Synaptic interface
From Tardis Wiki, the free Doctor Who reference
A synaptic interface was constructed by the Sixth Doctor using his TARDIS' telepathic circuits combined with his own symbiotic nuclei. The synaptic interface allowed him, recovering from regenerative collapse within the TARDIS, to observe or "spy on" Jack Harkness as he pretended to be the Doctor outside the TARDIS. (AUDIO: Piece of Mind)