The significance of crossed and uncrossed projections for the acquisition and retrieval of visual engrams in hooded and albino rats

Summary Occlusion of one eye and functional hemidecortication by cortical spreading depression (CSD) were used to examine the relative importance of crossed and uncrossed visual projections for pattern discrimination learning in hooded and albino rats. Whereas functionally hemidecorticate albino rats were unable to learn in 200 trials a horizontal-vertical discrimination when using the eye contralateral to the depressed hemisphere, hooded rats needed under similar conditions three times as many trials to criterion (167) than when using opposite eye and hemisphere (59). An engram established in intact animals with both eyes could be retrieved in functionally hemidecorticate rats of both strains even with the eye ipsilateral to the intact hemicortex, but retraining required about twice as many trials as when using the contralateral eye. Retrieval of monocularly acquired engrams was less efficient under similar conditions. Pattern discrimination formed through crossed or uncrossed visual projections during monocular occlusion and contralateral or ipsilateral CSD was completely lateralized, since relearning with naive eye and hemisphere proceeded at the same rate as the original learning. On the contrary, a black-white discrimination trained with the eye contralateral to the depressed hemisphere could be partly retrieved by the untrained eye and hemisphere. It is concluded that the ipsilateral visual projection is more effective in hooded than in albino rats and that it can be more efficiently used for retrieval than for acquisition.This research was partly supported by the Foundations' Fund for Research in Psychiatry, Grant G69-453.     

Vulnerability to depression,mild depression,and degree of self-schema consolidation

The present study investigated the degree of consolidation of self-schema content in mildly depressed individuals, individuals cognitively vulnerable to depression (but currently nondepressed), and nonvulnerable-nondepressed controls. All three groups of subjects were presented with pairs of adjectives involving one depressed and one nondepressed content adjective, and were asked to decide which of the two adjectives described them the best (or least). Following this, subjects rated each adjective on a 9-point degree of self-reference scale. On the basis of these two types of self-referent judgments, a measure of decision inconsistency was computed for each subject. In accord with predictions generated from a self-schema model of depression, similar decision inconsistency scores were found for mildly depressed and vulnerable-nondepressed individuals. In turn, both of these groups revealed greater decision inconsistencies than normal controls (the nonvulnerable-nondepressed group). Using the inconsistency measure as an index of the degree of consolidation of self-schema content, these findings suggest that relatively poor consolidation of depressed and nondepressed self-schema content may relate to both the etiology and maintenance of depression.     

The effects of gender and response style on depressed mood

Research has shown that gender differences in the rate of depression may be accounted for by different response styles. To examine whether response style affects mood, depressed mood was induced in 31 females and 33 males (all Caucasian) who were then randomly assigned to either a ruminating or a distracting response task. The findings supported the response style theory as the ruminating group remained depressed after the response task, while the distracting group became less depressed. Gender was not a factor in this experiment as both men and women reacted similarly to the mood induction and the experimental tasks. Although clinical implication cannot be determined from a study involving nondepressed subjects, it can be concluded that ruminating about one's depressed mood is not an effective method for overcoming depression.     

Reading disability and hemispheric interaction on a lexical decision task

The assumptions tested were that the relative contribution of each hemisphere to reading alters with experience and that experience increases suppression of the simultaneous use of identical strategies by the non-dominant hemisphere. Males that were reading disabled and phonologically impaired, reading disabled and phonologically normal, or with no reading disability were presented familiar words, orthographically correct pseudowords, and orthographically incorrect non-words for lexical decision. Accuracy and response times in all groups showed a shift from no asymmetry in processing non-words to a stable left hemisphere advantage and clear suppression of the right hemisphere in processing words. In the pseudoword condition, accuracy scores were higher when both hemispheres were free to engage, especially in those with a reading disability and responses slowed in the phonologically impaired group but not the phonologically normal groups when the right hemisphere was disengaged. As familiar words typically invoke lexical processing by both hemispheres while pseudowords invoke lexical processing by the right and non-lexical processing by the left hemisphere, and as non-lexical processing is weak in the phonologically impaired, the results support the assumptions that were tested.     

