Stimulus factors in the isolation-induced aggression of Bobwhite quail and Khaki Campbell ducklings

Two studies examined the relative abilities of conspecific-derived visual and tactile stimulation to modulate the occurrence of isolation-induced aggression in Bobwhite quail and Khaki Campbell ducklings. In Experiment 1, subjects were permitted visual stimulation from conspecifics but were deprived of conspecific tactile stimulation. In both species, these subjects subsequently showed significantly less aggression towards conspecifics than birds that had been deprived of both visual and tactile stimulation from conspecifics. In Experiment 2, one group of subjects was permitted conspecific tactile stimulation but was deprived of conspecific visual stimulation. Again for both species, these subjects subsequently exhibited significantly less aggressive behavior towards conspecifics than did subjects that had been both visually and tactually de-prived. In sum, the present research suggests that both tactile and visual stimulation from a conspecific are individually sufficient to reduce isolation-induced aggression in these precocial buds.     

The behavioral complications of pallidal stimulation: a case report

We report a case of recurrent manic episodes associated with chronic deep brain stimulation (DBS) targeting globus pallidus (GP) in the treatment of Parkinson's disease (PD). Cardinal PD symptoms and dyskinesia improved with DBS, and neuropsychological testing found improvements in visuospatial measures associated with left DBS and in verbal memory with right DBS when compared to the patient's preoperative baseline. Under conditions of right, left, and bilateral DBS, the patient experienced bouts of mania and hypomania lasting several days at a time. Positron emission tomography (PET) with (15)O-labeled water was performed after his first manic episode under four conditions: no stimulation, right DBS, left DBS, and bilateral DBS. Although no manic switch occurred during the course of the PET study, all three DBS conditions were associated with decreases in regional flow in the left parahippocampus and hippocampus and right mid-cingulate gyrus. Increases in flow in left inferior frontal area, bilateral insula, dorsolateral prefrontal cortex, and cuneus were common to all DBS conditions. GP stimulation in PD may be associated with behavioral and cognitive effects. Distributed blood flow changes observed with pallidal DBS support a role for the pallidum in cognition and affective regulation.     

The integration of habits maintained by food and water reinforcement through stimulus compounding.

In Experiment 1, a light and a tone were correlated independently with water reinforcement of bar pressing by rats. With different naive subjects in Experiment 2, one of these stimuli was correlated with food and the other with water reinforcement (counterbalanced). In both experiments the absence of tone and light signaled extinction. Tests of stimulus-reinforcer independence in Experiment 2 indicated that tone and light controlled behavior whose rate was specifically affected by deprivation state. In the stimulus-compounding tests of both experiments, response rates were higher to tone-plus-light than to tone or light presented alone (additive summation). This is the first report of additive summation produced through compounding stimuli paired with different reinforcers. The results are discussed in the context of the effects of incentive motivation on operant performance.     

Increased regional cerebral glucose metabolism and semantic memory performance in Alzheimer's disease: A pilot double blind transdermal nicotine positron emission tomography study

Nicotinic receptor dysfunction and impaired semantic memory occur early in Alzheimer's disease patients (AD). Previous research implied that nicotine's ability to enhance alertness, arousal, and cognition in a number of nonclinical populations was a function of its ability to stimulate CNS nicotinic cholinergic receptors. In this study it was hypothesized that transdermal administration of nicotine would increase both regional cerebral glucose metabolism (rCMRglc) and semantic memory (as assessed by verbal fluency). Two mild AD and two elderly controls underwent positron emission tomography scanning during a double blind nicotinic agonist verbal fluency challenge procedure. rCMRglc increases occurred in both AD patients, but not controls. In the two AD patients, verbal fluency scores increased by an average of 17%. One elderly control's verbal fluency increased, and the other decreased. These findings suggest that nicotine's effect on metabolism and verbal fluency is due to its ability to stimulate the cholinergic system.     

PUNISHMENT OF SELF-INJURIOUS BEHAVIOR USING AROMATIC AMMONIA AS THE AVERSIVE STIMULUS

Punishment with aromatic ammonia was used to eliminate self-injurious behavior of an autistic woman during experimental sessions. The effects were reversible but were limited to experimental sessions until staff used the ammonia on the ward at all times.     

Behavioral and dimensional contrast in rats.

