07a association cortex frontal lobe

1. Director Director
Function Function

2. Stretch Reflex

3. Withdrawal and Crossed Extensor Reflex

4. Locomotion

5. Autonomic Regulation of Cardiovascular Function

6. Emotional Circuit

7. Evolution of Brain

9. Anatomical organization of Cerebrum

10. Grey Matters

11. TheAssociationCortices

12. Cortical Architecture

13. Intracorticalcircuits

14. Cortical Lamination

15. Brodmann'scytoarchitectonicmapping of the human brain

17. Broadman's #
NAME
FUNCTION
17
Occipital Lobe
Visual Projection Cortex
18
Visual Association Cortex
19
Posterior Parietal Lobe
Visual Association Cortex
37
Tempero-parietal-occipital area
General Sensory Association Cortex
39
Angular Gyrus
Word Recognition
40
Supramarginal Lobe
Somatosensory Association Cortex
1,2,3
Postcentral Gyrus
Somatosensory Projection Cortex
5, 7
Superior Parietal Lobule
General Sensory Association Cortex
41, 42
Middle 1/3 of Superior Temporal
Cortex
Auditory Projection Cortex
22
Superior Temporal Gyrus
Auditory Association Cortex
21, 20, 38
Inferior Temporal Cortex
General Sensory Association Cortex
4
Precentral Gyrus
Primary Motor Cortex
1,2,3
Postcentral Gyrus
Somatosensory Projection Cortex
6,8,9
Premotor Cortex
Motor Association Cortex
41, 42
Middle 1/3 of Superior Temporal Cortex
Auditory Projection Cortex
44,45,46
Broca's Area
Motor Association Cortex - Specific to speech
10
Preftontal Cortex
General Motor Association Cortex
11
Orbital Gyri
General Motor Association Cortex

18. Input-output relationships of cortex.

19. Cerebral Cortex and Thalamus

20. Noradrenergic neurons in the pons
¾Important for focused attention

21. Dopaminergicneurons in the brain stem and hypothalamus
Dopamine in the caudate nucleus facilitates posture, whereas dopamine in the nucleus accumbens is
associated with an animal's speed (and pleasure).

22. SerotonergicCell Groups
Serotonin seems to have distinctive actions contributing to anxiety
and impulsive behavior.
Patients with ev idence of low serotonin levels have attempted suicide
by very dramatic means, such as cutting the throat

23. Cholinergic Cell Groups (wake sleep cycle)

24. Sensory Pathway

25. Visual Pathway

26. Auditory Pathway

27. Taste Pathway

29. Corticospinaltract

30. Cerebral Cortex: Functional Organization

31. Association cortices

32. Pathways to the somatosensory, visual, and auditory association areas

33. Unimodal sensory inputs converge on multimodal association areas

34. The Sequence of Information Processing Is Reversed in the Motor System

35. Sensory Motor Association Cortex

36. Frontal Lobe is an “Essence of Human being”
Gives our capacity to feel empathy, sympathy, understand humor and
when others are being ironic, sarcastic or even deceptive.

37. Evolution of Human Frontal Lobe The high, straight forehead that characterizes modern humans,
superceding the prominent brow ridges of our ancestors, is due to the
expansion of the cortex, and especially th e prefrontal cortex, in our species.
1. Australopithecus robustus2. Homo habilis3. Homo erectus 4. Homo sapiens neanderthalensis5. Homo sapiens sapiens

38. Phinease Gage (1848)
On 13
th
Sept 1848 a railroad
worker hard working,
diligent, reliable, responsible,
intelligent, good humored,
polite god fearing, family
oriented foreman
Following an explosion iron bar
drove into frontal lobe
1. He becomes unreliable and fails to
come to work and when present
he is "lazy."
2. He has no interest in going to
church, constantly drinks alcohol,
gambles, and "whores about."
3. He is accused of sexually molesting
young children.
4. He ignores his wife and children
and fails to meet his financial and family obligations.
5. He has lost his sense of humour. 6. He curses constantly and does so
in inappropriate circumstances.
7. Died of status epilepticus in 1861