Recognition of emotional facial expressions in depressed children and adolescents

Of the neurobiological models of children's and adolescents' depression, the neuropsychological one is considered here. Experimental and clinical evidence has allowed us to identify a lateralization of emotional functions from the very beginning of development, and a right hemisphere dominance for emotions is by now well-known. Many studies have also correlated depression with a right hemisphere dysfunction in patients of different ages. The aim of our study was to analyze recognition of different facial emotions by a group of depressed children and adolescents. Patients affected by Major Depressive Disorder recognized less fear in six fundamental emotions than a group of healthy controls, and Dysthymic subjects recognized less anger. The group of patients' failure to recognize negative-aroused facial expressions could indicate a subtle right hemisphere dysfunction in depressed children and adolescents.     

Hierarchical resurgence

In resurgence, conventionally a target response is trained and then extinguished while some alternative response is reinforced. In the most common procedure, when the latter is extinguished, the former resurges. The present experiments examined resurgence after two responses were trained sequentially and subsequently extinguished. In Experiments 1 and 2, keypecking to one key was trained and then extinguished as keypecking to a different key was trained then later extinguished. In both experiments, regardless of the spatial location of the different keys, the last‐trained response resurged before the first‐trained one. The results were replicated in Experiment 3 where reinforcement rate of the first‐trained response was four times that of the second‐trained response. The results in conjunction with earlier experiments suggest that resurgence occurs hierarchically, although whether more or less recently trained target responses resurge first or later may depend on both current and historical variables. The results also raise questions about the interpretation of responding on a control key that sometimes is included in resurgence experiments to isolate resurgence from extinction‐induced responding.     

Resistance to extinction and punishment following training with shock and non-reinforcement: Failure to obtain cross-tolerance

Two experiments investigated the phenomenon of cross-tolerance between the partial reinforcement extinction effect (PREE) and the partial punishment effect (PPE). Three groups of rats were trained in acquisition to run in a straight alley. The continuously reinforced (CRF) group received a reward on every trial. The partially reinforced (PRF) group was rewarded on a quasi-random 50% schedule. The partially punished (PP) group received food reward on every trial but, in addition, received foot shocks of gradually increasing intensity in the goal box on a random 50% of the trials. In the test stage, half of the animals in each training condition were tested in extinction, where no reward was given on any of the trials, and the other half were tested in punishment, with both food and shock presented on each trial. Experiment 1 used a 1-trial/day procedure; Experiment 2 used a multi-trial procedure. In both procedures, clear PREE and PPE were obtained. In the 1-trial/day procedure, no cross-tolerance was evident: animals trained on a PRF or PP schedule did not show increased resistance to punishment and extinction, respectively. In the multi-trial procedure, only weak cross-tolerance was obtained in animals trained on partial reinforcement and tested in punishment.     

Focal changes in cerebral blood flow produced by monetary incentive during a mental mathematics task in normal and depressed subjects

The purpose of this experiment was to determine the effect of incentive-induced arousal on the diffuse and regional cerebral blood flow (rCBF) response during cognitive activation for normal and depressed groups. Two normal rest CBF measurements were followed by two mental mathematics activation CBF measurements. For the first activation measurement, half the subjects in each group were offered monetary incentive for correct performance and half the subjects received no monetary incentive. All subjects were offered monetary incentive on the final activation run. The effect of monetary incentive on the first activation run was to increase CBF activation at four detectors in the left hemisphere. Incentive did not affect the CBF activation response when introduced following practice on the activation task (on the final run). Depressed groups had lower resting blood flow than normals, but the distribution of flow and the CBF response to incentive were almost identical in the two groups.     

Social problem-solving in depressed,conduct-disordered,and normal adolescents

Although past theory and research implicate social problem-solving deficits in both depression and aggressive disorders, research examining carefully diagnosed groups of adolescent depressed and conduct-disordered groups had not previously been conducted. In the current study three groups of adolescents (major depression, conduct-disordered, and normal) were studied using two social problem-solving measures. Both the Means-Ends Problem-Solving task (MEPS) and the Social Situations Analysis measure (SSA) failed to show social problem-solving problem deficits in the depressed group relative to their normal age peers, but did provide corroborative evidence for social problem-solving deficits in the conduct-disordered sample. Relative to the other two groups, the conduct-disordered adolescents were found to generate fewer means to a social end, to anticipate fewer obstacles in the pursuit of solutions to interpersonal situations, and to generate fewer assertive behavioral solutions to difficult social situations. The results are discussed in relation to other work with depressed and aggressive youth, and directions for future research are given.     

