The brain is a very important and special organ with nervous tissues that help us feel, move, and think; this is why the brain is strongly protected by the skull, fluid, and other muscles. The nervous tissue is very delicate and can be damaged very easily, which is why it must be protected at all times, and it has to be made sure that blood does not reach there.
The central nervous system basically has two parts: the central and the peripheral; the CNS includes the brain and spinal cord, while the peripheral has everything else.
The spinal cord, located in the spine, is an important part of the CNS, and it carries sensory signals from the brain to the rest of the body and relays information. The spinal cord in the spinal column is safeguarded by bones, meninges, and cerebrospinal fluids.
1. Brain and Stimuli – Cerebral Cortex and Sensory information
The cortex is divided into four parts, or lobes: frontal, parietal, occipital, and temporal. Each lobe has specific jobs.
- Frontal Lobe: It is located in the front of the brain and helps with things like moving our muscles, solving problems, paying attention, and using language. It has areas like the motor cortex (for moving muscles) and the Broca area (for language).
- Parietal Lobe: It is found towards the back; it deals with processing information. The somatosensory cortex in the parietal lobe helps us understand what we’re touching based on what we’ve felt earlier.
- Occipital Lobe: This lobe is all about vision. It works in a manner that takes information from the eyes and uses past experiences to understand what we see.
- Temporal Lobe: It is located on the sides. It deals with hearing and processes sound. It also has the Wernicke area, which helps in understanding speech.
So, each lobe has a special job in helping us move, think, see, and hear.
2. What is the Thalamus?
The thalamus is a roundish part in the middle of the human brain. It works like a relay station for all the messages about your body’s movement and senses—like hearing, taste, sight, and touch (but not smell).
Before these messages go to the outer layer of your brain (called the cerebral cortex) for further processing, like more thinking and understanding, they must pass through the thalamus, like a train passing through a station.
For the same purpose, it also has sensory receptors and motor neurons.
3. Functions of the Thalamus
Let us look at what the thalamus does:
- Relaying sensory information: It takes in nerve signals from all your sensory organs (except smell) and sends them to specific areas in your brain for processing, like auditory stimuli.
- Relaying motor functions (movement) information: Like sensory info, the thalamus is a hub for movement-related motor pathways.
- Prioritizing attention: It helps you decide what to focus on from the many things your senses pick up.
- Role in consciousness: The thalamus plays a part in keeping you awake and alert.
- Role in thinking (cognition) and memory: It’s connected to parts of your brain that handle emotions, memories, learning, and more.
In addition, the thalamus contributes to how you perceive things and has a role in your sleep and wakefulness.
4. How Does Your Thalamus Work?
Your thalamus works like a traffic cop for information. Messages, called sensory impulses, travel from your body through nerve fibers to your thalamus.
The thalamus has special areas called nuclei, each handling a specific type of information—like touch or sight.
These nuclei process the messages and send them through more nerve fibers to the right part of your brain’s outer layer (cerebral cortex) for understanding.
5. Where is the Thalamus Located?
The thalamus is found in the middle of your brain, right above the brain stem; even though it may seem like one big part, you have two thalamines on each side of your brain.
Picture it as the central hub of a bike wheel, and nerve fibers (like spokes on the wheel) connect to all parts of your brain’s outer layer (cerebral cortex). The diencephalon consists of the hypothalamus, subthalamus, and epithalamus, and this is the part of the brain that consists of the thalamus.
6. What Happens if the Thalamus is Damaged?
Your thalamus is like a central hub for information in your brain, helping with senses and movement. If it gets damaged, it can affect many things. Here are some signs of thalamus damage:
- Forgetting things (amnesia).
- Not feeling interested or excited about things (apathy).
- Trouble understanding or speaking (aphasia).
- Difficulty paying attention or staying alert.
- Problems with processing what you sense.
- Trouble moving.
- Feeling very sleepy.
- Chronic pain.
Severe thalamus damage can lead to:
- Unconsciousness or coma.
- Sleep issues like insomnia or a rare condition called fatal familial insomnia (which can be deadly).
- Speech problems with mixed-up or meaningless words (thalamic aphasia).
- Shaky movements (tremors).
- Persistent pain.
- Vision issues like loss of vision or sensitivity to light.
- Tingling or burning pain (thalamic pain syndrome).
The main reasons for thalamus damage are strokes and tumors in the thalamus.
7. What Conditions Affect the Thalamus?
Some conditions that can harm or affect your thalamus include:
- Fatal familial insomnia is an inherited disease related to a specific protein (prion) that affects a particular chromosome. People with this condition experience severe insomnia, panic attacks, paranoia, phobias, hallucinations, and an inability to sleep. As it progresses, there can be rapid weight loss, dementia, and loss of the ability to speak until death.
- Creutzfeldt-Jacob disease and Fabry disease: These illnesses share a feature called the pulvinar sign, which helps diagnose them. An MRI scan shows a change in density at the back (posterior) of the thalamus that looks like hockey sticks.
- Korsakoff syndrome: This syndrome, caused by alcohol, can damage a part of your brain called the mammillothalamic fasciculus, which extends into the thalamus.