Biomedical Engineering Reference
In-Depth Information
Figure 19.1
Major brain areas involved in the deployment of selective visual attention. Although
single-ended arrows are shown to suggest global information flow (from the eyes to
prefrontal cortex), anatomical studies suggest reciprocal connections, with the num-
ber of feedback fibers often exceeding that of feedforward fibers (except between
retina and LGN). Cortical areas may be grouped into two main visual pathways: the
dorsal “where/how” pathway (from V1 to DLPFC via PPC) is mostly concerned with
spatial deployment of attention and localization of attended stimuli, while the ventral
“what” pathway (from V1 to VLPFC via IT) is mostly concerned with pattern recog-
nition and identification of the attended stimuli. In addition to these cortical areas,
several subcortical areas including LGN and Pul play important roles in controlling
where attention is to be deployed.
Keytoabbreviations:
LGN: lateral geniculate
nucleus; Pul: Pulvinar nucleus; V1, V2, V4: early cortical visual areas; MT: Medial
temporal area; PPC: posterior parietal cortex; DLPFC: dorsolateral prefrontal cortex;
IT: inferotemporal cortex; VLPFC: ventrolateral prefrontal cortex.
important to note, however, that object recognition in the ventral stream can bias the
next attentional shift, for example via top-down control when an object is recognized
that suggests where the next interesting object may be located. Similarly, we will see
how attention strongly modulates activity in the object recognition system.
Among the brain regions participating to the deployment of visual attention in-
clude most of the early visual processing areas and the dorsal processing stream (Fig-
ure 19.1). These include the lateral geniculate nucleus of the thalamus (LGN) and
cortical areas V1 (primary visual cortex) through the parietal cortex along the dorsal
stream [51]. In addition, overt and covert attention have been shown to be closely re-
Search WWH ::
Custom Search