Reconstructing Spatiotemporal Trajectories of Visual Object Memories in the Human Brain
Metadatos
Mostrar el registro completo del ítemAutor
Lifanov-Carr, Julia; J. Griffiths, Benjamin; Linde Domingo, Juan; S. Ferreira, Catarina; Wilson, Martin; D. Mayhew, Stephen; Charest, Ian; Wimber, MariaEditorial
Society for Neuroscience
Materia
EEG feature reconstruction fMRI
Fecha
2024-09-06Referencia bibliográfica
Lifanov Carr, J. et. al. (2024), 11(9). [https://doi.org/10.1523/ENEURO.0091-24.2024]
Patrocinador
European Research Council (ERC) Starting Grant StG-2016-715714; Midlands Integrative Biosciences Training Partnership (MIBTP)Resumen
How the human brain reconstructs, step-by-step, the core elements of past experiences is still unclear.
Here, we map the spatiotemporal trajectories along which visual object memories are reconstructed
during associative recall. Specifically, we inquire whether retrieval reinstates feature representations
in a copy-like but reversed direction with respect to the initial perceptual experience, or alternatively,
this reconstruction involves format transformations and regions beyond initial perception. Participants
from two cohorts studied new associations between verbs and randomly paired object images, and
subsequently recalled the objects when presented with the corresponding verb cue. We first analyze
multivariate fMRI patterns to map where in the brain high- and low-level object features can be
decoded during perception and retrieval, showing that retrieval is dominated by conceptual features,
represented in comparatively late visual and parietal areas. A separately acquired EEG dataset is then
used to track the temporal evolution of the reactivated patterns using similarity-based EEG–fMRI fusion.
This fusion suggests that memory reconstruction proceeds from anterior frontotemporal to posterior
occipital and parietal regions, in line with a conceptual-to-perceptual gradient but only partly following
the same trajectories as during perception. Specifically, a linear regression statistically confirms that
the sequential activation of ventral visual stream regions is reversed between image perception and
retrieval. The fusion analysis also suggests an information relay to frontoparietal areas late during
retrieval. Together, the results shed light onto the temporal dynamics of memory recall and the transformations
that the information undergoes between the initial experience and its later reconstruction
from memory.