Dreams are the images, thoughts and feelings experienced while asleep, particularly strongly associated with rapid eye movement sleep. The contents and purpose of dreams are poorly understood, though they have been a topic of speculation and interest throughout recorded history.
There is no universally agreed biological definition of dreaming. General observation shows that dreams are strongly associated with rapid eye movement (REM) sleep, during which an electroencephalogram shows brain activity to be most like wakefulness. Participant-remembered dreams during non-REM sleep are normally more mundane in comparison. During a typical lifespan, a human spends a total of about six years dreaming (which is about two hours each night.It is unknown where in the brain dreams originate, if there is a single origin for dreams or if multiple portions of the brain are involved, or what the purpose of dreaming is for the body or mind.
Stages of sleep
When the body decides that it is time to sleep, neurons near the eyes begin to send signals throughout the body. According to J. Allan Hobson, these neurons are located in such close proximity to neurons that control eyelid big muscles that the eyelids begin to grow heavy. Glands begin to secrete a hormone that helps induce sleep and neurons send signals to the spinal cord which cause the body to relax
When the body decides that it is time to sleep, neurons near the eyes begin to send signals throughout the body. According to J. Allan Hobson, these neurons are located in such close proximity to neurons that control eyelid big muscles that the eyelids begin to grow heavy. Glands begin to secrete a hormone that helps induce sleep and neurons send signals to the spinal cord which cause the body to relax
Discovery of REM
EEG showing brainwaves during REM sleep
In 1953 Eugene Aserinsky discovered REM sleep while working in the surgery of his PhD advisor. Aserinsky noticed that the sleepers' eyes fluttered beneath their closed eyelids, later using a polygraph machine to record their brain waves during these periods. In one session he awakened a subject who was crying out during REM and confirmed his suspicion that dreaming was occurring. In 1953 Aserinsky and his advisor published the ground-breaking study in Science.
In 1976, J. Allan Hobson and Robert McCarly proposed a new theory that changed dream research, challenging the previously held Freudian view of dreams as subconscious wishes to be interpreted. The activation synthesis theory asserts that the sensory experiences are fabricated by the cortex as a means of interpreting chaotic signals from the pons. They propose that in REM sleep, the ascending cholinergic PGO (ponto-geniculo-occipital) waves stimulate higher midbrain and forebrain cortical structures, producing rapid eye movements. The activated forebrain then synthesizes the dream out of this internally generated information. They assume that the same structures that induce REM sleep also generate sensory information.
Hobson and McCarly's 1976 research suggested that the signals interpreted as dreams originated in the brain stem during REM sleep. However, research by Mark Solms suggests that dreams are generated in the forebrain, and that REM sleep and dreaming are not directly related. While working in the neurosurgery department at hospitals in Johannesburg and London, Solms had access to patients with various brain injuries. He began to question patients about their dreams and confirmed that patients with damage to the parietal lobe stopped dreaming; this finding was in line with Hobson's 1977 theory. However, Solms did not encounter cases of loss of dreaming with patients having brain stem damage. This observation forced him to question Hobson's prevailing theory which marked the brain stem as the source of the signals interpreted as dreams. Solms viewed the idea of dreaming as a function of many complex brain structures as validating Freudian dream theory, an idea that drew criticism from Hobson.
EEG showing brainwaves during REM sleep
In 1953 Eugene Aserinsky discovered REM sleep while working in the surgery of his PhD advisor. Aserinsky noticed that the sleepers' eyes fluttered beneath their closed eyelids, later using a polygraph machine to record their brain waves during these periods. In one session he awakened a subject who was crying out during REM and confirmed his suspicion that dreaming was occurring. In 1953 Aserinsky and his advisor published the ground-breaking study in Science.
In 1976, J. Allan Hobson and Robert McCarly proposed a new theory that changed dream research, challenging the previously held Freudian view of dreams as subconscious wishes to be interpreted. The activation synthesis theory asserts that the sensory experiences are fabricated by the cortex as a means of interpreting chaotic signals from the pons. They propose that in REM sleep, the ascending cholinergic PGO (ponto-geniculo-occipital) waves stimulate higher midbrain and forebrain cortical structures, producing rapid eye movements. The activated forebrain then synthesizes the dream out of this internally generated information. They assume that the same structures that induce REM sleep also generate sensory information.
Hobson and McCarly's 1976 research suggested that the signals interpreted as dreams originated in the brain stem during REM sleep. However, research by Mark Solms suggests that dreams are generated in the forebrain, and that REM sleep and dreaming are not directly related. While working in the neurosurgery department at hospitals in Johannesburg and London, Solms had access to patients with various brain injuries. He began to question patients about their dreams and confirmed that patients with damage to the parietal lobe stopped dreaming; this finding was in line with Hobson's 1977 theory. However, Solms did not encounter cases of loss of dreaming with patients having brain stem damage. This observation forced him to question Hobson's prevailing theory which marked the brain stem as the source of the signals interpreted as dreams. Solms viewed the idea of dreaming as a function of many complex brain structures as validating Freudian dream theory, an idea that drew criticism from Hobson.
Dreams and memory
Eugen Tarnow suggests that dreams are ever-present excitations of long-term memory, even during waking life. The strangeness of dreams is due to the format of long-term memory, reminiscent of Penfield & Rasmussen’s findings that electrical excitations of the cortex give rise to experiences similar to dreams. During waking life an executive function interprets long term memory consistent with reality checking. Tarn ow's theory is a reworking of Freud's theory of dreams in which Freud's unconscious is replaced with the long-term memory system and Freud's “Dream Work” describes the structure of long-term memory
4 comments:
Dream,
it is very nice from you to talk abut this important topic..
in fact, we need this to do our English essay..
But could you put many other things to make your blogger mre useful and (wonderful)?
oDreams are the images, thoughts and feelings experienced while asleep, particularly strongly associated with rapid eye movement sleep. The contents and purpose of dreams are poorly understood, though they have been a topic of speculation and interest throughout recorded history.
Hiii
Very nice topic as well as amazing blog
I wish you'll reach your dreams..
Hii Mesa
Since your blog is about Dreams..Could you tell me how can I sleep properly???
Thanks ,,,GOODLucK
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