Introduction To The CNS And Functional Localisation Of The Cerebrum Flashcards
Why is white matter white
The presence of myelin
Describe the spinal cord
Rostrally continuous with brainstem
Extends from foramen magnum to L1-L2
Vertebral foramen
Ends at conus medullaris
Cauda equine
Surrounded by dura
Cervical and lumbosacral enlargements
Ascending ….. tracts
Sensory
Descending …… tracts
Motor
Differing amounts of gray matter correspond to……
Axons innervating lower and upper limbs
What are the 5 main divisions of the adult human brain
Forebrain - Telenchephalon and Diencephalon
Midbrain - Mesencephalon
Hindbrain - Metencephalon and Myencephalon
Components of the forebrain
Telencephalon -> cortex, limbic system, basal nuclei
Diencephalon-> thalamus, hypothalamus, subthalamus
What are the components of the mid brain
Tectum
Tegmentum
What are the components of the hindbrain
Metencephalon -> pons, cerebellum
Myelencephalon -> medulla
Describe the cerebrum
Divided into 2 cerebral hemispheres consist of the cerebral cortex, limbic system and basal nucleus
What are the 4 lobes of the cerebrum
Parietal, frontal, occipital, temporal
Describe the frontal lobe
Largest lobe
Location of the precentral gyrus where the primary motor areas are housed
Essential not only for regulating voluntary motor behaviour but also initiating it
Expressive or motor aspects of language also processed on the lateral surface in Broca’s motor speech area
What is Broca’s area
Located in inferior frontal gyrus
Generation of language
Lesion leads to Broca’s aphasia
What is Broca’s aphasia
Difficulty generating written or spoken language
Little difficulty with language comprehension
Describe the prefrontal area
Towards frontal pole of frontal lobe
Electrical stimulation does not elicit movement
Extensive connections with other lobes via fasciculi
Monitors behaviours and controls higher processs eg judgement
PF association areas which are concerned with emotion, motivation, personality
On the medial aspect of cingulate gyrus, important for modulating emotional aspects of behaviour
Why were prefrontal lobotomy’s carried out
Surgical intervention to separate prefrontal cortex from the rest of frontal lobe and thalamus for treatment of neuropsychiatric disorders
Icepick inserted through orbit
Symptoms often improved but patients left with severe mental deficits
Describe the parietal lobe
Important in regulating somatosensory functions
• Location of the postcentral gyrus where the primary somatosensory area is housed
• Involved in the initial cortical processing & perception of pain, temperature and proprioception
• Houses Wernickes’ area responsible for the receptive or sensory aspects of language
• Also concerned with spatial orientation and perception
What is Wernicke’s area
Located in superior temporal gyrus
Comprehension of language - lesion leads to Wernicke’s aphasia
What is wernicke’s aphasia
Lesion in wernickes area in superior temporal gyrus
Difficulty understanding written or spoken language
Person can generate speech but the language is meaningless - unconnected words
Describe the occipital lobe
Primarily involved in the processing of visual information
• Visual association areas surround and cover the lateral surface of this lobe
• Separated from the parietal lobe by the parieto-occipital sulcus
• Separated from the temporal lobe by the calcarine sulcus