This study was aimed at investigating the effects of lamotrigine (LTG) on electrically evoked field excitatory postsynaptic potentials (fEPSP) and population spikes in the CA1 hippocampal region of guinea pigs. The concentration response curves showed different actions of LTG on fEPSP and on population spikes. The data are in contrast to previous findings that suggest the drug acts primarily on...

Foy, M. R., J. Xu, X. Xie, R. D. Brinton, R. F. Thompson, and T. W. Berger. 17b-estradiol enhances NMDA receptor-mediated EPSPs and long-term potentiation. J. Neurophysiol. 81: 925–929, 1999. Gonadal steroid hormones influence CNS functioning through a variety of different mechanisms. To test the hypothesis that estrogen modulates synaptic plasticity in the hippocampus, in vitro hippocampal sli...

It is well established that learning and experience lead to auditory cortical plasticity that is highly specific to the frequency of the acquired sound. Frequency specificity is demonstrated as the shift in the receptive field of cortical neurons towards the frequency of the acquired sound. Jafari and others showed that this frequency-specific receptive field shift of cortical neurons can be in...

Extensive trial-to-trial variability is a hallmark of most behavioral, cognitive, and physiological processes. Spontaneous brain activity (SBA), a ubiquitous phenomenon that coordinates levels and patterns of neuronal activity throughout the brain, may contribute to this variability by dynamically altering neuronal excitability. In freely-behaving male rats, we observed extensive variability of...

The first study, described in the companion article, reports that acute exposure of rat hippocampal slices to either hyperbaric oxygen (HBO: 2.84 and 4.54 atmospheres absolute, ATA) or normobaric reoxygenation (NBOreox; i.e., normobaric hyperoxia: 0.6 or 0.0→0.95 ATA) stimulates synchronous orthodromic activity in CA1 neurons, which includes activation of O2-induced potentiation (OxIP) and, in ...

Cerebral ischemic damage is an important cause of morbidity and mortality. However, there is conflicting evidence regarding the effect of the extracellular glucose concentration in focal and global ischemic injury. This study was designed to investigate this effect in ischemia-induced synaptic transmission damage in rat hippocampal slices. Slices were superfused with artificial cerebrospinal fl...

Emotionality as well as cognitive abilities contribute to the acquisition and retrieval of memories as well as to the consolidation of long-term potentiation (LTP), a cellular model of memory formation. However, little is known about the timescale and relative contribution of these processes. Therefore, we tested the effects of weak water maze training, containing both emotional and cognitive d...

Bath applied monoamines dopamine (DA), serotonin (5-HT), and noradrenaline (NE) strongly suppress the perforant path (PP) input to CA1 hippocampal region with very little effect on the Schaffer collaterals (SC) input (Otmakhova and Lisman, 2000). The effect of DA action on PP field EPSP (fEPSP) has been characterized in detail (Otmakhova and Lisman, 1999), but relatively little is known about t...

The impact of pentylenetetrazol-induced kindling on the effectiveness of theta pattern primed-bursts (PBs) for the induction of long-term potentiation (LTP) of field excitatory postsynaptic potentials (fEPSP) and population spikes (PS) were investigated in hippocampal CA1 of pentylenetetrazol-kindled rats in vivo. The results showed that shortly after kindling, control animals had normal LTP of...

Presynaptic inhibition is a form of neuromodulation that interacts with activity-dependent short-term plasticity so that the magnitude, and sometimes even the polarity, of that activity-dependent short-term plasticity is changed. However, the functional consequences of this interaction during physiologically relevant spike trains are poorly understood. We examined the effects of presynaptic inh...