Tuesday, May 3, 2022

What Part Of The Brain Is Responsible For Dreams

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Dreaming And The Different Parts Of The Brain

How to learn major parts of the brain quickly

Maybe its happened in one of your relationships: One morning, a partner wakes up and is angry at the other for something they did in a dream. Even though the dreamer logically understands that their partner is innocent of the perceived slight, the emotions from the dream remain, whether anger, sadness, or something else entirely.

If this has ever happened to you, you can thank the limbic system in your brain. The limbic system located in the center of your brain is responsible for your emotions both during sleep and wake periods. When you have an emotion in your dream, such as anger with a partner for doing something terrible, its triggered by the limbic system. However, the part of the limbic system thats most active during sleep is the amygdala, which is most commonly associated with fear, aggression, and unpleasant emotions. The amygdala is why we experience nightmares. Interestingly, brain scans indicate the amygdala tends to be most active during REM sleep, especially toward the early morning hours. Scientists suspect there is something biological happening during REM sleep that triggers this activity, but otherwise, theres no clear explanation.

Summary Of Main Findings

To the best of our knowledge, the current study is the first to evaluate differences in brain structure and functional connectivity of individuals who experience lucid dreams with high frequency. We found that compared to a control group matched on age, gender and dream recall frequency, individuals who reported lucid dreams spontaneously approximately every other night or more had increased resting-state functional connectivity between the left anterior prefrontal cortex and the bilateral angular gyrus , bilateral middle temporal gyrus and right inferior frontal gyrus . The frequent lucid dream group also showed decreased functional connectivity between left aPFC and bilateral insula. Whole-brain graph-theoretic analysis revealed that left aPFC had increased node degree and strength in the frequent lucid dream group compared to the control group. In contrast to these functional changes, we did not observe any differences in brain structure in any brain area between groups . Furthermore, no differences were observed between frequent lucid dream and control groups in behavioral or questionnaire measures of working memory capacity, prospective memory, mind-wandering frequency or trait mindfulness.

The Brain In Rem Sleep

The regulation of REM sleep is even more complex, since physiologically antagonistic phenomena occur at the same time, such as a profound decrease in alertness with a state of EEG activation or intense motor inhibition with generalized hypotonia together with rapid eye movements and other phasic motor activities .

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Common Characteristics Of Dreams

Hobson also suggested that there are five key characteristics of dreams. Dreams tend to contain illogical content, intense emotions, acceptance of strange content, strange sensory experiences, and difficulty remembering dream content.

To summarize, the activation-synthesis theory essentially made three key assumptions:

  • High levels of activity in the brainstem are necessary for dreaming to take place.
  • Activation in these areas of the brain results in REM sleep and dreaming, and by corollary, all dreaming takes place during REM sleep.
  • The forebrain attempts to place meaning on the random signals created from the activation of the brainstem, resulting in coherent dreams.
  • So why does the brain try to make meaning from these random signals that take place during sleep?

    “The brain is so inexorably bent upon the quest for meaning that it attributes and even creates meaning when there is little or none in the data it is asked to process,” Hobson suggested.

    What Happens When We Dream

    Biology of Lucid Dreaming

    Asked by: Tasha Henson, Norwich

    The whole brain is active during dreams, from the brain stem to the cortex. Most dreams occur during REM sleep. This is part of the sleep-wake cycle and is controlled by the reticular activating system whose circuits run from the brain stem through the thalamus to the cortex.

    The limbic system in the mid-brain deals with emotions in both waking and dreaming and includes the amygdala, which is mostly associated with fear and is especially active during dreams.

    The cortex is responsible for the content of dreams, including the monsters we flee from, the people we meet, or the experience of flying. Since we are highly visual animals the visual cortex, right at the back of the brain, is especially active, but so are many other parts of the cortex.

    Least active are some parts of the frontal lobes, and this may explain why we can be so uncritical during dreams, accepting the crazy events as though they are real until we wake up.

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    Demographic And Behavioral Results

    The mean age for both groups was 22.6±5.4 and both groups were composed of 5 males and 9 females. There was no significant difference in dream recall between the control group and lucid dream group . All 28 participants reported high dream recall . The frequent lucid dream group reported significantly more lucid dreams compared to the control group . The frequent lucid dream group reported a median of 75 lucid dreams in the last 6 months, a median of 90 lucid dreams for the highest number of lucid dreams in any 6-month period, and reported experiencing lucid dreams on average for 9.5±5.8 years. No significant differences between groups were observed for working memory capacity , or questionnaire assessments of mind-wandering frequency, prospective or retrospective memory or trait mindfulness .

    Table 1 Demographic, behavioral and questionnaire data for the frequent lucid dream group and control group.

