Emotional Thermalization is an asymmetrical representation of emotional control and processing in the brain. There is evidence for lateralization of other brain functions as well.
Emotions are complex and involve various physical and cognitive responses, many of which are not well understood. The general purpose of emotions is to generate a specific response to the stimulus. Feeling is the conscious perception of emotion, and when emotions are often or continuously this is called mood.
Various scientific studies have found lateralization of emotions. FMRI studies and lesions have demonstrated asymmetric activation of the brain area while thinking of emotions, responding to extreme emotional stimuli, and looking at emotional situations. The processing and production of facial expressions also appear asymmetric in nature. Many theories of lateralization have been proposed and some of them are specific to emotions. Please keep in mind that most of the information in this article is theoretical and scientists are still trying to understand lateral emotions and emotionalization. Also, some of the evidence is contradictory. Many areas of the brain are interconnected and the input and output of a particular region can come from and go to different regions.
Video Emotional lateralization
Teori lateralisasi
Dominasi belahan kanan
Some variations of right hemisphere dominance are...
a) The right hemisphere controls more emotions than the left brain b) The right hemisphere is dominant in emotional expression in the same way that the left hemisphere is dominant in the language c) The right hemisphere is dominant in the perception of facial expressions, posture, and prosody d) The right hemisphere is essential for processing primary emotions such as fear while the left brain is essential for processing social emotions.
Common lesions in the right hemisphere reduce or eliminate the electrodermal response (skin conductance response (SCR)) to emotionally significant stimuli while lesions in the left hemisphere show no change in SCR response.
The SB-2046 subject has a right, prefrontal lobe removed from cancer. While his IQ and most other normal functions are not hurt, it severely undermines the ability to make decisions especially when he should consider immediate and immediate rewards and punishments. His decisions are almost always guided by a direct reward or punishment and ignore the long-term consequences. The researcher was unable to condition the SB-2046 patient for nonverbal stimuli that contained emotional meaning (reward or punishment), but was able to condition the patient for verbal stimuli containing emotional significance.
Much of the production and processing of language takes place in the left hemisphere while most of the emotional processing and emotional production in the conversation takes place in the right hemisphere. People with schizophrenia usually have difficulty processing prosody. These patients also showed remarkable increases in lateralization leading to the right hemisphere of an emotionally and non-emotionally rich speech. Also, a decrease in the right hand causes an increase in right lateral hemispherealisation. Lateralization of the right hemisphere transcends prosodies for many aspects of language and speech processing in schizophrenic patients.
Complementarity specialization
Both hemispheres have a complementary specialty to control various aspects of emotion a) The left hemisphere primarily processes "positive" emotions and the right hemisphere primarily processes "negative" emotions. Most areas especially in the right hemisphere are activated during classic aversive conditioning
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- While this theory seems to apply to some emotions, this theory is generally considered outmoded; But some examples exist. For example, one study found that when subjects were given positive stimuli before hearing consonants, the left hemisphere was more active than the right hemisphere. Conversely, when subjects are given a negative stimulus, the right hemisphere is more active than the left hemisphere.
b) Other specialization divisions
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- The amygdala plays a role in awareness of emotional awareness (feeling) that results in perceptions of feelings, but experiments show the left and right amygdala have different roles in the conscious and unconscious process of emotion. The right amygdala plays a role in the unconscious process of emotion while the left amygdala is involved in the processing of conscious emotions. These results were obtained from studies containing coolant stimuli. Stimuli are presented in a very short time so that the subject is not aware of the stimuli but still able to show physiological changes.
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- The damage of the left hemisphere in the patient results in a marked increase in depression. Valence asymmetry may be due to more cholinergic and dopaminergic on the left hemisphere and the right hemisphere becomes more noradrenergic. Patients with right hemispheric damage have reduced stimulated responses to painful stimuli.
Homeostatic base
This model provides a neuroanatomical basis for emotional control and processing. The peripheral autonomic nervous system is not symmetrical. The afferent nerves in the parasympathetic and sympathetic system of the autonomic nervous system differ from the preservation of the various organs that maintain homeostasis such as the heart and face. The asymmetrical representation of the autonomic peripheral nervous system leads to asymmetrical representation in the brain. The left hemisphere is activated primarily by afferent homeostasis associated with parasympathetic function and the right hemisphere is activated primarily by afferent homeostasis associated with sympathetic function. This lateralization is very clear in anterior cingulate cortex (ACC) and anterior insular cortex (AI) associated with higher emotions such as romantic love and motivation correlated with homeostatic function. AI and ACC left more active during romantic feelings of romance and motherly attachment. AI and ACC are activated on both right and left sides while watching the pain inflicted on a loved one while only the correct AI and ACC are obtained during the feeling of subjective pain; it supports true AI associations in feelings ('sympathetic') and leaves AI in an affiliative feeling ('parasympathetic').
