This course outline is designed to provide you with a study guide. Use the lecture, book, and other resources to expand on its contents.
- Describe the 6 layers of the cortex, the basic function of each, and discuss the characteristic cells located in each layer .
- Explain the vertical unit organization of the cortex.
- What is meant by the term functional unit? Explain.
- Using the diagram, explain the functional organization of the cortex.
- Explain the similarities and differences between the small and large pyramidal cell layers of the cortex.
- How does the movement-versus-muscle controversy help explain how dendritic growth can begin to serve to integrate information in the cortex?
Description of Cerebral Cortex
Association - General function of the cortex
General structure of the cortex
- Behavioral flexibility
- Conditioned response (reflex)
- Thickness: 4 mm at precentral gyrus to 1.5 mm (visual)
- Layers: six layers -- two main zones
- Outer--receptive--where incoming fibers synapse
- Inner--efferent--cell bodies of fibers projecting to other areas
- Structure -- vertical units (independent systems which communicate with each other via association of fibers)
Techniques of Studying the Cortex
- Neuroradiological techniques
- Metabolism -- Blood Flow, PET, Beam
- Neuropsychological Assessment
Organization of Vertical Units
- Reverberation (feedback of circuits)
- Cytoarchitectonic Areas (based on histological differences)
- Cingulate gyrus-- poorly developed
- Projection areas --great differentiation
- Brodmann areas -- idea that anatomial differences relate to
- Recent cortical research
- Secondary areas
- Cortico-cortical connections
Organization of Cortex
- Postcentral gyrus (somatosensory projection)
- Also sensory projections to motor cortex
- Receptive field -- extent of skin area that will activate
a single cell
- Single cells respond to only one type of stimulus
- Cells responding to given type of stimulus tend to lie in
- Columns for different modalities from given areas tend to
lie close together
- Middle 1/3 of the Superior Temporal Cortex
- Occipital Lobe -- area 17 -- visual projection
- Motor Strip -- motor projection cortex.
- 2nd level - association cortex for modality
- Posterior 1/3 of superior temporal cortex --
- Area 18 & 19 of Occipital cortex -- vision.
- Supramarginal area -- somatosensory.
- Premotor cortex -- motor.
- General Association Cortex
- Prefrontal - planning, regulation, and feedback.
- Inferotemporal cortex & superior parietal -- general sensory
Motor Areas of the Cerebral Cortex
- Motor homunculus - Fritz& Hitzig (1870)
- Cortex arranged according to muscles but arrangement of dentrites according to movement
- Connections are such that large areas of cortex project in
an overlapping fashion to various motor neurons
- Discrete movements - result of complex synaptic interactions
at several levels
- Premotor area (Area 6)
- Stimulation -- more complex body movements than from primary
- Much of this area included in primary motor (body movement)
- Sensory homunculus
The functional unit is a representation of the manner in which information passes through the nervous system.
|General Motor Association Cortex
||General Sensory Association Cortex
|Motor Association Cortex
||Sensory Association Cortex
||Sensory Projection Cortex
|Motor Neuron Pool
|Effectors (muscles & glands)
Terms to Know
||General motor association areas
|Small Pyramidal Cell layer
||Sensory association areas
||General sensory association areas
|Granule cell layer
||Sensory projection areas
|Large Pyramidal cell layer
Links to Associated Areas