Avoidance training of hippocampal theta waves in flaxedilized dogs and its relation to skeletal movement.

1970 ◽  
Vol 70 (1, Pt.1) ◽  
pp. 15-24 ◽  
Author(s):  
A. H. Black ◽  
G. A. Young ◽  
C. Batenchuk
Keyword(s):  
Avoidance Training ◽  
Theta Waves ◽  
Hippocampal Theta

scholarly journals GABAergic Control of the Ascending Input From the Median Raphe Nucleus to the Limbic System

2005 ◽  
Vol 94 (4) ◽  
pp. 2561-2574 ◽  
Author(s):  
Shaomin Li ◽  
Viktor Varga ◽  
Attila Sik ◽  
Bernat Kocsis
Keyword(s):  
Limbic System ◽  
Theta Rhythm ◽  
Raphe Nucleus ◽  
Median Raphe ◽  
Median Raphe Nucleus ◽  
Hippocampal Theta Rhythm ◽  
Theta Waves ◽  
Short Period ◽  
Hippocampal Theta ◽  
Median Raphé

The median raphe nucleus (MRN) is the primary source of serotonergic afferents to the limbic system that are generally considered to suppress hippocampal theta oscillations. GABA receptors are expressed in the MRN by serotonergic and nonserotonergic cells, including GABAergic and glutamatergic neurons. This study investigated the mechanisms by which the fluctuating GABA tone in the MRN leads to induction or suppression of hippocampal theta rhythm. We found that MRN application of the GABAA agonist muscimol (0.05–1.0 mM) or GABAB agonist baclofen (0.2 mM) by reverse microdialysis had strong theta promoting effects. The GABAA antagonist bicuculline infused in low concentrations (0.1, 0.2 mM) eliminated theta rhythm. A short period of theta activity of higher than normal frequency preceded hippocampal desynchronization in 46% of rats. Bicuculline in larger concentrations (0.5, 1.0, 2.0 mM) resulted in a biphasic response of an initial short (<10 min) hippocampal desynchronization followed by stable theta rhythm that lasted as long as the infusion continued. The frequency and amplitude of theta waves were higher than in control recordings and the oscillations showed a conspicuous intermittent character. Hippocampal theta rhythm elicited by MRN administration of bicuculline could be completely (0.5 mM bicuculline) or partially (1.0 mM bicuculline) blocked by simultaneous infusion of the GABAB antagonist CGP35348 . Our findings suggest that the GABAergic network may have two opposing functions in the MRN: relieving the theta-generators from serotonergic inhibition and regulating the activity of a theta-promoting circuitry by the fluctuating GABA tone. The two mechanisms may be involved in different functions.

P.1.g.093 Effects of ketamine in acute and repeated dose on hippocampal theta waves in rats

2014 ◽  
Vol 24 ◽  
pp. S258
Author(s):  
M.C.A. Patrocínio ◽  
L.R.L. Sampaio ◽  
L.T.N. Borges ◽  
L.R.C. Martins ◽  
S.D. Nascimento ◽  
...  
Keyword(s):  
Repeated Dose ◽  
Theta Waves ◽  
Hippocampal Theta

scholarly journals Effects of antidepressants on cholinergic hippocampal theta waves.

1993 ◽  
Vol 61 ◽  
pp. 285
Author(s):  
Naoji Mikuni ◽  
Yoko Itagaki ◽  
Yoko Hikawa ◽  
Noriko Matsuura ◽  
Katsuo Kamoshita
Keyword(s):  
Theta Waves ◽  
Hippocampal Theta

Hippocampal Theta Waves and Forced Locomotion

1973 ◽  
Author(s):  
W. L. McFarland ◽  
E. Hedges ◽  
H. Teitelbaum
Keyword(s):  
Theta Waves ◽  
Hippocampal Theta

Enhancement of Synchronization Between Hippocampal and Amygdala Theta Waves Associated With Pontine Wave Density

2010 ◽  
Vol 103 (5) ◽  
pp. 2318-2325 ◽  
Author(s):  
Akihiro Karashima ◽  
Norihiro Katayama ◽  
Mitsuyuki Nakao
Keyword(s):  
Rem Sleep ◽  
Cross Correlation ◽  
P Wave ◽  
Retrieval Process ◽  
P Waves ◽  
Neuronal Communication ◽  
Theta Wave ◽  
Theta Waves ◽  
Theta Frequency ◽  
Hippocampal Theta

