Since 1971 when the results of single electrode recordings of neurons with “place fields” were first documented, scientists have produced an enormous body of research in an attempt to understand these small but significant components of the rat brain. This research has confirmed that after a rat has gained familiarity with a simple test environment, a neuron will respond strongly and selectivel...

Head direction (HD), boundary vector, grid and place cells in the entorhinal-hippocampal system form the brain’s navigational system that allows to identify the animal’s current location. How the functions of these specialized neuron types are acquired and how their computations relate to each other remain to be understood. Firing patterns of HD neurons are influenced by the ambulatory constrai...

Cortical neurogenesis is a highly stereotyped process in which progenitor cells generate neurons destined for specific cortical layers depending on the timing of cell cycle exit. Previous work has shown that during corticogenesis, progenitors become progressively restricted in their developmental potential. Recent work has uncovered some of the intrinsic mechanisms that underlie this fate restr...

Experiments showed that a neuron can fire when its membrane potential (an intrinsic quality related to electrical charge) reaches specific threshold. On theoretical studies, there are two crucial issues in exploring cortical neuronal dynamics: (i) what model describes spiking dynamics of each neuron, and (ii) how the neurons connected [E. M. Izhikevich, IEEE Trans. Neural Networks, 15 (2004)]. ...

A “weight” in an artificial neuron model is meant to be a representation of the amount of effect that a synaptic input has on the overall response of the neuron. The neuron that generates the synaptic input (the “action potential” or AP) is called the “presynaptic neuron”; the neuron receiving the effect of the action potential is called the “postsynaptic neuron”. The synapse is the biological ...

Recordings were made from single neurons in the hippocampus and parahippocampal gyrus while macaques were moved on a platform mounted on a free-moving robot or on wheels in a cue-controlled 2 m x 2 m x 2 m environment, in order to investigate the representation of space and of spatial memory in the primate hippocampus. The test conditions allowed factors that might account for spatial firing of...

Background and Objective: Ethanol has undesirable effects on memory and synaptic communication. However, its impact on the learned spatial memory is unclear. We investigated the damaging effects of ethanol on place neurons of rat’s hippocampal CA1.Materials and Methods: Sixty four male Wistar rats (250 g) were administered high (1-8 g/kg) or low (0.05-0.1 g/kg) doses of ethanol intraperit...

Integration in the head-direction system is a computation by which horizontal angular head velocity signals from the vestibular nuclei are integrated to yield a neural representation of head direction. In the thalamus, the postsubiculum and the mammillary nuclei, the head-direction representation has the form of a place code: neurons have a preferred head direction in which their firing is maxi...