Which of the following statements about 'Sham Range' is Not true:
B i.e. Abolished by DecoicationSham (false) rage is an outburst of pathological (inappropriate, uncontrolled & violent) anger & fear in decoicate animals on mild peripheral stimulation. It can be caused by stimulation of punishment center of hypothalamus and presents with features of sympathetic stimulationQ.Reward center (ie area of brain responsible for self stimulation reward on induction) includes medial forebrain bundleQ, especially in lateral and ventro medial nuclei of hypothalamusQ.Sham Rage (= False Anger) Reaction - Sham (false) rage is defined as an outburst of inappropriate, uncontrolled (pathological/ violent) rage (fear & anger) on mild peripheral provocation or stimulation. It is seen in decoicate animals (after removal of neocoex) and after destruction of venteromedial nuclei of hypothalamus & septa] nuclei, due to release of punishment centers of brain (esp in periventricular zone of hypothalamus & lateral hypothalamus) from coical and hypothalamic inhibitory control.It is misnomer, as originally it was thought that the rage attacks in decoicated animals (with fore brain, diencephalic lesions) represent only a physical - motor phenomenon of anger and lack emotional (mental) aspect. But now its proved wrong as animals develop unpleasant feelings directed with great accuracy at the source of irritation and develop extremely persistent conditioned avoidance response.Sham rage (like normal rage) can also be produced by strong (in normal) or mild (in decoicated animals) stimulation of punishment centers of hypothalamusQ and shows features of sympathetic stimulation like increased BP, increased hea rate, dilation of pupils and piloerection.Rage & Punishment Centers- Rage is an emotional behavior pattern that involves strong stimulation of the punishment centers of hypothalamus & other limbic structures (especially in periventricular zone of hypothalamus and in lateral hypothalamus) and cause animal to behave in a manner that one would expect from an animal being severely punished. It causes the animal to(1) Develop a defence posture(2) Lift its tail(3) Hiss, spit, growl or bite(4) Extend its claws(5) Develop sympathetic features like dilated pupils, wide open eyes & piloerection and(6) Cause an immediate savage (crudely violent) attack even on slightest provocation.- Normally, this rage phenomenon is held in check mainly by inhibitory signals from the ventero medial nuclei of hypothalamus. Poions of hippocampi & anterior limbic coex especially in anterior cingulate gyri and subcallosal gyri also help to suppress the rage reaction.Punishment or Escape Centers- Electrical stimulation of punishment center ie thin zone of periventricular nuclei (located adjacent to 3rd ventricle), adjoining central grey area of mesencephalon and lateral hypothalamus leads to unpleasant (aversive) fear, anger, defence, escape , terror, punishment (even sickness & pain) reactions.- Most potent areas for punishment & escape tendencies are found in central grey areasurrounding the aqueduct of Sylvius in mesencephalon, extending upwards into the periventricular zone of hypothalamus & thalamus; whereas less potent areas include amygdale and hippocampus.Stimulation of punishment center usually inhibit the reward & pleasure centers completely, showing that fear and punishment can take precedence over pleasure and reward.Reward or Pleasure CentersIf electrical stimulation of any area gives the animal a sense of reward, then it will stimulate the area by pressing lever again and again (sometimes even thousands of time per hour) - ie self stimulatory reward induction. When offered the choice between eating delectable (liked) food as apposed to stimulate the reward center, the animal often chooses electrical stimulation of reward induction.- Major reward centers are located along course of the media forebrain bundle especially in lateral and ventro medial nuclei of hypothalamus. Less potent reward centers which are secondary to major hypothalamic centers are found in the septum, amygdala, ceain areas of thalamus and basal ganglia and extending downward into the basal tegmentum of mesencephalon- Lateral nucleus, like many other areas, with weaker stimuli giving a sense of reward and with stronger stimuli a sense of punishment.
Caused by Hypothalamic stimulation
Abolished by Decoication
Pathological Rage Reaction
Association with sympathetic stimulation