Cerebrum I Flashcards
What is the function of the Primary Motor Area?
Isolated movement of simple nature without much skill
What is the location of the Primary Motor Area?
- Precentral gyrus
- Anterior part of Paracentral lobule
Define the motor homunculus
Representation of the body on the primary motor area, with the paracentral mobile representing the leg and perineum. This representation is disproportionate to the actual size of the body, with the largest representation being the lips and hands.
What are the connections of the Primary Motor Area?
- Afferents:
- Premotor area
- sensory cortex
- thalamus
- cerebellum
- basal nuclei
- Efferents:
- corticospinal
- corticonuclear
- cortipontine
What is the clinical presentation of a patient with a lesion in the Primary Motor Area?
- Hemiplegia
- UMN lesion (with +ve babinski sign)
What is the location of the Premotor area?
- Superior, Middle, and Inferior Frontal Gyri
What is the function of the Premotor Area?
- To prepare the body to carry out complex, skilled or learned movements
What is the location of the Writing center?
Upper part of area 6
What is the location of the Frontal eye field?
Area 8 of the Middle Frontal Gyrus
What is the function of the Frontal Eye Field?
Regulates voluntary conjugate movement
What is the clinical presentation of a patient with a lesion affecting the frontal eye field?
Eyes deviated to side of lesion and inability to turn eyes to the opposite side.
Involuntary tracking movement of eyes is unaffected
What is the location of Broca’s motor speech area?
Lower part of inferior frontal gyrus
What is the function of Broca’s motor speech area?
Regulates coordinated movement of lips, tongue, palate, larynx and pharynx
What is the clinical presentation of a patient presenting with a lesion in the Premotor area?
Hesitancy in performing learned movements (impaired performance of learned movements
What is the location of the Prefrontal area?
Anterior parts of the Superior, Middle and Inferior Frontal Gyrus, Orbital Gyrus, Medial Frontal gyrus, Anterior part of Cingulate Gyrus
What is the function of the Prefrontal Gyrus?
Executive function
Regulates depth of emotion
Social ‘control’
Abstract thinking, Mature Judgement, Foresight, Tactfulness
What is the clinical presentation of a patient presenting with a lesion in the Prefrontal area?
Symptoms mostly mental
Lack of sense of responsibility in personal affairs
Vulgarity in speech
Clownish behavior
What is the location of the Primary Somesthetic area?
Postcentral gyrus
Posterior part of paracentral lobule
What is the function of the Primary Somesthetic area?
Localizes, analyses & discriminates different modalities of sensation.
• The pain area predominates in the upper lip of the posterior ramus of the lateral sulcus along the post central
gyrus. The lower part of the postcentral gyrus acts as taste receptive centre.
What is the anatomical basis underlying the involuntary following of moving objects by the eyes?
involve the connection between visual cortex and frontal eye field through superior longitudinal fasciculus
What is the location of Wernicke’s area?
Posterior end of the superior temporal gyrus
What is the function of Wernicke’s area?
Understanding of written & spoken language (interpretation of language through visual & auditory stimuli)
What is the clinical presentation of a patient with a lesion affecting Wernicke’s area?
- sensory aphasia (word deafness) [patient speaks fluently without understanding]
- global aphasia [if lesion affected Broca + Wernicke’s]
What is astereognosis?
tactile agnosia, where the affected individual fails to name the object by touch.
What is alexia?
Inability to read
What is agraphia?
inability to read