It seems that time slot is currently most common, but that doesn’t prevent you from adhering to more (or less) traditional approaches.
Here is the google n-gram of the variants in use since 1940.
And it is always worth browsing at more venerable sources such as The New Yorker’s inimitable Comma Queen, Mary Norris, or, indeed, Wiktionary.
Both post-synaptic and postsynaptic are grammatical. So to are pre-synaptic and presynaptic.
The closed version is more common that the hyphenated version. (As shown by another answer here.)
For actual context, here are two paragraphs from the article in question. Note that the second comes some time after the first (the emphasis exists in the referenced ...
1. Everyday usage
Here's what Google Ngram indicates. I think postsynaptic wins by a considerable margin. Click on the link below the picture to do your own searches.
First of all, note that the problem is a little bit more complex.
English can separate parts of a compound with a space (orange juice), nothing (football), or sometimes a letter (bridesmaid).
German can use nothing (Fußball), a letter (Orangensaft, not Orangesaft), or, rarely a hyphen (Drucker-Zeugnis) to avoid confusion.
That being said, this is primarily a ...
There are plenty of unhyphenated compound words in English (teaspoon, greenhouse, laptop...). Gyles Brandreth in Have you eaten, Grandma says that hyphenated words are becoming less common. Even co-operate, which you would think needed the hyphen to stop you from pronouncing the first syllable coop, is now often written without one. There are no hard and ...
There is no general rule for the use of hyphens in compound words.
Compound words can be formed by combination of different kinds of words, i.e., noun/noun, adjective/noun, verb/preposition, preposition/noun etc. In any of the cases, there is no rule for hyphenation. One must know if a hyphen is involved in a word or not. For example, the word 'laughing-gas' ...
It depends what you mean.
lexical-functional grammar - a grammar that has lexical functionality
lexical functional grammar - a functional grammar that is also lexical
Note: See important comments below by @FumbleFingers