Effects of prefrontal lobotomy on conditioned fear and food responses in monkeys.

Emotional responses toward humans in monkeys with selective frontal lesions

“…As to decreased avoidance in a social colony, it is difficult to determine whether an operated animal's fear has lessened or whether its drive for some goal such as food, a mate or a preferred location has increased. Finally, it should be noted that the different emotional changes inferrable from this and other studies [1,8,10] have been produced by different types of frontal lesions. Until some of these behavioral and anatomical variables have been sorted out, and the apparent discrepancies explained, it would be hazardous to place undue emphasis on the present limited, but suggestive, findings…”

“…Orbital frontal cerebral cortex Lesions Avoidance of humans SEVERAL studies have suggested that emotional reactivity in monkeys is altered by damage to the frontal lobes. For example, following both lateral and ventral prefrontal ablations, monkeys show abnormally rapid extinction of preoperatively learned avoidance responses [8], and following prefrontal lobotomy they show decreased avoidance of shock [10] and decreased avoidance of other, more dominant monkeys in a social colony [1]. Such findings appear to indicate that frontal lesions lead to a generalized reduction in fear.…”

Evidence for dissociation of impairment on auditory discrimination and delayed response following lateral frontal lesions in monkeys

“…Limited lesions in some parts of the frontal lobe have been found to produce one type of behavioral alteration, while other limited lesions elsewhere in the frontal lobes have a different effect. For example, alterations in emotional behavior follow frontal lobotomy and medial and basal frontal lesions, but do not seem to follow lateral frontal lesions (5,31,37,41). On the other hand, lateral frontal lesions produce severe impairment on delayed response and delayed alternation, unlike cortical lesions elsewhere in the frontal lobe (4,17,25,27,28,30).…”

Animal Neuropsychology

“…One reason may be the inadequacy of some of the instrumental tasks utilized as indicators of fear (Brutkowski, 1965). Less efficient performance does not necessarily indicate less fear, a point worth considering in the light of demonstrations, some of them mentioned in the previous section, that prefrontal lesions impair the learning, retention, or extinction of avoidance tasks in primates (Waterhouse, 1957;Tanaka, 1973Tanaka, , 1974Izquierdo and Murray, 2005;Rudebeck et al, 2006), carnivores (Auleytner and Brutkowski, 1960;Warren, 1964;Warren et al, 1972;Zielinski, 1972Zielinski, , 1974Zielinski and Czarkowska, 1973), and rodents (Streb and Smith, 1955;Brennan and Wisniewski, 1982;Morgan et al, 1993). Tanaka (1973) observed that onestage lesions, but not seriatim lesions (Tanaka, 1974), involving the medial prefrontal cortex induced a deficit in instrumental avoidance of electric shock.…”