k possible partners from the existing network and joins them with probability delta by undirected edges. The "activity" of the node ends here; it will get new partners only if it is selected by a newcomer.

Dynamically detuned oscillations account for the coupled rate and temporal code of place cell firing.

Firing of place cells in the exploring rat conveys doubly coded spatial information: both the rate of spikes and their timing relative to the phase of the ongoing field theta oscillation are correlated with the location of the animal. Specifically, the firing rate of a place cell waxes and wanes, while the timing of spikes precesses monotonically as the animal traverses the portion of the environment preferred by the cell. We propose a mechanism for the generation of this firing pattern that can be applied for place cells in all three hippocampal subfields and that encodes spatial information in the output of the cell without relying on topographical connections or topographical input.

Mesoscopic neurodynamics.

An overview is given on the history, theory, and applications of mesoscopic neural models. It is shown why and how we can describe the behavior of a large population of neurons by the method of statistical neurodynamics. Normal and epileptic propagation of cortical activity have been simulated.