In particular, the cardiovascular function appears to be lateral and is tied to emotional stress. Intense emotional stimulation that causes stress can lead to changes in cardiovascular function. The right insular cortex may play the most significant role in this phenomenon. Similar lateralization may be involved in cardiovascular damage in patients with head injury, stroke, multiple sclerosis, brain tumors, meningitis and encephalitis, migraines, cluster headaches and neurosurgical procedures.
Lateralization due to lateralization of other functions
"It is impossible for the brain to evolve as an asymmetric control of emotional behavior, but it seems more likely that although there may be some asymmetry in emotional nerve control, the observed asymmetry is largely a product of asymmetric control of other functions such as movement control, language, or information processing sensorial complex, "Lateralization may be an evolutionary adaptation. Lateralization allows a wide variety of emotions. The left temporal cortex is involved in language processing while the right temporal cortex is involved in processing the face. This emphasis is also obvious when processing emotions.
Lateralization and gender differences
There may be differences in cortical activation between men and women. Activity in the right hemisphere is greater in women when exposed to unpleasant images than men, although men show more activation bilaterally when viewing a fun image. Another study found that women but not men, with women having greater activation of their right hemisphere when viewing unpleasant faces and activation of the left hemisphere when looking at a pleasant face. However, other studies found differences in sex contrast when recording EEG waves in the parietal and frontal lobes. Negative photographs activate the left hemisphere in women more than in men, and the right hemisphere in men more than in women when shown an unpleasant picture.
Maps Emotional lateralization
Evidence of lateralization
Most of the data comes from functional imaging, skin conductance response (SCR), standardized tests ranging from cognitive (eg IQ tests) to emotional intelligence, and subjective questionnaires such as judgments about how frightening or happy faces look. All tests have their strengths and weaknesses (see "Study Restrictions" below). This section primarily focuses on results on more subjective observations and outcomes that have unknown basis or nerve regions.
Differences in cortical behavior and activation
70% of right-hand patients showed a preference in seeing emotions expressed on the right side of the face (in the field of left view) according to research using chimeric faces produced using either right or left-left face. The left side of the face seems to be more fluent in expressing emotion which means the right cortical hemisphere is more fluent in expressing emotions. Handedness does not seem to affect the processing associated with seeing facial expressions.
Situations that conflict with moral teachings generally produce negative emotions. Watching people behave badly by breaking the most significant moral code activates the correct parahippocampal gyrus, right medial frontal gyrus, and leaves the amygdala. Watching the most emotionally negative situation activates the right amygdala. This study shows that the lateral processes of emotion transcend the basic emotions for higher cognitive responses.
Depression or previous depression may be caused by changes in brain structure or altering brain structure. Patients who are depressed or depressed exhibit more activation of negative stimuli in the emotions. When a negative stimulus is presented to the patient's right hemisphere, the patient is significantly more accurate and faster to respond to stimuli. Data in this study indicate that psychological disorders correlate with increased lateralization.
Emotional facial expression
Patients with damage to the left amygdala lesion were judged less afraid of faces than normal subjects. Similar findings suggest that regional blood flow increases in response to the face of fear while decreasing to the face of euphoria in the left amygdala.
Chimpanzees, other primates, and humans produce asymmetrical facial expressions with greater expression on the left side of the face (right hemisphere of the brain). The researchers also reported subjectively that the left side of the face expressed more emotion using left-faced left-handed images.
Leading lateralized brain structures and regions
Emotions are processed in many different areas of the brain, and certain emotions can be processed in many areas. Areas involved in emotional lateralization seem to follow a general convention that describes the role/function of a particular region of the brain. Below are some of the areas and structures involved in emotional processing that indicate functional lateralization.
Frontal lobe
Using a PET scan, the researchers found that activity in the medial and left lateral prefrontal cortex was associated with decreased activity in the amygdala. This finding implies that the prefrontal cortex modulates the amygdala activity. The left prefronatal cortex plays a role in the behavioral approach (the valent positive emotion), whereas the amygdala plays a role in the withdrawal behavior (negative emotions).
The superior frontal gyrus is the most actively active area when processing sorrow.
Patients with inferior frontal lobe damage produce less facial expressions and are less intense when presented with emotional stimuli, and they also have the problem of reading fear and disgust at others. People with left inferior frontal lobes produce fewer facial expressions and can not analyze emotional situations as well as those with right frontal lobe damage especially with fear and disgust. The lower left frontal gyrus (IFG) plays an important role in anger while the true IFG plays a larger role in disgust.
