• Home
  • Velayudhan Mohan Kumar
Velayudhan Mohan Kumar

Velayudhan Mohan Kumar
National Academy of Medical Sciences (India) · Kerala Chapter

Doctor of Philosophy

About

201
Publications
22,751
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,514
Citations
Introduction
Dr Kumar was Professor & Head of Physiology at AIIMS, Delhi. He did research on the “Role of the preoptic area in sleep”. He was made Emeritus Scientist by CSIR & ICMR. After superannuation from AIIMS joined SCTIMST, Trivandrum, and established Comprehensive Centre for Sleep Disorders. He is Patron of S&V, Assoc. Editor of SB, was a member of the Governing Council of NAMS. Dr. Kumar formed the Indian Society for Sleep Research, and was the President of ISSR, ASRS & Vice-President of WFSRS
Additional affiliations
July 1977 - May 1998
University of Milan
Position
  • Research Associate
December 1968 - September 2006
All India Institute of Medical Sciences
Position
  • Tutor to Professor & Head of Department
December 1968 - September 2006
All India Institute of Medical Sciences
Position
  • Head of Faculty

Publications

Publications (201)
Article
Full-text available
Objective Though there are excellent reviews on the functional significance of spontaneous arousals during sleep, associated electroencephalographic (EEG) and electromyographic (EMG) changes need further studies. Moreover, a comparison of these changes with early morning arousal from sleep will help in improving our understanding of sleep–wake regu...
Article
Full-text available
Capsaicin receptors are found not only in the skin, but also in many neural and non-neural tissues. Though their involvement in many functions is now known, their role in sleep regulation has not gained proper attention. As capsaicin receptors can alter body temperature, it has led to the belief that sleep changes result from an alteration in body...
Article
Full-text available
The current Russian war against Ukraine is of global concern. It builds on the annexation of Crimea in 2014 and subsequently the war in the Donbas region of Ukraine, and has become a large-scale Russian invasion of Ukraine from three directions, Crimea in the south, Russia in the east, and Belarus in the north. Despite the geopolitical background t...
Article
Objective Though there are excellent reviews on the functional significance of spontaneous arousals during sleep, associated electroencephalographic (EEG) and electromyographic (EMG) changes need further studies. Moreover, a comparison of these changes with early morning arousal from sleep will help in improving our understanding of sleep–wake reg...
Article
Full-text available
Thickly populated Kerala was the first Indian state to get affected by COVID-19 on 2nd Feb 2020. The number of cases here rose much faster than in the rest of India. The containment measures adopted by the state, which brought the infection rate to near zero by the first week of May 2020, were internationally acclaimed. When the expatriates started...
Article
Full-text available
On 14th June 2021, Philips Respironics issued a medical device recall notification (US only) and field-safety notice (International Markets) for mechanical ventilator devices including continuous positive airway pressure (CPAP), and bilevel positive airway pressure (bilevel PAP). This was in response to potential health risks related to the sound a...
Chapter
Sleep undergoes remarkable changes during early development in humans and the most studied experimental model rat. Albeit practical challenges, it is interesting to study the macro- and micro-architecture of EEG during critical stages of development to get an insight into the neuronal plasticity involved in network formation for the complex process...
Article
Full-text available
Free vaccination against COVID-19 commenced in India on January 16, 2021, and the government is urging all of its citizens to be immunized, in what is expected to be the largest vaccination program in the world. Out of the eight COVID-19 vaccines that are currently under various stages of clinical trials in India, four were developed in the country...
Article
Disturbed sleep during gestation may lead to adverse outcomes for both mother and child. Animal research plays an important role in providing insights into this research field by enabling ethical and methodological requirements that are not possible in humans. Here, we present an overview and discuss the main research findings related to the effect...
Article
Commonly used hypnotics are not very effective for the management of chronic insomnia as they produce several unpleasant side effects. According to a recent report, short-term administration of 10 mg/kg α-Asarone, an active principle of Acorus species, used in traditional Indian and Chinese medicine for a prolonged period without any ill-effects, p...
Article
Insomnia is associated with anxiety and memory deficits. α-Asarone, an active principle of Acorus species, which has anxiolytic and memory-restoring properties, was recently identified as a potential hypnotic with the least side effects. The current study was conducted in rats to find out whether the hypnotic dose of α-asarone can produce anxiolyti...
Article
There is a growing realization that proper sleep during pregnancy is essential for the health of the mother and the offspring. However, there are no reports on the effects of maternal sleep restriction on the sleep-wake profiles of newborns. So, this study was conducted to evaluate the effects of sleep restriction during the third term of pregnancy...
