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Mindfulness has been defined in modern psychological terms as "paying attention to relevant aspects of experience in a nonjudgmental manner", [1] and maintaining attention on present moment experience with an attitude of openness and acceptance. [2] Meditation is a platform used to achieve mindfulness. Both practices, mindfulness and meditation, have been "directly inspired from the Buddhist tradition" [3] and have been widely promoted by Jon Kabat-Zinn. Mindfulness meditation has been shown to have a positive impact on several psychiatric problems such as depression and therefore has formed the basis of mindfulness programs [4] such as mindfulness-based cognitive therapy, mindfulness-based stress reduction and mindfulness-based pain management. The applications of mindfulness meditation are well established, however the mechanisms that underlie this practice are yet to be fully understood. Many tests and studies on soldiers with PTSD have shown tremendous positive results in decreasing stress levels and being able to cope with problems of the past, paving the way for more tests and studies to normalize and accept mindful based meditation and research, not only for soldiers with PTSD, but numerous mental inabilities or disabilities. [5]
Four components of mindfulness meditation have been proposed to describe much of the mechanism of action by which mindfulness meditation may work: attention regulation, body awareness, emotion regulation, and change in perspective on the self. [4] All of the components described above are connected to each other. For example, when a person is triggered by an external stimulus, the executive attention system attempts to maintain a mindful state. There is also a heightened body awareness such as a rapid heartbeat which triggers an emotional response. The response is then regulated so that it does not become habitual, but constantly changes from moment to moment experience. This eventually leads to a change in the perspective of the self.
Attention regulation is the task of focusing attention on an object, acknowledging any distractions, and then returning your focus back to the object. Some evidence for mechanisms responsible for attention regulation during mindfulness meditation are shown below.
The ACC detects conflicting information coming from distractions. When a person is presented with a conflicting stimulus, the brain initially processes the stimulus incorrectly. This is known as error-related negativity (ERN). Before the ERN reaches a threshold, the correct conflict is detected by the frontocentral N2. After the correction, the rostral ACC is activated and allows for executive attention to the correct stimulus. [11] Therefore, mindfulness meditation could potentially be a method for treating attention related disorders such as ADHD and bipolar disorder.
Body awareness refers to focusing on an object/task within the body such as breathing. From a qualitative interview with ten mindfulness meditators, some of the following responses were observed: "When I'm walking, I deliberately notice the sensations of my body moving" and "I notice how foods and drinks affect my thoughts, bodily sensations, and emotions”. [12] The two possible mechanisms by which a mindfulness meditator can experience body awareness are discussed below.
The insula is responsible for awareness to stimuli and the thickness of its gray matter correlates to the accuracy and detection of the stimuli by the nervous system. [16] [17] Qualitative evidence suggests that mindfulness meditation impacts body awareness, however this component is not well characterized. [4]
Emotions can be regulated cognitively or behaviorally. Cognitive regulation (in terms of mindfulness meditation) means having control over giving attention to a particular stimuli or by changing the response to that stimuli. The cognitive change is achieved through reappraisal (interpreting the stimulus in a more positive manner) and extinction (reversing the response to the stimulus). Behavioral regulation refers to inhibiting the expression of certain behaviors in response to a stimulus. Research suggests two main mechanisms for how mindfulness meditation influences the emotional response to a stimulus.
Lateral prefrontal cortex (lPFC) is important for selective attention while ventral prefrontal cortex (vPFC) is involved in inhibiting a response. As noted before, the anterior cingulate cortex (ACC) has been noted for maintaining attention to a stimulus. The amygdala is responsible for generating emotions. Mindfulness meditation is believed to be able to regulate negative thoughts and decrease emotional reactivity through these regions of the brain. Emotion regulation deficits have been noted in disorders such as borderline personality disorder [22] and depression. [23] These deficits have been associated with reduced prefrontal activation and increased amygdala activity, which mindfulness meditation might be able to attenuate.
