title: Corticostriatal circuitry mediates fast-track visual categorization.
abstract: Previous studies have shown that briefly presented natural scenes containing non-animals elicited more negative potentials than images with animals even at 150 ms after stimulus onset (dN150). Cognitive models suggest that both feed-forward and feature weighting processes are involved in the rapid categorization of complex natural scenes. Here we examined the possible neuronal substrates of this model. Patients with Alzheimer's disease (AD) exhibited a delayed dN150, but in their case non-animals evoked more negative potentials similarly to the controls (presence of dN150). In contrast, in patients with Parkinson's disease (PD) animal and non-animal stimuli elicited nearly identical early responses (absence of dN150). The results indicate that when cortico-cortical pathways mediating feed-forward mechanisms are impaired (as in the case of AD), dN150 appears later, while in the case of corticostriatal dysfunctions (as in the case of PD) no differential response is present. This supports the hypothesis that corticostriatal circuits mediate perceptual feature weighting and integration in complex situations requiring categorical judgements.
authors.affiliation: Department of Physiology, University of Szeged, Szeged, Hungary. aantal@gwdg.de
authors.forename: Andrea
authors.initials: A
authors.lastname: Antal
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Kéri
authors.forename: Tamás
authors.initials: T
authors.lastname: Kincses
authors.forename: János
authors.initials: J
authors.lastname: Kálmán
authors.forename: György
authors.initials: G
authors.lastname: Dibó
authors.forename: György
authors.initials: G
authors.lastname: Benedek
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Janka
authors.forename: László
authors.initials: L
authors.lastname: Vécsei
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology; D002540:Cerebral Cortex / Q000502:physiology*; D003342:Corpus Striatum / Q000502:physiology*; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000502:physiology; D010300:Parkinson Disease / Q000503:physiopathology; D010775:Photic Stimulation; D014796:Visual Perception / Q000502:physiology*