Bear: Neuroscience: Exploring the Brain 3e Chapter 21: Attention Slide 1 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Introduction Attention: State of selectively processing simultaneous sources of information Benefits: Performance of behavioral tasks Brain Imaging – changes in cortical activity Behavioral manifestations Visual attention Slide 2 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Introduction Functions of attention Concentrate on one object in visual field Selectively attend to information (while ignoring other information) Preferential processing of sensory information Attention-deficit hyperactivity disorder Demonstrates critical nature of intact attentional mechanisms Brain imaging studies Show that cortical activity is altered by attention Slide 3 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Behavioral Consequences of Attention Visual attention Move eyes until object imaged on fovea Shifting attention Enhanced visual processing (1) Enhanced detection (2) Faster reaction times Slide 4 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Behavioral Consequences Of Attention Enhanced Detection Slide 5 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Behavioral Consequences Of Attention Faster Reaction Times Attention: Increases reaction speed Slide 6 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Behavioral Consequences Of Attention Neglect Syndrome as an Attentional Disorder Person ignores objects, people, and their own body to one side of the center of the gaze Slide 7 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects of Attention Shifting attention What happens to neural activity? What brain areas are involved? Observed in high-level cognitive and numerous sensory areas e.g., Area V1 to visual cortical areas in the parietal and temporal lobes Slide 8 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects of Attention Slide 9 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects Of Attention Functional MRI Imaging of Attention to Location Subjects view stimulus Change location of attended sector Brain activity shifts retinotopically Slide 10 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects of Attention PET Imaging of Attention to Features Same-different discrimination task Features: Color, shape, speed (A) Selective attention: one feature (B) Divided attention: all features Subtract B from A shows brain activity associated with attention to one feature Slide 11 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects of Attention PET Imaging of Attention to Features (Cont’d) V4, IT and other visual areas in temporal lobe Color & shape Area MT Speed of motion Slide 12 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects Of Attention PET Imaging of Attention to Features (Cont’d) Slide 13 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects Of Attention Enhanced Neuronal Responses in Parietal Cortex Attention: Experimental vs. Normal conditions What happens to attention under normal conditions? Assumption: Attention changes location prior to eye movement Wurtz, Goldberg, and Robinson Record neural activity from several brain regions Slide 14 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects Of Attention Enhanced Neuronal Responses in Parietal Cortex (Cont’d) Posterior parietal cortex neurons Directing eye movements Response significantly enhanced neuronal response when eyes went to target Spatially selective effect – not a general increase in excitablility Slide 15 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Physiological Effects Of Attention Receptive Field Changes in Area V4 Slide 16 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins How is Attention Directed? Cortical, subcortical areas Modulate the activity of neurons in sensory cortex areas The Pulvinar Nucleus Guiding attention Muscimol GABA agonist Neuron activity suppressed Slide 17 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins How is Attention Directed? Attention and Eye Movements Eye moves to attended object Eye movements & attention closely related Recent experiments Brain circuitry: Directing eyes to objects of interest Frontal Eye Fields (FEF) Cortical area FEF neurons Slide 18 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins How is Attention Directed? Attention and Eye Movements (Cont’d) Experiment Train monkeys to look at display of small light spots Place electrode in FEF and determine motor field of neurons at the tip Small electrical stimulation enhancement? Results FEF involved in directing attention; Enhancing visual performance V4 activity increased Slide 19 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins How is Attention Directed? Attention and Eye Movements Results (Cont’d) FEF stimulation mimics physiological and behavioral effects of attention Electrical stimulation of superior colliculus Conclusion Guidance of attention Integrated with system to move eyes Slide 20 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins Concluding Remarks Studies of attention Point to flexibility of the human brain More mental energy to one location Enhanced sensitivity & reaction time Ignoring competing stimuli Need for attention e.g.,- Cannot process information in area V1 Selects what information should access the limited processing resources Slide 21 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins End of Presentation Slide 22 Neuroscience: Exploring the Brain, 3rd Ed, Bear, Connors, and Paradiso Copyright © 2007 Lippincott Williams & Wilkins