Zusammenfassung der Ressource
Frontal lobes
- Anatomy of the frontal lobes
- Constitute 20% of
the neocortex
- Subdivisions
- Motor
- Area 4
- Premotor
- Areas 6, 8
- Premotor cortex
- Lateral area 6
- Supplementary motor cortex
- Medial area 6
- Frontal eye field
- Area 8
- Supplementary eye field
- Area 8A
- Prefrontal cortex
- Area of frontal lobe that receives
input from the dorsomedial
nucleus of the thalamus
- Divisions
- Dorsolateral prefrontal cortex
- Inferior frontal cortex
- Medial frontal cortex
- Connections of the motor
and premotor areas
- Motor cortex
- Projects to spinal motor
neurons, cranial nerves
that control the face
- Projects to the basal
ganglia and the red nucleus
- Premotor
- Projections to the motor cortex
- Projections to the spinal cord
- Receives projections from
parietal areas PE and PF
- Receives projections from
dorsolateral prefrontal area
- Eye fields
- Receive from PG and the
superior colliculus
- Connections of
the prefrontal areas
- End of dorsal and ventral
streams of visual input
- Dorsolateral prefrontal area
- Reciprocal connections with
the posterior parietal and STS
- Extensive connections with the
cingulate cortex, basal ganglia
and superior colliculus
- Receives input from
dopaminergic cells in
tegmentum
- Orbital frontal cortex
- Receives from the temporal lobe,
amygdala, gustatory cortex,
somatosensory cortex, olfactory cortex,
dopaminergic cells in tegmentum
- Projects to hypothalamus
and amygdala
- Frontal lobe function
- Planning and selection
- Persistence and ignoring
distracting stimuli
- Memory for what you have
already done
- Executive functions
- Responds to both internal,
external and context cues
- Functions of the
premotor cortex
- Selects movements to be executed
- Functions to choose
behaviour in response to
external cues
- An increase in activity in
the premotor cortex is seen
when cues become
associated with movement
- Functions of the
prefrontal cortex
- Controls cognitive processes so
that appropriate movements are
selected at the correct time
- Internal cues
- Temporal memory
- Memory for what has just happened
- External cues
- Feedback about rewarding
properties of stimuli
- Orbital frontal cortex
- Learning by
association
- Context cues
- Orbital ftontal
- Social interactions
- Autonoetic awareness
- Self knowledge
- Asymmetry of the
frontal lobes
- Left
- Language
- Encoding memories
- Right
- Retrieving memories
- Non verbal movements,
facial expression
- Symptoms of
frontal lobe lesions
- Disturbances of
motor function
- Loss of fine movements,
speed and strength
- Appears after damage
to the primary motor
cortex
- Loss of movements
programming
- Damage to the premotor
or dorsolateral cortex
- Changes in
voluntary gaze
- Damage to the
frontal eye fields
- Speech problems
- Damage to
Broca's area
- Agrammatism
- Damage to the
supplementary motor
cortex
- Mute
- Convergent vs.
divergent thinking
- Convergent thinking
- Only one answer
to the question
- Divergent thinking
- Questions that ask for
a variety of responses
- Frontal lobe patients
are impaired on
divergent thinking
- Loss of behavioural
spontaneity
- Decreased verbal fluency
- Decreased design fluency
- Reduction in
general behaviour
- Increased
perseveration
- Inability to form a
strategy
- Larger deficit when
completing novel tasks
- Loss of response
inhibition
- The Stroop test
- The Wisconsin
card sorting task
- Deficits in self
regulation
- Take more risks
- Iowa gambling task
- Appears after damage
to the orbitofrontal cortex
- Loss of associative
learning
- Inability to select from
competing responses
- Impaired social and
sexual behaviour
- Phineas Gage
- Changes in personality
- Pseudodepression
- Lesions of left frontal lobe
- Outward apathy, indifference,
loss of initiative
- Reduced sexual interest, little or no verbal output
- Pseudopsychopathy
- Lesions of the right frontal lobe
- Immature behaviour, lack
of tact and restraint
- Promiscuous sexual behaviour
- Coarse language, lack of social
graces, increased motor activity
- Deficits in social and
sexual behaviour
- Orbitofrontal lesions
- Reduces inhibitions with
abnormal sexual behaviour
- Leads to deficits
in identifying facial
expressions
- Dorsolateral lesions
- Reduce interest in sexual behaviour
- Spatial deficits
- May be a role for the frontal lobe
in selective visual locations
- Symptoms associated with
damage to the frontal facial area
- Sensory and motor
functions of the face are
preserved after damage
- Left - loss of verbal fluency
- Right - loss of design fluency
- Diseases
affecting the
frontal lobe
- Schizophrenia
- Abnormality in the mesocortical
dopaminergic projection
- Decrease in blood flow to the frontal
lobes and frontal lobe atrophy
- Parkinson's disease
- Loss of dopamine cells in the substantia
nigra that project to the prefrontal cortex
- Korsakoff's
- Alcohol induced damage to the
dorsomedial thalamus and a deficiency
in the frontal lobe catecholamines