6-emotion and brain models

8/2/2019 6-Emotion and Brain Models

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Emotion and Brain Modelsof the Mind

John Fayyad, M.D.

Balamand UniversityFaculty of Medicine

St. George Hospital University Medical Center

Dept. of Psychiatry & Clinical PsychologyInstitute for Development Research Advocacy and Applied Care(IDRAAC)

Ethology

Ethology is the systematic study of animal behavior.

Imprinting implies that, during a certain short periodof development, a young animal is highly sensitive toa certain stimulus that then, but not at other times,

provokes a specific behavior pattern. Lorenzdescribed newly hatched goslings.


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In a series of experiments, Harlow separated rhesusmonkeys from their mothers during their first weeks oflife. During this time, the monkey infant depends on itsmother for nourishment and protection, as well as forphysical warmth and emotional security contactcomfort, as Harlow first termed it in 1958. Harlowsubstituted a surrogate mother made from wire or clothfor the real mother. The infants preferred the cloth-covered surrogate mother, which provided contactcomfort, to the wire-covered surrogate, which providedfood but no contact comfort.

Social Deprivation in NonhumanPrimates

Type of social deprivat ion

Total isolation (not allowed to developcaretaker or peer bond)

Mother-only reared

Peer-only reared

Partial isolation (can see, hear, and smellother monkeys)

Separation (taken from caretaker after bondhas developed)

Effect

Self-orality, self-clasping, very fearful whenplaced with peers, unable to copulate. Ifimpregnated, female is unable to nurtureyoung (motherless mothers). If isolationgoes beyond 6 months, no recovery ispossible (effect of Therapist Monkeys).

Fails to leave mother and explore. Terrifiedwhen finally exposed to peers. Unable toplay or to copulate.

Engages in self-orality, grasps others in clingingmanner, easily frightened, reluctant toexplore, timid as adult, play is minimal.

Stares vacantly into space, engages in self-mutilation, stereotyped behavior patterns.

Initial protest stage changing to despair 48hours after separation; refuses to play.Rapid reattachment when returned tomother.


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Learned Help lessness

The learned helplessness model of depression, developed byMartin Seligman, is a good example of an experimentaldisorder. Dogs were exposed to electric shocks from whichthey could not escape. The dogs eventually gave up andmade no attempt to escape new shocks. The apparent givingup generalized to other situations, and eventually the dogsalways appeared to be helpless and apathetic.

A social application of this concept involves school childrenwho have learned that they fail in school no matter whatthey do; they view themselves as helpless losers, and thisself-concept causes them to stop trying.

Mothering Behaviors in Rat s

Experiments by Michael Meanay andColleagues

Variability in licking and grooming (LG)behavior of mother rats towards theiroffspring

This resulted in changes in offspringsbehavior and endocrine response. Was thisgenetic or environmentally mediated?


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Are there cellular mechanisms for social

attachments?

The work of Thomas Insel on prairie voles.

Monogamous prairie voles have a higher density ofoxytocin receptors in nucleus accumbens than donon- monogamous other vole species.

Blockade of these receptors by site-specific injectionof antagonists in the female prairie vole prevents

partner preference formation. Vasopression facilitates pair bonding in males and a

Vasporession 1a receptor antagonist inhibits pairbonding in males.


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Gene Environment I nteract ions

Those homozygous for the short allele of theserotonin transporter gene developeddepression only if exposed to adversities.

Those homozygous for Monoamine Oxides-Afunctional polymorphism that resulted in lowMAO-A activity developed conduct disorderonly when exposed to maltreatment inchildhood.

Caspi et al. Science 2003

Serot onin Transport er Gene (5 -HTT):Eff ect of Exposure t o Str essful Event s Betw een Ages 21 & 26

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The percentage of individuals meeting diagnostic

criteria for depression at age 26, as a function of 5-

HTT genotype and number of stressful life events

between the ages of 21 and 26

Caspi et al. Science 2003

MAOA Acti vit y and Specif ic Measures of Ant isocialBehavior

Cas i et al. Science 2002

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Sensory Deprivat ion

Volunteer subjects under conditions of visual, auditory, andtactile deprivation for periods of up to 7 days reacted withincreased suggestibility. Some subjects also showed characteristicsymptoms of the sensory deprivation state: anxiety, tension,inability to concentrate or organize thoughts, increasedsuggestibility, body illusions, somatic complaints, intense subjectiveemotional distress, and vivid sensory imagery usually visual andsometimes reaching the proportions of hallucinations with adelusionary quality.

The limbic system appears to house the emotional associationareas, which direct the hypothalamus to express the motor andendocrine components of the emotional state.

Frontal Lobe Funct ion

The massive size of the frontal lobes is the main feature thatdistinguishes the human brain from that of other primates and thatlends it uniquely human qualities.

There are four subdivisions:1) Motor strip2) Supplemental motor area3) Brocas area

4) Prefrontal cortex

Frontal lobe injury usually impairs the executive functions:motivation, attention, and sequencing of actions.


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Bilateral lesions of the frontal lobes are characterized bychanges in personality how persons interact with theworld. The frontal lobe syndrome, which is mostcommonly produced by trauma, infarcts, tumors,lobotomy, multiple sclerosis, or Picks disease, consistsof slowed thinking, poor judgment, decreased curiosity,social withdrawal, and irritability. Patients typicallydisplay apathetic indifference to experience that cansuddenly explode into impulsive disinhibition. Unilateralfrontal lobe lesions may be largely unnoticed becausethe intact lobe can compensate with high efficiency.

A famous case illustrating the result of frontal lobe damageinvolves Phineas Gage, a 25-year-old railroad worker. While he wasworking with explosives, an accident drove an iron rod throughGages head. He survived, but both frontal lobes were severelydamaged. After the accident his behavior changed dramatically.The case was written up by J.M. Harlow, M.D., in 1868, as follows:

[George] is fitfull, irreverent, indulging at times in the grossestprofanity (which was not previously his custom), manifestingbut little deference for his fellows, impatient of restraint oradvice when it conflicts with his desires His mind was radicallychanged, so decidedly that his friends and acquaintances saidhe was no longer Gage.


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Exam ple of Emot ions Related toDisorders

Major Depressive Disorder (Sad Mood)

Anxiety Disorders (Worry, Fear, Shyness)

PTSD (Fear related to trauma)

Bipolar Disorder (Happiness and elation)


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Did I hear something?

Auditory verbal hallucinations in patients with a psychoticdisorder are consistently preceded by deactivation of theparahippocampal gyrus. The parahippocampus has beenhypothesized to play a central role in memory recollection,sending information from the hippocampus to the associationareas. Dysfunction of this region could trigger inadequateactivation of right language areas during auditoryhallucinations.

Kelly M.J. Diederen, M.Sc. Sebastiaan F.W. Neggers, Ph.D. Kirstin Daalman, M.Sc.Jan Dirk Blom, M.D., Ph.D.

Rutger Goekoop, M.D., Ph.D. Ren S. Kahn, M.D., Ph.D. Iris E.C. Sommer, M.D., Ph.D. (2010). Deactivation

of the Parahippocampal Gyrus Preceding Auditory Hallucinations in Schizophrenia.American Journal ofPsychiatry, (doi: 10.1176/appi.ajp.2009.09040456).

Where is Love?

Filial love: recognition of infant cry.

Romantic love: anterior cingulate cortex (ACC)

Sexual attraction: oxytocin? Others?

Animal studies: glutamate transmission inpyramidal cells in ACC increases sexual drive

6-emotion and brain models

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