Lec 7 - Cerebral hemispheres

• 3 Fissures in the cerebral hemisphere

  • longitudinal fissure
  • transverse fissure
  • lateral fissure

  A) longitudinal

  B) transverse

  C) lateral

  
• The central sulcus can be distinguished because it does not go down all the way to touch the lateral fissure
• The parieto-occipital sulcus divides the parietal and occipital lobes
• The cingulate gyrus is a part of the limbic system which controls emotion, pain, etc.
• Brodmann's areas are functional correlations to areas of the cortex - contain pyramidal and granular cells
• The primary motor cortex lies between the central sulcus and the precentral sulcus and sends motor impulses
• The area in front of the precentral sulcus is the premotor area which is involved in the planning of motor movement and integration of information from the senses
• Label the areas indicated

  A) precentral sulcus

  B) central sulcus

  C) primary motor

  D) premotor

  E) motor language area

  
• Broca's aphasia

  • short or single word responses
  • understands language
  • wrong word choices
  • get frustrated because they have trouble expressing themselves
• The parietal lobe is involved in sensory function
• The primary sensory cortex lies between the central sulcus and the postcentral sulcus
• The somatosensory association area is where previous experiences and prior knowledge influence the response to incoming sensory information
• Label the parts of the parietal lobe

  A) postcentral sulcus

  B) somatosensory association area

  C) primary sensory cortex

  D) central sulcus

  
• Hemi-neglect syndrome

  • parietal lobe damage
  • patients ignore objects in one half of visual field
  • will ignore the half that is the opposite of the damage - example below is right sided damage

  
• The temporal lobe is divided into superior, middle, and inferior temple gyri
• Label the areas of the temporal lobe

  A) lateral fissure

  B) sensory language area

  C) superior temple gyrus

  D) middle temple gyrus

  E) inferior temple gyrus

  
• The insula is involved in visceral sensation, autonomic function, emotion, self awareness, and the gustatory cortex. Part of the cortex needs to be removed to visualize it
• The primary auditory area is on the superior surface of the superior temporal gyrus. It is tonally arranged from high frequency to low frequency

  
• The primary visual area lies on both sides along the calcarine sulcus

  
• Neuronal bodies, dendrites, and terminals are in the grey matter and fibers (axons) are in the white matter
• Grey matter in the cerebral cortex has pyramidal cells and interneurons
• The two types of neurons in the grey matter of the cortex

  • projection neurons (80%) - these neurons send their axons to other areas; all use glutamate (excitatory) and the majority are pyramidal neurons (>98%)
  • interneurons (20%) - their axons terminate within the same area where cell bodies are located; all use GABA (inhibitory) and are mainly multipolar neurons
• Axons of projection neurons may form 3 types of fibers

  • projection fibers
  • association fibers
  • commissural fibers
• Projection fibers - those going to subcortical areas (going to different parts of the brain) e.g., internal capsule
• Association fibers are those going to other areas (or lobes) of the ipsilateral (same side) of the cerebral cortex
• Commissural fibers are those going to the identical areas of the contralateral (opposite) cerebral cortex (e.g., corpus callosum)