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Visual Attention

Visual Attention. FEF. V4. spatial attention:  simultaneous neural recordings in V4 & Frontal Eye Fields (monkeys) Gregoriou , Gotts , Zhou, Desimone (2010). object attention:  MEG & fMRI in FFA (faces), PPA (places), & Inferior Frontal Junction (humans)

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Visual Attention

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  1. Visual Attention FEF V4 spatial attention: simultaneous neural recordings in V4 & Frontal Eye Fields (monkeys) Gregoriou, Gotts, Zhou, Desimone (2010) object attention: MEG & fMRI in FFA (faces), PPA (places), & Inferior Frontal Junction (humans) Baldauf & Desimone (2014)

  2. Technical Preliminaries Temporal synchrony: Local Field Potential: 0.7 – 100 Hz Spikes: 100 – 8000 Hz Spike triggered average of LFP (STA):

  3. Gregoriou et al.: spatial attention firing rate increases for attended stimulus  increase in V4 response follows the increase in FEF response, in time

  4. Temporal synchrony Coherence ≈ phase locking between two signals as a function of frequency increase in spike-field coherence in gamma band for attention inside the RF... ... especially when comparing between FEF and V4 consistent temporal delay ~10-12 ms from FEF  V4 Hypothesis about control of spatial attention? Coherence between spikes and LFPs at different temporal frequencies (Hz)

  5. Object Attention

  6. Magnetoencephalography (MEG) • measures magnetic fields generated by neuronal activity, non-invasively • analyze spatial distributions of magnetic fields to localize source of neuronal activity • superimpose source locations on MRI images • high temporal resolution (~10 ms) • high spatial resolution (~ 1 mm) • magnetic fields are extremely small, require very sensitive instrumentation and methods to eliminate environmental interference

  7. FFA/PPA/IFJ: power & coherence  increased power in IFJ & FFA at 2 Hz when attending faces increased power in IFJ & PPA at 1.5 Hz when attending houses associated increases in coherence between IFJ and FFA/PPA, also in gamma frequency band, temporal delay in coherence IFJ  FFA/PPA~ 20 ms Hypothesis about control of spatial attention?

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