Spatiotemporal overlap between brain activation related to saccade preparation and attentional orienting

Abstract

Recent brain imaging studies provided evidence that the brain areas involved with attentional orienting and the preparation of saccades largely overlap, which may indicate that focusing attention at a specific location can be considered as an unexecuted saccade towards that location (i.e. the premotor theory of attention). Alternatively, it may be proposed that attentional orienting is simply relevant for preparing saccades, but the two processes may also be completely unrelated. In two experiments, we examined temporal activation of brain areas by measuring the electroencephalogram. Central cues indicated the likely side (left or right) at which a to-be-attended target would occur, or to which a saccade had to be prepared. Cue direction-related activity was determined, time-locked to cue onset. In addition, in our second experiment, delayed saccades had to be carried out, which allows to focus on processes strongly related to saccade execution. In nearly all tasks, an early directing attention negativity (EDAN), an anterior directing attention negativity (ADAN), and a late directing attention positivity (LDAP) were observed, time-locked to cue onset. Source analyses supported the view that this activity probably originates from areas within the ventral intraparietal sulcus (vIPS) and the frontal eye fields (FEF). The saccade-locked analysis also indicated that the FEF plays an important role in triggering saccades, but the role of vIPS appears to be minimal. The latter finding disfavors the premotor theory of attention, as it suggests that the relation between attention and action is less direct.

Cognitive mechanisms and motor control during a saccadic eye movement task: evidence from quantitative electroencephalography

“…Therefore, our findings are in agreement with what was seen in Van der Lubbe et al The reduction of beta coherence for fixed condition during the post-stimulus moment can also be described as a decline of the focus of attention during the task performance 17 .…”

“…The analysis of O1/O2 electrode pairs, located over occipital cortex, showed a main effect for condition, with increased beta coherence for the random condition. The occipital lobe is subdivided into primary visual cortex, responsible for the detection of visual stimulus, and associative visual cortex, which is intimately involved in the processing and comprehension of visual information 17 . These finding suggest that the identification of the stimulus during the task in the stimulus-driven condition demands a greater participation of the associative visual cortex, since this area is responsible for the motor organization of information in the construction of visual images, i.e., it organizes the representation of the stimulus received in the primary visual cortex [24][25][26] .…”

How Human Electrophysiology Informs Psychopharmacology: from Bottom-up Driven Processing to Top-Down Control

“…Top-down modulated electrocortical processing in sensory and frontal cortex ('selection potentials') has been described extensively in the context of selective attention, but has thus far found only limited application in psychopharmacology. Furthermore, we argued that this approach should be supplemented by imaging the top-down signals that cause the attentional modulation (van der Lubbe et al, 2006). In this context ERP/F methods are especially suitable to track splitsecond changes in attentional settings as conveyed by equally rapidly changing environmental or task demands.…”

Pain & attention

“…An early contralateral negativity over occipito-parietal sites observed around 200-400 ms after cue onset, the early directing attention negativity (EDAN), is thought to reflect the selection and interpretation of the lateral relevant part of the cue (see . The later anterior directing attention negativity (ADAN) is often observed over anterior sites at around 400 ms after cue onset, and is suggested to reflect the control of spatial attention that affects subsequent posterior processes (e.g., see Grent-'t-Jong & Woldorff, 2007; for an alternative view, see Van der Lubbe et al, 2006). Finally, a late directing attention positivity (LDAP) is generally observed over posterior sites around 500-700 ms after cue onset, which is thought to reflect spatial selection processing based on a bodycentered reference frame .…”

“…A suitable task to study endogenous orienting and examine the involvement of different spatial reference frames is a variant of the Posner paradigm Van der Lubbe, Neggers, Verleger, & Kenemans, 2006). In this paradigm, a centrally presented visual cue is often used to indicate the location (left or right) to which attention has to be directed in anticipation of a relevant stimulus, which enables to study the orienting phase.…”