It is a challenge to reconcile Thomas Aquinas' approach to "nothing exists in the mind before it exists in the senses" and the physicalist account of concept-formation. Sadly, neuroscience has not yet developed a robust account of how we form concepts: Joseph Ledoux (The Emotional Brain) has a great picture whereby he shows how sensory stimuli become "conscious content." Alas! He describes the whole process as a "black box" that involves stimuli being processed and stored along with more processing and storage before stimuli become the contents of consciousness.
The complex feature about this whole process is that memory has a role in sensible phenomena becoming conscious contents. For instance, I've seen many apples in my relatively brief lifespan. So when I perceive my 1000th apple, things are not so simple as the apple/stimulus being converted into information, which eventually becomes a representational concept (on the physicalist explanation of things) or sensible matter (according to the Thomist account). Yet my brain does not engage in this process every time that I perceive an apple. Are we not thankful for the hippocampal region, the amygdala, synapses, and other parts of our neurobiology?
See also https://mitpress.mit.edu/books/consciousness-reconsidered by Owen Flanagan.