Elena Brazhnik

Learn More
Excessive beta frequency oscillatory and synchronized activity has been reported in the basal ganglia of parkinsonian patients and animal models of the disease. To gain insight into processes underlying this activity, this study explores relationships between oscillatory activity in motor cortex and basal ganglia output in behaving rats after dopamine cell(More)
 The electrophysiological properties of neurons of the medial septal nucleus and the nucleus of the diagnonal band of Broca (MS/DB) were studied using intracellular methods in urethane-anesthetized rats. Three types of rhythmically bursting neurons were identified in vivo on the basis of their action potential shapes and durations, afterhyperpolarizations(More)
The firing of rat hippocampal pyramidal cells is determined both by the animal's location and by the state of the hippocampal EEG. Because cholinergic transmission plays a role in EEG activity, we expected that its modification would alter place cell activity. We therefore investigated the effects on place cell activity of blocking muscarinic transmission(More)
Synchronized oscillatory neuronal activity in the beta frequency range has been observed in the basal ganglia of Parkinson's disease patients and hypothesized to be antikinetic. The unilaterally lesioned rat model of Parkinson's disease allows examination of this hypothesis by direct comparison of beta activity in basal ganglia output in non-lesioned and(More)
Exaggerated beta range (13-30Hz) synchronized activity is observed in the basal ganglia of Parkinson's disease (PD) patients during implantation of deep brain stimulation electrodes and is thought to contribute to the motor symptoms of this disorder. To explore the translational potential of similar activity observed in a rat model of PD, local field(More)
The influence of the medial septal nucleus and the nucleus of the diagonal band of Broca (MS-DB) on the hippocampal theta rhythm includes both cholinergic and γ-aminobutyric acid (GABAergic) components. To understand the intrinsic septal interactions and the separate contributions of the cholinergic and GABAergic septohippocampal neurons to the theta rhythm(More)
Most in vivo electrophysiological studies of substantia nigra have used rats. With the recent proliferation of the use of mice for in vitro neurophysiological studies because of the availability of various genetically modified strains to identify the roles of various channels and proteins in neuronal function, it is crucial to obtain data on in vivo(More)
The drugs, described as blocking the high-frequency (pentobarbital) or low-frequency (scopolamine, atropine) theta rhythm of the hippocampal electroencephalogram, were tested upon the rhythmically bursting septal cells. Three groups of chronic, unanaesthetized rabbits were used for the experiments: with intact septum; with septohippocampal disconnection;(More)
Using a dialysis probe near CA1 hippocampal recording electrodes, we infused nonspecific (scopolamine) and specific (methoctramine, pirenzepine) antagonists of muscarinic cholinergic transmission to determine their effects on the positional firing properties of place cells. Both low (0.5 mM) and high (2.0 or 3.0 mM) scopolamine significantly decreased(More)
Extracellular recording of neuronal activity of septal nuclei was performed in unanesthetized chronic rabbits in the following conditions: (1) intact septal nuclei; (2) complete interruption of connections with hippocampus; (3) complete basal undercutting of septum. Additional series of records were performed in transversal guinea pig septal slices(More)