The effects of sleep on neurons in isolated cerebral cortex

1979 ◽  
Vol 206 (1164) ◽  
pp. 281-291 ◽  
Keyword(s):  
Cerebral Cortex ◽  
Neural Activity ◽  
Geometric Standard Deviation ◽  
Neural Connections ◽  
Modal Interval ◽  
Isolated Cortex ◽  
Log Normal ◽  
Intact Cortex ◽  
The Brain ◽  
Unrestrained Animal

Slabs of cat parietal cortex with some 2 mm of underlying white matter were surgically isolated from the rest of the nervous system, without interference with the superficial blood supply. Wire micro-recording electrodes were inserted into the isolated cortex; bone, muscle and skin wounds were repaired and the animal allowed to recover from anaesthesia. The adequacy of surgical isolation was examined histologically 8-12 weeks after operation. Only one of the six preparations reported here showed surviving neural connections with the rest of the brain. Soon after operation, spontaneous bursts of neural activity appeared within the isolated area. These became more frequent until neural dis­charge was continuous but irregular. Our records were made from this time onwards. The interval distributions obtained from neurons within the isolated area did not differ significantly from log-normal curves. When the unrestrained animal fell asleep, there was no significant alteration in the modal interval or geometric standard deviation of interval distributions recorded from cells in isolated cortex. The interval distributions of neurons in isolated cerebral cortex resembled those of neurons in the intact cortex of an alarmed animal. It is concluded that the reduction of modal interval that is shown by neurons in intact cortex when an animal falls asleep is probably due to the neural influence of infracortical structures.

The effects of changing levels of arousal on the spontaneous activity of cortical neurones II. Relaxation and alarm

1976 ◽  
Vol 194 (1115) ◽  
pp. 239-251 ◽  
Keyword(s):  
Spontaneous Activity ◽  
Temporal Pattern ◽  
Discharge Rate ◽  
Geometric Standard Deviation ◽  
Sudden Increase ◽  
Lateral Cortex ◽  
Infrared Telescope ◽  
Modal Interval ◽  
Log Normal ◽  
Two Parameters

In a previous paper it has been shown that interval distributions derived from the activity of single cortical neurones can be described by log-normal curves. A cell’s temporal pattern of discharge can therefore be defined by the values of two parameters – a modal interval, and a geometric standard deviation (g. s. d.). It has also been shown that the values of both parameters change when an animal falls asleep. The modal interval becomes shorter, and the g. s. d. usually becomes larger. This paper deals with the effects of changes in arousal of animals which are awake; and, in particular, with the effects of the transition from relaxation to alarm. Single unit recordings have been made from neurones in the post-lateral and supra-sylvian gyri of unrestrained cats. In order to eliminate the direct effects of eye-movements, the experiments were carried out in complete darkness, and the animal was observed through an infrared telescope. Alarm was produced by the hiss of compressed air. An animal was said to be alarmed when he stood up abruptly and turned towards the source of the noise. Alarm produced a marked fall in the discharge frequency of those cells in post-lateral cortex which initially showed a low ( < 2 action potentials per second) rate of spontaneous activity. The discharge rate of the remaining neurones (whether in suprasylvian or post-lateral cortex) was unaffected by the sudden increase in arousal. But the temporal pattern of discharge of every cell was altered. The modal interval became longer when the animal was alarmed, and the g. s. d. usually became smaller. Such changes could have been predicted from a knowledge of the neural concomitants of the transition from sleep to wakefulness. These results suggest that the activity of all cortical neurones is affected by the level of arousal of the animal, and that this modulation takes the form of a continuum of possible modal intervals, and possible g.s.ds.

