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1

Amplitude and phase laminar profiles of theta in the hippocampal formation in vitro

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Kowalczyk T., Konopacki J.
Postępy Higieny i Medycyny Doświadczalnej
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2002
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vol. 56
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issue 3
353-360
EN
Amplitude and phase profiles of theta rhythm induced in the hippocampal formation slices by bath perfusion of carbachol was studied. Amplitude and phase profiles obtained in vitro closely resemble profiles of spontaneous theta rhythm recorded in freely behaving or anaesthetised rats. Electrotonic mechanism underlying the in vivo and in vitro theta are discussed
2
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Estimation of filter order for prescribed, reduced group delay FIR filter design

100%
Konopacki J., Mościńska K.
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2015
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issue 1
3
Content available remote

Effect of posterior hypothalamic injection of procaine on the hippocampal theta rhythm in freely moving cats

100%
Bocian R., Konopacki J.
Acta Neurobiologiae Experimentalis
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2001
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vol. 61
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issue 2
125-134
EN
Earlier in vivo studies conducted on freely moving and anesthetized rats demonstrated that the posterior hypothalamus (PH) comprises pathways critical for producing the synchronous hippocampal formation (HPC) theta rhythm. In addition, these findings suggested that the frequency of the HPC theta was encoded in the PH and then was fed via the medial forebrain bundle to the medial septum and HPC. In the present study we attempted to verify this hypothesis with use of a different in vivo model - freely moving cats. The microinjection of the local anaesthetic, procaine, into the PH region reversibly suppressed the spontaneous as well as sensory and electrically induced HPC theta. However, in contrast to rats, in freely moving cats microinjection of procaine into the PH reduced the amplitude of the HPC theta but had no effect on theta frequency. We conclude that in freely moving cats the PH region comprises a critical part of the ascending brainstem pathway, for production of the HPC theta rhythm. In contrast to rats, in freely moving cats ascending inputs from the brainstem to the PH contribute mainly to the amplitude of the HPC theta rhythm.
4

Electroencephalographic activity (EEG) recorded in vitro

81%
Konopacki J., Eckersdorf B., Golebiewski H.
Postępy Higieny i Medycyny Doświadczalnej
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2002
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vol. 56
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issue 3
421-431
EN
The generation of theta in the limbic cortex is a prime example of rhythmical activity involving central mechanisms of oscillations and synchromy. It was demonstrated that bath perfusion of hippocampal slice with carbachol resulted in theta-like oscillations. A number of our experiments have provided a strong evidence that theta-like activity recorded in vitro replicates pharmacological and physiological properties of in vivo recorded theta.
5

Basic microelectrophysiological techniques used in neurophysiology

81%
Konopacki J., Bland B. H., Dyck R.
Postępy Higieny i Medycyny Doświadczalnej
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2000
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vol. 54
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issue 3
261-278
EN
Problems of application of microelectrophysiological techniques in neurobiology are addressed. Authors focused on five basic recording techniques: micro-EEG, multi unit activity, single unit activity, intracellular recording and patch clamp techniques.
6

A novel parameter of quantitative evaluation of the hippocampal field activity-density of theta

81%
Golebiewski H., Eckersdorf B., Bocian R., Konopacki J.
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EN
Our experiments conducted in the last decade on freely moving cats, showed that commonly used theta parameters: frequency, amplitude and power are not sufficient for a precise characterization of theta field activity. It is specially seen in condition when the experimental protocol involves sensory or chemical stimalation in order to induce hippocampal theta. We described a novel theta parameter ? ?theta density?, that allows more adequate quantitative evaluation of this EEG pattern in freely moving cats.
7
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Cholinergic/GABAergic interaction in the production of EEG theta oscillations in rat hippocampal formation in vitro

