'Intellect' - is it a matter of the heart or brain in Islam?

This may sound like a very philosophical question but my only concern is to understand what Islam says about intellect. With so many Quranic verses and Hadith mentioning the importance of having a good heart and to use one's intellect, this question arises. What is *Aql* (intellect) in an Islamic perspective and what is it associated with?. Is it exclusive to the heart or is it just as we understand, from the mind/brain?. **Ps.** I am really interested to know if any great Islamic scholars have pondered on this thought. Have checked a couple of questions on this site regarding heart and mind but they did not provide an answer for me nor does those questions are asked in the same context as mine.