Fundamentals of Human Neuropsychology, Sixth Edition Chapter 15 Lecture PPT

1. Bryan Kolb & Ian Q. Whishaw’s Fundamentals of Human Neuropsychology, Sixth Edition Chapter 15 Lecture PPT Prepared by Gina Mollet, Adams State College

2. The Frontal Lobes

3. Portrait: Losing Frontal-Lobe Functions • E.L. • Highly organized college professor • Became disorganized, showed little emotion, and began to miss deadlines • Scores on intelligence and memory tests were superior • Showed impairment on frontal lobe tests

4. Anatomy of the Frontal Lobes • Constitute 20% of the neocortex • Subdivisions • Motor: Area 4 • Premotor: Areas 6 and 8 • Can be divided into: • Lateral area 6: Premotor cortex • Medial area 6: Supplementary motor cortex • Area 8: Frontal eye field • Area 8A: Supplementary eye field

5. Anatomy of the Frontal Lobes • Prefrontal Cortex • Area of the frontal lobe that receives input from the dorsomedial nucleus of the thalamus • Divisions • Dorsolateral Prefrontal Cortex • Inferior Frontal Cortex • Also called Orbitofrontal cortex • Medial Frontal Cortex • Sometimes considered part of the cingulate • Many areas of the frontal lobe are multimodal

8. Connections of the Motor and Premotor Areas • Motor Cortex • Projects to spinal motor neurons, cranial nerves that control the face • Projects to the basal ganglia and the red nucleus • Premotor • Projections to the spinal cord • Projections to the motor cortex

9. Connections of the Motor and Premotor Areas • Premotor • Receives projections from parietal areas PE and PF • Receives projections from dorsolateral prefrontal area • Eye fields • Receive from PG and the superior colliculus

10. Connections of the Prefrontal Areas • End of dorsal and ventral streams of visual input • Dorsolateral Prefrontal Area • Reciprocal connections with the posterior parietal and STS • Extensive connections with the cingulate cortex, basal ganglia, and superior colliculus • Receives input from dopaminergic cells in tegmentum

11. Connections of the Prefrontal Areas • Orbital Frontal Cortex • Receives from the temporal lobe, amygdala, gustatory cortex, somatosensory cortex, olfactory cortex, dopaminergic cells in tegmentum • Projects to hypothalamus and amygdala

14. A Theory of Frontal-Lobe Function • Planning and selection • Persistence and ignoring distracting stimuli • Memory for what you have already done • Executive Functions • Responds to both internal, external, and context cues

15. Functions of the Premotor Cortex • Selects movements to be executed • Functions to choose behavior in response to external cues • An increase in activity in the premotor cortex is seen when cues become associated with movement

16. Functions of the Prefrontal Cortex • Controls cognitive processes so that appropriate movements are selected at the correct time • Internal Cues • Temporal memory: Memory for what has just happened • External Cues • Feedback about rewarding properties of stimuli • Orbital Frontal Cortex - Learning by association

17. Functions of the Prefrontal Cortex • Context Cues • Orbital Frontal - Social Interactions • Autonoetic Awareness • Self knowledge • Binding together the awareness of oneself as continuous through time

18. Asymmetry of the Frontal Lobes • Left • Language • Encoding memories • Right • Nonverbal movements, facial expression • Retrieving memories

20. Heterogeneity of Frontal-Lobe Function • Frontal lobes perform a variety of functions • Frontal damage is unlikely to produce impairment to all functions

22. Snapshot: Heterogeneity of Function in the Orbitofrontal Cortex • Stephen Frey and Michael Petrides • Examined functions of the orbital region using PET • Increased activity in area 13 to unpleasant auditory stimuli • Increased activity in area 11 when learning new visual information • Functional dissociation between the two areas • Area 13: Responds to affective qualities • Area 11: Processes new visual information