The spontaneous activity of neurones in the cat’s cerebral cortex

1976 ◽  
Vol 194 (1115) ◽  
pp. 211-223 ◽  
Keyword(s):  
Standard Deviation ◽  
Action Potentials ◽  
Quantitative Description ◽  
Primary Auditory Cortex ◽  
Geometric Standard Deviation ◽  
Quiet Sleep ◽  
Modal Interval ◽  
Spontaneous Action ◽  
Log Normal ◽  
Two Parameters

Chronically implanted microelectrodes have been used to obtain extracellular records of trains of spontaneous action potentials from 30 neurones in the cerebral cortices of 13 unrestrained cats. Recorded neurones were in or near to primary visual cortex, primary auditory cortex, and in the supra-sylvian gyrus. Records were made with animals in several different behavioural states, which included sleep with rapid eye-movements and quiet sleep, peacefully awake, and alarmed. Interval distributions derived from trains of 200 action potentials recorded in less than 80 s did not differ significantly from curves in which the probability of any interval is normally distributed about a modal interval, when plotted on a logarithmic time-axis. Thus the complete interval distributions of neurones firing faster than 2.5/s can be described by two parameters – a modal interval, and a geometric standard deviation. This quantitative description of interval distributions proved equally applicable to neurones in all three cortical areas and was valid over the whole range of behavioural states examined. It does not usually hold when the discharge frequency of a neurone is lower than 2.5 action potentials per second. An acceptable fit for a log-normal curve can then only be obtained for intervals that are shorter than about ten times the modal interval. It is pointed out that mean frequency of discharge is a measure of neural activity which is a secondary parameter, since it is dependent upon both modal interval and geometric standard deviation. Our preliminary data show that the two parameters which define the best-fit log-normal curves can vary independently with the behavioural state of the animal in a way that suggests that they may be physiologically important.

The correlation between discharge times of neighbouring neurons in isolated cerebral cortex

1979 ◽  
Vol 203 (1153) ◽  
pp. 347-360 ◽  
Keyword(s):  
Cerebral Cortex ◽  
Nerve Cells ◽  
Temporal Relation ◽  
Mammalian Brain ◽  
Cortical Region ◽  
Suprasylvian Gyrus ◽  
Intact Brain ◽  
Isolated Cortex ◽  
Intact Cortex ◽  
Spontaneous Discharges

The purpose of the experiments was to find out whether neighbouring neurons in chronic preparations of neurally isolated cerebral cortex are more likely to fire synchronously than are similar neurons in the intact brain. Chronically implanted extracellular microelectrodes were used to obtain simultaneous records of the spontaneous discharges of neighbouring neurons in the suprasylvian gyrus of the unanaesthetized, unrestrained cat. We have examined multi-unit records obtained from neurons in islands of neurally isolated cortex; these records have been compared with similar records from neurons in the same cortical region of the intact brains of control animals. In isolated cortex, neighbouring neurons showed a tendency to discharge in near synchrony. In contrast, there was a random temporal relation between the firing times of adjacent nerve cells of intact cortex, provided the cat was awake. These results, taken together with the relevant observations of other workers, may indicate the manner in which biologically important information is transmitted within the mammalian brain.

The effects of changing levels of arousal on the spontaneous activity of cortical neurones I. Sleep and wakefulness

1976 ◽  
Vol 194 (1115) ◽  
pp. 225-237 ◽  
Keyword(s):  
Preceding Paper ◽  
Geometric Standard Deviation ◽  
Modal Interval ◽  
Efficient Test ◽  
Single Neurones ◽  
Single Interval ◽  
Log Normal ◽  
Two Parameters ◽  
Interval Distribution ◽  
Comparative Measure