DOES CONDITIONAL DISCRIMINATION LEARNING BY PIGEONS NECESSARILY INVOLVE HIERARCHICAL RELATIONSHIPS?

Four experiments demonstrate that when putative conditional and discriminative cues are presented simultaneously in the single reversal procedure, it is not possible to ascribe a uniquely conditional or uniquely discriminative function to either of the cues. In Experiment 1, pigeons were trained to respond to a blue key and not to a red key while the houselight was on; then in a different session they learned the reversal of this discrimination with the houselight off (single reversal). Separate groups were tested for color generalization with houselight conditions alternating in blocks of trials or for houselight intensity generalization with blue and red key colors alternating in blocks of trials. Both test procedures revealed a conditional relationship between houselight and key color conditions. Experiment 2 produced the same result following training in which the key colors were held constant across training sessions while the houselight and no houselight conditions varied within sessions. In Experiment 3, separate groups were trained with the two procedures but were tested with randomly ordered combinations of key colors and houselight intensities. The two groups yielded indistinguishable bidimensional generalization gradients with peaks at both previously reinforced stimulus combinations. In Experiment 4 the subjects were switched from one of these training procedures to the other with no decrement in their discriminative performance. We conclude that for successive discriminations between conditional- and discriminative-stimulus combinations, the notion of a hierarchical relation between conditional and discriminative stimuli must be extended to include a symmetrical relationship or the notion should be abandoned altogether.     

Right hemisphere sensitivity to arousal and depression.

Several lines of evidence show impaired right hemisphere function in depression. Lateralized simple reaction time tasks show impaired left visual field responses both in normals experiencing a depressed mood and in patients with mild unipolar depression. One interpretation for these findings is that depression impairs right hemisphere function by interfering with right hemisphere arousal and vigilance mechanisms. In order to test this hypothesis, subjects receiving either depression or relaxation mood suggestions performed an uncued reaction time task that has been shown to be sensitive to right posterior brain damage. Level of alertness was varied by contrasting uncued blocks with blocks in which targets were preceded by a warning tone. The results showed the predicted slowing of left visual field responses in the depressed mood, but only in women. The effect was significant only for the uncued blocks. The left visual field impairment was significantly larger during depression than in the relaxation state, but a smaller left visual field slowing was present in women in the relaxed state as well. These results may be consistent with the notion that depression interferes with right hemisphere function in part by influencing right hemisphere arousal mechanisms.     

抑郁症患者识别情绪词时执行功能实验研究

为了研究抑郁症患者识别汉语情绪词时的执行功能特征,采用神经扫描仪STIM刺激反应系统记录16名抑郁症患者和18名正常对照组执行四类Go／No go汉语情绪词识别作业时的反应时和正确率,抑郁自评量表(SDS)评价抑郁严重程度,自动思维问卷(ATQ)评价负性认知偏差程度。结果发现,识别正／负性词时抑郁症组反应时均明显延长,正确率明显降低。组内方差分析显示,随着情绪词识别作业难度增加,正常对照组正／负性词反应时缩短,正确率逐渐提高,且不受双重作业任务的影响。抑郁症组则表现为反应时延长,正确率变化不明显。重复测量多因素方差分析显示。词性、作业、组别间因素对反应时的主效应均有显著性意义;组别间因素对正确率的主效应均有显著性意义。抑郁症患者SDS、ATQ分与反应时、正确率相关无显著性。提示抑郁症患者区分正负性汉语情绪词时存在执行功能障碍。     

Stress reactivity and coping in seasonal and nonseasonal depression

Stress, stress reactivity, and coping skill use were examined in individuals with seasonal depression, nonseasonal depression, and nondepressed controls. Although participants in the two depressed groups reported using more avoidance coping strategies than controls, only participants in the seasonal depressed group reported using more season-specific coping (i.e., light-related strategies) than participants in the nonseasonal depressed and control groups. Individuals in the seasonal depressed group also reporting using acceptance coping strategies less frequently than individuals in the control group. Only participants in the nonseasonal depressed group, however, exhibited greater psychophysiological arousal in reaction to a laboratory stressor (i.e., unsolvable anagram task) when compared to participants in the seasonal and nondepressed control groups. Participants in both depressed groups reported greater impact of negative life events during the past 6 months than did controls. Similarities and differences in the two types of depression may have implications for the conceptualization and treatment of seasonal depression.     

