MOTIVATION/EMOTION and the FRONTAL LOBES

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MOTIVATION/EMOTION and the FRONTAL LOBES
left frontal lobe may be most involved in
processing positive emotions right frontal lobe
involved with negative emotions
Remember that the thalamus projects to both the
amygdala .and to sensory cortex areas.. Where
it is eventually processed by the frontal lobes
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The amygdala also projects to the frontal lobes
mainly to the Prefrontal cortex the frontal
cortical areas found anterior to the 2nd and
primary motor areas
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The Amygdala also projects to the Anterior
Cingulate cortex (ACC) of the frontal
lobes(sometimes referred to as the limbic lobe
)
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The frontal lobes, esp.the medial prefrontal
cortex (mPFC.. further specificity considered in
later slides) also project to amygdala
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Frontal lobes and the Amygdala

• What role does the pathway from the prefrontal
  cortex to the amygdala play in emotion and
  motivation??

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1. Cortex Dampens Subcortical Affect..SHAM RAGE

• sham rageoccurs following removal of the
  cerebral cortex from experimental animals..
• In Cats
• lashing of the tail, vigorous arching of the
  back, clawing and attempts to
• bite, and autonomic responses. It is called sham
  rage because unlike
• genuine rage ( or predatory aggression)
• the rage occurs spontaneously or can be triggered
  by
• mild tactile or other non-noxious stimuli.

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Evidence that the frontal lobes Regulate
Subcortical Affective impulses

• Phineas Gage-
• Emotional lability emotional outbursts
• irrationality
• (Deficits in emotional Impusle control)

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Prefrontal lobotomy
The effects of this procedure varied considerably
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Perhaps due to differences in procedure- two
general syndromes associated with frontal
lobotomy (as well as naturally incurred frontal
lobe damage)

• -Pseudopsychopathy- (indicates loss of regulatory
  functions)
• Immature impulsive behavior, aggressive
  outbursts, Inappropriate jocular affect , Poor
  judgment and insight , coarse language,
  promiscuity, general loss of social skills,
  euphoria, Emotional lability, Distractibility
  (see orbito-frontal cortex)
• Pseudodepression (loss of ME influences of
  PFC)
• Apathy, indifference, loss of initiative, loss of
  libido (see ventromedial ACC)

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Other effects of Frontal Lobe Damage relating to
affect and motivation

• -difficulty formulating common rules and goals.
• if a rule or goal is given to the patient there
  is great difficulty in using it to guide
  behavior. ..perhaps related to social motivations
• Actions are motivated by immediate gratification
  of simple impulses Relates to circumstantiality
• dissociation between the discriminative and
  affective aspects of pain. When stuck with a pin,
  such a patient reports that it hurts, but it
  doesn't bother him.

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Other effects of Frontal Lobe Damage

• Confabulation
• fabricate quick, impulsive answers to questions.
  Some responses may be quite fanciful and
  imaginative. The patient cannot inhibit a
  response in order to check its validity. This
  tendency to fabricate an answer is called
  confabulation.

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further evidenceOther Frontal Lobe Syndromes

• Frontal lobe epileptic seizures
• likely to involve brief episodes of screaming,
  bicycling movements, or even movements suggestive
  of sexual activityperhaps reflecting loss of
  regulatory functionslike pseudopsychopathy
• FL epilepsy inter-ictal characteristics
• hebephrenic characteristics (i.e. emotional
  withdrawal and blunted affect) activityperhaps
  reflecting depletion or fatigue of PFC generated
  ME effects..like pseudodepression

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Pseudodepression suggests that the frontal Lobes
may also produce emotional responses
The frontal lobes project to the amygdala
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The Anterior Cingulate Cortex may be critical in
frontal generation of emotion
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lesion of the ACC

• - patients described as apathetic and unconcerned
  when significant events occur, such as making
  mistakes (Eslinger and Damasio, 1985 Rylander,
  1947 )like pseudodepression

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Anterior Cingulate Ctx-Neuroimaging studies
(Caution, interpret with reservation)

• motivational valence assignment (12),
• motor response selection (1315),
• error detection/performance monitoring (16, 17),
• competition monitoring (18),
• anticipation (19),
• working memory (20),
• novelty detection (21),
• reward assessment (22),
• emotional responses to pain.
• ( the amygdala is also involved )

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Even More Specificity! ACC neuroimaging studies

