salaam all,
saba - readers of this thread may be unaware of free-minds hence my post. I always recommend researching multiple options in order to weigh them up, then opt for the most evidenced/logical option.
sardar - I cant summarise the discussions on free-minds as they extended to multiple pages and multiple options. Like this forum, it has a search function.
I wasn't entirely convinced by any particular option. My own thoughts several years ago was that it may refer to the spinal signal that results in the ejection of seminal fluid by the male. To my knowledge, according to latest research, the origin is actually a relay-centre in the spinal cord, not the brain.
I'm not convinced by br. Joseph's interpretation. For example, I'd have to see a clear example in Quran wherein something is stated as being between A and B, and what is meant is that thing is in motion from A to B. If such an example can be produced then it would give such an interpretation more weight.