Carbachol-induced theta-like activity in entorhinal cortex slices

Konopacki, Jan; Gołebiewski, H; Eckersdorf, B

doi:10.1016/0006-8993(92)90453-g

Cited by 18 publications

(6 citation statements)

References 19 publications

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“…Indeed, in HCN1 knock-out mice the frequency of the LFP theta in mEC is significantly lower than wild-type, suggesting that intrinsic oscillatory mechanism such as I h have a modulatory effect upon theta (Giocomo et al, 2011). In addition to intrinsic cellular properties in EC, there may also be features of the synaptic architecture which give rise to network level theta, which depend critically upon muscarinic acetylcholine receptor activation (mAChR) (Konopacki et al, 1992). …”

Section: Overview Of Ec Physiologymentioning

confidence: 99%

Effects of acetylcholine on neuronal properties in entorhinal cortex

Heys¹,

Schultheiss²,

Shay³

et al. 2012

Front. Behav. Neurosci.

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The entorhinal cortex (EC) receives prominent cholinergic innervation from the medial septum and the vertical limb of the diagonal band of Broca (MSDB). To understand how cholinergic neurotransmission can modulate behavior, research has been directed toward identification of the specific cellular mechanisms in EC that can be modulated through cholinergic activity. This review focuses on intrinsic cellular properties of neurons in EC that may underlie functions such as working memory, spatial processing, and episodic memory. In particular, the study of stellate cells (SCs) in medial entorhinal has resulted in discovery of correlations between physiological properties of these neurons and properties of the unique spatial representation that is demonstrated through unit recordings of neurons in medial entorhinal cortex (mEC) from awake-behaving animals. A separate line of investigation has demonstrated persistent firing behavior among neurons in EC that is enhanced by cholinergic activity and could underlie working memory. There is also evidence that acetylcholine plays a role in modulation of synaptic transmission that could also enhance mnemonic function in EC. Finally, the local circuits of EC demonstrate a variety of interneuron physiology, which is also subject to cholinergic modulation. Together these effects alter the dynamics of EC to underlie the functional role of acetylcholine in memory.

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Section: Overview Of Ec Physiologymentioning

confidence: 99%

Effects of acetylcholine on neuronal properties in entorhinal cortex

Heys¹,

Schultheiss²,

Shay³

et al. 2012

Front. Behav. Neurosci.

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“…The concentrations of carbachol and bicuculline are based on concentrations used in previous studies. Neocortical slices (Konopacki et al, 1992;Lukatch and MacIver, 1997) need a higher concentration of carbachol compared to hippocampal slices (Konopacki et al, 1987a(Konopacki et al, ,b, 1988(Konopacki et al, , 1997McVicar and Tse, 1989;Konopacki and Gołębiewski, 1993;Williams and Kauer, 1997;D'Antuono et al, 2001;Sun et al, 2001;Kowalczyk and Konopacki, 2002;Fellous and Sejnowski, 2004) to induce oscillations in the theta range. The bicuculline reduces the inhibition in slices and it has been shown that the combination of bicuculline and carbachol strongly facilitates the induction of oscillations in the theta range in the septally deafferented hippocampus in vivo (Colom et al, 1991).…”

Section: Drugsmentioning

confidence: 99%

Spatio‐temporal dynamics of theta oscillations in hippocampal–entorhinal slices

2009

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Theta oscillations (4-12 Hz) are associated with learning and memory and are found in the hippocampus and the entorhinal cortex (EC). The spatio-temporal organization of rhythmic activity in the hippocampal-EC complex was investigated in vitro. The voltage sensitive absorption dye NK3630 was used to record the changes in aggregated membrane voltage simultaneously from the neuronal networks involved. Oscillatory activity at 7.0 Hz (range, 5.8-8.2) was induced in the slice with the muscarinic agonist carbachol (75-100 microM) in the presence of bicuculline (5 microM). Time relations between all recording sites were analyzed using cross-correlation functions which revealed systematic phase shifts in the theta oscillation recorded from the different entorhinal and hippocampal subregions. These phase shifts could be interpreted as propagation delays. The oscillation propagates over the slice in a characteristic spatio-temporal sequence, where the entorhinal cortex leads, followed by the subiculum and then the dentate gyrus (DG), to finally reach the CA3 and the CA1 area. The delay from dentate gyrus to the CA3 area was 12.4 +/- 1.1 ms (mean +/- s.e.m.) and from the CA3 to the CA1 region it was 10.9 +/- 1.9 ms. The propagation delays between the hippocampal subregions resemble the latencies of electrically evoked responses in the same subregions. Removing the entorhinal cortex from the slice changed the spatiotemporal pattern into a more clustered pattern with higher local synchrony. We conclude that in the slice, carbachol-induced theta oscillations are initiated in the entorhinal cortex. The EC could serve to control the information flow through the neuronal network in the subregions of the hippocampus by synchronizing and/or entraining their responses to external inputs.

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“…A recent experiment tested this hypothesis directly by perfusing carbachol over an EC slice preparation. This manipulation resulted in the production of theta-like field oscillations (Konopacki et al, 1992). Studies should be conducted to determine if direct intraentorhinal cortex microinfu-sions of cholinergic agents such as carbachol and atropine can affect the local production of theta in vivo.…”

Section: Control Of Entorhinal Cortex Theta / Dickson Et Al 49mentioning

confidence: 99%

Extrinsic modulation of theta field activity in the entorhinal cortex of the anesthetized rat

1994

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Field recordings of the entorhinal cortex (EC) were studied and compared to those recorded concomitantly in the dentate region of the hippocampal formation (HPC) in the urethane anesthetized rat. The EC, like the HPC, showed two main variations of spontaneous field activity: a desynchronized, large amplitude irregular activity and a synchronized, rhythmic, slow frequency field activity (RSA or theta). Corroborating previous research, a phase reversal was seen across layer II of the EC and when recorded superficial to this layer, EC theta was phase-locked to that recorded from the HPC (dentate). Entorhinal cortex (and HPC) theta could be evoked by the application of moderate tail pinches (sensory stimulation), by pharmacological treatments enhancing cholinergic transmission, and by electrical stimulation of the posterior hypothalamus. Spectral analysis revealed that in all cases, theta was produced coherently across the two limbic structures. Entorhinal cortex (and HPC) production of theta could be abolished by pharmacological treatments disrupting cholinergic transmission, and by reversible procaine inactivation of the medial septal region. Therefore, it was concluded that limbic theta is modulated spontaneously, and with sensory and hypothalamic stimulation through the activity of cells in the medial septal region via muscarinic neurotransmission. It was also hypothesized that the activation of cells in the posterior hypothalamus linearly codes the frequency, and to a lesser extent the power, of EC and HPC theta. Given these findings and the coincidence and coherence of the occurrence of theta across the EC and HPC, it was postulated that it occurs via a parallel mechanism in the two areas.

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Carbachol-induced theta-like activity in entorhinal cortex slices

Cited by 18 publications

References 19 publications

Effects of acetylcholine on neuronal properties in entorhinal cortex

Effects of acetylcholine on neuronal properties in entorhinal cortex

Spatio‐temporal dynamics of theta oscillations in hippocampal–entorhinal slices

Extrinsic modulation of theta field activity in the entorhinal cortex of the anesthetized rat

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