In the preceding paper (Burns & Webb 1976), it was shown that the interval distributions derived from the activity of single cortical neurones can be described by log-normal curves. This description proved satisfactory for cells in visual parietal and auditory cortex. Thus, two parameters – a modal interval and a geometric standard deviation (g. s. d.) – are sufficient to define the whole temporal pattern of discharge for neurones that fire faster than 2.5/s. The same two parameters may be used to describe the first parts of the interval distributions of cells firing less frequently. The purpose of the present paper is to find out whether the values of these two parameters vary systematically with an animal’s state of alertness. Records have therefore been made from single neurones in various parts of the cerebral cortex of unrestrained male cats, when the animals were awake and when they were sleeping. A cat was said to be asleep when he lay with his head supported by some part of the apparatus, with eyes shut, and pinnae unresponsive to laboratory noises. R. e. m. sleep was identified by jerky movements of limbs and eyes. If one records from the same neurone when the cat is awake and when he is asleep, the values of both mode and g. s. d. change with the onset of sleep. Thus either parameter will provide a comparative measure of the animal’s state of alertness. On average the modal interval shortens by a factor of three when an animal falls asleep. This coincides with an increase of 42 % in the size of the g. s. d. The geometric coefficient of variation, which is a dimensionless measure of scatter about the mode - g. c. v. = [log (g. s. d. )]/[log (modal interval)] - also showed systematic changes. On average the g. c. v. increased by a factor of 2.4 when an animal fell asleep. The animal’s state of arousal could also be assessed by examining a single train of action potentials. Interval distributions with modal intervals which are shorter than 20 ms appear to be characteristic of neural activity recorded from a sleeping cat. This rule offers an 88 % chance of successfully classifying a single interval distribution. The size of the g. c. v. can also serve as an efficient ‘test’ of arousal. If one assumes that g. c. vs larger than 0.32 are diagnostic of records taken from animals which are asleep, one’s chance of making an accurate classification is also 88 %. No similar distinction could be made between quiet and r. e. m. sleep.

Glucuronyl 3-sulfate occurs exclusively on distal unmyelinated terminals of selected sensory neurons in the peripheral nervous system

1995 ◽  
Vol 53 ◽  
pp. 958-959
Author(s):  
S.S. Spicer ◽  
B.A. Schulte
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cerebral Cortex ◽  
Peripheral Nervous System ◽  
Sensory Neurons ◽  
Sensory Nerves ◽  
Tissue Antigens ◽  
The Central Nervous System ◽  
The Brain ◽  
Leu 7

Generation of monoclonal antibodies (MAbs) against tissue antigens has yielded several (VC1.1, HNK- 1, L2, 4F4 and anti-leu 7) which recognize the unique sugar epitope, glucuronyl 3-sulfate (Glc A3- SO4). In the central nervous system, these MAbs have demonstrated Glc A3-SO4 at the surface of neurons in the cerebral cortex, the cerebellum, the retina and other widespread regions of the brain.Here we describe the distribution of Glc A3-SO4 in the peripheral nervous system as determined by immunostaining with a MAb (VC 1.1) developed against antigen in the cat visual cortex. Outside the central nervous system, immunoreactivity was observed only in peripheral terminals of selected sensory nerves conducting transduction signals for touch, hearing, balance and taste. On the glassy membrane of the sinus hair in murine nasal skin, just deep to the ringwurt, VC 1.1 delineated an intensely stained, plaque-like area (Fig. 1). This previously unrecognized structure of the nasal vibrissae presumably serves as a tactile end organ and to our knowledge is not demonstrable by means other than its selective immunopositivity with VC1.1 and its appearance as a densely fibrillar area in H&E stained sections.

Neurotransmitter systems of female mouse brain during growth of malignant melanoma modeled on the background of chronic pain

2018 ◽  
pp. 49-55
Author(s):  
О.И. Кит ◽  
И.М. Котиева ◽  
Е.М. Франциянц ◽  
И.В. Каплиева ◽  
Л.К. Трепитаки ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Cerebral Cortex ◽  
Malignant Melanoma ◽  
Sciatic Nerve ◽  
Female Mouse ◽  
Combined Effects ◽  
Malignant Growth ◽  
Course Of Disease ◽  
The Brain ◽  
Melanoma Growth

