Two distinct neural mechanisms for category-selective responses

Uta Noppeney, Cathy J Price, Will D. Penny, Karl J Friston

Research output: Contribution to journalArticle

146 Citations (Scopus)

Abstract

The cognitive and neural mechanisms mediating category-selective responses in the human brain remain controversial. Using functional magnetic resonance imaging and effective connectivity analyses (Dynamic Causal Modelling), we investigated animal- and tool-selective responses by manipulating stimulus modality (pictures versus words) and task (implicit versus explicit semantic). We dissociated two distinct mechanisms that engender category selectivity: in the ventral occipito-temporal cortex, tool-selective responses were observed irrespective of task, greater for pictures and mediated by bottom-up effects. In a left temporo-parietal action system, tool-selective responses were observed irrespective of modality, greater for explicit semantic tasks and mediated by top-down modulation from the left prefrontal cortex. These distinct activation and connectivity patterns suggest that the two systems support different cognitive operations, with the ventral occipito-temporal regions engaged in structural processing and the dorsal visuo-motor system in strategic semantic processing. Consistent with current semantic theories, explicit semantic processing of tools might thus rely on reactivating their associated action representations via top-down modulation. In terms of neuronal mechanisms, the category selectivity may be mediated by distinct top-down (task-dependent) and bottom-up (stimulus-dependent) mechanisms.

Original languageEnglish
Pages (from-to)437-445
Number of pages9
JournalCerebral Cortex
Volume16
Issue number3
DOIs
Publication statusPublished - Mar 2006

Keywords

  • Adult
  • Brain Mapping
  • Cerebral Cortex
  • Computer Simulation
  • Female
  • Humans
  • Male
  • Neurological Models
  • Nerve Net
  • Neural Pathways
  • Speech Perception
  • Visual Perception
  • Clinical Trial

Cite this