The Bases of Human Behaviour — Psychology STD 11 Humanities — Question

Brain is one very important part of the central nervous system, the other being Spinal cord Brain is usually divided into following parts, and each part is further sub-divided as shown below:Hindbrain consists the following structures:

1. Medulla oblongata:

• It is the lowest part of the brain that exists in continuation of the Spinal cord.
• It contains neural centres, which regulate basic life-supporting activities like breathing, heart-rate, and blood pressure.
• Medulla is known as the vital centre of the brain.

2. Pons:

• It is connected with medulla on one side and with the midbrain on the other.
• Pons receives auditory signals relayed by our ears. It is involved in sleep mechanism.
• It contains nuclei controlling facial expressions also.

3. Cerebellum:

• It maintains and controls postures and equilibrium of the body.
• Its main function is coordination of muscular movements.
• It also stores the memory of movement patterns so that we do not have to concentrate on how to work, dance, or ride a bicycle.

Midbrain:

• The midbrain is relatively small in size.
• It connects the hindbrain with the forebrain. An important part of midbrain, known as Reticular Activating System (RAS), is responsible for our arousal.
• It makes us alert and active by regulating sensory inputs.
• It also helps us in selecting information from the environment.

Forebrain: It is considered to be the most important part of the brain because it performs all cognitive, emotional, and motor activities.
Four major parts of the forebrain:

1. Hypothalamus:

• The hypothalamus is one of the smallest structures in the brain, but plays a vital role in our behaviour.
• It regulates physiological processes involved in emotional and motivational behaviour, such as eating, drinking, sleeping, temperature regulation, and sexual arousal.
• It also regulates and controls, heart-rate, blood-pressure, temperature, and lates the secretion of hormones from various endocrine glands.

2. Thalamus:

• It is like a relay station that receives all incoming sensory signal from sense organs and sends them to appropriate parts of the cortex for processing.
• It also receives all outgoing motor signals coming from the cortex and sends them to appropriate parts of the body.

3. Limbic system:

• This system is composed of a group of structures that form part of the old mammalian brain.
• It helps in maintaining internal homeostasis by regulating body temperature, blood-pressure, and blood sugar level.

The limbic system comprises:

1. Hippocampus which plays an important role in long-term memory.
2. The amygdala plays an important role in emotional behaviour.

4. The Cerebrum (Cerebral Cortex):

• It regulates or higher levels of cognitive functions, such as attention, perception, learning etc.
• The cerebrum makes two-third of the total mass of the human brain.
• Its thickness varies from 1.5mm to 4mm, which covers the entire neural nets, and bundles of axons.
• All these make it possible for us to perform organized actions and create images, symbols, associations, and memories.
• The cerebrum is divided into two symmetrical halves,
• Two hemispheres appear identical, functionally one hemisphere usually dominates the other. e.g. the left hemisphere usually controls language behaviour. The right hemisphere is usually specialized to deal with images, spatial relationships, and pattern recognition.
• These two hemispheres are connected by a white bundle of myelinated fibers, called Corpus Callosum that carries messages back and forth between the hemispheres.
• Cerebral cortex has also been divided into four lobes.

Four lobes of the cerebral cortex are functions of these four lobes are following:

1. Frontal lobe:

1. Frontal lobe is mainly concerned with cognitive functions, such as attention, thinking, memory, learning, and reasoning.
2. It also exerts inhibitory effects on autonomic and emotional responses.

2. Parietal lobe: The Parietal lobe is mainly concerned with cutaneous sensations and their coordination with visual and auditory sensations.
3. Temporal lobe:

1. Temporal lobe is primarily concerned with the processing of auditory information.
2. Memory for symbolic sounds and words resides here.
3. Understanding of speech and written languages depends on this lobe.

4. Occipital lobe:

1. Occipital lobe is mainly concerned with visual information.
2. It is believed that interpretation of visual impulses, memory for visual stimuli and colour visual orientation is performed by this lobe.