Patients with dorsolateral frontal cortical lesions find it difficult to distinguish propositional attitudes. Patients with left lesions showed a further decrease.
parietal lobe
Damage to the inferior parietal region including the anterior (supramarginal gyrus) and posterior (angular gyrus) regions results in reduced SCR. Damage to the right hemisphere in these areas resulted in a significant decrease in SCR (p & lt; 0.001) while the damage to the left hemisphere of this area was not (p <0.05).
Temporal lobe
The superior superior temporal gyrus is the most active area during the happy processing. The right superior temporal gyrus is increasingly responding to the happier stimuli, while the left pulvinar increasingly responds to the increasingly frightening stimuli. The right pulvinar is activated during unpleasant conditions.
Amygdala
The amygdala plays a key role in emotional processing especially fear, and the function of the amygdala appears to be emotionally lateralized. When people look scared face the left amygdala and leave the periamygdaloid cortex increase in activation. There also appears to be a greater increase in neural activity in the left amygdala associated with an increasingly frightening stimulus. Recording of a single unit electrode on a monkey shows the same activation on the left amygdala. A man with impaired damage in the right amygdala can not produce a surprising response. The activity (measured by PET scan) in the right amygdala is correlated with the number of emotion-evoking movie clips capable of being recalled to the patient.
The activation of the unilateral amygdala because of the intimidating stimuli may also result in unilateral activation of other regions. Right middle temporal gyrus, right brain stem, left hippocampus, right brain, right fuisform gyrus, and left lingual gyrus are also activated during frightening stimuli. Activation of several brain regions indicates that emotions are processed in many parts of the brain and emotions are complex.
The amygdala may play a role in the process of conscious emotion. The left amygdala is activated during the processing of conscious stimuli while the right amygdala is active during processing of nonconscous stimuli.
The anterior cingulate cortex (ACC) plays a role in various functions including the emotional ones. ACC may be important in awareness of emotional awareness. Damage to ACC is associated with decreased SCR to physical and psychological stimulation. Bilateral and unilateral damage both result in decreased SCR indicating that right and left ACC can specialize in certain aspects of the emotional response.
Anterior insula (AI)
The left anterior insula (AI) increasingly responds to an increasingly frightening stimulus. AI may also be involved in emotionally conscious experiences.
src: slideplayer.com
Implications
Phenomena such as emotional lateralization can help explain how emotions emerge, persist, and change our behavior. Understanding emotional lateralization will help scientists understand emotions in general. Emotional lateralization can also play a role in psychological disorders such as depression and schizophrenia. Future treatment of psychological disorders may have a more targeted neurological treatment than a digested drug.
Symptoms that arise from limited areas of damage usually have stereotypical emotional and behavioral changes. The diagnosis of finding a damaged area that processes emotions can be aided by emotional changes that appear to be categorized under one of the lateral emotional control systems. Diagnosis and treatment for cardiovascular disorders arising from emotional states can be helped by understanding the physical basis of psychological influences. Instead of treating cardiovascular aberrations for psychological problems, treatment may target the lateral brain region.
src: www.jneurosci.org
Study Limitations
Like all human-based scientific experiments, there are limitations that can be done by researchers. Trying to study emotions is very difficult because emotions are complex and can cause subjective responses. Since most experiments in emotional lateralization have been feared, this leaves the question of whether other emotions are also repeated. Below are two main issues related to many experiments that study emotions that require further explanation.
Sample size
Most studies in humans are anomalies due to accidents, tumors, or attempts to cure diseases (eg seizures) using lesions. Because very few such cases, the sample size of human studies of emotional lateralization is generally very limited and may be as small as a single person. While this research can provide good insights into specific brain areas and their functioning conclusions are uncertain. Research on animals can help in understanding this problem but emotions in humans are generally considered more complicated than most animals.
Functional imagery
There are some limitations when using fMRI or PET to study emotional responses. Because fMRI measures blood oxygenation changes, using the BOLD effect, its temporal resolution is limited by the hemodynamic response for a few seconds. PET has similar limits, offering slightly better temporal resolution and slightly worse spatial resolution.
Lesioning
Lesions are rarely localized and can affect large areas of the brain. Processing in the brain is generally un-localized and requires many areas of the brain to be processed. Furthermore, the lesion may disrupt the pathway that reaches the lesion site. Thus, lesions are not always a good way to determine what a particular area of ​​the brain does. Therefore, the degree of skepticism should be kept in mind when looking at lateralization data from lesion studies.
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Note
src: rsbl.royalsocietypublishing.org
References
Source of the article : Wikipedia
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