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Questions and Answers
Which part of the prefrontal cortex is primarily responsible for executive function?
Which part of the prefrontal cortex is primarily responsible for executive function?
The frontal pole is involved in regulating behavioral responses based on reward and punishment.
The frontal pole is involved in regulating behavioral responses based on reward and punishment.
False
What is akinetic mutism?
What is akinetic mutism?
The worst form of apathy.
The medial prefrontal cortex is associated with _____ and motivation.
The medial prefrontal cortex is associated with _____ and motivation.
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Match the following PFC parts with their functions:
Match the following PFC parts with their functions:
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What is the primary function of the Betz cells in the primary motor cortex?
What is the primary function of the Betz cells in the primary motor cortex?
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30% of motor fibers originate from the primary motor cortex.
30% of motor fibers originate from the primary motor cortex.
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Which area of the brain is responsible for the planning and coordination of fine skilled voluntary movement?
Which area of the brain is responsible for the planning and coordination of fine skilled voluntary movement?
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The _____ is the area that initiates fine skilled voluntary movement.
The _____ is the area that initiates fine skilled voluntary movement.
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Match the following areas of the brain with their respective functions:
Match the following areas of the brain with their respective functions:
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What is the primary function of the Superior Parietal Lobule?
What is the primary function of the Superior Parietal Lobule?
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Apraxia is characterized by an inability to execute learned voluntary skilled actions despite normal neurological function.
Apraxia is characterized by an inability to execute learned voluntary skilled actions despite normal neurological function.
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What type of apraxia involves a present idea but poor execution of actions?
What type of apraxia involves a present idea but poor execution of actions?
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The ability to recognize objects by touch, vision, or sound is referred to as _______.
The ability to recognize objects by touch, vision, or sound is referred to as _______.
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Match the following types of apraxia with their descriptions:
Match the following types of apraxia with their descriptions:
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What is the primary function of Area 4 in the frontal lobe?
What is the primary function of Area 4 in the frontal lobe?
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The medial orbital gyrus is located on the inferior surface of the frontal lobe.
The medial orbital gyrus is located on the inferior surface of the frontal lobe.
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What are the areas classified under the prefrontal area in the frontal lobe?
What are the areas classified under the prefrontal area in the frontal lobe?
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Area _____ is known as Broca's area, which is involved in speech production.
Area _____ is known as Broca's area, which is involved in speech production.
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Match the following areas of the frontal lobe with their functions:
Match the following areas of the frontal lobe with their functions:
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Which lobe is located below the frontal lobe?
Which lobe is located below the frontal lobe?
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The visual cortex is primarily responsible for processing auditory information.
The visual cortex is primarily responsible for processing auditory information.
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What is one of the functions assessed by the Mini-Mental State Examination (MMSE)?
What is one of the functions assessed by the Mini-Mental State Examination (MMSE)?
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The __________ separates the frontal lobe from the parietal lobe.
The __________ separates the frontal lobe from the parietal lobe.
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Match the following areas of the brain with their functions:
Match the following areas of the brain with their functions:
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What type of weakness is associated with an MCA lesion?
What type of weakness is associated with an MCA lesion?
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A lesion of the motor cortex causes spasticity, indicating it is an upper motor neuron lesion.
A lesion of the motor cortex causes spasticity, indicating it is an upper motor neuron lesion.
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What is the characteristic effect of a left FEF lesion on eye movement?
What is the characteristic effect of a left FEF lesion on eye movement?
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An ACA lesion primarily causes weakness in the __________ limb.
An ACA lesion primarily causes weakness in the __________ limb.
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Which of the following is affected by a lesion in Broca's area?
Which of the following is affected by a lesion in Broca's area?
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In individuals with a frontal lobe lesion, they tend to look away from the lesion site.
In individuals with a frontal lobe lesion, they tend to look away from the lesion site.
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Jacksonian march is associated with __________ motor simple partial seizures.
Jacksonian march is associated with __________ motor simple partial seizures.
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Match the following conditions with their corresponding symptoms or effects:
Match the following conditions with their corresponding symptoms or effects:
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What is a major consequence of a lesion in the right parietal lobe?
What is a major consequence of a lesion in the right parietal lobe?
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Gerstman syndrome includes impairment in reading and writing.
Gerstman syndrome includes impairment in reading and writing.
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What are the symptoms associated with Gerstman syndrome?
What are the symptoms associated with Gerstman syndrome?
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A lesion in the fusiform gyrus causes _____, which is characterized by impaired reading without writing issues.
A lesion in the fusiform gyrus causes _____, which is characterized by impaired reading without writing issues.
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Match the condition with its corresponding description:
Match the condition with its corresponding description:
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What is the primary blood supply to the primary sensory cortex and primary motor cortex?