    Behavioral And Questionnaire Assessment

    Participants completed several additional assessments that measured cognitive variables which have been hypothesized to be associated with lucid dreaming and have been linked to PFC function, including working memory capacity , trait mindfulness and prospective memory . To measure WMC, participants completed automated versions of the operation span task , rotation span task and symmetry span task . These tasks have been validated to yield a reliable measure of WMC,. In brief, each task presents to-be-remembered stimuli in alternation with an unrelated processing task. In the OSpan the to-be-remembered stimuli are letters and the unrelated task is verifying the accuracy of an equation in the SymSpan the to-be-remembered stimuli are locations of red squares in a 4×4 grid and the unrelated task is verifying the vertical symmetry of an image in the RotSpan the to-be-remembered stimuli are arrows pointing in one of eight different directions and the unrelated task is whether a rotated letter is presented correctly. Participants completed two blocks of each task, which together provide a reliable measure of an individuals WMC. Following standard scoring procedures, span scores were calculated as the total number of items recalled in correct serial order across all trials.

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    Why Is The Pons Important

    The pons is important because your brain wouldnt be able to function properly without it.

    Think of the pons as a messenger that delivers messages from one part of the brain to another. If this messenger suddenly disappeared, the messages would no longer be able to reach their destination. This could render you unable to do certain things that you never had problems with before.

    Phenomenology Of Dreams And Their Relation To Brain Activity

    Why do we DREAM? | What causes DREAMS!?

    The level and nature of our conscious experience varies dramatically in sleep. During slow wave sleep early in the night, consciousness can nearly vanish despite persistent neural activity in the thalamocortical system. Subjects awakened from other phases of sleep, especially but not exclusively during REM sleep, report typical, full-fledged dreams – vivid, sensorimotor hallucinatory experiences that follow a narrative structure. The dreamer is highly conscious , is disconnected from the environment , but somehow her brain is creating a story, filling it with actors and scenarios, and generating hallucinatory images. How does the brain accomplish this remarkable feat? And, conversely, what do dreams tell us about the organization and working of the brain?

    Since awakenings from REM sleep regularly yield reports of typical dreams, we will first focus on neural activity during REM sleep, to gain insight into brain states that are compatible with dreaming. It should be emphasized at the outset, however, that dreams can occur in other brain states, such as late NREM sleep, as will be discussed below.

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    The Aim Model Of Dreaming

    Thanks to modern advances in brain imaging and the ability to monitor brain activity, researchers now understand more about the sleep-wake cycle, the different stages of sleep, and the different states of consciousness.

    The more recent version of the activation-synthesis theory is known as the AIM model, standing for activation, input-output gating, and modulation.

    This newer model tries to capture what happens in the brain-mind space as consciousness changes through waking, non-REM, and REM sleep states.

    Brain Stem Keeps You Breathing And More

    Another brain part that’s small but mighty is the brain stem. The brain stem sits beneath the cerebrum and in front of the cerebellum. It connects the rest of the brain to the spinal cord, which runs down your neck and back. The brain stem is in charge of all the functions your body needs to stay alive, like breathing air, digesting food, and circulating blood.

    Part of the brain stem’s job is to control your involuntary muscles the ones that work automatically, without you even thinking about it. There are involuntary muscles in the heart and stomach, and it’s the brain stem that tells your heart to pump more blood when you’re biking or your stomach to start digesting your lunch. The brain stem also sorts through the millions of messages that the brain and the rest of the body send back and forth. Whew! It’s a big job being the brain’s secretary!

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    Box 2the Development Of Dreams In Children

    When do children start dreaming, and what kind of dreams do they have? Since children often show signs of emotion in sleep, many assume they dream a great deal. However, a series of studies by David Foulkes showed that children under the age of 7 reported dreaming only 20% of the time when awakened from REM sleep, compared with 8090% in adults.

    Preschoolers dreams are often static and plain, such as seeing an animal or thinking about eating. There are no characters that move, no social interactions, very little feeling, and they do not include the dreamer as an active character. There are also no autobiographic, episodic memories, perhaps because children have trouble with conscious episodic recollection in general, as suggested by the phenomenon of infantile amnesia. Preschoolers do not report fear in dreams, and there are few aggressions, misfortunes, and negative emotions. Note that children who have night terrors, in which they awaken early in the night from SWS and display intense fear and agitation, are probably terrorized by disorientation due to incomplete awakening rather than by a dream. Thus, although children of age 25 can obviously see and speak of everyday people, objects and events, apparently they cannot dream of them.

    What Does The Pons Regulate

    The neurobiology of dreaming

    In addition to all these functions, the pons also plays a regulatory role in two vital processes.

    One of those processes is deep sleep. As already mentioned, it is the most refreshing sleep that helps your brain process, consolidate, and store information. Sleep also frees up space in your brain, thus making room for even more useful information.

    While youre sleeping, the pons sends signals to groups of muscles that are responsible for limb movements and body posture to rest along with the rest of your body. This, in turn, prevents you from acting out on your dreams, which can happen if your pons stops functioning properly.

    The pons is also home to the pneumotaxic center, which allows it to regulate the breathing process.

    This center is made up of a large number of nerve cells which monitor your oxygen levels throughout the day. At any given moment, the pneumotaxic center measures your breathing rate to determine how much air your body needs and how often you need to breathe in.

