Selecting category specific visual information: Top-down and bottom-up control of object based attention

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Visual Perception

Background:

• Selective attention relies on both internal goals (top-down) and external stimuli salience (bottom-up).
• Understanding the neural basis of how these attentional control mechanisms interact is crucial for explaining visual perception.
• Extrastriate visual areas process information in a category-selective manner, but their modulation by attentional control is not fully understood.

Purpose of the Study:

• To investigate the neural underpinnings of the interaction between top-down and bottom-up attentional control.
• To examine how this interaction affects extrastriate visual areas involved in category-selective processing.
• To identify brain regions involved in integrating attentional control signals.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Participants viewed images of bodies or buildings embedded in visual noise.
• Stimulus saliency and attentional focus (top-down instruction) were systematically manipulated.

Main Results:

• Highly salient stimuli, incongruent with the attentional set, activated bilateral inferior frontal junction and dorsal parietal regions.
• Stimuli consistent with the attentional set additionally engaged the insular cortex and parietal operculum.
• The extrastriate body area (EBA) showed top-down modulation only at intermediate stimulus saliency levels, suggesting context-dependent attentional effects.

Conclusions:

• The inferior frontal junction and posterior parietal regions play a key role in integrating top-down and bottom-up attentional control signals.
• Attentional modulation of category-selective visual areas like the EBA depends on the interplay between stimulus salience and internal attentional goals.
• These findings provide insights into the neural mechanisms governing selective visual attention and information processing.