Satchit Ghimire- The human brain is one of the most complex organs in the body. Weighing about 1.4kg it controls almost every vital life support system.
The human brain has three major structures:
- Forebrain
- Midbrain
- Hindbrain
Forebrain
The forebrain is the most anterior and most prominent part of the human brain. It represents 90 percent of the brain.
Parts of the forebrain
1. Thalamus
The thalamus is an egg-shaped structure that lies between the two cerebral hemispheres on the top of the brain stem.
It also acts as a relay station as most sensory information except smell goes first to the thalamus, which processes it and sends output
to the cerebral cortex. The thalamus is also thought to be involved in regulating levels of awareness, attention, and sleep.
2. Hypothalamus
Hypothalamus lies below the thalamus. The word hypothalamus is derived from the Greek meaning under the thalamus. The hypothalamus is responsible for regulating blood temperature, the concentration of salt in the blood, hormones, etc. Hypothalamus also plays a crucial role in maintaining the body’s internal balance called homeostasis.
3. Cerebrum
The cerebrum is the largest and the uppermost part of the central nervous system. The human cerebrum weighs about 1.4 kilograms. The cerebrum is divided into two cerebral hemispheres by a deep cleft called longitudinal fissure. A bundle of fibers, known as the corpus callosum, connects areas of one hemisphere with another hemisphere. Below the cerebrum lies a cluster of grey matter known as the basal ganglia. The cerebrum is divided into four areas; frontal lobe, temporal lobe, parietal lobe, and occipital lobe.
The frontal lobe, the largest lobe in the cerebral cortex is involved with reasoning, language, higher-level cognition, and executing voluntary movements. The temporal lobe located on the bottom of the brain is associated with receiving auditory information. The parietal lobe is involved in processing bodily information such as touch, temperature, pressure, and pain. Similarly, the occipital lobe located at the very back of the brain contains the primary auditory cortex which receives auditory information.
Limbic System
The group of interconnected nuclei forming the lower portion of the forebrain called the limbic system. The parts of the limbic system –
the amygdala and the hippocampus play a vital role in the regulation of emotions and the formation of memories respectively.
The amygdala is an almond-shaped structure at the base of the temporal lobe. The amygdala is involved in processing a variety of emotional responses including fear, anger, and disgust.
The word hippocampus comes from a Latin word meaning “sea horse.” As suggested by the name, the hippocampus does look a bit like the curved tail of a sea horse. The hippocampus plays an important in the formation of new memories of events and information. memories. Damage in the hippocampus may result in trouble with storing new memories but does not lose the memories people had before the damage occurred.
2. Midbrain
As the name implies, the midbrain is located between the forebrain and hindbrain. Midbrain is the smallest of the brain and works as a relay station for auditory and visual information.
3. Hindbrain
The hindbrain is the posterior part of the brain that connects the spinal cord with the rest of the brain. Sensory and motor pathways pass through the hindbrain to and from other regions of the brain. The hindbrain is made up of three structures- the medulla, the pons, and the cerebellum.
The medulla (also called medulla oblongata) is located just above the spinal cord. Damage to the medulla is fatal as it carries out the critical life functions. The medulla controls several critical body functions like breathing, heartbeat, and blood circulation.
Above the medulla lies a swelling of tissue called the pons that represents the uppermost level of the hindbrain. The literal meaning of the term pons in Latin is ‘bridge’; the name reflects the fact that the pons is a bridge of some sort. The pons acts as a transmitter of motor information, coordinating muscles, and integrating movement between the right and left halves of the body. (Feldman)
Located just above the medulla and behind the pons, the cerebellum plays an important role in the control of balance, and coordinated muscle movements. It is also involved in the coordination of sensory information and problem-solving. The people with cerebellar damage are clumsy and lose their balance and have trouble shifting their attention back and forth between auditory and visual stimuli.
- References:
- Discovering Psychology by Hockenbury and Hockenbury
- Biological Psychology by James W Kalat
- Introduction to Psychology by Charles Stangor And Jennifer Walinga
- Foundations of Psychology by Robert A. Baron and Michael J. Kalsher
- Understanding Psychology by Robert S. Feldman
- Introduction to Psychology by James Kalat
Featured Image Courtesy: Jesse Orrico on Unsplash