    If the pneumotaxic center detects an increased need for oxygen, your breathing rate will increase. This most often happens while youre performing physically demanding tasks like running or exercising. Conversely, your breathing rate will decrease while youre resting as your body needs less oxygen then.

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    Why Dreams Are So Difficult To Remember: Precise Communication Discovered Across Brain Areas During Sleep

    Date:
    California Institute of Technology
    Summary:

    Their findings may someday even help scientists understand why dreams are so difficult to remember.

    Scientists have long known that memories are formed in the brain’s hippocampus, but are stored elsewhere–most likely in the neocortex, the outer layer of the brain. Transferring memories from one part of the brain to the other requires changing the strength of the connections between neurons and is thought to depend on the precise timing of the firing of brain cells.

    “We know that if neuron A in the hippocampus fires consistently right before neuron B in the neocortex, and if there is a connection from A to B, then that connection will be strengthened,” explains Casimir Wierzynski, a Caltech graduate student in computation and neural systems, and first author on the Neuron paper. “And so we wanted to understand the timing relationships between neurons in the hippocampus and the prefrontal cortex, which is the front portion of the neocortex.”

    “This is exactly the kind of relationship that would be needed for the hippocampus to effect changes in the neocortex–such as the consolidation, or laying down, of memories,” adds Wierzynski.

    As it turns out, those thoughts were right–but only part of the time.

    On the other hand, during rapid-eye-movement sleep, the previously chatty neuron pairs seemed to talk right past each other, firing at the same rates as before but no longer in concert.

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    Why Do We Forget Dreams

    At present, it is thought that the production of dreams is associated with memories and the region of the hippocampus, an area located under the cerebral cortex, with an important role in memory.

    Landscapes and situations that we perceive in dreams are produced arbitrarily. All this is generated by our implicit memory, the same one that we use to do things automatically and that is responsible for relating abstract elements in our mind.

    Our memory works by association of ideas. Only when we associate something with a global situation can we remember it.

    This is the reason why, when we dream, our brain constructs complex narratives and does not remember isolated elements.

    Memories are formed, first, in the hippocampus, and then they are passed on to other parts of the brain, such as the neocortex.

    This synchronization, which occurs in our conscious state, is not easy to occur during sleep. Therefore it is difficult to remember what we dream.

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    What Part Of The Brain Do Dreams Come From

    Dreams form in the temporal lobe of the brain. This region is in charge of building, imagining and recreating memories.

    Dreams occur during the REM stage of sleep, the lightest and, in which, although we do not realize it, we quickly pass between sleeping and being conscious.

    Dreams occupy 95% of the REM phase time

    In the REM stage, the regulation between sleeping and waking is carried out by the reticular activation system, a circuit that goes from the brain stem, through the hypothalamus to reach the cerebral cortex.

    It is the cerebral cortex, responsible for generating dreams, and which is very active while we are in the REM stage.

    From there also comes the content of our dreams that, although they are fantasy, come from our own experiences. The fact that we see images when dreaming is in the activity of the visual cortex.

    Another system that is activated during sleep is the limbic system.

    We could say that our dreams are a composition created by different parts of our brain.

    The limbic system, which regulates emotions, is active while we dream, and the amygdala, a structure responsible for feelings of fear and anxiety, contributes its own.

    That is the reason why our dreams can be positive or turn into nightmares.

    Dreams are not usually logical and there is a reason for this: the least active areas of the brain are those of the frontal lobes, precisely those in charge of reasoning, so the illogical can seem normal when sleeping, but strange once we wake up.

    In The Late 1700s A Nightmare Was Defined As A Disease When A Man In His Sleep Supposes He Has A Great Weight Laying Upon Him

    Parts of the Brain-Human Brain Structure and Function

    This definition came from the popular reference text, An Universal Etymological English Dictionary, first published by Nathan Bailey in 1721 and reprinted through 1802. Although that definition doesnt surface often today, nightmares are still considered to be frightening dreams that result in feelings of terror, fear, distress, or anxiety.

    Despite our colloquial use of the term, for example, my commute was a nightmare, for an estimated 3 to 7 percent of the U.S. population, nightmares can be a real problem. Although adults can suffer from nightmares, they are more typical in children, especially those between the ages of 3 and 6. We think that some of this may be evolutionary, says Deirdre Barrett, PhD, an HMS assistant clinical professor of psychology at Cambridge Health Alliance and editor of Trauma and Dreams, published by Harvard University Press in 2001. Children are smaller and are vulnerable to many more threats than adults. Nightmares may partially reflect this vulnerability.

    Dreams are understood to be recent autobiographical episodes that become woven with past memories to create a new memory that can be referenced later, but nightmares are simply dreams that cause a strong but unpleasant emotional response. Dreams are part of the brains default networka system of interconnected regions, which includes the thalamus, medial prefrontal cortex, and posterior cingulate cortexthat remains active during comparatively quiet periods.

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