Disconnection of the amygdala from visual association cortex impairs visual reward-association learning in monkeys

Abstract

Cynomolgus monkeys (Macaca fascicularis) were trained in a task that assessed their ability to associate visual stimuli with food reward. Acquisition of stimulus-reward associations was measured under 2 conditions, a 2-stimuli acquisition condition and a 1-stimulus acquisition condition. On each trial in the 2-stimuli condition, the positive (correct) and negative (incorrect) stimuli were presented side by side and the animal chose one by touching it; if the choice was correct, a food reward was dispensed. On each trial in the 1-stimulus condition, either the positive or the negative stimulus was presented alone; if the stimulus was the positive, it was followed by reward delivery, regardless of the animal's response to it, and if it was the negative, it was not followed by reward delivery. Thus, reward delivery was contingent upon the animal's response to the stimuli in the 2- stimuli condition but not in the 1-stimulus condition. The effect of acquisition trials under these 2 conditions was measured, in both conditions, by the animal's subsequent choice when presented with the 2 stimuli side by side. Following preoperative training in this task, the animals were first subjected to unilateral ablation of the inferotemporal cortex. This operation had little effect on the animals' learning ability. Then, the amygdala was ablated in the hemisphere contralateral to that in which the unilateral inferotemporal ablation had been carried out. This combination of crossed unilateral lesions of the amygdala and of the inferotemporal cortex, which disconnects the amygdala from the output of visual association cortex, produced a profound impairment in stimulus-reward-associative learning.(ABSTRACT TRUNCATED AT 250 WORDS)

The enactive mind, or from actions to cognition: lessons from autism

“…A positron emission tomography study attempting to separate decontextualized human motions (point-light displays depicting a hand bringing a cup to one's mouth) from what can be seen as a more naturalistic human motion (a person dancing) showed that the perception of the latter also implicated limbic structures such as the amygdala (Bonda et al 1996). This finding is consistent with a perceptionfor-action system that not only perceives to act, but one that is embedded in an approach/withdrawal, affectivebased context (Gaffan et al 1988).…”

Selective Roles for Hippocampal, Prefrontal Cortical, and Ventral Striatal Circuits in Radial-Arm Maze Tasks With or Without a Delay

“…Specifically, a unilateral lidocaine-induced lesion of the origin of parallel efferent pathways in one hemisphere was used in combination with a contralateral lidocaine-induced lesion in one of the target areas of the efferent projection in the other hemisphere. This procedure has proven to be particularly useful in defining the route of serial information transfer between different brain regions in both rats (Everitt et al, 1991) and primates (Gaffan and Harris, 1987;Gaffan et al, 1988Gaffan et al, , 1989. Two patterns of bilateral inactivation were used in the following experiments: unilateral reversible lesions of the vSub in combination with a contralateral lesion of either (1) the PL region of the PFC or (2) the N.Acc.…”

Comparison of subcortical connections of inferior temporal and posterior parietal cortex in monkeys

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