Известно, что биогенные амины (БА) участвуют в злокачественном росте, их уровень изменяется в ЦНС при болевом воздействии, однако исследований о сочетанном влиянии хронической боли (ХБ) и онкопатологии на динамику БА в головном мозге не проводилось. Цель: изучить особенности баланса БА в коре головного мозга в динамике роста меланомы, воспроизведенной на фоне ХБ. Материалы и методы. Работа выполнена на 64 мышах-самках, весом 21-22 г. Животным основной группы меланому В16/F10 перевивали под кожу спины через 2 недели после перевязки седалищных нервов. Группой сравнения служили мыши с меланомой без боли. Уровни БА: адреналина, норадреналина, дофамина (ДА), серотонина (5-НТ), гистамина, а также 5-ОИУК определяли методом иммуноферментного анализа. Результаты. У мышей с ХБ уменьшается содержание большинства БА, однако уровень ДА не изменяется. Метаболизм 5-НТ происходит с участием МАО. Развитие меланомы сопровождается увеличением содержания ДА и 5-НТ, тогда как МАО - ингибируется. Направленность сдвигов БА при развитии меланомы на фоне ХБ оказалась практически такой же, как и без неё. В то же время ХБ ограничивает накопление 5-НТ в коре мозга при меланоме, что сопровождается более агрессивным её течением. Выводы. ХБ ограничивает включение стресс-лимитирующих механизмов в головном мозге при развитии меланомы у мышей, что приводит к более агрессивному течению злокачественного процесса. Biogenic amines (BA) are known to be involved in malignant growth, and their CNS levels change in pain; however, there are no studies of combined effects of chronic pain (CP) and cancer on BA dynamics in the brain. Aim: To study features of BA balance in the cerebral cortex during melanoma growth associated with CP. Material and methods. The study included 64 female mice weighing 21-22 g. In the main groups, B16/F10 melanoma was transplanted under the skin of the back two weeks following sciatic nerve ligation. Mice with melanoma without pain were used as the control. Concentrations of BA: adrenaline, noradrenaline, dopamine (DA), serotonin (5-HT), histamine and 5-HIAA were measured with ELISA. Results. Concentrations of BAs decreased in mice with CP although DA levels did not change. 5-HT metabolism involved MAO. The development of melanoma was accompanied by increases in DA and 5-HT whereas MAO was inhibited. The direction of BA changes during the development of melanoma was the same with and without CP. At the same time, CP with melanoma limited accumulation of 5-HT in the cerebral cortex, which resulted in even more aggressive course of cancer. Conclusion. CP restricted the activation of cerebral stress-limiting mechanisms during the development of melanoma in mice, which resulted in a more aggressive course of disease.

scholarly journals Long-Term Glucose Starvation Induces Inflammatory Responses and Phenotype Switch in Primary Cortical Rat Astrocytes

2021 ◽  
Author(s):  
Vanessa Kogel ◽  
Stefanie Trinh ◽  
Natalie Gasterich ◽  
Cordian Beyer ◽  
Jochen Seitz
Keyword(s):  
Cerebral Cortex ◽  
Synapse Formation ◽  
Inflammatory Responses ◽  
Glucose Starvation ◽  
Unfolded Protein ◽  
Genes Encoding ◽  
Phenotype Switch ◽  
The Unfolded Protein Response ◽  
The Brain

AbstractAstrocytes are the most abundant cell type in the brain and crucial to ensure the metabolic supply of neurons and their synapse formation. Overnutrition as present in patients suffering from obesity causes astrogliosis in the hypothalamus. Other diseases accompanied by malnutrition appear to have an impact on the brain and astrocyte function. In the eating disorder anorexia nervosa (AN), patients suffer from undernutrition and develop volume reductions of the cerebral cortex, associated with reduced astrocyte proliferation and cell count. Although an effect on astrocytes and their function has already been shown for overnutrition, their role in long-term undernutrition remains unclear. The present study used primary rat cerebral cortex astrocytes to investigate their response to chronic glucose starvation. Cells were grown with a medium containing a reduced glucose concentration (2 mM) for 15 days. Long-term glucose starvation increased the expression of a subset of pro-inflammatory genes and shifted the primary astrocyte population to the pro-inflammatory A1-like phenotype. Moreover, genes encoding for proteins involved in the unfolded protein response were elevated. Our findings demonstrate that astrocytes under chronic glucose starvation respond with an inflammatory reaction. With respect to the multiple functions of astrocytes, an association between elevated inflammatory responses due to chronic starvation and alterations found in the brain of patients suffering from undernutrition seems possible.

