What theories, models, and hypotheses are used to explain how knowledge is represented in the mind?

Knowledge Representation, Manipulation, and Organization

What theories, models, and hypotheses are used to explain how knowledge is
represented in the mind?

What are some of the characteristics of mental imagery?

What are analogical images and symbolic propositions?

How do spatial skills develop?

What is declarative knowledge and how is its representation and organization explained by various theories and theorists?
What is procedural knowledge and how is it represented in the mind? How does it differ from declarative knowledge?

Are there models that integrate knowledge types? If so, what are they?