Cogsci/Psychology 127: Lecture 24 Cognitive Control

1. Cogsci/Psychology 127: Lecture 24 Cognitive Control

2. Announcements No sections this week-- Eat the Bird! Lecture posting problem! “Frozen Access”

3. Sustained activity in PFC can extend for long intervals Cue indicates location for future response Make Response

4. What do the sustained activations represent? Long term representations? But PFC patients don’t have LTM problems.

5. What do the sustained activations represent? Long term representations? But PFC patients don’t have LTM problems. Transient links to LTM

6. Lateral PFC as WM Buffer for Task-Relevant Information

7. Working Memory as resulting from interaction of task-goal and long-term knowledge relevant to that goal. • 1. PFC can sustain representation of information that is not present or supported by environment (tell friend about trip to San Francisco). • Links with rest of brain allow task-relevant information to remain active.

8. Working Memory as resulting from interaction of task-goal and long-term knowledge relevant to that goal. • 1. PFC can sustain representation of information that is not present or supported by environment (tell friend about trip to San Francisco). • Links with rest of brain allow task-relevant information to remain active. • PFC performing a selection operation.

9. Lateral PFC and Selection Planning the Family Budget Food $350/month Clothing $175/month Housing $840/month Control Participant Focused on reducing $175/month for clothing: “That seems like a lot. Oh come on now. I haven’t spent that much money per month. That’s going to have to change.”

10. Lateral PFC and Selection Planning the Family Budget Food $350/month Clothing $175/month Housing $840/month Control Participant Focused on reducing $175/month for clothing: “That seems like a lot. Oh come on now. I haven’t spent that much money per month. That’s going to have to change.” PFC Patient PFC: “Shelter is the biggest item... Now if they can eliminate that... $10,800, they save a year. Exp: “But you need a place to live. PFC: Yes. Course I know a place that sells tents cheap. You can buy one of those.”

11. Lateral PFC and Selection Planning the Family Budget Food $350/month Clothing $175/month Housing $840/month Control Participant Focused on reducing $175/month for clothing: “That seems like a lot. Oh come on now. I haven’t spent that much money per month. That’s going to have to change.” PFC Patient PFC: “Shelter is the biggest item... Now if they can eliminate that... $10,800, they save a year. Math isn’t quite right ($840 x 12 = $10,080)

12. Working Memory as resulting from interaction of task-goal and long-term knowledge relevant to that goal. • PFC can sustain representation of information that is not present or supported by environment • e.g., A goal such as tell friend about trip to San Francisco • Links with rest of brain allow task-relevant information to remain active. • PFC performing a selection operation. • Mechanism of selection?

13. Working Memory as a Filtering Process: Amplification of task-relevant information? Inhibition of task-irrelevant information? Is the bridge really gold? Amplification Inhibition

14. Early evoked responses to irrelevant auditory clicks: PFC patients show stronger N1 response. Failure of inhibition of irrelevant stimuli. Temporal-parietal show reduced N1. Why?

15. Is modulation over longer periods also inhibitory? PFC activity is high during the stimulus and delay periods. But what happens in posterior regions specialized for processing faces and places?

16. Is modulation over longer periods also inhibitory? PFC activity is high during the stimulus and delay periods. Task-dependent enhancement and suppression during stimulus presentation.

17. Are amplification and inhibition different processes? Perhaps different neural systems, transmitters?

18. Are amplification and inhibition different processes? Perhaps different neural systems, transmitters? Aging study provides single dissociation. Data from PPA.

19. Effects of PFC damage viewed as failure for successful maintaining relevant information and filtering of irrelevant information. Performance of PFC-lesioned monkeys improves dramatically if room is darkened during delay period. Distraction leads to loss of goal.

20. Effects of PFC damage viewed as failure for successful maintaining relevant information and filtering of irrelevant information. Performance of PFC-lesioned monkeys improves dramatically if room is darkened during delay period. Distraction leads to loss of goal. Memory enhancement with eyes closed (Gazzeley).

21. Requirements for Goal-Oriented Behavior • Working memory: • -- Maintenance of goal • -- Inhibition of irrelevant information • and amplification of relevant information.

