In vitro electrical activity in the suprachiasmatic nucleus following splitting and masking of wheel-running behavior

Zlomanczuk, Piotr; Margraf, Russell R.; Lynch, G. Robert

doi:10.1016/0006-8993(91)90291-3

Cited by 57 publications

(24 citation statements)

References 23 publications

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“…Output from the SCN is thought to directly drive the daily/circadian patterns in sleep-wake consolidation (3,5,6,16,17). Both in vitro and in vivo recordings demonstrate that the daily changes in spontaneous neuronal activity within the SCN correlate well with the daily changes in locomotor activity and sleep; e.g., in nocturnal rodents a high level of spontaneous SCN activity is associated with consolidated periods of inactivity and sleep during the rest phase (11,30,31,56). Because sleep amount and consolidation in our arrhythmic hamsters were maintained at the levels reached during the rest phase in entrained hamsters, one could hypothesize that SCN activity should therefore also be maintained at the high levels typical for the rest period.…”

Section: Discussionmentioning

confidence: 99%

Homeostatic regulation of sleep in arrhythmic Siberian hamsters

Larkin

Yokogawa

Heller

et al. 2004

American Journal of Physiology-Regulatory, Integrative and Comp

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Sleep is regulated by independent yet interacting circadian and homeostatic processes. The present study used a novel approach to study sleep homeostasis in the absence of circadian influences by exposing Siberian hamsters to a simple phase delay of the photocycle to make them arrhythmic. Because these hamsters lacked any circadian organization, their sleep homeostasis could be studied in the absence of circadian interactions. Control animals retained circadian rhythmicity after the phase shift and re-entrained to the phase-shifted photocycle. These animals displayed robust daily sleep-wake rhythms with consolidated sleep during the light phase beginning about 1 h after light onset. This marked sleep-wake pattern was circadian in that it persisted in constant darkness. The distribution of sleep in the arrhythmic hamsters over 24 h was similar to that in the light phase of rhythmic animals. Therefore, daily sleep amounts were higher in arrhythmic animals compared with rhythmic ones. During 2- and 6-h sleep deprivations (SD), it was more difficult to keep arrhythmic hamsters awake than it was for rhythmic hamsters. Because the arrhythmic animals obtained more non-rapid eye movement sleep (NREMS) during the SD, they showed a diminished compensatory response in NREMS EEG slow-wave activity during recovery sleep. When amounts of sleep during the SD were taken into account, there were no differences in sleep homeostasis between experimental and control hamsters. Thus loss of circadian control did not alter the homeostatic response to SD. This supports the view that circadian and homeostatic influences on sleep regulation are independent processes.

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Section: Discussionmentioning

confidence: 99%

Homeostatic regulation of sleep in arrhythmic Siberian hamsters

Larkin

Yokogawa

Heller

et al. 2004

American Journal of Physiology-Regulatory, Integrative and Comp

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“…When exposed to a short photoperiod for 8 to 10 weeks most individuals undergo gonadal regression, weight loss, pelage color change, decreases in thermal conductivity, increases in basal metabolic rate, and episodes of spontaneous daily torpor which last for several hours during the rest phase (Hoffmann 1973;Heldmaier and Steinlechner 1981a;Heldmaier et al 1982;Elliot et al 1987). Circadian (Wee and Turek 1989;Ruby et al 1989;Zlomanczuk et al 1991;Puchalski and Lynch 1992), and seasonal rhythms (Bittman et al 1991;Lynch 1991, 1992), as well as daily torpor (Heldmaier and Steinlechner 1981a, b;Elliot et al 1987;Ruby et al 1989;Kirch et al 1991;Ouarour et al 1991;Ruf et al 1987Ruf et al , 1989Ruf et al , 1991 have been extensively investigated in this species. 24-h sleep studies in the Djungarian hamster are lacking and although it is well known that sleep and body temperature regulation are closely related (Glotzbach and Heller 1976;Obfil et al 1985;Parmeggiani 1987), the relation between vigilance and body temperature under euthermic conditions or during daily torpor has not been addressed.…”

Section: Introductionmentioning

confidence: 99%

Sleep and cortical temperature in the Djungarian hamster under baseline conditions and after sleep deprivation

