![visual testing conjuction vs easy eeg visual testing conjuction vs easy eeg](https://www.medrxiv.org/content/medrxiv/early/2020/10/23/2020.10.21.20209502/F5.large.jpg)
Such computational principles suggest that temporal synchrony may also mediate information integration for higher cognitive processes, not just the binding of sensory features in early vision. Computationally, each phase can act like a unique tag that identifies each collection of components (assembly) as a particular whole from which the components can be subsequently retrieved.Ī number of neural network architectures employ synchrony to model visual (e.g., ), and cognitive processes more generally (e.g., – ), as a way of building representations of complex entities out of the representations of their constituents. At the neuronal level, overlapping receptive fields, both from bottom-up and top-down influences, can drive temporally correlated activation between cell assemblies for the same complex object that mutually enhance/suppress activity from cells firing in/out of phase via recurrent excitatory/inhibitory connections (see – ). For instance, two sources of information (say, a colour and an orientation) may be integrated (or bound to a common object) by the phases of their respective carrier signals (phase-synchrony): e.g., red and vertical are bound to one object because the units (neurons) encoding these features oscillate in-phase with respect to each other (due to their common source location), but out of phase with respect to the colours and orientations associated with objects at other locations in the field of view. Inspired by work on primitive feature binding in early vision (see for a review), a popular framework for modeling information integration at the neural level is temporal synchrony (see ). This difference is often characterized as bottom-up (stimulus-driven) versus top-down (context-driven) control of attention (e.g.,, ).
![visual testing conjuction vs easy eeg visual testing conjuction vs easy eeg](https://media.springernature.com/lw685/springer-static/image/art%3A10.1007%2Fs42113-020-00087-7/MediaObjects/42113_2020_87_Fig9_HTML.png)
At the behavioural level, feature search is often relatively fast, accurate and efficient (i.e., less adversely affected by the number of items in the search display), whereas conjunctive search is often relatively slow, inaccurate and inefficient (i.e., more adversely affected by the number of items in the search display). To contrast unintegrated versus integrated information in a visual search task, participants are typically required to find a target object that is uniquely identifiable by a single feature (feature search) versus a tuple of features (conjunctive search) that are selected from, say, the colour dimension versus the colour and orientation dimensions (see for a review). In this regard, visual search tasks have been particularly fruitful at both behavioural and neural levels, because they involve relatively simple procedures and modifications that span both perceptual and cognitive (attentional) domains while being amenable to the constraints of neuroimaging. From vision to reasoning, a wide variety of experimental paradigms have been employed to elucidate the processes that underlie information integration. The capacity to integrate multiple sources of information is a prerequisite for complex cognitive behaviour. They also provide a potential window into cognitive development, seen as developing the capacity to integrate more sources of information. These results provide support for the idea that anterior-posterior phase-locking in the lower gamma-band mediates integration of visual information.
![visual testing conjuction vs easy eeg visual testing conjuction vs easy eeg](https://onlinelibrary.wiley.com/cms/asset/6e296bca-676c-4923-b919-99c9596c3b56/psyp13735-fig-0003-m.jpg)
No such effects were observed for pairs in the transverse plane (i.e., F3-F4, C3-C4, P3-P4). Linear regressions, under hierarchical false-discovery rate control, indicated significant positive slopes for number of sources on PLV in the 30–38 Hz, 175–250 ms post-stimulus frequency-time band for pairs in the sagittal plane (i.e., F3-P3, Fz-Pz, F4-P4), after equating conditions for behavioural performance (to exclude effects due to task difficulty). Here, we examine the first possibility by parametrically varying the number of integrated sources from one to three and measuring phase-locking values (PLV) of frontal-parietal EEG electrode signals, as indicators of synchrony. Whether this difference also reflects greater information integration, rather than just differences in cognitive strategy (e.g., top-down versus bottom-up control of attention), or task difficulty is uncertain. Recent studies identified greater frontal-parietal synchrony during conjunctive than non-conjunctive (feature) search. The capacity to integrate multiple sources of information is a prerequisite for complex cognitive ability, such as finding a target uniquely identifiable by the conjunction of two or more features.