Human Brain, Neurons and Behaviour

 Several years of research have made important advancements in explaining the functioning of human brain and explaining how biological processes can influence human thoughts, feelings and behaviour. For understanding biopsychology, it is important to understand the three most important physiological components of human anatomy, i.e. Brain, the neurotransmitters and the Nervous system.

The Nervous System and the Brain

The Central Nervous System

The central nervous system has two important parts: The Brain and the Spinal Cord. Communication in the Central Nervous system takes place with the help of Neurons. The brain and the spinal cord are indispensable and very important for the survival of human life; therefore, they are surrounded and protected by various protective barriers such as the bone (spine and skull) and meninges or the membrane tissues. In addition, both brain and spinal cord are protected by cerebrospinal fluid. The Central Nervous System is responsible for every thought which we experience or all kinds of sensations.

Cerebral cortex is the outermost portion of the brain, which is responsible for cognition, emotions, sensation, motor movements, etc. This part of the brain is responsible for making humans unique with distinctive human traits and capabilities. The brain comprises of four lobes:

1. Frontal Lobe: This is located in the frontal portion of the brain and is responsible for reasoning, higher level cognitive capabilities, language expression and motor skills. Frontal lobe receives information from the rest other lobes of the brain and makes use of this information for body movements. Damage to this lobe may result in the changes in the various habits, affect attention and socializing abilities.
2. The Occipital Lobe: This lobe interprets the visual stimuli and is located at the backside portion of the brain. Damage to Occipital lobe will mean colour blindness, various visual impairments and troubles in recognizing objects and words.
3. Parietal Lobe: This lobe is situated in the centre of the brain and is responsible for processing tactile sensory information like touch, pain and pressure. Somatosensory cortex is located in the parietal lobe, responsible for processing the sensory information.
4. Temporal Lobe: Temporal lobe is located in the bottom side of the brain and the primary auditory cortex is located in the temporal lobe. Primary auditory cortex helps in interpreting languages and sounds which we hear. Temporal lobe is equally responsible for memory formation because of the presence of Hippocampus. Damage to the temporal lobe will lead to memory problems, speech and language issues.

The Peripheral Nervous System

The peripheral nervous system comprises of the nerves or the network of nerves which are actually bundled as axons, situated outside the central nervous system. It is subdivided into two parts:

1. The efferent (motor) division: The efferent (motor) division is responsible for connecting the central nervous system with the glands and muscles.
2. The afferent (sensory) division: The afferent (sensory) division is responsible for transmitting all kinds of sensory information to the central nervous system.

Autonomic Nervous System

The automatic functioning processes or the involuntary body functions such as breathing, heart rate and blood pressures are regulated by the autonomic nervous system. Autonomic nervous system is also related with emotional responses such as sweating or crying.

Autonomic nervous system has two parts:

1. Sympathetic Nervous System: This part prepares the body for reflex actions to respond to the danger or any environmental threat, exhibited as flight or fight responses. This system prepares the body to respond to respond to emergencies and when this system is active body exhibits various indications. The heart beat increases, breathing rate increases, pupils dilate, digestion either slows down or stops and excessive sweating happens.
2. The Parasympathetic Nervous System: This nervous system brings the body to a state of rest after a danger or threat ceases to exist or has passed and regulates digestion processes.

Neurons and Neurotransmitters-the role played by them in the Nervous System

A neuron is considered to be basic building block in the nervous system of a human anatomy. These are specialized or complex nerve cells responsible for transmitting information to the body in the form of electrical and chemical signals. A human body has many types of neurons each responsible for performing different function. These are sensory neurons, motor neurons and interneurons

Structure of a Neuron: Neurons just like other cells of the body has nucleus which holds information about genes. Neurons are protected by a membrane which surrounds the cell and these cell bodies contain organelles which supports life.

Neurons can be divided into 3 parts:

1. The axon
2. The dendrites
3. The cell body

The axons and dendrites are responsible for the transmission and receipt of information from other cells and from one neuron to another. The dendrites receive information from the neurons or sensory receptors and pass it to the cell body and to the axons. Information received in the axon is then further transmitted down to the entire length of the axon as an electrical signal which is known as action potential.

Once the information reaches the entire length of the axon, the information is then transmitted through the synapses to the dendrites of another neuron. Neurotransmitters are the chemical messengers which are released at the axon terminal cross the synapses and meet the receptor sites of the other neurons. Neurotransmitters carry electrical messages between various parts of the body to the brain and vice versa. Neurotransmitters can be of various types which affect the functioning of the body in different ways.

A psychologist may investigate or study various neurotransmitters for understanding their effects on human behaviour. Example, dopamine which is one kind of neurotransmitter is associated with learning and movement. An excess of neurotransmitter dopamine can lead to mental conditions like schizophrenia, or its deficit can be responsible for Parkinson's disease. Similarly, another kind of neurotransmitter is Acetylcholine, which is related to memory and learning. Lack of Acetylcholine can be associated with Alzheimer's disease. Endorphin is another kind of neurotransmitter which is associated with emotional feelings and the perception of pain.