Article
In contrast to newborns, who spend 16–20 h in sleep each day, adults need only about sleep daily. However, many elderly may struggle to obtain those 8 h in one block. In addition to changes in sleep duration, sleep patterns change as age progresses. Like the physical changes that occur during old age, an alteration in sleep pattern is also a part o...
Article
In this letter to the editor/correspondence, the aim was to draw attention towards prevailing sleep loss during peri-partum in the present society that has serious consequences on the cognitive development of children. Recent research has provided several evidences for it and this issue is a big challenge of wider consideration and interest.
Article
Commonly used hypnotics have undesirable side-effects, especially during continuous usage. On the other hand, some herbal products, which are used for prolonged periods, are suggested to have a sleep inducing property, though the claims have not been validated scientifically. The hypnotic potential of α-Asarone, an active principle of Acorus specie...
Article
Full-text available
PurposeIt is well established that loss of sleep leads to lapses in learning and memory. The brain regions including hippocampus, amygdala and the prefrontal cortex are associated with memory processes. However, there are not many studies on the changes in neuronal communications between these brain areas during sleep deprivation. Methods In this s...
Article
Sleep deprivation during pregnancy is an emerging concern, as it can adversely affect the development of the offspring brain. This study was conducted to evaluate the effects of deprivation of rapid eye movement (REM) sleep during the third term of pregnancy on the sleep-wake profiles of neonates in the Wistar rat model. Sleep-wake patterns were as...
Chapter
Ayurveda, which literally means knowledge of life, is the traditional school of Indian medicine. The chief source of information about Ayurveda is available in the Samhitas (encyclopedias), written in Sanskrit around 1000 BC, by Acharyas (the great scholars) Charaka and Sushruta. In Ayurvedic literature, Nidra (sleep) is mentioned as one of the thr...
Article
To develop an animal model for studies on peri-partum sleep disorders, sleep patterns in female Wistar rats during pregnancy, post-partum and after weaning, were assessed and associated adaptive changes in their anxiety were examined. Adult nulliparous female rats, maintained in standard laboratory conditions with ad libitum food and water, were su...
Article
Sleep deprivation is emerging as a major health concern due to the changing life style in the current 24X7 society. Each one of us has experienced insomnia, acute or chronic, at some point of our lives. With the great initiatives taken by health experts in the last couple of years, sleep disorders have been classified as per ICSD-3 and DSM-V criter...
Article
India is an ancient country with a vast population, diverse geography and culture. Although sleep medicine has been rapidly progressing during the last decade in the country, the ancient Indian literature is rich in descriptions of sleep physiology and the importance of sleep in life. In spite of rapid industrialization and the emergence of a moder...
Chapter
Full-text available
In ancient India, as in other countries, people had shown great interest in understanding sleep and interpreting dreams. One can always find the emphasis being laid on deep sleep in ancient Indian literature. The Vedas, written about 2000 or more years before Christ are the chief sources of knowledge about sleep medicine in ancient India. These rel...
Article
Full-text available
Ayurveda, the traditional school of Indian medicine, considers Nidra (sleep) along with Ahara (diet) and Brahmacharya (celibacy), as the three supporting sub-pillars of good health. Ancient Indian scriptures mention about sleep with dream and without it, much before the modern scientific world described REM and Non-REM sleep [1,2]. The chief source...
Article
Full-text available
Health systems planning for, and research into, sleep health care must be adaptable to the wide variations in social, economic, and medical conditions and structures. Community-based primary health care schemes should be linked to specialized levels to optimize the quality of care, depending upon the requirements of the patient and the availability...
Article
Full-text available
Hypothalamic temperature (Thy) alteration is one of the important stimuli that brings about thermoregulatory measures including the changes in wakefulness and muscular activity. The role of the lateral preoptic area (lPOA) in thermoregulation and sleep is well documented. But it is not known whether the integrity of the lPOA is essential for bringi...
Conference Paper
The prevalence of sleep disorders in India is comparable to that reported from rest of the world. But sleep medicine does not find a place in the curriculum of most of the medical colleges in India. A symposium on sleep medicine conducted, primarily for undergraduate students and clinical residents, by the National Academy of Medical Sciences (NAMS...
Conference Paper
OBJECTIVE: In the present world, it is of supreme importance to find a relatively safe drug substitute for the insomnia condition. The present study is aimed at investigating the effect of alpha-asarone (10mg/kg), an active principle from Acorus calamus Linn, on sleep-wakefulness, brain temperature and body temperature during an acute total sleep d...