81%
Golebiewski H., Eckersdorf B., Konopacki J.
Acta Neurobiologiae Experimentalis
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1996
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vol. 56
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issue 1
147-153
EN
The generation of EEG theta rhythm (RSA) in the hippocampal formation is a prime example of rhythmic activity involving central mechanisms of oscillation and synchrony. Cholinergic nature of the in vitro and the in vivo induced RSA has been undoubtedly established. Recently, we have demonstrated in vitro that the hippocampal formation theta rhythm resulted from interaction between the cholinergic and GABAergic systems. In the present study we have provided additional in vitro evidence that the hippocampal GABA-A receptors are actively involved in the mechanism of theta production. Specifically, we demonstrated that bicuculline - GABA-A antagonist significantly augmented carbachol induced theta response increasing amplitude and power of rhythmical slow waves. In separate experiments the carbachol+bicuculline induced RSA were studied in the presence of muscarinic M1 and M2 antagonists - pirenzepine and gallamine (respectively) and GABA-A agonist - muscimol. Both pirenzepine and muscimol antagonized induced theta oscillations and gallamine was found to be completely ineffective in blocking this EEG response. The results provided evidence for M1 cholinergic/GABA-Aergic interaction in mechanisms responsible for theta production.
8

The use of trans-slice technique in microencephalography in vitro

81%
Golebiewski H., Kowalczyk T., Konopacki J.
Postępy Higieny i Medycyny Doświadczalnej
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2000
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vol. 54
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issue 3
279-290
EN
The present paper reviews the experimental data concerning the use of trans-slice preparation technique in investigation of theta-like activity generation in the limbic cortex. Specyfic aspects of the technical arrangement of the hippocampal formation and entorhinal cortex microelectroencephalographic registration were emphasized.
9
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The spontaneous theta rhythm recorded from the hypocalmus posterior in the cat in vivo

71%
Grabowski R., Blaszczyk M., Eckersdorf B., Golebiewski H., Konopacki J.
Acta Neurobiologiae Experimentalis
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1996
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vol. 56
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issue 1
155-159
EN
Rhythmical slow activity (theta) was mapped in the hypothalamic regionin freely moving cats. We recorded well synchronized and high amplitude theta rhythm in the medial part of hypothalamus posterior area. The EEG recordings made from lateral part of this hypothalamic region contained only irregular activity. These findings support earlier observations concerning the topography of hippocampal formation desynchrony and synchrony system. The observations of the present study also suggest that the hypothalamus posterior area is actively involved in the mechanisms responsible for generating theta oscillations in the cats.
10
Content available remote

The rhytmic slow activity recorded from enthorhinal cortex in freely moving cats

71%
Blaszczyk M., Grabowski R., Eckersdorf B., Golebiewski H., Konopacki J.
Acta Neurobiologiae Experimentalis
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1996
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vol. 56
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issue 1
161-164
EN
The relationships between the entrohinal cortex (EC) and the hippocampal formation (Hipp) field potentials were examined in the present study. The detailed analyses of the signal let us group the patterns of theta appearance into three categories: (1) Theta rhythm dominating in both recordings from the EC and from Hipp (2) Theta rhythm dominating in the Hipp with irregular activity in the EC (3) Theta rhythm dominating in the EC with irregular activity in the Hipp. These findings provide the evidence for the intrinsic generator of theta rhythm to be localized in entorhinal cortex in cats.
11
Content available remote

In vitro recorded theta-like activity in the limbic cortex: comparison with spontaneous theta and epileptiform discharges

71%
Konopacki J., Golebiewski H., Eckersdorf B., Kowalczyk T., Bocian R.
Acta Neurobiologiae Experimentalis
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2000
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vol. 60
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issue 1
67-85
EN
The generation of EEG theta rhythm in the mammalian limbic cortex is a prime example of rhythmic activity that involves central mechanisms of oscillations and synchrony. This EEG pattern has been extensively studied since 1938, when Jung and Kornmller (1938) demonstrated the first theta recordings in the hippocampal formation of rabbits. In 1986 in collaboration with Drs. B.H. Bland, S.H. Roth and B.M. MacIver we demonstrated for the first time that bath perfusion of hippocampal slices with the cholinergic agonist, carbachol, resulted in theta-like oscillations. Since this initial demonstration of in vitro theta-like activity, we have carried out a number of experiments in an attempt to answer the basic question: what are the similarities between cholinergic-induced in vitro theta-like activity and theta rhythm which naturally occurs in the in vivo preparation. Thus far, our studies have provided strong evidence that theta-like activity recorded in vitro shares many of the physiological and pharmacological properties of theta rhythm observed in vivo. The question whether in vitro theta-like oscillations reflect features of epileptiform activity is also adressed in this review.
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