Functional Areas Diagram
I. Motor Areas (posterior part of the frontal lobes)
- Primary motor cortex - precentral gyrus in the frontal lobe
- Large neurons (pyramidal cells) allow conscious control of movement of skeletal muscles
- The pyramidal cells’ long axons from voluntary motor tracts called pyramidal (corticospinal) tracts
- Motor areas have been spatially mapped = somatotropy.
- Premotor cortex - anterior to the precentral gyrus in the frontal lobe
- Regions controls learned motor skills that are repeated or patterned
- Also coordinates the movements of muscles simultaneously and\or sequentially by sending activating
impulses to the primary motor cortex
- Broca’s area - anterior to the premotor area
- Involved in directing motor speech.
- Frontal eye field - anterior to the premotor cortex and superior to Broca’s area
- Controls voluntary movement of eyes.
II. Sensory Areas (parietal, temporal, and occipital lobes)
- Primary somatosensory cortex - postcentral gyrus of parietal lobe (immediately behind primary motor cortex)
- Neurons receive info (from sensory receptors, skin, and muscles) and identifies body region being stimulated
- Endows spatial discrimination.
- Somatosensory association area - lies posterior to the primary somatosensory cortex
- Integrate and analyze somatic sensory inputs (e.g. temperature and pressure) into comprehensive evaluation.
- Visual areas - occipital lobes contain primary visual cortex (receive information from retina) and visual association area (interprets information from retina).
- Auditory areas - temporal lobes contain primary auditory cortex (receives impulses from inner ear) and auditory association area (interprets sound).
- Olfactory cortex - temporal lobe in region called the uncus; enables conscious awareness of odors.
- Gustatory cortex - parietal lobe deep to temporal lobe; involved in perception of taste.
III. Association Areas
- Somatosensory cortex - posterior to the primary somatosensory cortex
- Somatosensory cortex and each special sensory area have nearby association areas with which they communicate
- The association areas, in turn, communicate with the motor cortex and with other sensory association areas to analyze, recognize, and act on sensory inputs.
- Prefrontal cortex - anterior portions of frontal lobe
- Involved with intellect and complex learning (cognition) and personality
- Tumors may lead to personality disorders - prefrontal lobotomy are performed in severe cases of mental illness.
- Gnostic area - undefined area in temporal, occipital, and parietal lobes
- Only one hemisphere
- Receives input from all sensory association areas and stores complex memory patterns associated with sensation
- Sends assessment of sensations to prefrontal cortex which adds emotional overtones
- Injury to gnostic area causes one to become an imbecile - interpretation to various sensations/stimuli lost.
- Language areas - found in Wernick’s area of temporal lobe of one hemisphere (usually left)
- Involved in interpretation of language.