PSYC 415 - Notes on the Frontal Lobes

I. Divisions
     A. primary motor cortex (area 4)
     B. motor association cortex (area 6)
     C. supplementary motor area, preSMA, etc. (area 8)
     D. Broca's area (areas 44, 45)
     E. prefrontal cortex (PFC)

II. Definitions of prefrontal cortex
     A. cytoarchitectonic
          1. predominance of granular cells
          2. Brodman areas 8, 9, 10, 11, 12, 13, 44, 45, 46, 47
     B. projection area of the dorsomedial nuc. of the thalamus
     C. projection area in the frontal lobe of the mesocortical dopamine pathway

III. Executive functions
     A. management of other cognitive functions
     B. especially in novel, unfamiliar circumstances
     C. situations that:
          1. involve planning or decision making
          2. require error correction or troubleshooting
          3. require novel sequences of actions
          4. are dangerous or technically difficult
          5. require overcoming a strong habitual response
          6. require resisting temptation

IV. The executive must be able to...
     A. focus attention on and direct behavior towards a task when appropriate
     B. shift attention and behavior towards a new task when appropriate
     C. focus attention on task relevant features of the environment
          1. selective attention
          2. perhaps by increasing gain on sensory neurons
     D. monitor and select appropriate emotions and mood states
     E. pull appropriate information out of memory into working memory
     F. ignore all the inappropriate information in long-term memory (LTM)
     G. pull new information out of LTM on a moment's notice when task changes

V. Tests for executive functions
     A. Stroop test
     B. Wisconsin Card Sorting Test
     C. several others

VI. Divisions of the PFC
     A. areas with motor association functions
     B. dorsolateral prefrontal cortex (areas 9 and 46)
     C. inferior prefrontal cortex (orbitofrontal cortex) (areas 11-14)
     D. medial frontal cortex

VII. Connections
     A. specific thalamic projections - dorsomedial thalamic nucleus
     B. diffuse projections from intralaminar thalamic nucleus - arousal
     C. commissural connections from the contralateral hemisphere
     D. unilateral association cortex connections
     E. connections from the limbic system
          1. basolateral amygdala
          2. anterior cingulate gyrus
          3. hippocampus
     G. extrathalamic modulatory connections from the brainstem