This paper is concerned with the processes, both psychoanalytic and neuroscientific, involved in the undoing of dissociation in a 3-year-old, who was seen weekly over a nine month period. A neuroscientific and psychoanalytic developmental framework is used to follow a sequence of phenomena that emerged over the duration of relatively brief once weekly psychotherapy. Splintered aspects of the personality are shown to co-exist using different but related primitive defences, namely: dissociation, projective identification and somatic tremor. Clinical material of this traumatised child is used to illustrate the struggle to regulate changing affective states and their manifestations and to suggest a developmental progression occurring during the psychotherapy. Speculatively it is suggested that whilst mirror neurons would have been present from birth, the process of dissociation inhibited their functioning. One of the outcomes of therapy was to recruit mirror neurons in the service of developing processes of identification and empathy. Only then could a transference relationship begin.