SOKENDAI physiology lecture course 2013"Neuroscience of Cognition and Motor control" #4"Attention and Motor Control"May 24, Friday 10:00-12:00, Myodaiji Staff Hall 2F Meeting roomMasatoshi Yoshida (NIPS and SOKENDAI, Assistant professor)1. Introduction1-1. What is attention? -- Let’s start fromexamples• We cannot consciously perceive a big changein a scene when we do not pay attention to it.• Attention has a strong influence on what wesee.1-2. Definition of attention• William James (Principles of Psychology(1890)): "Everyone knows what attention is. Itis the taking possession by the mind in clearand vivid form, of one out of what seemseveral simultaneously possible objects...Itimplies withdrawal from some things in order todeal effectively with others..."1.3 Taxonomy of attention• Two kinds of attention• Selective attention: ability to focus onpositions or objects• Sustained attention: alertness, ability toconcentrate• What drives selective attention?• Bottom-up: stimulus-driven (pre-attentive,pop-out)• Top-down: goal-directed• What is selected in selective attention?• Position: spatial attention• Object (feature): object (feature)-basedattention• Bottom-up vs. top-down attention in pre-cuetask• Bottom-up attention1• Top-down attention2. Attention and eye movements2-1. Neural network for attention andsaccadic eye movements• Brain regions involved in bottom-up attention• Brain regions involved in top-down attention2• Brain regions involved in saccadic eyemovements2-2. Overt attention and covert attention inhuman• Overt attention and Covert attention3• Overt selection of visual features containedwithin a portrait as revealed by the scanningeye movements.• The female monkey on the left is lookingstraight ahead. However, it is apparent thatshe is fully attending to her neighbor.• Overt attention and covert attention activatethe same brain regions. 4,52-3. Overt attention and covert attention inmonkey• Saccade control system• FEF: frontal eye field (premotor cortex foreye)• SC: superior colliculus (one of the midbrainstructures)• FEF is involved in covert attention6• Electrical stimulation to FEF directs covertattention without evoking saccades.• SC is involved in covert attention7• Inactivation of SC leads to deficits in covertattention but does not affect MT and MST.• The effect of inactivation is not an indirect
effect on MT/MST but a direct effect on SC(or FEF).• Cortex is not necessary for attention!3. Dorsal and ventral attention network3-1. Dorsal and ventral attention network inhuman• When top-down attention is manipulated bypre-cue, both dorsal and ventral attentionsystems are activated.8• Note these are NOT the dorsal and ventralvisual pathway• Resting state BOLD activity8• Strong and significant positive temporalcorrelation of spontaneous activity at rest.• The dorsal network is anti-correlated with thedefault network.3-2. Spatial hemineglect as a disorder ofattentional network• What is spatial hemineglect?• The inability to report, respond, or orient tostimuli in the contralesional space.• The deficit must not be fully attributable toprimary sensory deficits (e.g., hemianopia) ormotor disturbance (e.g., hemiparesis).• Neglect occurs more commonly in those withbrain injury affecting the right corticalhemisphere.• Where is the key lesion site?• Hemineglect as a disorder of network9• Activity of MFG and STS shows a sign ofrecovery in the chronic period.• However, functional connectivity did notrecover in the chronic period.3-3. Ventral attention network in monkey?• The ventral attention system (TPJ-IFG) is notidentified in monkeys.• Monkeys have no BA40 (TPJ/SMG).• (Putative BA40 is part of BA7).• The dorsal network may be mediated by SLFII.• SLF(the superior longitudinal fasciculus)• SLFII: spatial attention and spatialawareness• The ventral network may be mediated by AF(the arcuate fasciculus).10• AF connection is very sparse in macaque114. Saliency computational model4-1. What is saliency map?• What is saliency?• salient (adj): “very easy to notice”• visual salience (or visual saliency): thedistinct subjective perceptual quality whichmakes some items in the world stand outfrom their neighbors and immediately grabour attention.