scholarly journals Understanding Quantitative Circadian Regulations Are Crucial Towards Advancing Chronotherapy

Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 883 ◽  
Author(s):  
Debajyoti Chowdhury ◽  
Chao Wang ◽  
Ai-Ping Lu ◽  
Hai-Long Zhu
Keyword(s):  
Circadian Rhythms ◽  
Molecular Mechanisms ◽  
Temporal Stability ◽  
Biological Rhythms ◽  
Integrative Approach ◽  
Peripheral Tissues ◽  
Innovative Strategies ◽  
Neural Connections ◽  
Core Components ◽  
The Brain

Circadian rhythms have a deep impact on most aspects of physiology. In most organisms, especially mammals, the biological rhythms are maintained by the indigenous circadian clockwork around geophysical time (~24-h). These rhythms originate inside cells. Several core components are interconnected through transcriptional/translational feedback loops to generate molecular oscillations. They are tightly controlled over time. Also, they exert temporal controls over many fundamental physiological activities. This helps in coordinating the body’s internal time with the external environments. The mammalian circadian clockwork is composed of a hierarchy of oscillators, which play roles at molecular, cellular, and higher levels. The master oscillation has been found to be developed at the hypothalamic suprachiasmatic nucleus in the brain. It acts as the core pacemaker and drives the transmission of the oscillation signals. These signals are distributed across different peripheral tissues through humoral and neural connections. The synchronization among the master oscillator and tissue-specific oscillators offer overall temporal stability to mammals. Recent technological advancements help us to study the circadian rhythms at dynamic scale and systems level. Here, we outline the current understanding of circadian clockwork in terms of molecular mechanisms and interdisciplinary concepts. We have also focused on the importance of the integrative approach to decode several crucial intricacies. This review indicates the emergence of such a comprehensive approach. It will essentially accelerate the circadian research with more innovative strategies, such as developing evidence-based chronotherapeutics to restore de-synchronized circadian rhythms.

THE METABOLISM OF NORMAL BRAIN AND HUMAN GLIOMAS IN RELATION TO CELL TYPE AND DENSITY

1955 ◽  
Vol 33 (3) ◽  
pp. 395-403 ◽  
Author(s):  
Irving H. Heller ◽  
K. A. C. Elliott
Keyword(s):  
Cerebral Cortex ◽  
White Matter ◽  
Brain Tumors ◽  
Corpus Callosum ◽  
Oxygen Uptake ◽  
Glial Cells ◽  
Cerebellar Cortex ◽  
Unit Weight ◽  
Uptake Rates ◽  
The Brain

Per unit weight, cerebral and cerebellar cortex respire much more actively than corpus callosum. The rate per cell nucleus is highest in cerebral cortex, lower in corpus callosum, and still lower in cerebellar cortex. The oxygen uptake rates of the brain tumors studied, with the exception of an oligodendroglioma, were about the same as that of white matter on the weight basis but lower than that of cerebral cortex or white matter on the cell basis. In agreement with previous work, an oligodendroglioma respired much more actively than the other tumors. The rates of glycolysis of the brain tumors per unit weight were low but, relative to their respiration rate, glycolysis was higher than in normal gray or white matter. Consideration of the figures obtained leads to the following tentative conclusions: Glial cells of corpus callosum respire more actively than the neurons of the cerebellar cortex. Neurons of the cerebral cortex respire on the average much more actively than neurons of the cerebellar cortex or glial cells. Considerably more than 70% of the oxygen uptake by cerebral cortex is due to neurons. The oxygen uptake rates of normal oligodendroglia and astrocytes are probably about the same as the rates found per nucleus in an oligodendroglioma and in astrocytomas; oligodendroglia respire much more actively than astrocytes.

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