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Frontallobe dr prashant mishra

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frontal lobe ppt svs medical college

Text of Frontallobe dr prashant mishra

  • Presenter :Dr. Prashant MishraModerator : Dr. V Sharbandh Raj
  • 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
  • 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.
  • FRONTAL LOBE A. Lateral surface 1. Posterior - Central sulcus 2. Inferio-Posterior sylvian fissure. B. Medial surface C. Orbital surface
  • 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. Brocas area
  • Sub cortical structures a b 1 c d 2
  • 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
  • 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
  • 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
  • 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
  • BROCAS SPEECH AREA (AREA 44,45) Input: Wernickes area Output: primary motor cortex Function: speech production (dominant hemisphere); emotional, melodic component of speech (non-dominant) Lesions: motor aphasia; monotone speech
  • 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
  • MEDIAL SURFACE FRONTAL LOBE Between cingulate sulcus and superior medial margin of hemisphere Posterior part vertical sulcus
  • 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
  • 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
  • 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
  • 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
  • FIVE FRONTAL SUBCORTICAL CIRCUITS1. Motor Motor cortex2. Oculomotor3. Dorsolateral prefrontal Lateral4. Lateral orbitofrontal Inferior Prefrontal cortex5. Anterior cingulate Medial
  • 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
  • 2.FRONTAL OCULOMOTOR CIRCUIT Frontal Eye field Central Thalamus Caudate Globus Pallidus & Substantia Nigra Voluntary scanning eye movement Independent of visual stimuli
  • 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
  • 4. LATERAL ORBITOFRONTAL CIRCUIT Infero-Lateral Pre- Frontal Orbito-Frontal Caudate Globus Pallidus & Thalamus Substantia Nigra Emotional life and personality structure Arousal, motivation, affect
  • 5. ANTERIOR CINGULATE CIRCUIT Ant. Cingulate MD Thalamus Striatum Thalamus Globus Pallidus & Substantia Nigra Abulia lack of initiative Akinetic mutism - neither move nor speak
  • 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
  • NEUROTRANSMITTERS: NOREPINEPHRINETRACTS Origin: locus ceruleus in brainstem lateral brainstem tegmentum Projections: anterior cortex Functions: alertness, arousal, cognitive processing of somatosensory information
  • NEUROTRANSMITTERS: SEROTONIN TRACTS Origin: raphe nuclei in brainstem Projections: number of forebrain structures Function: minor role in prefrontal cortex; sleep, mood, anxiety, feeding
  • 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
  • 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
  • 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
  • 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.
  • 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.
  • 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
  • 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.
  • 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.
  • 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
  • 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.
  • 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.
  • 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.
  • 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
  • FRONTAL LOBE TESTS 1. Attention 2. Memory 3. Abstraction 4. Judgment 5. Planning 6. Language 7. Motor sequencing
  • Tests of attention and memoryo Alternative sequence (e.g. copying MNMN)o Lurias fist-edge-palm test (show 3X)o Go/no-go: otap once if I tap twice, dont tap if I tap once otap for A oread 60 letters at 1/sec; N: < 2 errors
  • Tests of attention and memory cont oDigit span orepeat 3-52; 3-52-8; 3-52-8-67.. N: >5 o Recency test orecall sequence of stimuli / events o Imitation (of examiner) / utilization (of objects presented)
  • 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
  • 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 (Brocas vs transcortical) o Ball o Methodist
  • MOTOR SEQUENCING: KINETIC MELODY1. Hand position test (three-step hand sequence)2. Rhythm tapping tasks3. Go no go test4. Copying tasks
  • 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
  • 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
  • Wisconsin Card Sorting Test perseverenceUsed 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.
  • 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.
  • 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
  • Tower of London TestsUse:for the assessment of executive functioning specifically to detect deficits in planning
  • Reference:1. CTP2. OTP3. Snells neuroanatomy4. Internet
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