Sub-threshold neuronal activity and the dynamical regime of cerebral cortex.

Cortical neurons exhibit temporally irregular spiking patterns and heterogeneous firing rates. These features arise in model circuits operating in a 'fluctuation-driven regime', in which fluctuations in membrane potentials emerge from the network dynamics. However, it is still debated whether the cortex operates in such a regime.

Can ferritin be a surrogate marker for CD4 cells in human immunodeficiency virus patients? A cross-sectional study of association of serum ferritin levels with immunological staging of human immunodeficiency virus patients.

Introduction: The human immunodeficiency virus (HIV)/AIDS in India came into public view in 1986 with the detection of the first case of HIV in Chennai, Tamil Nadu, and the first AIDS case in Mumbai, Maharashtra in 1987. In acute phase response, iron distribution occurs in the liver and mononuclear phagocytic system. A high prevalence of elevated serum ferritin levels is reported in HIV infection and serum ferritin levels increase with the clinical worsening of infection and with decreasing CD4 lymphocyte counts.

Reward expectations direct learning and drive operant matching in .

Foraging animals must use decision-making strategies that dynamically adapt to the changing availability of rewards in the environment. A wide diversity of animals do this by distributing their choices in proportion to the rewards received from each option, Herrnstein's operant matching law. Theoretical work suggests an elegant mechanistic explanation for this ubiquitous behavior, as operant matching follows automatically from simple synaptic plasticity rules acting within behaviorally relevant neural circuits.

Distributing task-related neural activity across a cortical network through task-independent connections.

Task-related neural activity is widespread across populations of neurons during goal-directed behaviors. However, little is known about the synaptic reorganization and circuit mechanisms that lead to broad activity changes. Here we trained a subset of neurons in a spiking network with strong synaptic interactions to reproduce the activity of neurons in the motor cortex during a decision-making task.