Sleep talking? Dream on!

QUESTION Is it true that it’s impossible to read or tell the time in dreams? LANGUAGE-related functions such as reading, writing and deciphering symbols are very difficult while dreaming.

During rapid eye movement sleep, which is associated with dreaming, certain parts of the brain are inactive — crucially, Broca’s and Wernicke’s areas, which are in the dominant left side of the brain.

Broca’s area is associated with speech and articulation; Wernicke’s area is primarily for speech comprehension.

stringing a coherent sentence together is practically impossible when Wernicke’s area is asleep. Most dreamers also lose the ability to read or comprehend signs, but may feel they can communicate by telepathy.

however, those with a great facility for language, such as poets, are able to formulate complex language in their sleep. Famously, samuel Taylor Coleridge wrote his classic Kubla Khan after ‘seeing’ it in a dream.

Conrad Smith, St Andrews, Fife. QUESTION Are sweet potatoes related to potatoes? Which is better for us? FURThER to the earlier answer, in Uganda in the Nineties, children would have protein deficiency and rotten teeth because they only ate maize, sugar cane and sweet potatoes.

A key difference between the irish potato, as it’s called in Uganda, and sweet potato is the protein content.

A sweet potato contains little, but the irish potato is 15 per cent protein, which made a big nutritional difference. Dr S. Brennan, hope Valley, Derbys.