39. Frontal Lobe ablation in Monkey and Dogs (Bianchi) "The frontal lobes are the seat of c oordination and fusion of the incoming
and outgoing products of the several sensory and motor areas of the
cortex" (Bianchi, 1895)
• Loss of "perceptive power", leading to defective attention and object
recognition.
• Reduction in memory. • Reduction in "associative power", leading to lack of coordination of the
individual steps leading towards a given goal, and thus to severe
difficulty solving anything but the most simple problem.
• Altered emotional attachments, leading to serious changes in "sociality"
[one of the main aspects of Phineas Gage's post-traumatic behaviour].
• Disruption of focal consciousness and purposive behaviour, leading to
apathy and/or distractibility [ one of the main aspects of Becky'spost-
operative behaviour].
Bianchi 1922

40. History Dandy’s (1936)
– following bilateral frontal
lobotomy during removal of
meningioma
Feuchtwanger (1923)
200 case of frontal lobe injury – Lack of initiative – Vacillation – Euphoria – Inattentiveness – Normal intellect and memory
Jacobson (1935)
– Premotor lobotomy in
primates ->
– Social indifference – Tameness –Placidity – Forgetfulness – Difficulty in problem solving
Æ
EgasMoniz 1935
– Prefrontal lobotomies in
psychotics

41. Inferiomesial Frontal leukotomy Egas Moniz 1935
Hours
–Drowsy – Apathetic – Incontinent – Akinetic –Mute
Days
– Decreased initiative – Lack of concern – Freedom from anxiety – Apathetic
Weeks to months
– Regained memory and
intellect
– With personality changes – Indifferent to the others
problem
– No thought to their conduct – Tactless – Distractible – Socially inept – Euphoria and emotional
outburst

42. Frontal lobe and Psychiatry Schizophrenia :
– Involving dorsolateral
prefrontal cortex
– affective changes, impaired
motivation, poor insight. and
other "defect symptoms
– Evidence : Neuropathologic
studies, (23) in EEG studies,
(24) in radiological studies
using CT measures, (25) with
MRI, (26) and in cerebral
blood flow (CBF) studies.
Personality disorder: Antisocial
Personality disorder with impulsivity of
frontal lobe
Attention deficit syndrome with distractibility of frontal lobe

43. Attention skills ¾Selective attention: the ability to efficiently 'f ilter' information; to detect
information that is relevant and ignore irrelevant or distracting
information.
¾Sustained attention: the ability to actively at tend to a task, goal, or own
behavior despite there being little stimulation for such continued
processing.
¾Divided attention: the ability to monitor or at tend to two things at once. ¾Shifting attention : the ability to shiftattention between two or more
tasks.

44. Thinking skills ¾Organization: the ability to arrange or place things in a meaningful
system.
¾Planning: the ability to create a 'bluepri nt' or strategy for reaching goals
or completing a task.
¾Time management: the ability to effectively estimate how much time one
has, how to spend that time, and how to stay within time limits and meet
deadlines.
¾Working memory : the ability to hold information in immediate awareness
while performing a mental operation on that information.
¾Metacognition: the ability to think about one's own thoughts, behaviors,
and feelings in a given situation. It in volves being able to self-monitor or
evaluate one's skills.

45. Monitoring skills ¾Response inhibition: the ability to think befor e acting. Doing so, gives
one the time to evaluate a situati on and determine how one's behavior
might affect it.
¾Self-regulation of affect : the ability to manage emotions in order to
achieve goals, complete tasks, or control and direct behavior.
¾Task initiation: the ability to start a task without procrastinating. ¾Flexibility: the ability to revise plans or directed behavior when there are
obstacles, setbacks, new information, or mistakes; adapting to
environmental changes.
¾Goal-directed persistence: the ability to self-motivate and see things
through to completion or reaching of a goal
.