What is the primary blood supply to the primary sensory cortex and primary motor cortex?
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The frontal eye field (FEF) is affected by damage to the post central gyrus.
The frontal eye field (FEF) is affected by damage to the post central gyrus.
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What is the term for the inability to recognize objects by touch?
What is the term for the inability to recognize objects by touch?
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The _____ lobe is located posterior to the central sulcus.
The _____ lobe is located posterior to the central sulcus.
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Match the following functions with the appropriate sensory deficits:
Match the following functions with the appropriate sensory deficits:
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Which deficit is associated with Wernicke's aphasia?
Which deficit is associated with Wernicke's aphasia?
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Auditory agnosia results in a complete loss of hearing.
Auditory agnosia results in a complete loss of hearing.
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What area of the temporal lobe is primarily responsible for auditory processing?
What area of the temporal lobe is primarily responsible for auditory processing?
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The __________ lobe is known to have the most epileptogenic foci in the body.
The __________ lobe is known to have the most epileptogenic foci in the body.
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Match the following auditory deficits with their descriptions:
Match the following auditory deficits with their descriptions:
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Which of the following is NOT a characteristic feature of Kluver-Bucy syndrome?
Which of the following is NOT a characteristic feature of Kluver-Bucy syndrome?
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The amygdala is primarily involved in processes related to memory.
The amygdala is primarily involved in processes related to memory.
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What area of the brain is affected leading to hypermetamorphosis in Kluver-Bucy syndrome?
What area of the brain is affected leading to hypermetamorphosis in Kluver-Bucy syndrome?
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Kluver-Bucy syndrome is associated with abnormalities in the _____ body.
Kluver-Bucy syndrome is associated with abnormalities in the _____ body.
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Match the following functions with the respective brain areas involved in Kluver-Bucy syndrome:
Match the following functions with the respective brain areas involved in Kluver-Bucy syndrome:
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Study Notes
Prefrontal Cortex (PFC) / Area 9, 10, 11, 12
- Dorsolateral PFC: Involved in executive function, including cognitive inhibition, response inhibition, and set shifting (flexibility). It also plays a role in energization and motivation, and when impaired, can lead to apathy, abulia, and akinetic mutism.
- Medial PFC (cingulate gyrus): Plays a role in emotion and motivation.
- Orbital PFC: Responsible for behavioral response based on reward and punishment, including judgment, insight, problem-solving, fluency, and abstract thinking.
- Frontal pole: Involved in Theory of mind, including sympathy, empathy, and metacognition (understanding oneself).
Bilateral Frontal Lobe Pathology
- Prefrontal personality changes:
- Urinary incontinence: Caused by bilateral lesions of the paracentral lobule.
- Primitive reflexes: Occur due to premotor cortex involvement.
- Akinetic mutism: The most severe form of apathy.
- Gait apraxia: Seen in Normal Pressure Hydrocephalus, whereby patients feel like their feet are stuck to the floor (ignition failure).
Superior Parietal Lobule
- Function: Generates praxicons (movement formulas/sensory guidance for movement).
- Apraxia: Inability to execute learned voluntary skilled actions, despite normal cerebellum, motor, and sensory function & comprehension.
- Lesion in SPL: Leads to inability to generate praxicons.
-
Types of apraxia:
- Ideational apraxia: Lack of the idea for the movement.
- Ideomotor apraxia: Idea is present, but execution is poor.
Inferior Parietal Lobule (IPL)
- Supramarginal gyrus : Involved in gnosis, which is the ability to recognize objects by touch, vision, or sound.
- Visual Agnosia: Inability to identify objects by vision, affecting the supramarginal gyrus and parieto-occipital association area (visuospatial orientation).
Dominant Parietal Lobe
- Right-handed: 5% dominance for right lobe, 40% for left lobe.
- Left-handed: 90-95% dominance for left lobe, 50-60% dominance for right lobe.
Non-Dominant Parietal Lobe
-
Pseudoapraxia:
- Constructional apraxia: Inability to perceive and imagine geometric relationships.
- Dressing apraxia: Inability to dress, specifically the inability to put on a jacket.
- Visuospatial disorientation: Inability to differentiate places, e.g., bedroom, bathroom.
Language
- Part of the dominant lobe.
Functions of Frontal Lobe
Area 4 / Primary motor cortex / Precentral gyrus
- Only 30% of motor fibers originate here.
- Betz cells: Specialized cells with the lowest threshold to initiate motor activity. They are responsible for initiating fine-skilled voluntary movements.
Premotor Area (PMA) & Supplementary motor area (SMA)
- 30% of motor fibers originate in this area.