Conference Paper
OBJECTIVE: Sleep restriction during pregnancy can adversely affect several components of cognition in the offspring as the developing fetal neural networks may be highly vulnerable to maternal sleep loss. The study is aimed to identify the alteration in sleep-wake (S-W) profile of neonates born to sleep-deprived (SD) mothers and to explore possibil...
Conference Paper
OBJECTIVE: Synchronization between theta waves in hippocampus (HC) and amygdala (Amyg) and pontine waves in pons (P) during REM component of sleep is essential for memory retrieval and consolidation. The study was aimed to investigate if acute sleep loss modulates the neural dynamics in HC, Amyg and Pons in adult male Wistar rats. METHODS: Sleep-w...
Article
Full-text available
The effects of rapid eye movement sleep restriction (REMSR) in rats during late pregnancy were studied on the ultrasonic vocalizations (USVs) made by the pups. USVs are distress calls inaudible to human ears. Rapid eye movement (REM) sleep was restricted in one group of pregnant rats for 22 hours, starting from gestational day 14 to 20, using stand...
Conference Paper
Full-text available
Insufficient sleep has become a global problem due to changing lifestyle in current civilization. For pregnant women, sleep loss could be detrimental not only to their health but can also affect the optimal cognitive development of offspring. Rapid eye movement (REM) component of sleep is reduced during 3rd trimester of pregnancy even in healthy wo...
Article
Full-text available
Human sleep, defined on the basis of electroencephalogram (EEG), electromyogram (EMG) and electrooculogram (EOG), is divided into rapid eye movement (REM) sleep and four stages of non–rapid eye movement (NREM) sleep. Collective monitoring and recording of physiological data during sleep is called polysomnography. Sleep which normally starts with a...
Article
Full-text available
The role of the preoptic area (POA) in thermoregulation is well documented. Microinjection of various neurotransmitters into the POA in rats has been shown to influence body temperature. Alhough there are reports showing changes in temperature on administration of L-glutamate into the POA, the role of this excitatory amino acid in thermoregulation...
Article
Changes in ambient temperature produce complex effects on sleep–wakefulness. In order to find out the mechanisms involved in temperature-sensitive changes in sleep in rats, their thermal preference, body temperature and sleep were studied before and after the destruction of both peripheral and central warm receptors, by systemic administration of 3...
Article
Full-text available
Regulation of body temperature and sleep are two physiological mechanisms that are vital for our survival. Interestingly neural structures implicated in both these functions are common. These areas include the medial preoptic area (POA), the lateral POA, the ventrolateral POA, the median preoptic nucleus, and the medial septum, which form part of t...
Article
Full-text available
Exposure to cold ambient temperature (Ta) affects sleep-wake (S-W) state. The vigilance states on the other hand influence thermal status of the animals. Simultaneous recording of body temperature (Tb) with S-W is crucial to understand the homeostatic relationship between the two. In the present study we recorded both Tb and hypothalamic temperatur...
Article
The role of the medial septum in suppressing paradoxical sleep and promoting slow wave sleep was suggested on the basis of neurotoxic lesion studies. However, these conclusions need to be substantiated with further experiments, including chemical stimulation studies. In this report, the medial septum was stimulated in adult male rats by microinject...
Conference Paper
Objective : Ambient temperature (Ta) affects both sleep-wakefulness (S-W) and body temperature (Tb). Peripheral and central warm receptors convey the thermal status of changing Ta to the preoptic area (POA). The POA regulates both S-W and Tb. There is reduction in total sleep time when exposed to extreme low and high Ta. In order to understand the...
Article
Full-text available
Warm sensitive neurons (WSN) play a major role not only in body temperature regulation, but also in sleep regulation. The present study was undertaken to investigate the role of WSN of the preoptic area (POA) in mediating the ambient temperature (T(amb)) related changes in sleep. The effect of T(amb) changes on sleep and body temperature was studie...
Article
A large body of evidence has established the role of the medial preoptic area (mPOA) in regulation of slow wave sleep (SWS). Although the mPOA neurons contain excitatory neurotransmitter glutamate, its role in sleep-wakefulness is not known. In the present study microinjection of monosodium glutamate (40, 80 and 120 ng) into the mPOA augmented SWS....
Article
According to traditional belief, prolonged wakefulness during the day is followed by brain rest at night in the form of sleep. This passive theory of sleep was replaced by the active sleep genesis concept, mainly after the realization that brain activity is only slightly reduced during sleep. There is now growing evidence to suggest that sleep is a...
Article
Changes in sleep and body temperature in rats at ambient temperatures below and above the self-selected temperature zone, are lacking in literature. In this report, the temperature preferred by the rats was first assessed before studying the changes in their sleep and body temperature, when they were exposed to ambient temperatures ranging from 18...
