Associative learning, including classical conditioning and operant conditioning, is regarded as the most fundamental type of learning for animals and human beings. Many models have been proposed surrounding classical conditioning or operant conditioning. However, a unified and integrated model to explain the two types of conditioning is much less studied. Here, a model based on neuromodulated s...

Plasticity of cortical circuits is maximal during critical periods of postnatal development. Ocular dominance plasticity is a classical model to understand the role of experience in development of the visual cortex. Recent studies are beginning to unravel the synaptic mechanisms underlying this form of plasticity and to elucidate the different plasticity of juvenile and adult animals at mechani...

Rapid phenotypic adaptation is critical for populations facing environmental changes and can be facilitated by phenotypic plasticity in the selected traits. Whereas recurrent environmental fluctuations can favour the maintenance or de novo evolution of plasticity, strong selection is hypothesized to decrease plasticity or even fix the trait (genetic assimilation). Despite advances in the theore...

In this paper, a new dynamic model describing the epileptic seizure initiation through transition from interictal to ictal state in a brain predisposed to epilepsy is suggested. The model follows Freeman’s approach where the brain is viewed as a network of interconnected oscillators. The proposed nonlinear model is experimentally motivated and relies on changes in synaptic strength in response ...

A simple constitutive model for the inelastic response of steel under monotonic and random cyclic loading conditions is developed within the framework of bounding surface plasticity. The particular feature that distinguishes this model from other similar ones is the ability of the bounding surface formulation to describe in a very simple way the initial “plateau” type of perfectly plastic respo...

Long-term synaptic plasticity leading to enhancement in synaptic efficacy (long-term potentiation, LTP) or decrease in synaptic efficacy (long-term depression, LTD) is widely regarded as underlying learning and memory in nervous systems. LTP and LTD at excitatory neuronal synapses are observed to be induced by precise timing of pre- and postsynaptic events. Modification of synaptic transmission...

BACKGROUND/AIMS Anxious responses are evolutionarily adaptive, but excessive fear can become disabling and lead to anxiety disorders. Translational models of anxiety might be useful sources for understanding the neurobiology of fear and anxiety and can contribute to future proposals of therapeutic intervention for the disorders studied. Brain-derived neurotrophic factor (BDNF), which is known f...

Amyloid-β (Aβ)-induced changes in synaptic function in experimental models of Alzheimer's disease (AD) suggest that Aβ generation and accumulation may affect fundamental mechanisms of synaptic plasticity. To test this hypothesis, we examined the effect of APP overexpression on a well characterized, in vivo, developmental model of systems-level plasticity, ocular dominance plasticity. Following ...

Networks of living neurons exhibit an avalanche mode of activity, experimentally found in organotypic cultures. Here we present a model that is based on self-organized criticality and takes into account brain plasticity, which is able to reproduce the spectrum of electroencephalograms (EEG). The model consists of an electrical network with threshold firing and activity-dependent synapse strengt...

The purpose of this note is to propose an improvement to the widely-used Steinberg-Lund model for rate-dependent plasticity. The improved model is rate-dependent above, as well as below, the Peierls stress. As a result of this change, one material constant in the Steinberg-Lund model acquires a new value, and we thereby obtain a revised estimate for the dislocation density in tantalum. 1. Intro...