From neuronal to mental topography - Neurophenomenology of auditory hallucinations.

Auditory verbal hallucinations [AVH] are one of the most common psychopathological symptoms in psychosis and schizophrenia [SZ]. While various studies demonstrate the neuronal features of AVH in specific regions and networks including changes in structural and functional connectivity, the relation of their neuronal topography to the organization or structure of the subjects' experience, i.e. the phenomenology of their 'mental topography', remains yet unclear. Addressing this gap in our knowledge, we review recent findings to formulate two neurophenomenological hypotheses of AVH (which extend our earlier Resting state hypothesis). First, we hypothesize that structural and functional dysconnectivity in AVH with desynchronization and temporal fragmentation between sensory auditory, interoceptive somatic and cognitive linguistic regions [e.g., auditory cortex, insula and Broca's area] relate to the experience of analogous temporal fragmentation on the mental level, that is, among the contents in perception and thought - this is manifest in 'hyperreflexivity', the attribution of abnormal salience and attention to single isolated objects or elements in perception. Secondly, we propose that the topographic distinction and gradient of unimodal and transmodal regions are reduced in individuals with AVH. We hypothesize that such 'inner-outer neuronal topographic dedifferentiation and compression' is manifest in the experience of overlaps and confusions between the subject's outer interpersonal social and inner intrapersonal spaces - analogous to the neuronal level, this reflects an 'inner-outer mental topographic dedifferentiation and compression'. Together, we propose two testable neurophenomenological hypotheses of AVH showing shared structural-topographic changes in both brain and experience as their "common currency". This directly connects changes in the brain's neuronal topographic organization with the structure of experience, that is, the mental topographic organization of the subjects' experience of AVH in SZ.