Rats pressed a nose key for brain stimulation reinforcement presented on a fixed-interval schedule. Stimuli were drawn at random from a continuum of 12 white noise intensities in the range 62-95 decibels, spaced in 3 decibel steps. Experiment 1 varied the number of stimuli and the reinforcement contingencies associated with them. In Condition I (baseline) all stimuli signaled reinforcement; in Conditions II and III stimuli from one half of the continuum signaled reinforcement and those from the other half, extinction. However, in Condition II the 6 stimuli from the middle of the continuum were omitted. Experiment 2 held constant the number of stimuli and varied their spacing. In Condition I, each of 6 sounds signaled reinforcement. In Conditions II and II, three stimuli from one half of the continuum signaled reinforcement and three from the other half, extinction. However, in Condition II the stimuli were near the extremes of the continuum (Stimuli 1, 3, 4, 9, 10, 12). Condition III replaced Stimulus 3 with Stimulus 6 and Stimulus 10 with Stimulus 7. Behavioral contrast was seen in an increase over baseline in response rate to the stimuli associated with the constant schedule component when the variable component was changed to extinction. Dimensional contrast was seen in a further elevation of rate to intermediate positive stimulus values when stimuli were added to the border region between positive and negative values.     

The puzzle of responding maintained by response-contingent shock.

Four squirrel monkeys were first exposed to a sequence of procedures that reliably generate responding maintained by brief response-contingent electric shocks arranged according to a fixed-interval schedule. After responding had become stable on the fixed-interval schedule, additional contingencies were added in tandem, whereby after completion of the interval, the spacing of responses affected shock delivery. In one procedure, responses had to be spaced more widely than their previous median value if shock were to be delivered. In the other procedure, responses had to be spaced more closely to produce shock. On the first of these procedures, decreased but stable responses rates would indicate that shock functioned as a positive reinforcer; on the second, increased response rates would indicate the positively reinforcing function. Instead, response rates accelerated on the procedure that targeted more widely spaced responses for shock delivery, and decelerated or ceased on the procedure that arranged for shocks to be produced by more closely spaced responses. Consistent with other recent findings, these results question the interpretation of performances maintained by response-contingent shock as engendered by positive reinforcement and are consistent with aversive-control interpretations. The details of that aversive control are not entirely clear, however, and these same procedures would be informative if applied to shock-maintained behavior that is generated in other ways.     

腹内侧前额叶在内隐认知重评中的因果作用

情绪调节对维持个体心理健康、适应社会生活十分重要, 然而以往研究主要关注外显情绪调节, 目前我们对内隐情绪调节的认知神经机制的了解还非常有限。为揭示内隐情绪调节的核心脑区, 本研究使用句子整理任务启动内隐认知重评, 并采用经颅直流电刺激(transcranial direct current stimulation, tDCS)激活内侧前额叶特别是腹内侧前额叶(ventromedial prefrontal cortex, vmPFC), 考察该脑区在内隐情绪调节中的因果作用。结果表明, vmPFC被激活的被试组(实验组, n = 40)在内隐认知重评启动条件下比tDCS伪刺激组(对照组, n = 40), 在观看负性图片时报告了更少的负性情绪, 同时负性图片诱发的晚正成分(late positive potential, LPP)波幅更低(LPP是情绪体验强度的客观指标)。同时, 实验组比对照组在观看负性图片时表现出更低的枕区P1波幅(P1为早期视觉注意程度的客观指标)。以上结果说明, 激活以vmPFC为代表的内侧前额叶不但能增强内隐情绪调节的效果, 还能减少被试对负性刺激的早期注意分配。本研究是采用tDCS技术考察启动引起的内隐情绪调节的首次尝试, 研究结果不但表明了以vmPFC为代表的内侧前额叶在内隐认知重评中的关键作用, 还为临床应用研究指出了增强内隐情绪调节能力的神经调控潜在靶点。     

Sensory modality and stimulus control in the pigeon: Cross-species generality of single-incentive selective-association effects

In earlier studies with rats, the effectiveness of the auditory element of a tone–light discriminative stimulus was enhanced when the conditioned incentive value of the compound was negative rather than positive. The present experiment systematically replicated these results in pigeons trained to press a treadle in the presence of a tone–light compound under food-reinforcement or shock-avoidance schedules. Positive incentive value was conditioned to the compound by associating it with either food or relative safety from shock. The compound was made negative in other groups by associating it with shock or the absence of food. When tone and light were presented separately following this training, control by the auditory element was significantly enhanced in the conditions designed to make the compound negative rather than positive. The similarity of this constraint on learning in rats and pigeons suggests that it involves a fundamental attentional and incentive-motivational process with widespread species generality.     

Vibration-Induced Kinesthetic Illusions and Corticospinal Excitability Changes

The authors' aim was to investigate the changes of corticospinal excitability during kinesthetic illusions induced by tendon vibration. Motor-evoked potentials in response to transcranial magnetic stimulation were recorded from the vibrated flexor carpi radialis and its antagonist, extensor carpi radialis. The illusions were evoked under vision conditions without feedback for the position of the wrist (open or closed eyes). In these two conditions motor-evoked potential changes during vibration in the antagonist were not identical. This discrepancy may be a result of 2 simultaneously acting, different and opposite influences and the balance between them depends on visual conditions. Thus, the illusion was accompanied by the facilitation of corticospinal excitability in both vibrated muscle and its antagonist.