EMOTION DETECTION AND REACTION OF BRAIN

 HOW THE HUMAN BRAIN IDENTIFIES THE EMOTIONS AND REACTS TO THE PARTICULAR EMOTION 

Introduction

The brain is a complex part of the body; it controls feelings and gives signals to the various parts of the body to perform actions. As it senses any changes in its surroundings, it reacts very quickly and gives a prompt response to the related organ with the help of motor nerves. 

But there is a question: how does it feel the emotion, or how does it generate the emotions for a particular stimulus? 

So, it is a fascinating question in science about human feelings. Scientists have discovered that the responses of the human brain can reveal to us the action and generation of the emotions related to particular instances.

Hypothalamus

The hypothalamus is an almond-shaped area located deep at the base of the brain. It is located just below the thalamus and just above the pituitary gland. It controls the hormone production and regulates the body temperature and emotions. It is involved with the endocrine gland for controlling the regulation of hormones. It has many nuclei that help it to control various actions and emotions. It includes anterior, medial, and posterior parts. 

Different Parts of the Brain 

The brain is divided into three parts: i) cerebrum, ii) cerebellum, and iii) brainstem. Each part of the brain performs a different function. The cerebrum is the largest part of the human brain and is subdivided into two hemispherical parts. And further, it has four lobes: a) the frontal lobe, b) the parietal lobe, c) the temporal lobe, and d) the occipital lobe. 

i) Cerebrum

a) Frontal lobe

It is the front area of the brain where thinking, judgment, detection of personality, self-control, and emotions are managed. Creativity, logical reasoning, judgment, and processing of the complexities involved in the messages to the nearby parts are the main functions of the frontal lobe. It decides how to perform and manage the social activities. Self-control, denial of any activity, work memory, and movement of hands and legs (voluntary action) are examples of its function. If a person wants to catch the ball, touch the girlfriend, write a letter, or do pending work, running is an example that is governed by the frontal lobe. [1] 

b) The parietal lobe

The parietal lobe is subdivided into two parts: a) the superior parietal gyrus and b) the inferior parietal gyrus. The parietal lobe collects the senses and integrates them. So, a person gets mixed signals about what he sees in this world. Example: Cut an apple and an onion and observe their smell and color. Can we identify which one is an apple and which one is an onion? [2]

c)The temporal lobe 

It is an area on the left and the right side of the brain near the temples and ears. Its main function is to manage emotions, process the senses, and store and retrieve memories. This part helps to understand the language and meaning of a sentence if we have prior experience with the language and the words . The "amygdala" inside this part helps to understand the type of emotion. 

Example: When someone denies doing our work, we feel bad. Why does this negative sense come into the brain? If anyone gets a positive response from their girlfriend, then why does he become joyful? [3]

d) Occipital lobe

When the eyes see the picture, it encodes the visual senses. The retina in the eye takes this properly encoded signal via the optic nerves to the brain. The thalamus relays this code to the occipital lobe. Here, these signals are decoded, and we get a clear image of the object. [4]

ii) Cerebellum 

Its function is to perform social and emotional learning. This cerebellar function is supported by three systems and related neural networks: a limbic network that supports basic emotional (dis)pleasure and arousal processes; a mentalizing system that helps one understand one's mental and emotional state and is supported by a mentalizing network; and a biological action observation system that is a part of an extended sensorimotor integration network. [5]. It is an important part of the brain that regulates motor function. It has two hemispherical parts: i) Grey matter & ii) White matter

i) Grey matter

It is situated on the cerebellum's outside. The cerebellar cortex is formed by its tightly folded structure. This is involved in higher-order cognitive processes, including learning and decision-making, as well as the processing of sensory data, perception, voluntary movement, memory, and emotions.

ii) White matter

It is situated underneath the cortex of the cerebellum. The four cerebellar nuclei—the dentate, emboliform, globose, and fastigi nuclei—are embedded in the white matter [6]. It acts as a network for communication inside the brain and between the brain and the body [6]. 

iii) Brainstem

Neural networks that regulate arousal, autonomic function, motor control, and somatosensation work together to produce emotions. Though previous research on the neuroanatomic basis of emotion, especially in the human neuropsychological literature, has primarily concentrated on the contributions of cortical rather than subcortical structures, brainstem nodes play crucial roles in each of these networks [7]

Hippocampus

The hippocampus helps to manage memory and helps to identify the spatial arrangement of the surroundings. It helps to remember the past history of life that manages to balance the emotions. it helps to find the meaningful insights of an emotion from the past of the life. It remembers the episodic memory of the body that can reconnect to the past.

