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Frontallobe dr prashant mishra

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frontal lobe ppt
svs medical college

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Frontallobe dr prashant mishra

  1. 1. Presenter :Dr. Prashant MishraModerator : Dr. V Sharbandh Raj
  2. 2. OUTLINE: FRONTAL LOBE 1. Evolution 2. Anatomy and connections 3. Physiology 4. Circuits and Neurotransmitters 5. Dysfunction  Frontal lobe Syndromes  Frontotemporal Lobe Dementia  Frontal Lobe Epilepsy  Expressive aphasia  Schizophrenia  Depression 6. Frontal lobeTesting
  3. 3. MAMMALS FRONTAL LOBE EVOLUTION  33% of Brain area  Most recently evolved  Well developed only in primates  Human species is due to frontal lobe  Last to develop in ontogeny from age 1-> 6years  Gives our capacity to feel empathy, sympathy, understand humor and when others are being ironic, sarcastic or even deceptive.
  4. 4. FRONTAL LOBE A. Lateral surface 1. Posterior - Central sulcus 2. Inferio-Posterior – sylvian fissure. B. Medial surface C. Orbital surface
  5. 5. FUNCTIONAL FRONTAL LOBE ANATOMY Premotor area Primary motor area B6 B4 Central sulcus Supplementary motor area (medially) Frontal eye field B8 Prefrontal area B 9, 10, 11, 12 Lateral sulcus/ Motor cortex Sylvian fissure 1. PrimaryPrefrontal cortex Motor speech 2. Premotor 1. Dorsolateral area of Broca 3. Supplementary 2. Medial 4. Frontal eye 3. Orbitofrontal B 44, 45 field 5. Broca’s area
  6. 6. Sub cortical structures a b 1 c d 2
  7. 7. MOTOR CORTEX
  8. 8. PRIMARY MOTOR CORTEX Motor fibres cross in medulla to opp. side Input: thalamus, BG, sensory, premotor Output: motor fibers to brainstem and spinal cord Function: executes design into movement Lesions: / tone; power; fine motor function on contra lateral side
  9. 9. PRE MOTOR CORTEX Input:  thalamus,  BG,  sensory cortex Output: primary motor cortex Function:  stores motor programs;  controls coarse postural movements Lesions: moderate weakness in proximal muscles on contralateral side
  10. 10. SUPPLEMENTARY MOTOR CORTEX Input:  cingulate gyrus,  thalamus,  sensory cortex  prefrontal cortex Output:  Premotor cortex,  primary motor cortex Function:  intentional preparation for movement;  procedural memory Lesions:  mutism,  akinesis
  11. 11. FRONTAL EYE FIELDS Input:  Parietal cortex  Temporal cortex Output:  Caudate nucleus  Superior colliculus  Paramedian pontine reticular Formation (PPRF) Function:  executive: selects target and commands movement (saccades) Lesion:  eyes deviate ipsilaterally with destructive lesion  eyes deviate contralaterally with irritating lesions
  12. 12. BROCA‟S SPEECH AREA (AREA 44,45) Input: Wernicke‟s area Output: primary motor cortex Function:  speech production (dominant hemisphere);  emotional, melodic component of speech (non-dominant) Lesions:  motor aphasia;  monotone speech
  13. 13. PRE FRONTAL CORTEX
  14. 14. LATERAL SURFACE FRONTAL LOBE SULCI  Vertical  Central sulcus  Precentral sulcus •GYRI •Precentral gyrus  Horizontal •Superior frontal gyrus  Super frontal sulcus •Middle frontal gyrus  Inf frontal sulci •Inf erior frontal gyrus
  15. 15. MEDIAL SURFACE FRONTAL LOBE Between cingulate sulcus and superior medial margin of hemisphere Posterior part vertical sulcus
  16. 16. ORBITAL SURFACE FRONTAL LOBE  Divided into four orbital gyri by a well-marked H-shapedM L orbital sulcus.  The medial, anterior, lateral, and posterior orbital gyri.  The medial orbital gyrus presents a well-marked antero-posterior sulcus, the olfactory sulcus, for the olfactory tract;  the portion medial to this is named the gyrus rectus
  17. 17. FUNCTIONAL ANATOMY OF PRE FRONTAL CORTEX
  18. 18. DORSOLATERAL PREFRONTAL CORTEX Connections:  motor / sensory convergence areas,  thalamus,  globus pallidus,  caudate nucleus, Subcortical structures  substrantia nigra Functions:  motor planning, organization, and regulation  monitors and adjusts behavior using „working memory‟ DLPFC Lesions:  executive function deficit;  disinterest  attention to relevant stimuli
