道德直觉加工机制的理论构想

认知和情绪因素在道德判断中的作用机制是社会认知神经科学研究中最具争议的热点问题之一。本文认为, 人类拥有一种普遍性的道德直觉, 它是一种可能同时包含道德知识和情绪情感的自动化加工系统, 决定人们对一个道德违反情境作出快速的判断。据此, 本文就如何深入揭示道德直觉的加工机制提出了研究构想, 研究将首先采用经颅磁刺激技术, 探索当认知功能受抑制后人们的道德加工的特点, 初步探索道德直觉存在的可能性; 然后采用事件相关电位技术, 从外显和内隐两个维度上探讨道德直觉的时程加工机制; 最后采用侧向化运动准备电位指标, 进一步探索道德直觉和基本厌恶情绪的分离。     

Further evaluation of methods to identify matched stimulation

The effects of preferred stimulation on the vocal stereotypy of 2 individuals were evaluated in two experiments. The results of Experiment 1 showed that (a) the vocal stereotypy of both participants persisted in the absence of social consequences, (b) 1 participant manipulated toys that did and did not produce auditory stimulation, but only sound-producing toys decreased his vocal stereotypy, and (c) only noncontingent music decreased vocal stereotypy for the other participant, but sterotypy paradoxically increased when toys were presented with music. Using a three-component multiple schedule, the results of Experiment 2 showed that the vocal stereotypy of both participants remained below preintervention levels following the removal of auditory stimulation and that 1 participant's vocal stereotypy increased following the removal of contingent reprimands. These patterns suggest that auditory stimulation functioned as an abolishing operation for vocal stereotypy and reprimands functioned as an establishing operation for vocal stereotypy. Together, the two experiments provide a method for identifying alternative stimulation that may substitute for automatically reinforced behavior.     

Cortical Language Mapping in Epilepsy: A Critical Review

One challenge in dominant hemisphere epilepsy surgery is to remove sufficient epileptogenic tissue to achieve seizure freedom without compromising postoperative language function. Electrical stimulation mapping (ESM) of language was developed specifically to identify essential language cortex in pharmacologically intractable epilepsy patients undergoing left hemisphere resection of epileptogenic cortex. Surprisingly, the procedure remains unstandardized, and limited data support its clinical validity. Nevertheless, ESM for language mapping has likely minimized postoperative language decline in numerous patients, and has generated a wealth of data elucidating brain–language relations. This article reviews the literature on topographical patterns of language organization inferred from ESM, and the influence of patient characteristics on these patterns, including baseline ability level, age, gender, pathology, degree of language lateralization and bilingualism. Questions regarding clinical validity and limitations of ESM are discussed. Finally, recommendations for clinical practice are presented, and theoretical questions regarding ESM and the findings it has generated are considered.     

Electrical stimulation of the pedunculopontine tegmental nucleus in freely moving awake rats: time- and site-specific effects on two-way active avoidance conditioning

The pedunculopontine tegmental nucleus (PPTg) is involved in the regulation of thalamocortical transmission and of several functions related to ventral and dorsal striatal circuits. Stimulation of the PPTg in anesthetized animals increases cortical arousal, cortical acetylcholine release, bursting activity of mesopontine dopaminergic cells, and striatal dopamine release. It was hypothetized that PPTg stimulation could improve learning by enhancing cortical arousal and optimizing the activity of striatal circuits. We tested whether electrical stimulation (ES) of the PPTg, applied to freely-moving awake rats previously implanted with a chronic electrode, would improve the acquisition and/or the retention of two-way active avoidance conditioning, and whether this effect would depend on the specific PPTg region stimulated (anterior vs posterior) and on the time of ES: just before (pre-training) or after (post-training) each of three training sessions. The treatment consisted of 20 min of ES (0.2 ms pulses at 100 Hz; current intensity: 40-80 microA). The results showed that (1) this stimulation did not induce either any signs of distress nor abnormal behaviors, apart from some motor stereotyped behaviors that disappeared when current intensity was lowered; (2) pre-training ES applied to the anterior PPTg improved the acquisition of two-way active avoidance, (3) no learning improvement was found after either post-training ES of the anterior PPTg, or pre- and post-training ES of the posterior PPTg. The results give support to a role of PPTg in learning-related processes, and point to the existence of functional PPTg regions.     

The effects of reinforcer magnitude on timing in rats

The relation between reinforcer magnitude and timing behavior was studied using a peak procedure. Four rats received multiple consecutive sessions with both low and high levels of brain stimulation reward (BSR). Rats paused longer and had later start times during sessions when their responses were reinforced with low-magnitude BSR. When estimated by a symmetric Gaussian function, peak times also were earlier; when estimated by a better-fitting asymmetric Gaussian function or by analyzing individual trials, however, these peak-time changes were determined to reflect a mixture of large effects of BSR on start times and no effect on stop times. These results pose a significant dilemma for three major theories of timing (SET, MTS, and BeT), which all predict no effects for chronic manipulations of reinforcer magnitude. We conclude that increased reinforcer magnitude influences timing in two ways: through larger immediate after-effects that delay responding and through anticipatory effects that elicit earlier responding.     