24. Symptoms of Frontal Lobe Lesions • Disturbances of Motor Function • Loss of fine movements, speed, and strength • Typically appears after damage to the primary motor cortex • Loss of movement programming • Damage to the premotor or dorsolateral cortex • Changes in voluntary gaze • Damage to the frontal eye fields

26. Symptoms of Frontal Lobe Lesions • Disturbances of Motor Function • Corollary discharge or reafference • Internal neural signal that movement will occur • Frontal lobe damage disrupts corollary discharge • Speech Problems • Damage to Broca’s area • Agrammatism • Damage to the supplementary motor cortex • Mute

27. Symptoms of Frontal Lobe Lesions • Convergent vs. Divergent Thinking • Convergent thinking: Only one answer to the question • Divergent thinking: Questions that ask for a variety of responses • Frontal lobe patients are impaired on divergent thinking • Loss of behavioral spontaneity • Decreased verbal fluency • Decreased design fluency • Reduction in general behaviors

30. Symptoms of Frontal Lobe Lesions • Increased perseveration • Inability to form a strategy • Larger deficit when completing novel tasks • Loss of response inhibition • The Wisconsin Card Sorting Task • The Stroop Test

31. The Wisconsin Card Sorting Test

32. The Stroop Test

33. Symptoms of Frontal Lobe Lesions • Take more risks • Iowa Gambling Task • Appears after damage to the orbitofrontal cortex • Deficits in self-regulation • Loss of associative learning • Inability to select from competing responses

34. Testing Associative Learning

35. Symptoms of Frontal Lobe Lesions • Poor Temporal Memory • Five animal experiments indicate a role for the frontal lobe in temporal memory • Area 46 • Role in providing an internal representation of spatial information • Active during delayed response test • Medial regions • Role in object recognition

36. Experiments Showing Deficits of Temporal Memory

37. Symptoms of Frontal Lobe Lesions • Poor Temporal Memory • Studying Temporal Memory in Humans • Recency memory • Tests memory for the order in which things have occurred • Frontal lobe patients show impairment on this task • Recent Findings on Temporal Memory • Critical role for the prefrontal cortex • Fuster and colleagues • Single cell recording of sensory associations across time

39. Symptoms of Frontal Lobe Lesions • Impaired social and sexual behavior • Example: Phineas Gage

40. Symptoms of Frontal Lobe Lesions • Impaired social and sexual behavior • Changes in personality • Pseudodepression • Appears after lesions of the left frontal lobe • Outward apathy, indifference, loss of initiative • Reduced sexual interest, Little or no verbal output • Pseudopsychopathy • Appears after lesions of the right frontal lobe • Immature behavior, lack of tact and restraint • Promiscuous sexual behavior • Coarse language, lack of social graces, increased motor activity

41. Symptoms of Frontal Lobe Lesions • Impaired social and sexual behavior • Deficits in Social and sexual behavior • Orbitofrontal lesions • Reduce inhibitions and may introduce abnormal sexual behavior • Leads to deficits in identifying facial expressions • Dorsolateral lesions • Reduce interest in sexual behavior

42. Symptoms of Frontal Lobe Lesions • Spatial Deficits? • May be a role for the frontal lobe in selecting visual locations • Symptoms Associated with Damage to the Frontal Facial Area • Sensory and motor functions of the face are preserved after damage • Left: Loss of verbal fluency • Right: Loss of design fluency

43. Clinical Neuropsychological Assessment of Frontal Lobe Damage

44. Imaging Frontal Lobe Function

46. Diseases Affecting the Frontal Lobe • Schizophrenia • Abnormality in the mesocortical dopaminergic projection • Decrease in blood flow to the frontal lobes, and frontal lobe atrophy • Parkinson’s Disease • Loss of dopamine cells in the substantia nigra that project to the prefrontal cortex • Korsakoff’s • Alcohol-induced damage to the dorsomedial thalamus and a deficiency in frontal lobe catecholamines