introduction: antibiotic supplements are regularly used in neuronal culture media to control contamination however, they can interfere with the neuronal excitability and affect electrophysiological properties. therefore, in this study, the effect of penicillin/streptomycin supplements on the spontaneous electrophysiological activity of hippocampal pyramidal neurons was examined. methods: electr...

Previous computational modeling studies suggested a set of rules underlying the modulation of principal cell firing rates by heterogeneity in the synaptic parameters (peak amplitude and decay kinetics) of populations of GABAergic inputs. Here we performed dynamic clamp experiments in CA1 hippocampal pyramidal cells to test these ideas in biological neurons. In agreement with the simulation stud...

No matter what you’re doing at any given moment, from walking to talking or even sleeping, your brain is doing its own thing. Networks of neurons constantly and often spontaneously generate rhythmic electrical activity in the cortex, the brain’s outermost layer and the seat of judgment, decision making, and other higher order functions. These cortical networks contain pyramidal cells that can e...

Previous studies have focused considerable attention on the effects of estrogen on excitatory synaptic input to hippocampal CA1 pyramidal cells. Estrogen increases the density of dendritic spines and synapses on CA1 pyramidal cells and increases the sensitivity of these cells to excitatory synaptic input. Little is known, however, about the effects of estrogen on inhibitory synaptic input to CA...

In the prefrontal cortex (PFC) during working memory tasks fast-spiking (FS) interneurons might shape the spatial selectivity of pyramidal cell firing. In order to provide time control of pyramidal cell activity, incoming excitatory inputs should excite FS interneurons more vigorously than pyramidal cells. This can be achieved if subthreshold excitatory responses of interneurons are considerabl...

Background and Objectives: Study of deleterious effect of neurotoxins on the animals' brain is a fascinating research plan. In this project, the damage effect of colchicine on the hippocampal cornu ammonis 1 (CA1) was examined by the studying the hippocampal tissue. Materials and Methods: Injections of colchicine (1-75 μg/rat, intra- hippocampal CA1) were performed in cannulated male Wistar rat...

Cellular activity in the CA1 area of the hippocampus waxes and wanes at theta frequency (4-8 Hz) during exploratory behavior of rats. Perisomatic inhibition onto pyramidal cells tends to be strongest out of phase with pyramidal cell activity, whereas dendritic inhibition is strongest in phase with pyramidal cell activity. Synaptic plasticity also varies across the theta cycle, from strong long-...

Unraveling pyramidal cell structure is crucial to understanding cortical circuit computations. Although it is well known that pyramidal cell branching structure differs in the various cortical areas, the principles that determine the geometric shapes of these cells are not fully understood. Here we analyzed and modeled with a von Mises distribution the branching angles in 3D reconstructed basal...

Medial entorhinal cortex (MEC) plays an important role in physiological processes underlying navigation, learning, and memory. Excitatory cells in the different MEC layers project in a region-specific manner to the hippocampus. However, the intrinsic microcircuitry of the main excitatory cells in the superficial MEC layers is largely unknown. Using scanning photostimulation, we investigated the...

Whole-cell voltage recordings were obtained from 64 synaptically coupled excitatory layer 4 (L4) spiny neurones and L2/3 pyramidal cells in acute slices of the somatosensory cortex ('barrel' cortex) of 17- to 23-days-old rats. Single action potentials (APs) in the L4 spiny neurone evoked single unitary EPSPs in the L2/3 pyramidal cell with a peak amplitude of 0.7 +/- 0.6 mV. The average latency...