Subconscious
noun, の adjective
If 意識 is consciously, then what exists concealed in your mind is your subconscious.
せんざいいしき
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
夢ってのは、僕たちの潜在意識を反映しているとよく言われるよね。
Dreams are often said to reflect our subconscious.