• Dorsal ACC- cognitive and motor control, but the
  mechanisms of these functions remain unclear.
  (Posner and DiGirolamo, 1998 ).
• Ventral medial ACC - involvement in depression
  (like pseudodepression?), also transient mood
  changes (Mayberg et al., 1999 ), and anxiety
  disorders (Mayberg et al., 2000 Brody et al.,
  2001 ) and the perception of pain (Rainville et
  al., 1997 ).
•  decreased dorsal ACC activation and increased
  ventromedial ACC activation in induced sadness
  and depression (Mayberg et al., 1999 ).
•  

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Ventromedial ACC
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ACC and Self-reflection

• Can cognitive and affective components of
  self-reflection can be dissociated using
  functional magnetic resonance imaging.
• Test procedure-subjects judged the personal
  relevance of personality characteristics that
  were either favorable (e.g., "honest") or
  unfavorable (e.g., "lazy")
• distinct neural circuits in adjacent regions of
  the prefrontal cortex subserved the cognitive and
  emotional aspects of self-reflection.
• The medial prefrontal cortex responded only to
  material that was self-descriptive, and this did
  not differ as a function of the valence of the
  traitcognition
• When material was judged to be self-relevant, the
  valence of the material was associated with
  changes in activity in the ventral ACC.

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VON ECONOMO NEURONS and the ACC
When we interact with another person we create a
mental model of how that persons thinks and
feels. We are likely to have initial, quick
intuitions about the person, which are then
followed by slower, more reasoned
judgments. Both intuition and deliberation are
influenced by emotional value judgments. Von
Economo neurons (VENs) are a recently evolved
cell type which may be involved in the fast
intuitive assessment of complex situations.
VENs emerge mainly after birth and increase in
number until age 4 yrs.
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The Social Function of VENs?

• Social bonding ?
• More active when subjects view an image of a
  loved one compared with that of an acquaintance
• Certainty
• active when subjects make decisions under a high
  degree of uncertainty.
• Pain?
• Active when subjective experience of pain which
  is powerfully magnified by uncertainty.
• also active when subjects experience guilt,
  embarrassment and engage in deception
• ACC also active in humor (Watson and Allman,
• trust, empathy, and the discrimination
• of the mental states of others
• All of these social emotions are influenced by
  the degree of uncertainty involved.

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Orbito-frontal cortex and Frontal Poles
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Counterfactual processing -The consequence of a
decision/behavior can lead to feelings such as
satisfaction, relief, or regret evaluation of
the potential outcomes of alternative
decisions.Testing the role of the
orbito-frontal cortex in counterfactual
reactions- a simple gambling task was used-
subjects choices were categorized in terms of
their anticipated and actual emotional impact.
Normal subjects reported emotional responses
consistent with counterfactual thinkingthey
chose to minimize future regret and learned from
their emotional experience. (also associated
with increased activity in the orbito-frontal
regions)Patients with orbitofrontal cortical
lesions, however, did not report regret or
anticipate negative consequences of their
choices.
ORIBITO-FRONTAL CORTEX- counterfactualprocessing/
Regret?
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Damage to the orbito-frontal cortex? May
partially account for the pseudopsychopathic
syndrome

• lack of originality and creativity
• impairment of attention
• difficulty initiating behavior when they do
  engage in activity, they may continue the
  activity without stopping.
• They may only start activity when prompted by
  others (circumstantiality?).
• Like pseudopsychopathy-Emotional disturbance
  most often results from lesion of the orbital
  frontal areas.
• superficial emotional expression like laughing,
  crying etc in situations inappropriate to the
  emotion. The patient usually has no awareness
  that their emotional response is incorrect or
  extreme.

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The Frontal Poles (FPC)and goal directed
behaviors
the most anterior part of the frontal
lobes Neuroimaging studies suggest critical
involvement in Prioritization of Goals ( this
logically would require the suppression of lower
priority impulsesso the pseudopsychopathy like
symptoms associated with damage here is logically
consistent ) Very Active when there is
competition between two concurrent behavioral
plans or mental tasks (that may vary in
respective reward expectations) capacity appears
highly limited, which suggests that the FPC may
be especially important for protecting long-term
high priority goals/plans from immediate
environmental demands or temptations.
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The Ventral tegmental Area (VTA) Dopaminergic
pathways

• dopamine neurons in the VTA project to wide areas
  of the neocortex, esp the frontal lobes ( the
  Mesocortical DA pathway)
• The amygdala and to the nucleus accumbens ( the
  Mesolimbic DA pathways)
• The Mesocortical pathways are believed to play a
  role in selective attention which is a critical
  component of cognitive Bias.

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VTA-Cortical Dopaminergic pathways
The VTA projects to the amygdala, the nucleus
accumbens and to the frontal cortex