Vṛttis are mental waves — thoughts, emotions, memories, and perceptions constantly rising and falling. Cognitive events (thoughts, perceptions, emotions) / contents of working memory.

Manas is the part of the mind that collects sensory data and handles attention — like a gatekeeper deciding what to focus on. Working memory / attention / sensory integration.

Citta is the overall field of mind-stuff: it stores memories, habits, and deeper patterns.  Long-term memory / unconscious processing.

If the mind were a lake, vṛttis are the ripples, manas is the surface movement reacting to wind, and citta is the deep water reflecting everything.

The function that identifies the pure “I” (aham) with thoughts, roles, body, emotions — forming the personal identity and ego. It says “I am this.” and "I do".

Cognitive Science Correlates: Narrative self / autobiographical identity, Self-concept and ego structure, Ego-identification / default mode network (DMN) activity

The capacity to discriminate, reason, judge, and make decisions. It evaluates inputs from manas and chooses a response.

Cognitive Science Correlates: Executive function / decision-making / Analytical reasoning /Cognitive control & inhibition

The deepest layer of identity — pure awareness, witness of all experiences, beyond mental content and roles. In some philosophical traditions equivalent to substrate of the universe.

Cognitive Science Correlates: Pure consciousness / background awareness, the ultimate substrate