老年抑郁个体注意偏向的发生阶段

本研究以老年抑郁量表、自评抑郁量表和汉密顿抑郁量表为工具筛选出老年抑郁个体和老年正常对照组为研究对象,通过空间线索化范式,以及分离的情绪Stroop范式考察了刺激呈现时间、线索呈现条件对老年抑郁个体注意偏向的影响,并探讨了老年抑郁个体注意偏向的发生阶段。研究结果表明：（1）在空间线索任务中,当刺激呈现时间为250ms或500ms时,老年抑郁组与老年正常组的返回抑制效应在各种情绪刺激下均无显著差异（P>0.05）,即老年抑郁个体没有呈现出对任何情绪刺激类型的注意偏向现象;当刺激呈现时间为750ms或1000ms时,老年抑郁组的返回抑制效应在不同情绪刺激条件下差异显著,F(2, 66)=3.22,P=0.046,而老年正常组则不存在返回抑制效应在情绪刺激类型上的差异（P>0.05）,提示老年抑郁组对不同情绪类型的刺激注意返回抑制能力不同;进一步检验得知：返回抑制效应在悲伤条件下,存在组间差异,分别是F(1, 33)=10.03,P=0.003;F(1, 33)=18.21,P=0.000,即老年抑郁组的返回抑制效应弱于老年正常组。（2）在Stroop实验中,老年抑郁组在单中性、双中性与单悲伤面孔、中性悲伤面孔、双悲伤面孔线索类型下的反应时差异显著;且当线索类型为单悲伤面孔、中性悲伤面孔、双悲伤面孔时,老年抑郁组与老年正常组的反应时差异均显著,即老年抑郁组的反应时明显长于老年正常组,F(1, 41) = 5.37,P=0.026;F(1, 41) = 7.08,P=0.011;F(1, 41) = 7.28,P=0.010;而当线索类型为单中性和双中性面孔时,老年抑郁组与老年正常组的反应时差异不显著（P>0.05）;提示抑郁组可能在自动化注意选择分配期存在注意偏向。研究认为,老年抑郁个体的注意偏向可能发生在注意初始分配阶段和解释阶段,且受加工深度的影响。在刺激呈现时间较长的条件下,注意偏向的效应更明显。     

Facilitating adaptive emotional analysis: distinguishing distanced-analysis of depressive experiences from immersed-analysis and distraction

Two studies examined the psychological processes that facilitate adaptive emotional analysis. In Study 1, participants recalled a depression experience and then analyzed their feelings from either a self-immersed (immersed-analysis) or self-distanced (distanced-analysis) perspective. Participants in the distanced-analysis group focused less on recounting their experience and more on reconstruing it, which in turn led to lower levels of depressed affect. Furthermore, comparisons to a distraction group indicated that distanced-analysis was as effective as distraction in reducing depressed affect relative to the immersed-analysis group. Study 2 replicated these findings and showed that both 1 day and 7 days after the experimental manipulations, participants in the distanced-analysis group remained buffered against depressed affect and reported experiencing fewer recurring thoughts about their depression experience over time compared to both the immersed-analysis and distraction groups.     

Extinction of a discriminative operant following discrimination learning with and without errors

Different groups of pigeons were trained to respond to red and not to green with and without errors (responses to green) under a free operant procedure, in which responding to red was intermittently reinforced, and under a trial procedure in which all responses to red were reinforced. The response to red was then extinguished under a procedure in which the discriminative stimuli were successively alternated as during discrimination training. The performances of those birds that learned the discrimination without errors under the trial procedure were seriously disrupted during extinction; the birds persistently responded to green for the first time. The performances of those subjects that learned the discrimination without errors under the free operant procedure were not disrupted during extinction. In a second experiment, the same discrimination was trained without errors under a trial procedure in which the response to red was intermittently reinforced. Extinction did not disrupt discrimination performance. Thus, errorless discrimination performance was shown to remain intact during extinction so long as the response to red was intermittently reinforced during discrimination training.     