Important functions and chemicals 

Amygdala

It specifically plays a crucial role in identifying anger and fear. For instance,  it can remember the past instance that occurred with your lovely pet and make you fear that animal. 

Limbic cortex

This region includes the parahippocampal gyrus and the cingulate gyrus. They affect motivation, emotion, and judgment collectively.

Controlling Fear

As an emotional warning system, the amygdala reacts quickly to inputs that are interpreted as dangers or violent triggers. This reaction combines quick, unconscious processing with a more deliberate, delayed assessment of the circumstances. 

The fear and flight response is regulated by the hormones called adrenaline (epinephrine) and noradrenaline (norepinephrine). 

The adrenal gland releases the hormone that prepares the human to fear or fight the situation. 

Love Feeling 

 According to Dr. Helen Fisher, love may be separated into three main brain systems: attachment, romance, and sex. With various components, hormones, and neurotransmitters involved at various points in the interaction.

Sex feeling 

Lust originates from the hypothalamus, a brain area that regulates basic wants like hunger and thirst. It is linked to the autonomic nervous system, which controls heart rate and respiration. Hormone receptors, like testosterone, initiate physical reactions, leading to a strong desire for reproduction.

Dopamine:

Brain's nerve cells normally release dopamine, a chemical messenger that interacts with cells in various regions to cause a variety of effects.
Dopamine plays a part in addiction because it serves the purpose of producing a positive sensation after engaging in a pleasant activity, which encourages a person to repeat it. The brain requires dopamine to regulate an individual's movements as well; Parkinson's disease is brought on by low dopamine levels in certain brain regions.
Mental disorders like schizophrenia and depression also result in a dopamine imbalance.
To help manage the symptoms of either too much or too little dopamine, you could require medication [8].

Oxytocin and Vasopressin

It has been demonstrated that the pituitary neuropeptides oxytocin and vasopressin influence social activities in animals. These chemicals and their receptors are gaining attention as possible causes of social abnormalities in neurodevelopmental diseases, such as autism spectrum disorder, and as potential therapies for these illnesses. These peptides are linked to individual social capacities, according to a number of behavioral-genetic studies; nonetheless, an explanatory model that connects complex human behavior to hormonal activity at the receptor level is still elusive [9]. 

References

[1] https://my.clevelandclinic.org/health/body/24501-frontal-lobe.

[2] Parietal lobe, http://sciencedirect.com/topics/engineering/parietal-lobe.

[3] The temporal brain, https://my.clevelandclinic.org/health/body/16799-temporal-lobe.

[4] The occipital lobe, https://my.clevelandclinic.org/health/body/24498-occipital-lobe.

[5] Van Overwalle, F. Social and emotional learning in the cerebellum. Nat. Rev. Neurosci. 25, 776–791 (2024). https://doi.org/10.1038/s41583-024-00871-5.

[6] https://teachmeanatomy.info/neuroanatomy/structures/cerebellum/.

[7] Venkatraman A, Edlow BL, Immordino-Yang MH. The Brainstem in Emotion: A Review. Front Neuroanat. 2017 Mar 9; 11:15. doi: 10.3389/fnana.. 2017.00015.

[8] https://www.healthdirect.gov.au/dopamine.

[9] Baribeau DA, Anagnostou E. Oxytocin and vasopressin: linking pituitary neuropeptides and their receptors to social neurocircuits. Front Neurosci. 2015 Sep 24; 9:335. doi: 10.3389/fnins.2015.00335.