What Is the Relationship Between Neurotransmitters and Mood?

The physiological mechanism of emotion refers to the physiological process of emotional experience and emotional physical response. Early attempts to elucidate the physiological mechanisms of emotion were American psychologist W. James and Danish physiologist CG Langer.

Physiological mechanism of emotion

The physiological mechanism of emotion is the physiological process of emotional experience and emotional physical response.

Early attempts to elucidate the physiological mechanisms of emotion were American psychologist W. James and Danish physiologist CG Langer. They independently proposed similar theories in 1890 and 1885, collectively known as the James-Langer theory, and they believed that visceral responses provided signals of emotional experience. They said: because we cry, we are worried; because we are hitting, we are angry; because we are trembling, we are afraid; we do not cry when we are sad; when we are angry, we are trembling. Their conclusion: Emotion is just a feeling of a physical state, and its cause is purely physical.

American physiologist WB Cannon opposed James-Langue's theory on the grounds that: the complete separation of the internal organs from the central system does not harm emotional behavior; the same internal organ changes can occur in very different emotional and non-emotional states; The internal organs are relatively insensitive structures, and it is difficult to distinguish different emotions based on their feedback; Internal organ changes are too slow as a signal source of emotional experience; artificially cause some internal organ changes, and do not cause typical Emotions.

In 1927, Cannon put forward the theory of emotional thalamus. According to the fact that after the thalamus is damaged or the activity of the thalamus loses control of the cerebral cortex, the emotion becomes easily agitated or pathological changes occur. The most important role. He believes that nerve impulses enter the thalamus, and acquire certain "emotional characteristics" in the thalamus. Then, neural impulses with emotional characteristics enter the cerebral cortex on the one hand to cause emotional experience, and on the other hand, stimulate the autonomic nervous system and cause corresponding emotional responses. This was later expanded by P. Bard, known as Cannon-Bard theory. But Cannon has also been criticized because other parts of the nervous system can cause symptoms similar to those in the thalamus (such as forced laughter and crying). In addition, many patients with thalamic injury only have emotional manifestations, but no subjective emotional experience. For example, a patient may cry but not feel sad. Some scholars have pointed out that after all the thalamus is removed from the cerebral cortex animals, the anger response still exists. Only when the hypothalamus is also removed, the emotional response disappears. If the emotional response is due to the release of thalamus from the cerebral cortex, a continuous, long-lasting anger response should be generated after the inhibition of the cortex has been ruled out. But the actual anger reaction is temporary rather than continuous. And anger can also occur when the hypothalamus, cerebral cortex and even the cerebellum are stimulated.

American psychologist DB Linsley proposed the activation theory of emotional mechanism in 1951. Because many neural pathways to the cerebral cortex send out collateral fibers into the reticular structure, collateral impulses in the reticular structure can cause diffuse reticular excitement, which in turn activates the entire cerebral cortex through the thalamus. So Linsley thinks the upside

It mainly includes the directional nervous system, hypothalamus and limbic system.

Autonomic nervous system

Sympathetic and parasitic

Including pituitary gland, adrenal gland and thyroid.

Pituitary

Divided into anterior pituitary and posterior pituitary. The anterior pituitary secretes six hormones, including adrenocorticotropin (ACTH), hormones, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, and lactogen. Two hormones are secreted from the back of the pituitary: vasopressin (also known as antidiuretic hormone) and oxytocin.
There are embryological, neurological, vascular, and functional connections between the hypothalamus and the pituitary, so it is called the hypothalamic-pituitary system. Some special neurons in the hypothalamus secrete various release and inhibitory hormones and directly enter the portal blood It is transported to the front of the pituitary gland to stimulate or inhibit the synthesis and release of hormones in the front of the pituitary gland. Stimulations that cause emotional stress can cause corticotropin secretion. Under the influence of stressful mental burden, women's menstrual cycle may be disturbed. This is because it affects the pituitary's gonadotropic function, which changes the activity of the gonads. In different emotional states, changes in hypothalamic activity can also affect the secretion of antidiuretic hormones, resulting in too much or too little urination.

Adrenal gland

Consists of adrenal cortex and adrenal medulla. The adrenal cortex secretes adrenal corticosteroids. There are 3 types of corticosteroids: glucocorticoids, mineralocorticoids and androgens. Glucocorticoid synthesis and secretion are directly controlled by ACTH secreted by the anterior pituitary. All harmful stimuli in the internal and external environment and panic, anxiety, tension, anger, etc. can cause a large amount of adrenocortical hormones, especially glucocorticoids, through the hypothalamus and anterior pituitary gland, which is extremely important for the body to adapt to these harmful stimuli Role.

The adrenal medulla secretes epinephrine and norepinephrine. The activity of the adrenal medulla is governed by sympathetic nerves. Norepinephrine is also a transmitting substance of the sympathetic nervous system, and it plays a direct role in activating the neurons of the sympathetic nervous system. Increased emotional activity can cause increased adrenal medulla secretion. Some early studies have suggested that adrenaline is associated with fear and anxiety, while norepinephrine is associated with anger and aggressive emotions. Experiments have shown that both adrenaline and norepinephrine secretion increase when emotional activity increases. The amount of secretion has little to do with emotional properties, but is related to emotional intensity.

thyroid

Thyroxine secretion is controlled by the thyroid-stimulating hormone secreted by the pituitary. Emotional excitement can increase thyrotropin secretion, so thyroid hormone secretion also increases. Thyroxine tends to increase the rate of metabolism of all cells in the body, increase blood pressure, and increase heart rate. Excessive levels of this hormone usually make people irritable and nervous.

Emotional neurochemicals and emotionally related neurotransmitters are catecholamines. Studies have shown that emotional stress or stress conditions lead to increased synthesis and application of norepinephrine in the brain. The electrical stimulation of cats' amygdala causes norepinephrine levels in the brain when anger is caused. Drugs that increase or inhibit norepinephrine also increase or suppress anger. Drugs that change people's mood also affect the secretion of norepinephrine. For example, patients who take reserpine for a long time to treat hypertension can develop depression, while reserpine is a depletion of monoamine neurotransmitters in the brain. Depressants Increase the content of norepinephrine in the brain. Endorphins may also be related to emotions, and there are reports that endorphins can make normal domesticated rats violent and angry.

Changes in the autonomic nervous system and endocrine activities that occur in the body during emotional states provide an objective measure of mood. Such as skin electrical response, skin electrical conductivity changes due to changes in skin vasoconstriction and sweat gland secretion in an emotional state. Skin electrical response is a sensitive indicator of the level of sympathetic nervous system activity, and is called psychological electrical reflex. Changes in breathing frequency and amplitude, blood pressure, heart rate, blood vessel volume, skin electricity, and changes in epinephrine and norepinephrine content can be used as physiological indicators for measuring mood. ^[1]