Pain is known to activate the following regions of the brain: the anterior cingulate cortex, anterior/posterior insula, primary/secondary somatosensory cortices, and the thalamus. [24] Mindfulness meditation may provide several methods by which a person can consciously regulate pain. [24]
Brown and Jones found that meditators showed no difference in pain sensitivity but rather the anticipation in pain. However, Grant's research showed that meditators experienced lower sensitivity to pain. These conflicting studies illustrate that the exact mechanism may vary with the expertise level or meditation technique. [24]
In the human brain, the anterior cingulate cortex (ACC) is the frontal part of the cingulate cortex that resembles a "collar" surrounding the frontal part of the corpus callosum. It consists of Brodmann areas 24, 32, and 33.
Von Economo neurons (VENs), also called spindle neurons, are a specific class of mammalian cortical neurons characterized by a large spindle-shaped soma gradually tapering into a single apical axon in one direction, with only a single dendrite facing opposite. Other cortical neurons tend to have many dendrites, and the bipolar-shaped morphology of von Economo neurons is unique here.
The insular cortex is a portion of the cerebral cortex folded deep within the lateral sulcus within each hemisphere of the mammalian brain.
Affective neuroscience is the study of the neural mechanisms of emotion. This interdisciplinary field combines neuroscience with the psychological study of personality, emotion, and mood. The putative existence of 'basic emotions' and their defining attributes represents a long lasting and yet unsettled issue in the field.
Affective sensation is an occurrence of sensation accompanied with a strong compulsion to act on it. It refers, mostly in neuroscience, to the emotional sensibility in response to affective stimuli of a particular valence. It is transmitted via the spinothalamic tract through the spinal cord, and can be associated with reflex actions such as the scratch, gag, and withdrawal reflexes. Sensory processing in the brain interacts with behavioral choices, such as decisions to eat or to stop eating, in both healthy individuals and those with eating disorders.
Executive functions are a set of cognitive processes that are necessary for the cognitive control of behavior: selecting and successfully monitoring behaviors that facilitate the attainment of chosen goals. Executive functions include basic cognitive processes such as attentional control, cognitive inhibition, inhibitory control, working memory, and cognitive flexibility. Higher-order executive functions require the simultaneous use of multiple basic executive functions and include planning and fluid intelligence.
The reward system is a group of neural structures responsible for incentive salience, associative learning, and positively-valenced emotions, particularly ones involving pleasure as a core component. Reward is the attractive and motivational property of a stimulus that induces appetitive behavior, also known as approach behavior, and consummatory behavior. A rewarding stimulus has been described as "any stimulus, object, event, activity, or situation that has the potential to make us approach and consume it is by definition a reward". In operant conditioning, rewarding stimuli function as positive reinforcers; however, the converse statement also holds true: positive reinforcers are rewarding.
The psychological and physiological effects of meditation have been studied. In recent years, studies of meditation have increasingly involved the use of modern instruments, such as fMRI and EEG, which are able to observe brain physiology and neural activity in living subjects, either during the act of meditation itself or before and after meditation. Correlations can thus be established between meditative practices and brain structure or function.
The ventromedial prefrontal cortex (vmPFC) is a part of the prefrontal cortex in the mammalian brain. The ventral medial prefrontal is located in the frontal lobe at the bottom of the cerebral hemispheres and is implicated in the processing of risk and fear, as it is critical in the regulation of amygdala activity in humans. It also plays a role in the inhibition of emotional responses, and in the process of decision-making and self-control. It is also involved in the cognitive evaluation of morality.
Scientific studies have found that different brain areas show altered activity in people with major depressive disorder (MDD), and this has encouraged advocates of various theories that seek to identify a biochemical origin of the disease, as opposed to theories that emphasize psychological or situational causes. Factors spanning these causative groups include nutritional deficiencies in magnesium, vitamin D, and tryptophan with situational origin but biological impact. Several theories concerning the biologically based cause of depression have been suggested over the years, including theories revolving around monoamine neurotransmitters, neuroplasticity, neurogenesis, inflammation and the circadian rhythm. Physical illnesses, including hypothyroidism and mitochondrial disease, can also trigger depressive symptoms.
The biology of obsessive–compulsive disorder (OCD) refers biologically based theories about the mechanism of OCD. Cognitive models generally fall into the category of executive dysfunction or modulatory control. Neuroanatomically, functional and structural neuroimaging studies implicate the prefrontal cortex (PFC), basal ganglia (BG), insula, and posterior cingulate cortex (PCC). Genetic and neurochemical studies implicate glutamate and monoamine neurotransmitters, especially serotonin and dopamine.
