The Atman is indicated as something
other than the gross, subtle and causal bodies,
beyond the five sheaths of matter; a witness to the
Waking, dream and deep sleep states
of Consciousness and the perceiver in the sense organs,
and the thinker in the intellect.
(Despite Atman being independent of sharira , its manifestation in sharira (body), attributes to the reason why it is identified with the body. The nature of Atman is explained thru neti-neti in Upanishads)
Chaitanya is intrinsic in Atman , as Atman is sat chit ananda.
Chaitanya ,pure consciousness is unconditioned, whereas Chetana the pratibimba of Chaitanya , is conditioned by its avidya
Brahman is Existence-Consciousness-Bliss(sat chit ananda). The existence aspect alone is manifested in inanimate objects, but not consciousness and bliss. This is because inanimate objects have no subtle body which alone can reflect consciousness and bliss. The
consciousness aspect is manifested in all animate beings, even when the mind is agitated, for we see that even a person who is unhappy is conscious. But the bliss aspect is manifested only when the mind is calm. A doubt arises as to why, when Brahman has both the aspects of consciousness and bliss, only one of them, consciousness, is reflected in an agitated mind. When you look at the reflection of your face in a mirror, you find that the face in its entirety is reflected and not only some aspects of it. This doubt is answered by giving two examples. When water is in contact with fire, only the heat aspect of fire is absorbed by the water and not the light of fire. But when a log of wood comes into contact with fire, it absorbs both the heat and the light aspects. Similarly, only the consciousness aspect of Brahman is reflected in an agitated mind, but both the consciousness and the bliss aspects are reflected when the mind is calm.
Panchadasi chapter 15 , Sri SN Saastri.
In terms of Gita 7.5
This is My lower nature. Know My other and higher nature which is the soul, by which this world is upheld,
O Mighty-armed (Arjuna).
The Supreme is Iśvara, the personal Lord of the universe
Who contains conscious souls and unconscious
nature . The two are regarded as His higher (para)
lower (aparā) aspects. He is the life and form of every
being .The Universal Being
of God includes the totality of
the unconscious in His lower nature and the totality of
conscious in His higher. The embodiment of the soul in body
life, sense, mind and understanding gives us the the ego, which
uses the material setting for its activity. Each individual
two sides, the soul and the image, Kşetrajña and ksetra. These
are the two natures of
Iśvara who is superior to them both
Dr. S Radhakrishnan
How can one enhance their level of consciousness?
Gita chap 16 enumerates the , divine virtues that enhances spiritual progress (thereby level of consciousness), and demonic qualities ,that clutches one into samsaara..Also Gita suggests, karma , bhakti , jnana Marg to spiritual ly elevate oneself. Jnana is more subtler than karma and bhakti Therefore, Sri Krishna time and again emphasize s Karma yoga(as precursor) , becos if a yog that is more grosser is impossible , there is no point venturing into those that are subtler (like dhyana -meditation etc).
V Apte page 498(In the context of Vedanta by and large Chaitanya seems to connote pure consciousness only, yet there could be exceptions , (connotation may change depending on the treatise ))
V Apte page 493
वेदानां मध्ये सामवेदः अस्मि। देवानां रुद्रादित्यादीनां वासवः इन्द्रः अस्मि। इन्द्रियाणाम् एकादशानां चक्षुरादीनां मनश्च अस्मि संकल्पविकल्पात्मकं मनश्चास्मि। भूतानाम् अस्मि चेतना- कार्यकरणसंघाते नित्याभिव्यक्ता बुद्धिवृत्तिः चेतना।।(Sri Shankara Bhagavad Padaa s commentary for Gita 10.22)
So here chetana seems to connote conditioned consciousnes manifested on the budhi /intellect sheath, being above the intellect sheath(yo buddheḥ paratas tu saḥ Gita 3.42)