22. Requirements for Goal-Oriented Behavior • 1. Working memory: • -- Maintenance of goal • -- Inhibition of irrelevant information and amplification of relevant information. • 2. Cognitive control: Mental operations that support flexible behavior. • Planning • Task management • Attention and selection • Monitoring

23. Imaging studies consistently show activation across range of tasks involving “cognitive control in medial frontal cortex. -- Areas 24 and 32 (anterior cingulate cortex (ACC) -- Ventromedial zone of Areas 8 and 6 (pre-SMA)

24. Functional Role of Medial Frontal Cortex? A success story of cognitive neuroscience.

25. Functional Role of Medial Frontal Cortex 1. Top of attentional control hierarchy: Supervisory Attentional System (SAS) -- a “smart” hypothesis

26. MFC as coordinating WM buffers in PFC Medial Frontal Cognitive Control

27. Functional Role of Medial Frontal Cortex • 1. Top of attentional control hierarchy • Error detection: • Error-related negativity (ERN) in ERP signal

28. Functional Role of Medial Frontal Cortex • 1. Top of attentional control hierarchy • Error detection: • Error-related negativity (ERN) in ERP signal • Encompasses Attention hypo: Errors signal that control is needed.

29. Functional Role of Medial Frontal Cortex • 1. Top of attentional control hierarchy • Error detection • Problems for error detection account: a. How do you know when an error has been made? The homunculus problem. b. MFC active in many conditions in which errors do NOT occur • Control Experimental • Verb generation: APPLE “Apple” “Peel” • Stroop: GREENGREEN

30. Functional Role of Medial Frontal Cortex 1. Top of attentional control hierarchy 2. Error detection 3. Conflict monitoring MFC signals activation of multiple responses. Encompasses: Error detection: Errors more likely to occur when multiple responses active. Attention hierarchy: Conflict situations are ones that require increased control.

31. Lateral prefrontal cortex and MFC are both recruited when need for cognitive control is high. Stroop: The MOST consistent neuroimaging result. No Conflict: GREEN Conflict: GREEN

32. Lateral prefrontal cortex and MFC are both recruited when need for cognitive control is high. Stroop: The MOST consistent neuroimaging result. Characterizing their differential functions: event-related fMRI using slow motion “Cued Stroop” Easy Rule: Word Low Conflict: Congruent Hard Rule: Color High Conflict: Incongruent

33. Rule Conflict Cue Epoch Stimulus Epoch Red: Word/Easy Black: Congruent Black: Color/Hard Green: Incongruent

34. Component analysis of regions implicated in imaging studies of mental flexibility Functional Hypotheses Lateral PFC: Maintain current rule or goal Basal Ganglia: Implement change in cognitive set Medial Frontal: Monitor (via sensitivity to conflict)

35. Component analysis of regions implicated in imaging studies of mental flexibility Functional Hypotheses Lateral PFC: Maintain current rule or goal Basal Ganglia: Implement change in cognitive set Medial Frontal: Monitor (via sensitivity to conflict) Cognitive control via “dumb” mechanisms. PFC representing goal (information not in environment) BG releasing new state when activation reaches threshold. MFC bolsters rule/goal representation when conflict is present.

36. Trouble in Paradise Do lesions of Medial Frontal Cortex impair cognitive control?

37. Trouble in Paradise Do lesions of Medial Frontal Cortex impair cognitive control? Four patients with ACC/MFC lesions Stroop task with High Conflict: Expectancy of incongruent words is low 80% congruent 20% incongruent Low Conflict: Expectancy of incongruent words is high 20% congruent 80% incongruent Predictions? 1. Congruent vs. Incongruent 2. Incongruent trials in High vs. Low Conflict

38. Trouble in Paradise Do lesions of Medial Frontal Cortex impair cognitive control? Four patients with ACC/MFC lesions Stroop task with High Conflict: Expectancy of incongruent words is low Low Conflict: Expectancy of incongruent words is high High Conflict Low Conflict DV: Increase in RT on incongruent trials. • Failed Predictions of ACC control model: • Patients do not show increased Stroop effect • Patients show normal modulation of effect as function of expectancy manipulation.

39. Functional Role of Medial Frontal Cortex • 1. Top of attentional control hierarchy • 2. Error detection • Conflict monitoring • Arousal • The ultimate “dumb” mechanism?