  19. 19. DORSOMEDIAL PREFRONTAL CORTEX Connections:  temporal cortex  parietal cortex  thalamus, caudate, GP, substantia nigra,  cingulate cortex Functions:  motivation, initiation of activity Lesions:  Paucity of spontaneous movement and gesture,  Sparse verbal output (repetition may be preserved),  Lower extremity weakness and loss of sensation,  Incontinence
  20. 20. ORBITAL PREFRONTAL CORTEX Connections:  temporal cortex  parietal cortex  thalamus, globus pallidus, caudate,  insula,  amygdala Part of limbic system •The limbic system Function: •Hippocampus  emotional input, •Amygdalae  arousal, • anterior thalamic nuclei  suppression of distracting signals •Septum  Decision making •limbic cortex •Fornix, Lesions: •functions including Disinhibited, impulsive behaviour •Emotionbehavior, Inappropriate jocular affect, •motivation, euphoria ,emotional lability, •long-term memory, Poor judgment and insight, •olfaction Distractibility
  21. 21. FIVE „FRONTAL SUBCORTICAL CIRCUITS‟1. Motor Motor cortex2. Oculomotor3. Dorsolateral prefrontal Lateral4. Lateral orbitofrontal Inferior Prefrontal cortex5. Anterior cingulate Medial
  22. 22. 1. FRONTAL SUBCORTICAL MOTOR CIRCUIT SMA, Premotor,MotorHypo-thalamus Putamen Thalamus Globus Pallidus Supplementary Motor & Premotor : planning, initiation & storage of motor programs; fine-tuning of movements Motor : final station for execution of the movement according to the design
  23. 23. 2.FRONTAL OCULOMOTOR CIRCUIT Frontal Eye field Central Thalamus Caudate Globus Pallidus & Substantia Nigra  Voluntary scanning eye movement  Independent of visual stimuli
  24. 24. 3.DORSOLATERAL PREFRONTAL CIRCUIT Lateral Pre- Frontal Thalamus Caudate Globus Pallidus & Substantia Nigra Executive functions: motor planning, deciding which stimuli to attend to, shifting cognitive sets Attention span and working memory
  25. 25. 4. LATERAL ORBITOFRONTAL CIRCUIT Infero-Lateral Pre- Frontal Orbito-Frontal Caudate Globus Pallidus & Thalamus Substantia Nigra  Emotional life and personality structure  Arousal, motivation, affect
  26. 26. 5. ANTERIOR CINGULATE CIRCUIT Ant. Cingulate MD Thalamus Striatum Thalamus Globus Pallidus & Substantia Nigra Abulia –lack of initiative Akinetic mutism - neither move nor speak
  27. 27. NEUROTRANSMITTERS: DOPAMINERGICTRACTS Origin: ventral tegmental4 area in midbrain 1 Mesocortical tract Projections:  prefrontal cortex (mesocortical tract  limbic system (mesolimbic tract) 2 Function:  reward;  motivation; 3  spontaneity;  arousal
  28. 28. NEUROTRANSMITTERS: NOREPINEPHRINETRACTS Origin:  locus ceruleus in brainstem  lateral brainstem tegmentum Projections: anterior cortex Functions:  alertness,  arousal,  cognitive processing of somatosensory information
  29. 29. NEUROTRANSMITTERS: SEROTONIN TRACTS Origin: raphe nuclei in brainstem Projections: number of forebrain structures Function:  minor role in prefrontal cortex;  sleep,  mood, anxiety,  feeding
  30. 30. FRONTAL LOBE FUNCTION Motor Cognitive Behavior Arousal Voluntary Memory Personality Attention movements Planning, Problem Social and Initiation solving sexual Spontaneity Judgment Impulse control Language Abstract Mood and Expression thinking affect Eye movements
  31. 31. FRONTAL LOBE SYNDROMES
  32. 32. PHINEASE GAGE (1848) 1. He becomes unreliable and failsOn 13th Sept 1848 a railroad to come to work and when worker, hard working, present he is "lazy." 2. He has no interest in going to diligent, reliable, church, constantly drinks alcohol, gambles, and "whores about." responsible, intelligent, 3. He is accused of sexually good humored, polite god molesting young children. fearing, family oriented 4. He ignores his wife and children and fails to meet his financial and foreman family obligations. 5. He has lost his sense of humour.Following an explosion iron 6. He curses constantly and does so bar drove into frontal lobe in inappropriate circumstances. 7. Died of status epilepticus in 1861
