Cross-correlation analysis of septohippocampal neurons during ≡-rhythm

Information processing and storing by brain networks requires a highly coordinated operation of multiple neuronal groups. The function of septal neurons is to modulate the activity of archicortical (e.g. hippocampal) and neocortical circuits. This modulation is necessary for the development and normal occurrence of rhythmical cortical activities that control the processing of sensory information and memory functions.Damage or degeneration of septal neurons results in abnormal information processing in cortical circuits and consequent brain dysfunction. Septal neurons not only provide the optimal levels of excitatory background to cortical structures, but they may also inhibit the occurrence of abnormal excitability states.

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“…2). Similar neurons are absent at the hippocampal formation level (Alonso et al . 1987; Colom and Bland 1991; Bland and Colom 1993; Bland et al .…”

Section: The Septal Region and Hippocampal Theta Rhythmmentioning

confidence: 93%

Septal networks: relevance to theta rhythm, epilepsy and Alzheimer's disease

Colom¹

2006

Journal of Neurochemistry

132

113

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“…It is known that the neurons called theta cells fire with the theta rhythms on phase in the CA1 and the DG where both types of theta are generated [2,11,12]. The theta cells at least in the CA1, are not pyramidal cells but rather interneurons [11,12].…”

Section: Discussionmentioning

confidence: 99%

“…A: EEG recorded from the freely moving rat hippocampus (Type 1 theta recording condition), the type 1 theta recorded from the walking rat (1) and LIA recorded from the immobile rat (2). B: EEG from the urethane anesthetized rat hippocampus (the type 2 theta recording condition), the type 2 theta induced by PON stimulation (1) and abolishment of the type 2 theta by atropine administration (2).…”

Section: Methodsmentioning

confidence: 99%

Age-Related Changes in Rat Hippocampal Theta Rhythms: A Difference between Type 1 and Type 2 Theta.

Abe

Toyosawa

1999

The Journal of Veterinary Medical Science

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ABSTRACT. The age-related changes in two types of theta rhythms recorded from the hippocampus in young (4 months-old), mature (12-13 months-old) and aged (22-25 months-old) rats were investigated. The type 1 theta rhythm was measured from hippocampal EEG recorded from walking rats and the type 2 theta was measured from the EEG induced by reticular pontin oralis nucleus (PON) stimulation in urethane anesthetized rats. The peak frequency and the peak power were detected from power spectra calculated on each theta sample by fast Fourier transformation (FFT). No age-related alteration was observed on the peak frequency of type 1 theta rhythm. However, on type 2 theta rhythm, the peak frequency was decreased in the aged rats compared with the young and the mature rats. The type 2 theta rhythm is cholinergic, and therefore this result suggests that age-related deterioration can be clearly observed in the cholinergic system including the hippocampus in rats.-KEY WORDS: aging, hippocampus, rat, theta rhythm.J. Vet. Med. Sci. 61 (5): [543][544][545][546][547][548] 1999 theta rhythms and aging remains unclear.In this study, we attempted to clarify the age-related changes in the two types of hippocampal theta rhythms associated with different pharmacological systems. MATERIALS AND METHODSMale Wistar rats supplied by SLC Co., Ltd. were used in this study. For the measurement of the type 1 theta, three aged rats (22-25 months-old), four mature rats (12-13 months-old) and four young rats (3-4 months-old) were used. For the type 2 theta, four aged rats, four mature rats and three young rats were used. Aged and mature rats were purchased as retired rats (6-7 months-old) and housed in our animal facility for 6 months and 18 months respectively. The animal facility was maintained on a 12 hr light/dark cycle, at 21 ± 1°C and 50-60% humidity.The rats used for the type 1 theta experiments were deeply anesthetized by pentobarbital sodium (50 mg/kg, i.p.) and then placed into a stereotaxic frame. A pair of staggered electrodes (200 µm stainless steel wires insulated except at cut ends) were chronically implanted in the bilateral hippocampal formation. The deep electrode was directed at the molecular layer of the dentate gyrus (DG), and the surface electrode at the CA1 pyramidal cell layer. Two stainless steel screw electrodes for reference and ground were fixed in the skull above the cerebellum. After 1 week of recovery from surgery, the type 1 theta recordings were carried out. The rats were placed in an open field box (100 × 70 × 33 cm) without a roof, which was painted gray. The hippocampal EEG and the behavioral data in the freely moving rats were recorded and stored simultaneously on a video tape using a video converter system (NEC Sanei) which received the signals from a multichannel amplifier and a CCD camera. Walking was selected as a type 1 theta

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“…In the hippocampus, regular activity originating in the septum (Brazhnik and Fox, 1999) is believed to cause 8 Hz oscillations of the membrane potential by modulating the GABAergic inhibition of pyramidal cells via networks of interneurons (Alonso et al, 1987;Stewart and Fox, 1990). A similar mechanism appears to cause theta rhythm oscillations in limbic cortices due to rhythmic activity of basal forebrain neurons Manns et al (2000).…”

Section: Short-term Memory Based On Persistent Spiking Enabled Spikementioning

confidence: 99%

An Integrate-and-fire Model of Prefrontal Cortex Neuronal Activity during Performance of Goal-directed Decision Making

Koene

Hasselmo

2005

Cerebral Cortex

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The orbital frontal cortex appears to be involved in learning the rules of goal-directed behavior necessary to perform the correct actions based on perception to accomplish different tasks. The activity of orbitofrontal neurons changes dependent upon the specific task or goal involved, but the functional role of this activity in performance of specific tasks has not been fully determined.Here we present a model of prefrontal cortex function using networks of integrate-and-fire neurons arranged in minicolumns. This network model forms associations between representations of sensory input and motor actions, and uses these associations to guide goal-directed behavior. The selection of goal-directed actions involves convergence of the spread of activity from the goal representation with the spread of activity from the current state. This spiking network model provides a biological implementation of the action selection process used in reinforcement learning theory. The spiking activity shows properties similar to recordings of orbitofrontal neurons during task performance.

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Cross-correlation analysis of septohippocampal neurons during ≡-rhythm

Cited by 66 publications

References 38 publications

Septal networks: relevance to theta rhythm, epilepsy and Alzheimer's disease

Septal networks: relevance to theta rhythm, epilepsy and Alzheimer's disease

Age-Related Changes in Rat Hippocampal Theta Rhythms: A Difference between Type 1 and Type 2 Theta.

An Integrate-and-fire Model of Prefrontal Cortex Neuronal Activity during Performance of Goal-directed Decision Making

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