Logical studies--Measurements of activity in visual cortex have offered the neural : Différence entre versions

Version actuelle en date du 13 janvier 2018 à 04:47

Consistent with all the feature-similarity obtain model, this pattern of responses suggests that attending to one orientation biased the population activity toward the attended orientation, the behaviorally relevant stimuli, at the expense of behaviorally irrelevant stimuli (see also Serences Boynton, 2007; Serences, Saproo, Sive nutrition for the duration of early life, which include embryo or fetal development Scolari, Ho, Muftuler, 2009). FBA selectively modifies the neural representations of elements within visual scenes that match the at present attended function. An early study of FBA in location V4 illustrates this modification. Monkeys had been trained to view a rapid sequence of gratings and to respond when they saw a grating that matched the orientation of a cue grating. The responses of most recorded neurons varied according to which orientation the animal was seeking (Haenny et al., 1988; see also Hayden Gallant, 2005; Maunsell et al., 1991). The neural signatures of FBA have also been investigated employing neuroimaging procedures. Early PET and fMRI (Beauchamp, Cox, DeYoe, 1997; Shulman et al., 1999; Watanabe et al., 1998) research indicate that FBA modulates activity in many visual regions (e.g., V1 and MT+/V5) in response to expectations regarding the task-relevant feature dimension. Paying focus to stimulus functions across the entire visual field enhances neural activity inside the cortical areas specialized to process these attributes (Liu et al., 2003; O'Craven et al., 1997; Schoenfeld et al., 2007). By way of example, a study combining fMRI and neuromagnetic recordings discovered that a moving stimulus elicited a larger neural response in title= bmjopen-2016-012517 the motionsensitive location MT when movement was relevant than when color was relevant, whereas a color-change stimulus made higher activity inside the color-selective location V4/V8 when color was attended than when movement was relevant (Schoenfeld et al., 2007). Neuroimaging research have also shown FBA modulation of targets which are spatially coextensive with distractors of different function values. For instance, attending to a single colour in a show containing intermingled colored moving dots increases the amplitude ofVision Res. Author manuscript; accessible in PMC 2012 July 05.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptCarrascoPageSSVEPs to that colour in comparison with when that color is not attended (Muller et al., 2006). Research using voxel-based multivariate pattern classification overcome the spatial resolution limitations of fMRI, thus enabling the assessment of featural attentional effects in particular retinotopic visual areas. When participants attended to one particular of two superimposed grid patterns, a classifier determined by voxels from V1 to V4 could reliably predict the attended orientation (Kamitani Tong, 2005). Consideration increases the BOLD response in voxels tuned for the attended orientation (or close to it), relative to voxels tuned title= 2016/5789232 for the unattended orientation. Consistent using the feature-similarity achieve model, this pattern of responses suggests that attending to one particular orientation biased the population activity toward the attended orientation, the behaviorally relevant stimuli, at the expense of behaviorally irrelevant stimuli (see also Serences Boynton, 2007; Serences, Saproo, Scolari, Ho, Muftuler, 2009). One more beneficial strategy to investigate FBA across various areas in human visual cortex is fMRI response adaptation. Measurements of adaptation with fMRI let scientists to create title= fmicb.2016.01271 inferences about neural activity in the subpopulation level beyond the resolution of a single image voxel (Grill-Spector Malach, 2001; Krekelberg, Boynton, van Wezel, 2006).