Article
Full-text available
The available information on simultaneous assessment of body and hypothalamic temperatures in rats are lacking. In the present study these temperatures were recorded for 24 h, on three alternate days, in rats maintained at an ambient temperature of 26 +/- 1 degrees C. Hypothalamic temperature was significantly higher than body temperature during th...
Article
Afferents from the perirhinal cortex (PRh) form a major input to the hippocampal formation, which is known to be involved in sexual behavior in rodents. But there is a lacuna in literature regarding the role of the PRh in sexual behavior. Bilateral neurotoxic lesions of the PRh delayed the ejaculation latency and prolonged the mean inter-intromissi...
Article
Full-text available
Sleep is a complex neurological state, with its primary function of providing rest and restoring the body's energy levels. The importance of sleep could be seen from the fact that people spend about one-third of their lifespan in sleep. Normal human sleep is divided into non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, and the alte...
Article
Full-text available
The chronic changes in sleep-wakefulness (S-W), body temperature (Tb), locomotor activity (LMA) and thermal preference were studied in male Wistar rats after the destruction of neurons in both the medial preoptic area (mPOA) and the medial septum (MS) by intracerebral injection of N-methyl-D-aspartic acid. An increase in the Tb, and a preference fo...
Article
Several studies have shown the importance of the medial preoptic area in the regulation of sleep-wakefulness and of body temperature. The medial preoptic area has a rich noradrenergic innervation, coming mostly from the lateral tegmental noradrenergic system. The accumulating evidences show that the noradrenergic afferents to the medial preoptic ar...
Article
Full-text available
Brain mechanisms for the refractory period that characteristically follows ejaculation in animals and human are poorly understood. The possibility of active inhibition of brain areas being responsible for the post-ejaculatory inhibitory state has not been ruled out. Using Blood Oxygen Level Dependent (BOLD) functional magnetic resonance imaging (fM...
Article
Full-text available
This paper reviews the recent studies that led to the conclusion that the noradrenergic neurons projecting to the medial preoptic area (mPOA) are hypnogenic and that they mediate this action through alpha(1) adrenergic receptors. Microinjection of noradrenaline (NA) into the mPOA induced arousal. Studies using alpha(2) adrenergic drugs showed that...
Article
Changes in sleep-wakefulness (S-W) and body temperature (T(b)) on administration of alpha(1) agonist (methoxamine) and antagonist (prazosin) into the medial preoptic area (mPOA) were studied in rats. Presynaptic catecholaminergic terminals of the mPOA were destroyed by injecting 6-hydroxydopamine at the ventral noradrenergic bundle (VNA), before ad...
Article
Several studies have suggested that noradrenergic afferents to the medial preoptic area might be involved in hypnogenesis and in lowering the body temperature, and that the alpha1 adrenergic receptors might be mediating these responses. This study was undertaken to find out the changes in sleep-wakefulness and body temperature in rats, when these a...
Article
The effects of the destruction of the medial preoptic area and the lateral preoptic area with N-methyl-d-aspartic acid on sleep-wakefulness, brain temperature and thermoregulation were studied in two groups of male Wistar rats. Electroencephalogram, electrooculogram and electromyogram, along with brain temperature, were recorded for 3 days, prior t...
Article
The effects of the destruction of the medial septal neurons (MS) with N-methyl-d-aspartic acid on sleep-wakefulness (S-W), body temperature (Tb), locomotor activity (LMA) and thermal preference were studied in male Wistar rats. When these rats were given a choice of three ambient temperatures (Tamb) of 24, 27 and 30 degrees C, they preferred 27 deg...
Article
Full-text available
The effects of chronic exposure to a mildly cold ambient temperature (T(a)) of 18 degrees C on sleep wakefulness (S-W) and brain temperature (T(br)) were studied in the medial preoptic area (mPOA) lesioned male Wistar rats. Electroencephalogram (EEG), electrooculogram (EOG) and electromyogram (EMG) electrodes were chronically implanted to assess S-...
Article
Brain temperatures (Tbr) of male Wistar rats were recorded at every 15 min interval for 24 h, prior to the destruction of the medial septal (MS) neurons with N-methyl-D-aspartic acid, and on the 7th, 14th and 21st days after the destruction. The capacity of the rats to regulate their body temperature under severe cold and heat was assessed by recor...
Article
Ambient temperature related sleep changes in rats neonatally treated with capsaicin. PHYSIOL BEHAV 00(0) 000-000, 2004. The study was conducted on adult male Wistar rats, neonatally treated with capsaicin to destroy the peripheral warm receptors. The sleep-wakefulness was recorded for 5 h at an ambient temperature (T(amb)) of 18, 24, 30 and 33 degr...