Who performs the actions of the senses (e.g hearing, speaking, tasting)?
Brahman Or Atman (soul) is ultimately the performer of the actions of the senses.
But as said earlier He is just a witness. He is not the Experiencer of fruit of the action of the senses. Who is the illuminator of the senses that to say because of this atman all the senses are in action.
This is explained in the The Kena Upanishad -verse 2
श्रोत्रस्य श्रोत्रं मनसो मनो यद्वाचो ह वाचं स उ प्राणस्य
अतिमुच्य धीराः प्रेत्यास्माल्लोकादमृता
śrotrasya śrotraṃ manaso mano yadvāco ha vācaṃ sa u prāṇasya
atimucya dhīrāḥ pretyāsmāllokādamṛtā
bhavanti || 2 ||
It is the ear of the ear, mind of the mind, tongue of the tongue, and
also life of the life and eye of the eye. Being disabused of the
false notion, the wise, having left this body, become immortal.
Our Mind is our sixth organ /sense , which is the actual Experiencer of the Pain and pleasure. And under whose direction Our senses work.
I.e. Our Mind is the controller of these senses ,who kept them at bay
This is explained in The Katha Upanishad - Verse 1.3.3 with the analogy of Ratha or chariot.
आत्मानँ रथितं विद्धि शरीरँ रथमेव तु ।
बुद्धिं तु सारथिं विद्धि
मनः प्रग्रहमेव च ॥ ३ ॥
ātmānam̐ rathitaṃ viddhi śarīram̐ rathameva tu |
sārathiṃ viddhi manaḥ pragrahameva ca || 3 ||
Know the âtman as the lord of the chariot, the body as only the chariot, know also intelligence as the driver; know the minds as the
Shankara’s Commentary:- Know also the intelligence to be
the driver, furnished with the capacity for determination, because the
body is mainly guided by the intelligence, as the chariot is mainly
guided by the driver; for, everything done by the body is generally
done by the intelligence.
This verse from Katha Upanishad -also
shows us that Mind is the controller of the senses. i.e. we can control senses through our mind.
यस्त्वविज्ञानवान्भवत्ययुक्तेन मनसा सदा ।
दुष्टाश्वा इव सारथेः ॥5॥
yastvavijñānavānbhavatyayuktena manasā sadā |
tasyendriyāṇyavaśyāni duṣṭāśvā iva sāratheḥ || 5 ||
But of him who is not possessed of discrimination, and whose mind is
always uncontrolled, the senses are not controllable as vicious horses
of a driver.
Although our Mind initiate the senses /organs to perform action and control senses and the senses work under our buddhi. But all these senses ultimately function or live just because of presence of Atma itself, without Atman they can’t work , which is in vedanta also equal with Prana.
Senses perform actions in our body under control of
Buddhi ,intellect ,mind , but this mind and all the senses are
ultimately illuminated by Brahman or Atman only. I.e. Our senses
perform action guided by Buddhi illuminated by Atman.