Rodents commonly exhibit age-related impairments in spatial learning tasks, deficits widely thought to reflect cellular or synaptic dysfunction in the hippocampus. Using whole-cell recordings, we examined the afterhyperpolarization (AHP) in CA1 pyramidal cells in hippocampal slices from young (4-6 months of age) and aged (24-26 months of age) Fisher 344 male rats that had been behaviorally char...

Calcium-activated K(+) channels of the K(Ca)2 type (SK channels) are prominently expressed in the mammalian brain, including hippocampus. These channels are thought to underlie neuronal excitability control and have been implicated in plasticity, memory, and neural disease. Contrary to previous reports, we found that somatic spike-evoked medium afterhyperpolarizations (mAHPs) and corresponding ...

Fragile X syndrome, caused by a mutation in the Fmr1 gene, is characterized by mental retardation. Several studies reported the absence of long-term potentiation (LTP) at neocortical synapses in Fmr1 knockout (FMR1-KO) mice, but underlying cellular mechanisms are unknown. We find that in the prefrontal cortex (PFC) of FMR1-KO mice, spike-timing-dependent LTP (tLTP) is not so much absent, but ra...

Large-scale recording from a population of neurons is a promising strategy for approaching the study of complex brain functions. Taking advantage of the fact that action potentials reliably evoke transient calcium fluctuations in the cell body, functional multineuron calcium imaging (fMCI) monitors the suprathreshold activity of hundreds of neurons. However, a limitation of fMCI is its semi-man...

In the present study, we studied the ability of glutathione (GSH) to detoxify exogenously applied cumene hydroperoxide (CHP). Exposure of leech Retzius nerve cells to CHP (1.5 mM) induced a marked prolongation of the spontaneous spike potential of these cells. Early after depolarization, and a cardiac-like action potential with a rapid depolarization followed by a sustained depolarization or pl...

The role of the electrogenic Na(+)-Ca(2+)-exchange mechanism in regulating the spike activity of the ureter was studied. The ureter cells were shown to be capable of generating action potentials (AP) in sodium-free Krebs solution. The time during which the spikes are generated is in exponential dependence on the concentration of calcium ions in the medium, [Ca2+]o within 2.5 to 15 mmol/l. Simul...

Directional selectivity, in which neurons respond strongly to an object moving in a given direction ("preferred") but respond weakly or not at all to an object moving in the opposite direction ("null"), is a critical computation achieved in brain circuits. Previous measures of direction selectivity have compared the numbers of action potentials elicited by each direction of movement, but most s...

Calcium imaging permits optical measurement of neural activity. Since intracellular calcium concentration is an indirect measurement of neural activity, computational tools are necessary to infer the true underlying spiking activity from fluorescence measurements. Bayesian model inversion can be used to solve this problem, but typically requires either computationally expensive MCMC sampling, o...

Climbing fiber (CF) afferents modulate the frequency and patterns of cerebellar Purkinje cell (PC) simple spike (SS) activity, but its mechanism is unclear. In the present study, we investigated the mechanisms of spontaneous CF discharge-evoked pauses and the output modulation of cerebellar PCs in urethane-anesthetized mice using in vivo whole-cell recording techniques and pharmacological metho...