Re-examination of the role of the instrumental contingency in the sodium-appetite irrelevant incentive effect

Thirsty rats were trained to perform one action—either lever pressing or chain pulling—for a sodium chloride solution and the other for water on a concurrent random interval schedule. When the experimental groups were tested in extinction under a sodium appetite, the instrumental action trained with the sodium solution was not performed at a significantly higher rate than that reinforced by water relative to control groups tested while thirsty. In a second experiment all animals were tested in extinction under a sodium appetite after training with either a sodium solution and water in the experimental condition or a potassium chloride solution and water in the control condition. The experimental animals chain-pulled more rapidly on test than the control rats, irrespective of whether this action was reinforced with the sodium solution or with water. These results confirm the findings of Dickinson and Nicholas (1983a) that the instrumental contingency plays little role in the irrelevant incentive effect based upon a sodium appetite.     

Discrimination training and stimulus compounding: consideration of non-reinforcement and response differentiation consequences of S

In Exp. 1, four rats were trained on a two-component multiple schedule with tone and light each associated with different variable-interval schedules. Extinction in light-out no-tone, common to previous studies reporting additive summation to compounded discriminative stimuli, was omitted from training. In testing, the simultaneous presentation of tone and light controlled a response rate intermediate between that controlled by these stimuli presented singly. In Exp. 2, animals were trained on three-ply multiple schedules. While tone and light were each associated with variable-interval schedules for both groups, light-out no-tone signalled extinction for one and differential-reinforcement-of-behavior-other-than-bar-pressing for the other. This permitted response reduction during light-out no-tone to be viewed independently of non-reinforcement. Responding of both groups showed summation to tone plus light in testing, with the effect clearly larger for extinction-trained subjects. These experiments indicate that: (1) discrimination training afforded by extinction has been integral to additive summation previously reported, (2) response differentiation and non-reinforcement consequences of extinction training contribute to the magnitude of summation, and (3) summation and peak shift might be functionally related phenomena.     

Learning when reward is delayed: a marking hypothesis

Rats were trained on spatial discriminations in which reward was delayed for 1 min. Experiment 1 tested Lett's hypothesis that responses made in the home cage during the delay interval are less likely to interfere with learning than responses made in the maze. Experimental subjects were transferred to their home cages during the delay interval, and control subjects were picked up but then immediately replaced in the maze. Contrary to Lett's hypothesis, both groups learned. Further experiments suggested that handling following a choice response was the crucial variable in producing learning: No learning occurred when handling was delayed (Experiment 2) or omitted (Experiment 3). One possible explanation for the fact that handling facilitated learning is that it served to mark the preceding choice response in memory so that subjects were then more likely to recall it when subsequently reinforced. In accordance with this interpretation, learning was found to be just as strong when the choice response was followed by an intense light or noise as by handling (Experiment 4). The implication of marking for other phenomena such as avoidance, quasi-reinforcement, and the paradoxical effects of punishment is also discussed.     

Left ear dichotic listening performance on consonant-vowel combinations and digits in subtypes of reading-disabled children

Twenty reading comprehension-disabled (CD) and 20 reading comprehension and word recognition-disabled (CWRD), right-handed male children were matched with 20 normal-achieving age-matched controls and 20 normal-achieving reading level-matched controls and tested for left ear report on dichotic listening tasks using digits and consonant-vowel combinations (CVs). Left ear report for CVs and digits did not correlate for any of the groups. Both reading-disabled groups showed lower left ear report on digits. On CVs the CD group showed a high left ear report but only when there were no priming precursors, such as directions to attend right first and to process digits first. Priming effects interfered with the processing of both digits and CVs. Theoretically, the CWRD group seems to be characterized by a depressed right hemisphere, whereas the CD group may have a more labile right hemisphere, perhaps tending to overengagement for CV tasks but vulnerable to situational precursors in the form of priming effects. Implications extend to (1) subtyping practices in research with the learning-disabled, (2) inferences drawn from studies using different dichotic stimuli, and (3) the neuropsychology of reading disorders.