Are dreams pathways of realms into the ‘beyond’?
Are dreams the subconscious mind relaying special messages?
Are dreams an artifact of the brain on ‘night shift’ duty?
For a long time, dream has been under the radar of many scientists. It has been such a mythical phenomenon that many would like to know more about. More importantly, many of us are curious about the answer to the question “Why do we dream?”.
There is no certainty about the actual function of sleep or dreams. And everybody dreams, yet memories of dreams remembered varies.
What do dreams do to us? Do they serve any purposes at all?
This is a question that remains unanswered. The speculations and theories continue.
A common theory is that sleep and dreams work as a team, helping the brain to refresh and restore after capturing millions of inputs each day. The inputs are sensory details that may be minor like colours and major mind boggling details like those in seminars or presentations. While sleeping, the brain sifts through the information and refines it, keeping what is needed and disposing content into the recycle and trash compartments. Researchers have speculated that dreams are a tool in this process.
Dreaming is the protoconscious state. This occurs during the Rapid Eye Movement (REM) stage of sleep. It also occurs at other stages including the fourth stage of sleep ( Slow Wave Sleep-SWS). This is the deepest stage of sleep. Studies shown dreams vary according to sleep stage they occur in. Most dreams are reported during the REM stage. 
Emerging neuroscience views insinuate that dreams are linked to memory consolidation that occurs during sleep. These many include recording and organising memories according to emotional drives as well as transferring memories between regions in the brain.
Daytime episodic memories are stored in the hippocampus region. This is the long term memory section of the brain that is for quick learning. At night they get transferred to the processing, knowledge and cognition section, the cerebral cortex. 
Studies have revealed that hippocampus neural activity replays day events. This is faster than real time and happens in a reverse motion. The replay activity correlates with neutral patterns of activity in the prefrontal (goals planning and strategy) and the visual cortex (visual experiences).
This memory replay occurs during the REM sleep stage where dreaming occurs. 
Is there Association between dreams and the Subconscious?
About the subconscious and dreams…..let us look into the bizarre realm of dreams. Question is, is it the brain attempting to make sense of signals that are generated in the memory consolidation phase, the model of activation-synthesis as Alan Hobson (Harvard) suggests?
Do dreams mean anything at all?
Searching for the meaning of dreams has been an ongoing venture through many ages. A random cacophony of memory fragmentation is not satisfying and unlikely for many.
Interpretations of dreams are usually coded in terms of beliefs, motivations and symbols that have to mean to the dreamer. Imagine that the process of memory consolidation is not actually random, it is focused on experiences in the past and then goals that are biologically determined. Motivational tensions then surface content of dreams 
“People who hold dream experiences in great esteem may be correctly affirming the importance of affective information that is encoded through our ancient emotional urges for the proper conduct of our waking activities… the REM system may now allow ancient emotional impulses to be integrated with the newer cognitive skills of the more recently evolved brain waking systems. This could help explain many striking attributes of REM sleep, ranging from its heavy emotional content to its apparent functions of enhancing learning and solidifying memory consolidation.” 
So dream content may not be our subconscious relaying messages to us. Dream analysis may reveal an underlying structure of motivational forces that drive our vision of choices and life strategy.
“reflect an attempt, on the part of the brain, to identify and evaluate novel cortical associations in the light of emotions mediated by limbic structures activated during REM.” In other words, the brain is trying to interlink our experiences of the world with our emotional drives”. 
Dreams may be a tool for the brain to explore situations that are hypothetical in an abstract way to refine strategies for future action. The images in dreams could be a result of the sense making program that processes signals that are generated by internal systems of motivation that are not constrained by any sensory input.
In simple terms, the imagery of dreams could the brain making sense of the ” test patterns” generated by the brain.
|||^||NatureReviewsNeuroscience: REM Sleep and dreaming: Toward a theory of protoconsciousness|
|||^||Learning&Memory: Sleep, dreams, and memory consolidation: The role of the stress hormone cortisol.|
|||^||WileyOnlineLibrary: The relationship between memory systems and sleep stages.|
|||^||ScienceDirect: Temporally Structured Replay of Awake Hippocampal Ensemble Activity during Rapid Eye Movement Sleep.|
|||^||PsychiatryOnline: The Dream in Contemporary Psychiatry.|
|||^||Amazon: Affective Neuroscience: The Foundations of Human and Animal Emotions|
|||^||Science: Sleep, Learning, and Dreams: Off-line Memory Reprocessing.|