1. Human Neuropsychology,
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
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