- Prepare for fine-skilled voluntary movement: Tone of posture, proximal muscle alignment, antagonist muscle inhibition.
- Lesion in area 8/1: Spasticity (tone issue) and primitive reflexes.
Process of Fine-Skilled Voluntary Movement
- Prepare (setting up): By PMA/SMA
- Initiation: By the primary motor area.
- Finesse: By the cerebellum.
- Planning & coordination: By the basal ganglia.
Motor Homunculus
- Lower limb: Medial surface (supplied by the anterior cerebral artery (ACA)).
- Face & upper limb: Superolateral surface (supplied by the middle cerebral artery/MCA).
Neurology
Active Space
- MCA lesion: Face and upper limb weakness, urinary incontinence (paracentral lobule on the medial surface).
- ACA lesion: Lower limb weakness.
-
Lesion of motor cortex:
- Contralateral weakness (fine-skilled voluntary movements).
- Upper motor neuron (UMN) lesion: Spasticity (hypertonia).
- Initiate lesion: Contralateral motor simple partial seizure: Jacksonian march.
- Upper motor neuron (UMN): From the cortex to the anterior horn cell (in the grey matter).
Frontal Eye Field (FEF)
- FEF activation activates the right lateral rectus (LR) and left medial rectus (MR) muscles, causing the eyes to look to the right.
- A lesion in the left FEF results in an inability to look to the right, causing the patient to look to the left (the side of the lesion).
- Frontal lobe lesions in the frontal eye field cause the patient to look towards the side of the lesion.
- Brainstem lesions in the PPRF cause the patient to look away from the side of the lesion.
Broca's area/Area 44, 45
- Fluency affected (non-fluent aphasia).
- Lesions anterior to the central sulcus: Fluency affected.
- Lesions posterior to the central sulcus: Comprehension affected.
Areas of the Frontal Lobe
- Area 6: Premotor area.
- Area 8: Supplementary motor area (medially).
- Area 8: Frontal eye field.
- Area 9, 10, 11, 12: Prefrontal area.
- Area 44, 45: Motor speech area (Broca's area) (in the inferior frontal gyrus).
- Area 4: Primary motor area (Precentral gyrus).
Medial Surface
- Precuneus
- Parieto-occipital fissure
- Cuneus
- Calcarine fissure
- Lingual gyrus
- Paracentral Lobule
- Superior Frontal Gyrus
- Cingulate Gyrus
- Cingulate sulcus
- Corpus callosum
- Fornix
- Hippocampal gyrus
- Fusiform gyrus
- Inferior temporal gyrus
Inferior Surface
- Gyrus rectus
- Olfactory sulcus
- Medial orbital gyrus
- Anterior orbital gyrus
- Posterior orbital gyrus
- Lateral orbital gyrus
- Orbital sulcus (H-shaped).
Lateral Sulcus/Sylvian Fissure
- A fissure (deep groove) separating the frontal and parietal lobes from the temporal lobe.
Functional Frontal Lobe Anatomy
- The diagram shows the regions and their functions within the frontal lobe.
Neurology
Active Space
Hemispatial neglect (Anosognosia/Asomatognosia)
- Caused by a disruption in visual scanning (body schema) that leads to neglect of activities related to one of the hemispheres.
- Right parietal lobe lesion: Left hemispatial neglect.
- Left parietal lobe lesion: No abnormality.
Extrapersonal Space
- Right parietal lobe lesion: Neglect of right and left spaces.
- Left parietal lobe lesion: Neglect of right space.
Topographic agnosia
- Right parietal lobe lesion: Loss of orientation to topography.
Constructional apraxia
- Impaired ability to draw or copy geometric designs.
Angular gyrus
- Functions: Reading, writing, naming, and spatial orientation with respect to finger, number, and body sites.
- Hemispatial neglect: Related to the function of the angular gyrus.
Gerstmann syndrome
- Lesion of the dominant angular gyrus.
- Characteristics: Alexia (impaired reading), agraphia (impaired writing), anomia (impaired naming), finger anomia/acalculia/right to left disorientation.
Left Posterior Cerebral Artery (PCA) Infarct + Splenium of Corpus Callosum
- Disconnection syndrome: Loss of connection between cortices.
- Alexia without agraphia: Specific impairment in reading without writing difficulties.
Occipital Lobe lesion
- Vision normal (macular sparing): Central vision remains intact.
- Contralateral homonymous hemianopia: Loss of vision in the same visual field in both eyes.
Pure Alexia
- Lesion of the fusiform gyrus.
Visual Abnormalities
- Frontal lobe lesion: Contralateral hemianopia.
- Parietal lobe lesion: Inferior homonymous quadrantanopia (pie in the floor).
