Music, memory and mechanisms in Alzheimer's disease

Abstract

This scientific commentary refers to ‘Why musical memory can be preserved in advanced Alzheimer’s disease’, by Jacobsen et al. (doi:10.1093/brain/awv135).

Figure 1

A framework for analysing the effects of dementias on music cognition. The cut-away brain schematic (top centre) shows cerebral networks associated with components of music cognition, based on clinical and normal functional neuroanatomical evidence, including the work of Jacobsen and colleagues. The right cerebral hemisphere is projected forward in the schematic, however musical functions are bi-hemispherically distributed. Coronal MRI brain sections (side panels; right hemisphere shown on the left in each section) represent canonical neurodegenerative syndromes predicted to affect these music networks, with characteristic profiles of regional cerebral atrophy: Alzheimer’s disease (AD), bilateral symmetrical mesial temporal lobe atrophy; behavioural variant frontotemporal dementia (bvFTD), asymmetric (predominantly right-sided) frontal and temporal lobe atrophy; progressive non-fluent aphasia (PNFA), asymmetric (predominantly left-sided) peri-sylvian atrophy; and semantic dementia (SD), asymmetric (predominantly left-sided) anterior temporal lobe atrophy. The musical score (below) shows excerpts from the Aria that opens and closes (da capo) the ‘Goldberg Variations’ by J.S. Bach. Components relevant to music cognition are colour coded throughout as follows: blue, tracking of musical events and musical episodic memory; green, elementary musical property (e.g. tempo) processing; cyan, scale and key processing; red, recognition of familiar musical motifs (musical semantic memory); gold, musical emotion. The figure illustrates the close cognitive and neuroanatomical relations between musical memory and emotion; the return of the Aria’s simple theme after a long series of 30 increasingly elaborate variations triggers both recall of a musical episode and an emotional highpoint of the Goldbergs for many listeners. AC = anterior cingulate; a-h = amygdala–hippocampus; ATL = anterior temporal lobe; BG = basal ganglia; IFG = inferior frontal gyrus/frontal operculum; ins = insula; PFC = prefrontal cortex; PMC = posterior medial cortex (posterior cingulate, precuneus); SMA = supplementary motor area; STG = superior temporal gyrus; TPJ = temporo-parietal junction.