Biological

Emotional states are accompanied by complex, interacting physical responses that is unknown to us all.

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The Autonomic Nervous System

The autonomic nervous system (ANS) participates in the general arousal associated with emotional states and has two components, the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).

When activated, the SNS prepares the body for emergency actions; it controls glands of the neuroendocrine system (thyroid, pituitary, and adrenal glands). Activation of the SNS causes the production of epinephrine (adrenaline) from the adrenal glands, increased blood flow to the muscles, increased heart rate, and other readiness reactions.
Conversely, the PNS functions when the body is relaxed or at rest and helps the body store energy for future use. PNS effects include increased stomach activity and decreased blood flow to the muscles.

Autonomic responses associated with negative emotions are stronger than those associated with positive emotions.

In the forebrain, there is the limbic system (fig. 1) and it includes the amygdala, the hippocampus, the cingulate gyrus, structures that are parts of the hypothalamus and more.


http://www.tsbvi.edu/seehear/summer05/image004.gif
Fig. 1

The word limbic means “border” and describes this system because its structures seem to form a rough border along the inner edge of the cerebrum.
Studies have associated the limbic system with such emotions as fear and aggression as well with as drives, including those for food and sex.

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Amygdala

As mentioned before, the amygdala is responsible for emotions and it participates in the active exploration of social environment and the interpretation of the results of that exploration.
Damage to the amygdala interrupts previously learned fear responses and prevents further learning about new sources of danger. Also, bilateral damage to the amygdala produces reduced emotionality.

In an experiment, researchers removed both temporal lobes in rhesus monkeys. Following recovery, the monkeys were:

• Tamer, having less intense emotions
• Oblivious to normal fear-producing stimuli
• Overly reactive to visual stimuli but cannot recognize familiar objects

This set of symptoms, whether observed in humans or monkeys, collectively became known as Klüver-Bucy syndrome.

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The Cingulate Cortex

Anterior cingulate cortex is the target of a number of pathways communicating information about physical pain.
It also participates in the processing of social pain, negative feelings associated with being socially excluded by others.

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The Cerebral Cortex

Frontal lobe damage is associated with a reduction in emotional feelings especially fear and anxiety.
An individual will became calmer if the frontal lobes are removed.
Left hemisphere is correlated with positive emotions while the right hemisphere is correlated with negative emotions.
Patients who suffer from damage to the left hemisphere are often depressed.
Patients who suffer from damage to the right hemisphere are often cheerful. The left side of the face is more expressive than the right side.

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Did you know?
We do not have “happy centers” and “sadness centers” in the brain. Widespread areas of the brain appear to be associated with each specific emotion, and areas associated with different emotions show considerable overlapping.