Dyslexia and the Visual Thalamus

What is Dyslexia

• Dyslexia is a language-based learning disability. It is characterised by difficulties in recognizing words accurately and fluently, misspellings and a reduction in decoding abilities. Students suffering from it usually experience difficulties in other language skills such as spelling, writing and pronunciation of words.
• However, it is not an intelligence-related problem and students suffering from it can learn successfully through appropriate teaching methods.
• Dyslexia affects about 5%-10% of people worldwide. Famous people suffering from it include Albert Einstein, Ludwig van Beethoven, Charles Darwin, Ernest Hemingway, Agatha Christie and Whoopi Goldberg.

Symptoms of dyslexia

• Symptoms of dyslexia can appear in early childhood and boys are two to three times more likely to be affected than girls.
• People suffering from it may have problems with language and may have difficulty expressing themselves clearly or fully understanding what others mean.

Causes of Dyslexia

• Dyslexia is caused by changes in the function and structure of a specific part of the human brain called the visual thalamus.
• Also, children born to parents who are dyslexic are more likely to be born with dyslexia.

What is the visual thalamus

• The ‘visual thalamus’ refers to a specific part of the thalamus in the brain. It connects the eyes to the cerebral cortex and is important for the ability to reason, feel, think, memory, language and consciousness.
• The lateral geniculate nucleus (LGN) within the thalamus is the primary relay center for visual information. It receives signals from the retina and processes them before sending the information to the primary visual cortex in the occipital lobe of the brain.
• This pathway is important for visual perception, which involves processing visual stimuli and integrating them into a coherent visual experience.
• The scientists studied the visual thalamus with the help of a special MRI system. People with dyslexia show changes in the function and structure of the motion-sensitive part of the visual thalamus.