Theta waves in the amygdala are known to be synchronized with theta waves in the hippocampus. Synchronization between amygdala and hippocampal theta waves is considered important for neuronal communication between these regions during the memory-retrieval process. These theta waves are also observed during rapid eye movement (REM) sleep. However, few studies have examined the mechanisms and functions of theta waves during REM sleep. This study examined correlations between the dynamics of hippocampal and amygdala theta waves and pontine (P) waves in the subcoeruleus region, which activates many brain areas including the hippocampus and amygdala, during REM sleep in rats. We confirmed that the frequency of hippocampal theta waves increased in association with P wave density, as shown in our previous study. The frequency of amygdala theta waves also increased with in associated with P wave density. In addition, we confirmed synchronization between hippocampal and amygdala theta waves during REM sleep in terms of the cross-correlation function and found that this synchronization was enhanced in association with increased P wave density. We further studied theta wave synchronization associated with P wave density by lesioning the pontine subcoeruleus region. This lesion not only decreased hippocampal and amygdala theta frequency, but also degraded theta wave synchronization. These results indicate that P waves enhance synchronization between regional theta waves. Because hippocampal and amygdala theta waves and P waves are known to be involved in learning and memory processes, these results may help clarify these functions during REM sleep.

Biochemical and Electroencephalographic Changes in the Brain of Rabbits Injected With 5-Hydroxytryptophan (Influence of Chlorpromazine Premedication)

1958 ◽  
Vol 194 (1) ◽  
pp. 214-220 ◽  
Author(s):  
E. Costa ◽  
F. Rinaldi
Keyword(s):  
High Voltage ◽  
Normal Values ◽  
Behavioral Changes ◽  
Serotonin Concentration ◽  
Serotonin Content ◽  
Theta Waves ◽  
Eeg Changes ◽  
Hippocampal Theta ◽  
The Brain ◽  
Brain Parts

After the administration of 5HTP (75 mg/kg i.v.) to rabbits, the serotonin concentration increased significantly in the telencephalon, the hippocampus, the medulla-pons and most of all in the midbrain; in the cerebellum the increase was much less. The augmentation of serotonin concentration occurred during the first 2 hours after the injection of 5HTP and reached its maximum at the 2nd hour. At the 3rd hour a decline toward more normal values was observed. During the first 2 hours after the injection of 5HTP behavioral changes (excitation with unresponsiveness to alarming stimuli), as well as EEG changes (monorhythmic diffuse high voltage activity; disappearance of cortical fast rhythms and hippocampal theta waves followed by a generalized depression of voltage) occurred. The administration of chlorpromazine alone does not modify the serotonin content of the brain. But in the various brain parts of chlorpromazine pretreated animals the administration of 5HTP caused increases of serotonin concentration which were of greater magnitude and longer duration than those found in animals treated with only 5HTP. When animals were pretreated with chlorpromazine, the injection of 5HTP did not produce behavioral hyperexcitation and the animals did not arouse from chlorpromazine tranquilization.

Hippocampal theta waves as an electrocardiogram rhythm timer in paradoxical sleep

1999 ◽  
Vol 276 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Marisa Pedemonte ◽  
Alberto Rodrı́guez ◽  
Ricardo A Velluti
Keyword(s):  
Paradoxical Sleep ◽  
Theta Waves ◽  
Hippocampal Theta

Hippocampal Theta and Disinhibition: A Counterreply

1969 ◽  
Vol 24 (2) ◽  
pp. 583-586 ◽  
Author(s):  
Robert J. Douglas
Keyword(s):  
Discrimination Learning ◽  
Behavioral Disinhibition ◽  
Theta Waves ◽  
Hippocampal Lesions ◽  
Behavioral Evidence ◽  
Hippocampal Theta

Evidence was presented against an argument by Bennett (1969) that hippocampal lesions result in a deficit in simple 2-choice discrimination learning and/or delayed responding. It was shown that behavioral evidence suggests that hippocampal theta waves may be an index of behavioral disinhibition.

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