- Temporal lobe lesion: Upper homonymous quadrantanopia (pie in the sky).
Frontal Lobe
Mini-Mental State Examination (MMSE)
- This test assesses higher mental functions/cognitive status based on orientation, registration, attention, recall, language, and copying.
Anatomy of the Frontal Lobe
Superolateral surface
- Frontal lobe: The largest lobe at the front of the brain.
- Temporal lobe: Located below the frontal lobe.
- Parietal lobe: Located behind the frontal lobe.
- Occipital lobe: Located at the back of the brain.
- Central sulcus: A groove separating the frontal and parietal lobes.
- Sylvian fissure: A deep groove that separates the frontal and temporal lobes.
- Motor cortex: Located in the frontal lobe, responsible for voluntary movement.
- Somatosensory cortex: Located in the parietal lobe, responsible for processing touch sensations.
- Visual cortex: Located in the occipital lobe, responsible for processing visual information.
- Auditory cortex: Located in the temporal lobe, responsible for processing auditory information.
Parietal Lobe
- Located posterior to the central sulcus.
Post Central Gyrus (PCG)
-
Primary Sensory Cortex:
- Origin of 40% motor fibers.
- Contralateral upper motor neuron (UMN) weakness (middle cerebral artery).
- Tone: Less affected.
- Frontal Eye Field (FEF): Spared.
-
Cortical sensations: Impaired.
- Tactile localization, two-point discrimination, stereognosis, graphesthesia.
- Association with pre-motor and supplementary motor area: Tone, FEF.
- Primary sensory cortex and primary motor cortex: Blood supply by the middle cerebral artery.
Temporal and Occipital Lobe
Temporal Lobe
-
Superolateral Temporal Lobe
-
Auditory Cortex (Area 41, 42):
- Bilateral (B/L) temporal lobe.
- Auditory connection fibers (auditory cortex to Wernicke's area).
- Auditory association cortex.
- Wernicke's area (Superior temporal gyrus): Area 22: Comprehension of spoken language.
- Temporo-occipital association area: Visuospatial function.
-
Auditory Cortex (Area 41, 42):
Defects
- Deafness (Auditory inattention): Inability to hear.
- Pure word deafness: Inability to comprehend spoken language despite intact hearing.
- Auditory agnosia: Inability to recognize sounds.
- Wernicke's aphasia : Language (Comprehension): Impairment in understanding language.
- No Weakness: No motor weakness.
- Visual agnosia: Inability to identify objects by vision.
Additional Notes
- Auditory, olfactory, and gustatory hallucinations can be seen in lateral temporal lobe lesions.
Medial Temporal Lobe (Limbic Cortex)
- Most epileptogenic foci in the body.
Kluver Bucy Syndrome
- Definition: Bilateral limbic abnormality; Bilateral medial temporal abnormality; Bilateral amygdala abnormality.
-
Features:
- Hypersexuality: Excessive interest in sexual activity.
- Hyperorality: Excessive tendency to put objects in the mouth (due to affected hypothalamus - feeding, satiety center).
- Visual Agnosia: Inability to recognize objects visually.
- Hypermetamorphosis: Visual inattention (need to touch any object to recognize them).
- Decreased fear, increased aggression: Reduced fear response and increased aggression.
- Goal-directed behavior: Intact prefrontal cortex (PFC) - not affected.
Components in the Diencephalon
- Anterior group of thalamic nuclei
- Hypothalamus
- Mamillary body
- Amygdaloid body
Components in the Cerebrum
- Cingulate gyrus
- Hippocampus
- Parahippocampal gyrus
Amygdala
- Plays a role in memory.
- Present on the inferior surface.
- Uncus: Elevation/bulge of amygdala on the inferior surface; herniation affects pupil (3rd nerve palsy).
Additional Notes
- Korsakoff's amnesic state: Bilateral temporal lobe lesion.
- Abnormality in the mamillary body: Associated with Korsakoff's syndrome.
Functions of the Brain Areas (HOMES)
- Homeostasis: Regulation of bodily functions.
- Olfaction: Sense of smell.
- Memory: Formation and retrieval of memories.
- Emotion: Processing and regulation of emotions.
- Sexuality: Sexual desire and function.
Components
- Superior temporal gyrus.
- Inferior temporal gyrus.
- Hippocampus.
- Parahippocampus.
- Fusiform gyrus.
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Description
Test your knowledge on the anatomy and functions of the prefrontal cortex, including the dorsolateral, medial, and orbital areas. Discover how bilateral frontal lobe pathology can impact personality and behavior, leading to conditions such as akinetic mutism and gait apraxia. This quiz covers essential concepts for understanding the complexities of frontal lobe functions.
