RESUMEN
Attention allows us to select relevant information by modulating neural activity within sensory brain areas processing that information. Previous research has shown that visual perception of body stimuli recruits visual cortices together with observer's body representation in somatosensory cortex, which is known for processing body-related information (e.g., haptics, kinematics). However, whether attentional selection of visual body stimuli involves just visual or additional somatosensory areas remains elusive. Here we elicited visual and somatosensory evoked activity during a visual search task, whereby participants searched for target hand images defined by either visual (colour) or bodily (posture) features. In line with previous studies, we found electrophysiological evidence for attentional selection over visual areas (i.e., N2pc) regardless of the feature type. Importantly, after dissociating somatosensory from visual evoked activity, we show that only attentional selection of hand posture - but not hand colour - elicits modulation of somatosensory evoked electrocortical activity over somatosensory cortex. This suggests that attention may not only modulate cortical activity associated with the input-sensory modality (in this case, visual), but, depending on the type of attended information, it may also modulate cortical activity associated with another task-relevant sensory modality (in this case, somatosensory). Overall, our results provide evidence for a flexible attention mechanism that operates according to specific behavioural goals and the information embedded in the percept.
Asunto(s)
Atención/fisiología , Encéfalo/fisiología , Potenciales Evocados Somatosensoriales/fisiología , Percepción del Tacto/fisiología , Percepción Visual/fisiología , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
Working memory (WM) supports temporary maintenance of task-relevant information. This process is associated with persistent activity in the sensory cortex processing the information (e.g., visual stimuli activate visual cortex). However, we argue here that more multifaceted stimuli moderate this sensory-locked activity and recruit distinctive cortices. Specifically, perception of bodies recruits somatosensory cortex (SCx) beyond early visual areas (suggesting embodiment processes). Here we explore persistent activation in processing areas beyond the sensory cortex initially relevant to the modality of the stimuli. Using visual and somatosensory evoked-potentials in a visual WM task, we isolated different levels of visual and somatosensory involvement during encoding of body and non-body-related images. Persistent activity increased in SCx only when maintaining body images in WM, whereas visual/posterior regions' activity increased significantly when maintaining non-body images. Our results bridge WM and embodiment frameworks, supporting a dynamic WM process where the nature of the information summons specific processing resources.