1994

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The Djungarian hamster (Phodopus sungorus) is a markedly photoperiodic rodent which exhibits daily torpor under short photoperiod. Normative data were obtained on vigilance states, electroencephalogram (EEG) power spectra (0.25-25.0 Hz), and cortical temperature (TCRT) under a 16:8 h light-dark schedule, in 7 Djungarian hamsters for 2 baseline days, 4 h sleep deprivation (SD) and 20 h recovery. During the baseline days total sleep time amounted to 59% of recording time, 67% in the light period and 43% in the dark period. The 4 h SD induced a small increase in the amount of non-rapid eye movement (NREM) sleep and a marked increase in EEG slow-wave activity (SWA; mean power density 0.75-4.0 Hz) within NREM sleep in the first hours of recovery. TCRT was lower in the light period than in the dark period. It decreased at transitions from either waking or rapid eye movement (REM) sleep to NREM sleep, and increased at the transition from NREM sleep to waking or REM sleep. After SD, TCRT was lower in all vigilance states. In conclusion, the sleep-wake pattern, EEG spectrum, and time course of TCRT in the Djungarian hamster are similar to other nocturnal rodents. Also in the Djungarian hamster the time course of SWA seems to reflect a homeostatically regulated process as was formulated in the two-process model of sleep regulation.

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“…Figure 6 shows the variation of the mean CTS-output frequency along with 24 h, where one can observe that the CTS-output frequency varies from 0 Hz to a maximal value oscillator 3.5 Hz within the time interval of 6-12 h (midday), falling then to 0 Hz at 18 h. These results are in agreement with experimental data found in literature for suprachiasmatic neurons, presenting spontaneous activity, in experiments in vivo and in vitro. Most of these studies have been done in rodents, and the registered firing frequencies range from 0.5 to 14 Hz (Aujard et al 2001;Walsh et al 1992;Schaap et al 1999;Pennartz et al 1998;Kononenko and Dudek 2004;Glotzbach et al 1987;Zlomanczuk et al 1991). Such interval appears to be compatible with the firing frequency of neurons able to signalize the circadian cycle and hormone releasing (Fig.…”

Section: Numerical Results and Discussionmentioning

confidence: 89%

“…Glotzbach et al (1987) recorded single unit activity from the SCN of Wistar rats and observed that most of the cells spontaneously fired with frequencies below 12 Hz. Discharges of about 5.4 Hz and two troughs of about 1.8 and 2.4 Hz were registered by Zlomanczuk et al (1991) from neurons in SCN of hamsters which exhibited a split in explicit behavior. The troughs coincided with the projected time of wheel-running activity.…”

Section: Numerical Results and Discussionmentioning

confidence: 98%

Computational modeling of synchronization process of the circadian timing system of mammals

et al. 2009

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This paper presents a model for the circadian temporization system of mammals which associates the synchronization dynamics of coupling oscillators to a set of equations able to reproduce the synaptic characteristics of somatodendritic membrane of neurons. The circadian timing system is organized in a way to receive information from the external and internal environments, and its function is the timing organization of physiological and behavioral processes in a circadian pattern. Circadian timing system in mammals is constituted by a group of structures which includes the suprachiasmatic nucleus, the intergeniculate leaflet and the pineal gland. In suprachiasmatic nucleus are found neuron groups working as a biological pacemaker-the so-called biological master clock. By means of numerical simulations using the Kuramoto model, we simulated the dynamics behavior of the biological pacemaker. For this we used a set of 1,000 coupled oscillators with long-range coupling, which were distributed on a 10 x 10 x 10 spherical lattice, and a new method to estimate the order parameter, which characterizes the degree of synchronization of oscillator system. Our model has been able to produce frequency responses in accordance with physiological patterns, and to reproduce two fundamental characteristics of biological rhythms: the endogenous generation and synchronization to the light-dark cycle.

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In vitro electrical activity in the suprachiasmatic nucleus following splitting and masking of wheel-running behavior

Cited by 57 publications

References 23 publications

Homeostatic regulation of sleep in arrhythmic Siberian hamsters

Homeostatic regulation of sleep in arrhythmic Siberian hamsters

Sleep and cortical temperature in the Djungarian hamster under baseline conditions and after sleep deprivation

Computational modeling of synchronization process of the circadian timing system of mammals

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