46. ~ 1/3 of cortical surface Most recently evolved Well developed only in primates
– the advent of the human
species: "age of the frontal
lobe"
develops late in ontogeny
– differentiation through age 1 – maturation through age 6
Prefrontal cortex

47. Input from association cortex
(occipital, parietal, temporal &
olfactory areas)
convergence of higher-order
input
from all modalities.
Reciprocal connections:
prefrontal processing modulates perceptual processing.
LIMBIC connections
(memory/emotion)
Input to premotor areas
-
controls/programs behavior.
Connectivity of Prefrontal regions

48. Premotor & Motor Areas Premotor areas (6) - input from
prefrontal regions and parietal
association areas (5,7).
Area 4: primary motor cortex
– input from premotor area (6)
and area 44
– sends output to spinal cord,
and other motor structures (basal ganglia)
Frontal network controls voluntary,
planned actions.

49. “Planning Neurons”in the Monkey Frontal Cortex

50. Neuron Firing in the Principal Sulcustrack the working Memory

51. Working Memory

52. Imaging of Working Memory

53. Interaction Among Association Areas

54. Beyond Motor Planning ¾Frontal lobe has evolved from being the main motor planner/organizer
to a higher level behavioral/strategic planner/organizer.
¾Mental model, considering options, selecting behaviors based on
context, feedback, stored knowledge
¾Making predictions about what will work.

55. Impaired divergent thinking ¾Decreased consideration of alternative strategies/ behaviors; reduced
flexibility
¾Decreased spontaneity, initiative , may appear lazy, unmotivated ¾Knowledge/intelligence may seem intact (e.g. IQ) but its not used to
generate strategies or solve problems efficiently

56. Decreased Inhibition ¾Problems inhibiting incorrect/ineffe ctive responses & switching to a
new strategy
¾Perseverates; not responsive to feedback or changes in environment ¾Violates rules, expectancies; takes risks ¾Not adaptable ¾Decreased social inhibitons as well

57. Impaired association learning ¾Reduced response to consequences ¾Impaired on delayed response tasks ¾Impaired responsiveness to social & contextual cues

58. Impaired temporal learning ¾Impaired memory for order ¾Could affect problem-solving, planning and impair systematic,
organized behaviours

59. Personality and emotional changes ¾Apathetic, indifferent, loss of initiative, lack of emotion or somewhat
depressed, little verbal output. Most common after left frontal damage;
called "pseudodepression"
¾Lack of tact & restraint, immature, coarse,lack of social graces, inappropriate sexual behavior, increased motor activity. More
common after right frontal damage; called "pseudopsychopathic"

60. Memory defect
¾Part of more general disturbance in thinking ¾Can recall the details of prob lem, error in trying to solve ¾Could not put them to use in the correction of further
performance.
¾Cannot categorizes series of item in group for recall

61. Frontal lobe and arousal ¾Right frontal lobe exerts bilateral influences on arousal ¾The right frontal lobe is also lar ger than the left suggesting a greater
degree of interconnections with other brain tissue, and it appears to
exert bilateral inhibitory influences on attention and arousal
¾However, because the right frontal lobe appears to exert bilateral
inhibitory influences, whereas the influences of the left are unilateral
and excitatory, when the left fronta l region is damaged, the right may
act unopposed and there may be excessive left cerebral inhibition or
reduced activity

62. Personality and behavior ¾Lack of initiative and spontaneity ¾Placidity: worry, anxiety, self concern, hypochondriasis, and pain
reduces
¾Psychomotor retardation: number of movements, spoken words and
thought per unit of time diminish. Mi ld form abulia and severe akinetic
mutism.
¾Organic driveness: brief but intense meaningless activity. ¾Loss of ego strength: Witzelsucht or moria : socially uninhibited and
lack aunawerness of their abnormal behavior.
¾Loss of regards to social conventio ns , only interested in personal
gratification.

63. Disinhibited sexuality ¾It is not unusual for a hypersexual, disinhibited frontal lobe injured
individual to employ force.
¾Seizure activity arising from th e deep frontal regions have also been
associated with increased sexual behaviour, including sexual
automatisms, exhibitionism, genital manipulation, and masturbation

64. Summary Frontal lobe function
MotorCognitive Behavior Arousal Voluntary
movements
Memory Personality
Language
Expression
Problem solving Social and sexual
Eye movements Judgment Impulse control
Initiation
Spontaneity
Abstract
thinking
Mood and affect
Attention