title: Effects of attending selectively to the spatial position of reflex-eliciting and reflex-modulating stimuli.
abstract: The question of whether automatic, sensory processes can be modified by selectively directing attention to stimuli was addressed by comparing effects on brainstem reflexes that share a common efferent pathway but have distinct afferent limbs. Subjects judged the duration of brief but intense blink-eliciting tones (Experiment 1) or weak tones preceding a blink-eliciting air puff at interstimulus intervals producing blink inhibition (Experiment 2). Tones occurred unpredictably at left, right, or midline loci; designation of the target location varied across blocks of trials. Latency of blinks to lateralized blink-eliciting targets was facilitated selectively, and the magnitude of blinks evoked by air puff following lateralized prestimulus targets was inhibited selectively. There was no evidence for a midline selective effect. Results appear to support a preset differential processing of stimuli in sensory pathways at low, possibly subcortical, levels and the consequent modification of obligatory, automatic processes.
mesh_terms: D000161:Acoustic Stimulation; D000344:Afferent Pathways / Q000502:physiology; D001288:Attention / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001767:Blinking; D004525:Efferent Pathways / Q000502:physiology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007266:Inhibition, Psychological / Q000502:physiology; D008297:Male; D011930:Reaction Time; D013017:Sound Localization / Q000502:physiology*