Presentation on theme: "MOTIVATION/EMOTION and the FRONTAL LOBES left frontal lobe may be most involved in processing positive emotions right frontal lobe involved with negative."— Presentation transcript:
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
The amygdala also projects to the frontal lobes mainly to the “Prefrontal cortex” …the frontal cortical areas found anterior to the 2 nd and primary motor areas
The Amygdala also projects to the Anterior Cingulate cortex (ACC) of the frontal lobes …(sometimes referred to as the “limbic lobe” )
The frontal lobes, esp.the medial prefrontal cortex (mPFC.. further specificity considered in later slides) also project to amygdala
Frontal lobes and the Amygdala What role does the pathway from the prefrontal cortex to the amygdala play in emotion and motivation??
1. Cortex Dampens Subcortical Affect…..SHAM RAGE sham rage—occurs 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.
Evidence that the frontal lobes Regulate Subcortical Affective impulses Phineas Gage- Emotional lability emotional outbursts irrationality (Deficits in emotional Impusle control)
Prefrontal lobotomy The effects of this procedure varied considerably
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 M&E influences of PFC) –Apathy, indifference, loss of initiative, loss of libido (see ventromedial ACC)
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.
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.
further evidence;Other Frontal Lobe Syndromes Frontal lobe epileptic seizures likely to involve brief episodes of screaming, bicycling movements, or even movements suggestive of sexual activity…perhaps reflecting loss of regulatory functions…like pseudopsychopathy FL epilepsy inter-ictal characteristics hebephrenic characteristics (i.e. emotional withdrawal and blunted affect)… activity…perhaps reflecting depletion or fatigue of PFC generated M&E effects..like pseudodepression
Pseudodepression suggests that the frontal Lobes may also produce emotional responses The frontal lobes project to the amygdala
The Anterior Cingulate Cortex may be critical in frontal generation of emotion
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
Anterior Cingulate Ctx- Neuroimaging studies (Caution, interpret with reservation)Caution, interpret with reservation motivational valence assignment (12),12 motor response selection (13–15),1315 error detection/performance monitoring (16, 17),1617 competition monitoring (18),18 anticipation (19),19 working memory (20),20 novelty detection (21),21 reward assessment (22),22 emotional responses to pain. –( the amygdala is also involved )
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 ).
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 trait…cognition When material was judged to be self-relevant, the valence of the material was associated with changes in activity in the ventral 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. VON ECONOMO NEURONS and the ACC
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.
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- subject’s choices were categorized in terms of their anticipated and actual emotional impact. Normal subjects reported emotional responses consistent with counterfactual thinking; they 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- counterfactual processing/ Regret?
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.
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 impulses…so 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.
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.
VTA-Cortical Dopaminergic pathways The VTA projects to the amygdala, the nucleus accumbens and to the frontal cortex