Thoughts, Memories, Vrittis

Thoughts are related to how we have conceptualised something, and, from that, emotion can be triggered. What has been conceptualised resides in the higher mind, vigyanamaya kosha. It lives there unseen, but is affecting us on a daily basis.
If for example, we have conceptualised that it's okay to smack children, no emotion will be triggered when we see it happen. If we have conceptualised that that is not okay emotions such as grief or anger (two sides of the same coin) will be triggered.
Once emotion is triggered, that can easily trigger a whole swathe of memories and concepts, ones which may or may not be directly related, each one in turn has the capacity to trigger more emotion - keeping the whole emotional thing going. 
All of this expressed activity is taking place in manomaya kosha. The part of the mind responsible for 'expressing stuff'. Eventually, the triggering and the emotions, subside, manomaya quietens. The concepts are still there, in vigyanamaya kosha, just not triggered.

All mindful yoga & meditation helps to thin and soften the stuff stored in vigyanamaya kosha, helping us in turn to function at a higher level of calm and wisdom. Antar mouna meditation works directly and profoundly.

Thoughts - categorised into five types

According to the ancient yogis, these are:  

Thought comprising correct data. 

i.e. actually correct, not just believed to be correct.

Thought comprising incorrect data.

Thought comprising as yet uneventuated data. 

i.e. wishful, imagined past or present, ideas, etc.

Thought comprising memory data. 

i.e. experiences stored as perceived, although perception can alter.

Thought comprising no data. 

i.e. drawing a blank, inability to retrieve data due to shock, shame, hunger, etc etc.

Every one of the five categories can trigger emotion. Some thoughts with correct data will activate joy, some will activate deep pain, or wounding. That is to say thought in each category can be pleasant or unpleasant. If it is neutral it is considered to be pleasant.

A thought from one category, can then trigger thoughts and emotions from other categories. Depending upon the intensity of the experience this can cause emotional outbursts which go on for many minutes/hours. The manomaya becomes enthralled by the experience and gets right into it. Eventually though, manomaya tires of it, and the outburst slowly subsides. 

How nature created all this is a mystery, superb, daunting and thrilling!  

The expression of thought and emotion comes from a part of the mind known ads manomaya kosha. Also referred to as the lower mind because it is not the part of the mind which contains the material, it is the part which expresses it. The container of experiences is known as vigyanamaya kosha, and as the higher mind.

Meditation such as antar mouna, taught for decades by Swami Satyananda, encourages greater self-awareness through knowing thoughts are subject to change, and do not represent the Real us. The Real Self. All yoga is actually a means to self-awareness. All yoga is meditation. If, that is, it is practiced mindfully.

Asana, whether practiced with kindness, moderation or harshness can trigger contentment, or sadness. The response in the mind, to any yoga practice will NOT always be the same.  An asana one day can trigger profound affection, the next day tears of loss, irritation, and so on. All other yoga techniques, including mudra, bandha, pranayama, kirtan, meditation, all act on the mind afresh each day. This is because just as the river is not the same river every day, nor is the mind always the same. The ebbs and flows of life, people, requirements, circumstances and environments, all stir the mind, just as the weather and debris stirs the river.

Thought is an amazing construct of the manomaya mind, but it is not the mind. Mind is something most of us cannot imagine. It is the barely recognised, or even recognisable, field of pure potentiality. Many of us have learnt how important it is to liberate ourselves by leaving some things behind and embracing other things. Some people have learnt how to activate greater potential within themselves, others barely at all. The same is true with emotion some have learnt how to master it, others have not.

Try not to take your thoughts for granted, nor believe they represent you in any permanent way. They need you to master and shape them.

Deeply quiet meditation activates a part of the central nervous system called the insula, this is responsible for increasing self-awareness. Self-awareness provides endless opportunities for self development. Out of the extreme calm of meditation comes wisdom and happiness, better quality thoughts and emotions. A happier you.

All meditation is mindful.