(Scholarpedia by Laurent Itti)• What grabs our attention?• Where is the object that is different from therest?• Feature integration theory12• Original computational model13• A unique saliency map, independent offeatures• Winner-take-all rule (WTA)• Selection was made on the saliency map• What is saliency map?• An explicit 2D map that encodes the saliencyof objects in the visual environment• A computational concept• Saliency computational model14• Iterative calculation of center-surrounddifferentiation and normalization• Intracortical lateral inhibition ismathematically equivalent to secondderivative (=laplacian). It is used for edgedetection.4-2. Applications of the saliency model• Application #1: Modeling visual search• Application #2: Advertisement• AD people collect eye-tracking data toevaluate the effect of advertisement.• But it is expensive and time-consuming.• You do not need to collect eye-tracing data if
you use the saliency model instead.• Now it is commercially available.4-3. Saliency map in the brain• Brain network involved in saliency4-4: Saliency map in the brain - Parietalcortex• Temporal saliency drives LIP neurons15• Visual information (stimuli in RF) issufficient?• Or saliency (abrupt onset of stimuli) isnecessary?• Stimuli with low saliency (stable stimuli) didnot drive a LIP neuron.• Visual information (stimuli in RF) is notenough!• Stimuli with high salience (recently flashedstimuli) drive a LIP neuron.• LIP represents visual salience.• Decoding saliency from the brain16• The difference of saliency in four quadrantscan be decoded from pIPS and early visualcortex.4-5: Saliency map in the brain - Is V1necessary?• Computational model predicts monkey’s gaze• Salient stimuli attract gazes of blindsightmonkeys17• The gaze positions have higher saliency,than expected from random eye movement.• Revised view of saliency computation4-6: Clinical application 1 - ADHD• Classification of neurological disorders18• Eye-tracking (20min) is sufficient to classifysubjects, if combined with the saliencymodel.4-7: Clinical application 2 - autism• Autistic people do not look at eyes. But why?• Visual saliency of eyes and mouth matters.19• The authors generated many images withdifferent saliency for eyes and mouth.• The autistic people see the mouth evenwhen the saliency is low.• The autistic people do not avoid the eyes.Rather, they preferentially look at the mouth.4-8: Clinical application 3 - schizophrenia• Aberrant salience hypothesis of psychosis205. Summary• Attention and eye movements share the samebrain circuitry.• Dorsal and ventral attentional networks areidentified in humans (but not yet in monkeys).• Saliency computational model is able topredict gaze of humans and monkeys.References1. Ikeda, T., Yoshida, M. & Isa, T. Lesion of primaryvisual cortex in monkey impairs the inhibitory butnot the facilitatory cueing effect on saccade.Journal of Cognitive Neuroscience 23, 1160–1169(2011).2. Baluch, F. & Itti, L. Mechanisms of top-downattention. Trends in Neurosciences 34, 210–224(2011).3. Moore, T., Armstrong, K. M. & Fallah, M.Visuomotor origins of covert spatial attention.Neuron 40, 671–683 (2003).4. Beauchamp, M. S., Petit, L., Ellmore, T. M.,Ingeholm, J. & Haxby, J. V. A parametric fMRIstudy of overt and covert shifts of visuospatialattention. NeuroImage 14, 310–321 (2001).5. de Haan, B., Morgan, P. S. & Rorden, C. Covertorienting of attention and overt eye movementsactivate identical brain regions. Brain Research1204, 102–111 (2008).6. Moore, T. & Fallah, M. Control of eye movementsand spatial attention. Proc Natl Acad Sci USA 98,1273–1276 (2001).7. Zénon, A. & Krauzlis, R. J. Attention deficits withoutcortical neuronal deficits. Nature 489, 434–437(2012).8. Corbetta, M. & Shulman, G. L. Spatial neglect andattention networks. Annu. Rev. Neurosci. 34,569–599 (2011).9. He, B. J. et al. Breakdown of FunctionalConnectivity in Frontoparietal Networks UnderliesBehavioral Deficits in Spatial Neglect. Neuron 53,905–918 (2007).10. Petrides, M. & Pandya, D. N. Distinct Parietal andTemporal Pathways to the Homologues of BrocasArea in the Monkey. Plos Biol 7, e1000170 (2009).
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