1. Cognitive Neuropsychology Interface between cognitive psychology and neuroscience at the systems level. –Systems level: brain “regions” –anatomical (sulci/gyri) to functional (Broca’s area) –areas with consistent neural architecture »Brodmann’s Areas –areas with a “unified” cognitive function »e.g., Dorsolateral prefrontal cortex (BA 9/46, superior parts of 45 and 10 )

2. Brodmann’s areas

3. Functional Regions vs. Brodmann’s Areas

4. Major Sulci and Gyri

5. Orientation and Navigation

6. Cognitive Neuropsychology Goals (for the field and the course): 1)Test cognitive theories of information processing Primary goal of all cognitive neuropsychologists 2) Map cognitive functions to neural regions Ascribe functions to individual regions Localization Determine how multiple regions work together as a system Connectionism Not a primary goal of ultra/radical cognitive neuropsychologists 3) Understand the consequences of brain damage and potential for rehabilitation Primary goal of clinical neuropsychology

7. Cognitive Neuropsychology Focus: behavior of patients with brain injury Explain patterns of impaired/intact cognitive performance in brain-injured patients in terms of damage to one or more components of a theory or model of normal cognitive functioning Draw conclusions about normal, intact cognitive processes from the patterns of impaired/intact capabilities seen in brain-injured patients.

8. Case ‘AC’ Case AC: 67-year old man, formerly employed as a clerical worker in New South Wales, Australia –Neurological profile: Recent stroke in territory of left middle cerebral artery –What regions affected? CT revealed older small lesions in both hemispheres –History of cardiovascular disease

9. Case ‘AC’ –Behavioral profile: Severe Reading deficit: –Could not match upper to lowercase letters (A: a or e?) –How do we know it is not a vision problem? »Could correctly match uppercase letters (A: A or E) –How do we know it is an acquired and not a developmental reading disability? »Formerly employed as a clerk! Severe Writing deficit: –Could not write anything to dictation except name & address –Could not draw to dictation well (pictures) –Could not write the lowercase letter to match an upper case example –How do we know he doesn’t have a motor problem? »Could correctly copy exactly what was shown visually (when didn’t have to translate auditory to visual)

10. Case ‘AC’ Very poor knowledge about properties of animals “The Oyster with Four Legs” (Sartori & Job, 1988) MC: How many legs does an oyster have? AC: A few MC: I see. What about an ant? AC: Some MC: A caterpillar? AC: No legs MC: What about a snake? AC: None MC: And a seagull? AC: Four legs? –Performance was at chance on further testing… –Suggests loss of information…perceptual or semantic?

11. Case ‘AC’ –Problems with “animal” information? Compared performance on animals with legs (e.g., bird, dog) to inanimate objects with legs (e.g., chair, sofa) Performance is at chance; deficit is not animal specific –Problems with “leg-specific” information? Question about “tails” yielded chance performance too Deficit is not leg-specific –Problems with “parts” of an object? No; Unable to make judgments about overall shapes of objects (round or not) or color (black or white) –Damage to information about “perceptual properties”? Most likely: semantic knowledge of objects looks intact Correctly classified animals as dangerous or not, where found, whether used as food, etc. –Damage to information about “visual perceptual properties”? Yes! Could successfully retrieve information about auditory and olfactory features of objects

12. Case ‘AC’: Case Closed! –AC has selectively damaged ability to use visual perceptual information about objects (storage) –Other abilities are mostly intact –What does this tell us about the normal object processing system? –Complex systems reveal their inner workings more clearly when they are malfunctioning –Relies upon assumption of modularity When one part of cognitive system is damaged, others stay intact Building box models…

13. Methods: Considerations What are the component processes required to perform a given cognitive test? Issues in choosing patients Single case vs. Group Studies Selection on the basis of lesion site or functional deficit Time of test: acute vs. chronic stages Site of injury: focal vs. diffuse Distance effects: disconnection and diaschisis What is the appropriate control group? How do you define “normal” performance?

14. Cognitive Neuropsychology and Other Techniques Strong theories of brain-behavior relationships require converging evidence from complementary techniques: ERP, EEG, MEG (neuromonitoring) fMRI (neuroimaging) Virtual lesions (TMS) How does this method complement functional neuroimaging? –Best at determining whether region is critical for process With fMRI, regions other than those critical for process may become activated (e.g., due to feedback connections, strategies) –Can do extensive testing without time limit or methodological constraints With TMS, “lesion” effects are brief, although “patients” can serve as their own controls

15. Functional Neuroimaging of Patients Detect regions of residual responsiveness in perilesional area Detect abnormal responses in distant regions that result from diaschesis (clues about systems…) –Less activation than in normals: region has lost inputs –More activation than in normals: disinhibition (unmasking), compensation Reveals alternative neuronal mechanisms that can support the same task (degeneracy) –Words can be read either by “whole word route” or by “letter to phoneme conversion” –Objects can be recognized by wholes or by parts Reveals structural and functional plasticity/recovery