Emotional lateralization is the asymmetrical representation of emotional control and processing in the brain. There is evidence for the lateralization of other brain functions as well.
Meditation and its effect on brain activity and the central nervous system became a focus of collaborative research in neuroscience, psychology and neurobiology during the latter half of the 20th century. Research on meditation sought to define and characterize various practices. Meditation's effect on the brain can be broken up into two categories: state changes and trait changes, respectively alterations in brain activities during the act of meditating and changes that are the outcome of long-term practice.
Pain empathy is a specific subgroup of empathy that involves recognizing and understanding another person's pain. Empathy is the mental ability that allows one person to understand another person's mental and emotional state and how to effectively respond to that person. When a person receives cues that another person is in pain, neural pain circuits within the brain are activated. There are several cues that can communicate pain to another person: visualization of the injury causing event, the injury itself, behavioral efforts of the injured to avoid further harm, and displays of pain and distress such as facial expressions, crying, and screaming. From an evolutionary perspective, pain empathy is beneficial for human group survival since it provides motivation for non-injured people to offer aid to the injured and to avoid injury themselves.
The neurocircuitry that underlies executive function processes and emotional and motivational processes are known to be distinct in the brain. However, there are brain regions that show overlap in function between the two cognitive systems. Brain regions that exist in both systems are interesting mainly for studies on how one system affects the other. Examples of such cross-modal functions are emotional regulation strategies such as emotional suppression and emotional reappraisal, the effect of mood on cognitive tasks, and the effect of emotional stimulation of cognitive tasks.
Neuromorality is an emerging field of neuroscience that studies the connection between morality and neuronal function. Scientists use fMRI and psychological assessment together to investigate the neural basis of moral cognition and behavior. Evidence shows that the central hub of morality is the prefrontal cortex guiding activity to other nodes of the neuromoral network. A spectrum of functional characteristics within this network to give rise to both altruistic and psychopathological behavior. Evidence from the investigation of neuromorality has applications in both clinical neuropsychiatry and forensic neuropsychiatry.
Meditation and pain is the study of the physiological mechanisms underlying meditation-specifically its neural components- that implicate it in the reduction of pain perception.
Bipolar disorder is an affective disorder characterized by periods of elevated and depressed mood. The cause and mechanism of bipolar disorder is not yet known, and the study of its biological origins is ongoing. Although no single gene causes the disorder, a number of genes are linked to increase risk of the disorder, and various gene environment interactions may play a role in predisposing individuals to developing bipolar disorder. Neuroimaging and postmortem studies have found abnormalities in a variety of brain regions, and most commonly implicated regions include the ventral prefrontal cortex and amygdala. Dysfunction in emotional circuits located in these regions have been hypothesized as a mechanism for bipolar disorder. A number of lines of evidence suggests abnormalities in neurotransmission, intracellular signalling, and cellular functioning as possibly playing a role in bipolar disorder.
Social cognitive neuroscience is the scientific study of the biological processes underpinning social cognition. Specifically, it uses the tools of neuroscience to study "the mental mechanisms that create, frame, regulate, and respond to our experience of the social world". Social cognitive neuroscience uses the epistemological foundations of cognitive neuroscience, and is closely related to social neuroscience. Social cognitive neuroscience employs human neuroimaging, typically using functional magnetic resonance imaging (fMRI). Human brain stimulation techniques such as transcranial magnetic stimulation and transcranial direct-current stimulation are also used. In nonhuman animals, direct electrophysiological recordings and electrical stimulation of single cells and neuronal populations are utilized for investigating lower-level social cognitive processes.
Affect labeling is an implicit emotional regulation strategy that can be simply described as "putting feelings into words". Specifically, it refers to the idea that explicitly labeling one's, typically negative, emotional state results in a reduction of the conscious experience, physiological response, and/or behavior resulting from that emotional state. For example, writing about a negative experience in one's journal may improve one's mood. Some other examples of affect labeling include discussing one's feelings with a therapist, complaining to friends about a negative experience, posting one's feelings on social media or acknowledging the scary aspects of a situation.