  33. 33. FROTNAL LOBE SYNDROMES •executive function deficit; •apathy; •disinterest / emotional •decreased reactivity; drive/awareness/ • attention to relevant spontaneous stimuli movements; •akinetic- Lateral abulic& mutism •emotional lability, Medial •disinhibition, •distractibility, • ‘hyperkinesis’ Orbital
  34. 34. FRONTAL LOBE SYNDROMES The DLPFC is concerned with planning,strategy formation, and executive function. Abnorm in DLPFC  apathy,  personality changes,  abulia, and  lack of ability to plan or to sequence.  patients have poor working memory The frontal operculum = expression of language.  left frontal operculum lesion = Broca aphasia and defective verb retrieval,  right opercular lesions = expressive aprosodia.Aprosodia is a neurological condition characterized by theinability of a person to properly convey or interpret emotional prosody.
  35. 35.  Patients with orbitofrontal lesions shows disinhibition, emotional lability, and memory disorders. Personality changes from orbital damage include impulsiveness, a jocular attitude, sexual disinhibition, and complete lack of concern for others. Patients with superior mesial lesions typically develop akinetic mutism. Patients with inferior mesial (basal forebrain) lesions tend to manifest anterograde and retrograde amnesia and confabulation.
  36. 36. FRONTAL LOBE SYNDROME -CAUSES Mental retardation Traumatic brain injury Brain tumors Degenerative dementias including  Alzheimer disease,  Dementia with lewy bodies,  Parkinsonian dementias,  Frontotemporal dementias Cerebrovascular disease Multiple sclerosis Schizophrenia Major depression Acute alcohol intoxication and drug abuse
  37. 37. CLINICAL PICTURE Profound change in personality. Lack of initiation and spontanity. Response are sluggish. Occasionally patient are hyperactive and restless. Mood is often euphoric and out of keeping with patients situation. Irritability and outbursts are common. Loss of finer senses. Judgements are impaired. Fail to plan and carry through ideas.
  38. 38. FRONTOTEMPORAL LOBE DEMENTIA FTLD is a neurodegenerative disease : frontal and temporal lobe Typical age of onset is between 50 and 60 yrs. In contrast to Alzhiemer Disease, in which memory loss is usually the first symptom, the initial symptoms of FTLD often involve changes in personality, behavior, affective symptoms, and language function. The core features of FTLD as defined by the Neary criteria (Neary et al., 1998) are  early decline in social and personal conduct  emotional blunting  loss of insight.
  39. 39. FRONTAL LOBE EPILEPSY Frontal lobe epilepsy is characterized by recurrent seizures arising from the frontal lobes. In most centers frontal lobe epilepsy accounts for 20-30% of operative procedures involving intractable epilepsy. Patients with frontal lobe seizures may present with a clear epileptic syndrome or with unusual behavioral or motor manifestations that are not immediately recognizable as seizures - may be associated with facial grimacing, vocalization, or speech arrest. Seizures often bizarre and may be diagnosed incorrectly as psychogenic
  40. 40. EXPRESSIVE APHASIA Expressive aphasia, known as Brocas aphasia caused by damage or developmental issues in (area 44,45). For them, speech is difficult to initiate, non-fluent, labored, and halting. Similarly, writing is difficult as well. Intonation and stress patterns are deficient. Language is reduced to disjointed words and sentence construction is poor. Comprehension is generally preserved, meaning interpretation dependent on syntax and phrase structure is substantially impaired. Patients who recover go on to say that they knew what they wanted to say but could not express themselves.
