3.5 Neuropsychology
Week 4
Attention, Executive
Functions, Learning &
Memory
,Kolb & Wishaw (2015) → Chapter 16: The Frontal
Lobe
Frontal lobe anatomy
● Subdivisions of the frontal cortex
○ General
■ Frontal lobe are all the tissue anterior
to central sulcus
■ 30-35% of the neocortex
■ Frontal lobe can only perform functions
with relevant sensory info
○ Primary motor cortex
■ M1, specifies elementary movements,
controls movement force and
direction
■ Projects to subcortical motor structures
and basal ganglia, red nucleus and spinal cord
○ Premotor cortex
■ Anterior to motor cortex
■ Dorsal region → supplementary motor cortex
■ Dorsal premotor cortex → active for choosing
movements from movement lexicon
■ Ventral premotor cortex → mirror neurons,
recognize others’ movements and select similar
or different actions
■ Inferior frontal gyrus (Broca’s area) → same
function as ventral
■ Can influence movements directly (corticospinal
projections) or indirectly (projections through M1)
■ Frontal eye fields received visual input from
posterior parietal region & midbrain superior
colliculus → controls eye movements & sends
projections to these regions
■ All premotor areas receive projections from
dorsolateral PFC → involved in controlling limb
and eye movements
○ Prefrontal cortex
■ Anterior to motor, premotor and anterior cingulate
cortex
■ Receives projections from dorsomedial
nucleus of thalamus, parallel to projections of
lateral and medial geniculate thalamic nuclei to
visual & auditory cortex
, ■ Receives input from mesolimbic dopamine cells in tegmentum
(modulatory input), plays a role in regulating how prefrontal neurons react
to stimuli (stress & emotions)
● Abnormalities play a role in schizophrenia & drug addiction
■ Dorsolateral PFC
● Reciprocal connections with posterior parietal and superior
temporal sulcus
● Extensive connections with regions that the posterior parietal
cortex also projects to (cingulate cortex, basal ganglia, superior
colliculus)
● Functions are related to posterior parietal cortex
■ Orbitofrontal cortex (OFC)
● Receives input from all sensory modalities (mainly temporal lobe,
including auditory regions of superior temporal gyrus and visual
regions of inferotemporal cortex, TE, STS, subcortical amygdala)
● Connections from S2, gustatory cortex in insula, olfactory regions
of the pyriform cortex
● Projects subcortically to amygdala and hypothalamus →
influences autonomic NS, important in emotional responses
■ Ventromedial PFC
● Receives connections from DLPFC, posterior cingulate cortex,
medial temporal cortex
● Connects subcortically with amygdala & hypothalamus as well and
with periaqueductal gray (PAG) in brainstem
● Linked with structures of emotional behavior in whole body
○ Anterior cingulate cortex
■ Economo neurons → specialized neocortex
■ Makes extensive bidirectional connections with motor, premotor, PFC and
insula
● Connectome and frontal cortex
○ Most studied cortical network → default network (active during resting,
autobiographical memory, thinking about future, wandering mind)
○ Salience network → correlated activity of ACC, supplementary motor cortex,
anterior insular cortex
■ Most active when behavioral
change is needed, modulates
other networks’ activities
○ PFC is a major participant in many
cortical networks involved in
emotional behavior (especially
VMPFC)
○ Frontal lobes extensive connection
with other regions can modulate
functions of rest of cortex
, Theory of frontal lobe function
● General
○ Frontal lobe contains control systems that implement behavior strategies in
response to both internal & external cues (executive functions)
● Functions of the premotor cortex
○ Selects from its lexicon the movements to be executed → response to internal
& external events
○ Eye movements selected by frontal eye fields
○ Supplementary motor region selects and directs motor sequences
○ Motor acts can become associated with cues
● Functions of the prefrontal cortex
○ General
■ Controls cognitive processes that select appropriate movements at the
correct time and place (depending on cue)
○ Internal cues
■ Developing internalized information needs development of “rules” that
guide thoughts and actions
● Internalized record → temporal, working, or short term memory
● Temporal memory → neural record of recent events and their
order, can be derived from object recognition (ventral) or motor
(dorsal) streams of processing
■ Both dorsal & ventral streams project to PFC, but to different areas
(memory for both streams is localized in different areas)
● Dorsolateral areas are especially engaged in selecting behavior
based on temporal memory
○ External cues
■ If temporal memory is defective → become reliant on environmental cues
to determine their behavior
■ Frontal lobe injury → difficulty inhibiting behavior directed to external
stimuli
■ Feedback about the rewarding properties of stimuli → learned
associations
○ Context cues
■ Roles are governed by behavior rules we are expected to follow →
behavior is context dependent
■ Makeup of a social group determines behavior
■ Frontal lobe is very large in social primates
■ Choosing behavior dependent on context requires detailed sensory
information → received from temporal lobe to inferior frontal cortex
■ Context may also be affective → amygdala is involved
■ Orbitofrontal lesions (common in TBI) → difficulty with context
○ Autonoetic awareness