Let’s talk about brain structure

Today I would like to talk about quite simple things. It is about the structure of the brain. I will not go into complicated names and definitions. I will limit myself to a simple division into lobes and what they are responsible for. I believe that we need to know such basics because it is a simplification of life and simply interesting :)

The human brain is the main component of the central nervous system (CNS), which regulates and coordinates the functions of the body's internal organs while also responding to external stimuli.

Let’s start.

Triune brain

Some of you may have already heard that we have triune bran that consists of the following:

• reptilian complex (basal ganglia)

• paleomammalian complex (limbic system)

• neomammalian complex (neocortex)

This theory was developed by Paul D. MacLean in 1960 XX. Nowadays, this hypothesis has been rejected because of criticism in the neuroscience field. However, psychologists use this concept often because it helps them explain emotions in a very simple way to their clients.

The brain is generally categorized into three main sections: the forebrain, midbrain, and hindbrain. The forebrain is the largest and most advanced region, mainly consisting of the cerebrum and its underlying structures.

The cerebrum is divided into two hemispheres by a deep groove, and these hemispheres are connected by a thick bundle of nerve fibers known as the corpus callosum, located at the bottom of the groove. The cerebrum is outlayed by the cerebral cortex ( “grey matter”).

Then the brain is divided into 4 lobes and the cerebellum. Each lobe is paired. Now, let's move on to the division.

The Occipital lobe

The occipital lobe is responsible for:

1. Vision

2. Analysis of color, shape, depth, movement

3. Visual association

So you can remember it as almost everything related to vision ans visual functions.

Damage to the occipital lobe can lead to:

• "holes" in the visual fields

• difficulty locating objects seen

• visual hallucinations, imprecise vision of objects, seeing halos

• difficulty recognizing colors

• difficulty recognizing signs, symbols, written words

• difficulty recognizing drawings

• difficulty recognizing the movement of an object

• difficulty reading and writing

The Temporal lobe

The temporal lobe is responsible for:

• hearing

• speech understanding (Wernicke's area),

• grammar, prosody

• object recognition

• object categorization,

• verbal memory,

• sound analysis

• remembering

In a simple way remeber it as hearing and sounds or speech lobe.

Damage to the temporal lobe causes:

• hearing disorders, speech understanding, sound perception

• selective attention disorders to auditory and visual stimuli

• problems in recognizing seen objects; difficulties in recognizing faces (prosopagnosia)

• impairment in organizing and categorizing verbal information

• left hemisphere - difficulties in speech understanding (Wernicke's aphasia)

• damage to the right hemisphere can cause word-flow

• difficulties in describing seen objects

• memory disorders - amnesia

The Parietal lobe

The parietal lobe is responsible for:

• sensory impressions (touch, temperature, pain)

• spatial orientation

• purposeful movements

• integration of movement and vision

• integration of sensation and vision

• understanding symbolic language, abstract, geometric concepts

Remember it as sensation, perception and interpretation of sensory information.

Damage to the parietal lobe causes:

• complete undivided attention

• difficulties in spatial orientation

• difficulties in integrating visual impressions into a whole

• inability to perform purposeful action requiring movement (apraxia)

• right side - lack of awareness of some areas of space and body parts (unilateral neglect)

• difficulties in counting and mathematics

• inability to name an object

• inability to locate written words

• reading problems

• inability to distinguish directions, left-right

• difficulties in coordinating eye and hand movements

• anosognosia, denial of disability

• difficulties in drawing

• difficulties in constructing objects

• personality disorders (usually parietal-temporal lesions)

The Frontal lobe

The frontal lobe is responsible for:

• left side - Broca's area (responsible for generating speech)

• "realizing"

• planning

• initiating action in response to external events, assessing the situation

• predicting the consequences of actions

• decision-making

• social conformism, tact, sense of situation

• analysis and control of emotional states, linguistic expression

• control of emotions

• Executive functions (formulating a goal, planning to achieve a goal, implementing a plan)

So - planning, realising, decision making.

Damage to the frontal lobe causes:

• loss of the ability to move parts of the body, Brock's aphasia

• inability to plan the execution of a sequence of movements

• inability to act spontaneously, schematic thinking

• "looping", persistent returning to one thought

• difficulty in concentrating on a given task, problem

• emotional instability; mood changes, aggressive behavior

• left side - depression, right - contentment

• right side - difficulty in understanding jokes and funny drawings,

• preference for undemanding

Cerebellum

Cerebellum is responsible for:

• coordination of purposeful movements

• maintaining balance

• regulation of muscle tension

• the memory of some reflexes

Remember - coordinatiion of voluntary movements

Cerebellar damage causes:

• lack of coordination of movements, clumsiness; lack of precision of movements

• problems with maintaining a normal body posture; balance disorders

• difficulty in assessing the range and moment of stopping movement; difficulty in catching objects

• inability to perform rapid alternating movements, body tremors

• stumbling, the tendency to fall, and "walk on wide legs"

• poor muscle tone (hypotonia)

• slurred speech

• rapid eye movements

Of course, let's not forget about the cerebral cortex. It is about 2-4 mm thick and is the outermost part of the brain. Its surface is about 2000 square cm and is made up of 16-20 billion nerve cells. It covers both hemispheres and consists of layers. In humans, the surface of the cortex is strongly folded.

Evolutionarily, the cerebral cortex is divided into:

• new cerebral cortex (neocortex or isocortex)

• old cerebral cortex (archi- or paleocortex)

The neocortex is involved in receiving and processing sensory impressions, planning, and executing voluntary movements and cognitive processes (memory, thinking, and language functions). It constitutes approximately 95% of the entire cortex. Paleocortex forms the structures of the limbic system, which is involved in processes related to emotions, motivation, and the formation of some types of memory. Within the cortex are cortical maps - central representations of the body surface. (Feeling a body part stimulates a specific region of the cortex).

In conclusion, our brains are incredibly complex yet elegant in their structure and function. Understanding the basic divisions, from the lobes and cortex to the larger structures like the cerebellum, provides insight into how we think, perceive, move, and even feel emotions. This knowledge, though simplified, highlights the intricate balance of brain functions that allow us to interact with the world and with ourselves.

Despite the fascinating variety of roles each part plays, it’s the harmonious cooperation between them that creates our unique human experience. The next time you solve a puzzle, recognize a familiar face, or recall a memory, remember that it’s all thanks to this remarkable organ, constantly at work, seamlessly coordinating our thoughts and actions. This knowledge doesn’t just explain brain function; it deepens our appreciation for how truly incredible—and essential—our brains are.

xxx, M.