The role of the right posterior parietal cortex in temporal order judgment

Perceived order of two consecutive stimuli may not correspond to the order of their physical onsets. Such a disagreement presumably results from a difference in the speed of stimulus processing toward central decision mechanisms. Since previous evidence suggests that the right posterior parietal cortex (PPC) plays a role in modulating the processing speed of a visual target, we applied single-pulse TMS over the region in 14 normal subjects, while they judged the temporal order of two consecutive visual stimuli. Stimulus-onset-asynchrony (SOA) randomly varied between -100 and 100 ms in 20-ms steps (with a positive SOA when a target appeared on the right hemi-field before the other on the left), and a point of subjective simultaneity was measured for individual subjects. TMS stimulation was time-locked at 50, 100, 150, and 200 ms after the onset of the first stimulus, and results in trials with TMS on right PPC were compared with those in trials without TMS. TMS over the right PPC delayed the detection of a visual target in the contralateral, i.e., left hemi-field by 24 (+/-7 SE) ms and 16 (+/-4 SE) ms, when the stimulation was given at 50 and 100 ms after the first target onset. In contrast, TMS on the left PPC was not effective. These results show that the right PPC is important in a timely detection of a target appearing on the left visual field, especially in competition with another target simultaneously appearing in the opposite field.     

Sensitivity to aversive events in depression: Antecedent,concomitant, or consequent?

This study tested whether sensitivity to aversive events is a concomitant versus antecedent/consequent of depression. Twenty currently depressed subjects, twenty subjects with remitted depression, and twenty control subjects completed psychophysiological and learning tasks involving aversive components. Both currently depressed and remitted subjects, when compared to control subjects, exhibited greater decreases in skin resistance response reactions to negative social scenes and a greater sensitivity to extinction in the learning condition involving an aversive component. The fact that the responses of remitted subjects were very similar to those of currently depressed subjects on both tasks is consistent with the view that sensitivity to aversive events is an antecedent or consequent of depression, as opposed to being only a concomitant. The results also provide some support for the passive avoidance model of depression.This study was based on portions of a doctoral dissertation by the first author, with the second author as chairperson, at the University of North Carolina at Greensboro.This research was aided by a Grant-in-Aid of Research to the first author from Sigma Xi, The Scientific Research Society, an award from the Jill Shelby Memorial Fund to the first author, and support from National Institute of Mental Health Grant MH17071, awarded to C. R. Snyder.Portions of this paper were presented at the meeting of the American Psychological Association, New Orleans, August 1989, and at the meeting of the Association for the Advancement of Behavior Therapy, Washington, DC, November, 1989.     

Evidence of the origin of specific spontaneous head turns during intertrial intervals

Direction and the frequency of spontaneous head movements during the ITIs following forward and backward paired trials were compared to an acquisition of a conditioned orienting (alpha) response directed to the side of the tone source. The head movements were analyzed from video recordings using classification of head turns to preferred and to nonpreferred directions. The results showed a significant increase in the alpha responses during the forward paired conditioning to the preferred direction and rapid extinction during the subsequent backward conditioning sessions. Spontaneous head movements during the ITIs increased to the same preferred direction as the conditioned alpha responses. The results of this experiment suggest that the response initially elicited by the CS can later appear as “spontaneous,” instrumental behavior, the form and the nature of which is determined by the characteristics of the conditioned alpha response developing as a result of classical conditioning.     

MANIPULATION OF POTENTIAL PUNISHMENT PARAMETERS IN THE TREATMENT OF SELF-INJURY1

The self-injurious behavior (SIB) of a blind, profoundly retarded male was observed within a field setting as multiple forms of punishment were applied. The effects of hair-tug punishment were first systematically examined, then hair-tug and electric shock punishment were administered in varing ratios (of punishment deliveries per SIB response) supplemented by continuous restraint contingencies and made contingent on recurrent antecedents of SIB cycles. Treatments were applied over six months of consecutive daily sessions ranging from 30 min to 8 hr duration. Posttreatment followup observations were taken 12, 24, and 34 months after treatment. Partial suppression was produced as a direct function of hair-tug punishment in the initial phase. A generally progressive decrement was produced on already lowered SIB rates with the succeeding components of the treatment package. Extended periods of total SIB suppression occurred as punishment was rendered contingent on antecedent components of each SIB response cycle. Followup observations of nearly 3 yr duration indicated total suppression generalized over all settings in which the subject functioned. The findings were related to the contrasting limits prevailing in most reports of punishment-based SIB suppression.     

Rule-violations sensitise towards negative and authority-related stimuli

Rule violations have usually been studied from a third-person perspective, identifying situational factors that render violations more or less likely. A first-person perspective of the agent that actively violates the rules, on the other hand, is only just beginning to emerge. Here we show that committing a rule violation sensitises towards subsequent negative stimuli as well as subsequent authority-related stimuli. In a Prime-Probe design, we used an instructed rule-violation task as the Prime and a word categorisation task as the Probe. Also, we employed a control condition that used a rule inversion task as the Prime (instead of rule violations). Probe targets were categorised faster after a violation relative to after a rule-based response if they related to either, negative valence or authority. Inversions, however, primed only negative stimuli and did not accelerate the categorisation of authority-related stimuli. A heightened sensitivity towards authority-related targets thus seems to be specific to rule violations. A control experiment showed that these effects cannot be explained in terms of semantic priming. Therefore, we propose that rule violations necessarily activate authority-related representations that make rule violations qualitatively different from simple rule inversions.