  41. 41. SCHIZOPHRENIA & FRONTAL LOBE some schizophrenic symptoms are found in frontal lobe disorder, in particular that involving dorsolateral prefrontal cortex. Symptoms included are those of the affective changes, impaired motivation, poor insight. Evidence  EEG studies, in  CT scan,  with MRI,  cerebral blood flow studies.  Hypofrontality in PET.
  42. 42. DEPRESSION & FRONTAL LOBE Right frontal lobe demonstrated increased activity in response to negative moods whereas left frontal activity decreases. Not only reductions in left frontal activity, but injuries to the left frontal lobe have been consistently associated with depression, "psycho-motor" retardation, apathy, irritability, and blunted mental functioning. In severely depressed patients demonstrate insufficient activation and a significant lower integrated amplitude of the eeg evoked response over the left vs right frontal lobe.
  43. 43. FRONTAL LOBE HISTORY TAKING Personality changes (over familiar, tactless and sexual indiscretions) Hyperorality Distractibility Poor motivation Inability to adapt to new situations Poor problem solving skills
  44. 44. FRONTAL LOBE TESTS 1. Attention 2. Memory 3. Abstraction 4. Judgment 5. Planning 6. Language 7. Motor sequencing
  45. 45. Tests of attention and memoryo Alternative sequence (e.g. copying MNMN)o Luria‟s „fist-edge-palm‟ test (show 3X)o Go/no-go: o”tap once if I tap twice, don‟t tap if I tap once” o“tap for A” oread 60 letters at 1/sec; N: < 2 errors
  46. 46. Tests of attention and memory cont‟ oDigit span orepeat 3-52; 3-52-8; 3-52-8-67..” N: >5 o Recency test o“recall sequence of stimuli / events” o Imitation (of examiner) / utilization (of objects presented)
  47. 47. Tests of abstraction and judgmento Interpret proverbs (e.g.“the golden hammer opens iron doors”)o Explain why conceptually linked words are the same (e.g. coat & skirt)o Plan & structure a sequential set of activities (“how would you bake a cake?”)o Insight / reaction to own illness
  48. 48. Language tests o Thurstone / word fluency test (“recite as many words beginning with „F‟ in 1 min as you can, then with „A‟, „S‟”); N: >15 o Repetition (Broca‟s vs transcortical) o “Ball” o “Methodist”
  49. 49. MOTOR SEQUENCING: KINETIC MELODY1. Hand position test (three-step hand sequence)2. Rhythm tapping tasks3. Go no go test4. Copying tasks
  50. 50. FRONTAL RELEASE SIGN – PRIMITIVE REFLEXES Grasp reflex  Snout reflex  Forceful grapping of object on touching palm or sole  Palmomental Sucking reflex  Glabellar tap  By touching the lips Groping reflex  Involuntary following with hand/eye of moving object
  51. 51. Formal Tests• Abstract thinking and set shifting • Wisconsin Card Sorting Test• Visuo-motor track, conceptualization, set shift • Trail Making• Attention, shift sets • Stroop Color & Word Test• Planning • Tower of London Test • Block design • Maze lest
  52. 52. Wisconsin Card Sorting Test perseverence•Used to assess the following "frontal" lobe functions: •strategic planning, •organized searching, •utilizing environmental feedback to shift cognitive sets, •directing behavior toward achieving a goal •modulating impulsive responding.
  53. 53. Trail Making Test 5 B A 4 6 1 C 2 3 D 7It provides information about •visual search speed •scanning, •speed of processing, •mental flexibility, and executive functioning.
  54. 54. Stroop Color and Word Tests “Please read this as fast as you can” RED BLUE ORANGE YELLOW GREEN RED PURPLE RED GREEN YELLOW BLUE RED YELLOW ORANGE RED GREEN BLUE GREEN PURPLE RED attention, shiftingLesion : anterior cingulate cortex and dorsolateral prefrontal cortex
  55. 55. Tower of London TestsUse:for the assessment of executive functioning specifically to detect deficits in planning
  56. 56. Reference:1. CTP2. OTP3. Snells neuroanatomy4. Internet
  57. 57. Thank You

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