Differential conditioning to facial emotional expressions: effects of hemispheric asymmetries and CS identification

Previous studies on aversive learning have suggested a right hemispheric advantage for eliciting autonomic reactions to a masked conditioned facial stimulus (CS) depicting anger. The present study investigated the effects of visual field (VF), stimulus awareness, and emotional valence of the CSs on indicators of conditioning (bilateral SCRs, HR) using a differential conditioning paradigm (N = 41). In Group 1, four different negatively valenced facial expressions (CS+) but not four positively valenced CS- were associated with an unconditioned stimulus (US, aversive vocalization, 97 dB, 3 s) during acquisition. Group 2 received a treatment reversal with positive CS+ associated with the US. In a repeated measures design, CSs were presented with or without awareness during extinction (two weeks interval, order counterbalanced). SOAs were adapted for each subject and condition prior to the experiment so that identification performance was approaching chance level. The results revealed that both negative and positive facial expressions could be aversively conditioned providing evidence for a generalization of learning in the valence dimension. During extinction, preattentive negative CS+ presented to the left VF showed a trend towards greater electrodermal and cardiac reactions. However, no such effect emerged under full awareness of the CSs. These results confirm and further specify the nature of hemispheric asymmetries in emotional associative learning.

Aversive learning in patients with unilateral lesions of the amygdala and hippocampus

The present study applied a visual half field paradigm with emotional facial expressions in patients with selective unilateral amygdalo-hippocampectomy (AHE) to elucidate the contributions of the left and right medial temporal lobe and amygdala to emotional learning. Electrodermal indicators of aversive learning were studied in 14 left AHE and 12 right AHE patients, as well as 13 controls matched in sex and age. In a differential conditioning paradigm with negative (CS+) and positive (CS-) facial expressions, CS+ were associated with an aversive vocalization (US, 95 dB, 3 s). During extinction, stimuli were presented laterally and preattentively using backward masking. Appropriate CS durations yielding preattentive presentation were individually determined prior to conditioning. In contrast to controls, both left and right AHE patients failed to show an autonomic conditioning effect following left visual field presentations of masked negative CS+ during extinction. AHE patients also showed no clear differential acquisition. Moreover, right AHE patients poorly recognised that negative valence was an affiliating dimension of the CS-US compound.

Pioneers of affective neuroscience and early concepts of the emotional brain

Views on the representation of emotion in the brain, as formulated about a century ago, are described, with a focus on the Vienna physiologist and psychologist Sigmund Exner, the psychoanalyst Sigmund Freud, and the French physician Israel Waynbaum. All three can be characterized as forerunners in the field of "affective neuroscience". By the turn of the century, they had developed a neural network theory of emotion which included a stage of pre-cortical processing. In spite of their otherwise very diverse theoretical backgrounds, their concepts of parallel processing routes were highly similar. It is interesting to note that their ideas were on line with present-day views on the neural substrates and physiological characteristics of emotional processing, although none of the three scientists could rely on the refined anatomical knowledge available nowadays.

A possible role of the human cerebellum in conditioning of the jaw-opening reflex

The role of the human cerebellum in classical conditioning of the jaw-opening reflex was investigated using positron emission tomography (PET) in healthy subjects. The jaw-opening reflex was elicited by electrical stimulation of the right corner of the mouth (unconditioned stimulus, US). The conditioned stimulus was a tone preceding the US and coterminating with the US. Changes of regional cerebral blood flow (rCBF) were correlated with the rate of conditioning per PET scan. Conditioning effects were present in one third of all subjects. In these subjects, a significant increase of rCBF in the ipsilateral, intermediate cerebellum was shown during ongoing conditioning. Thus, the intermediate cerebellum appears to be involved in classical conditioning of the jaw-opening reflex in humans.

Neurobehavioral toxicity of total body irradiation: a follow-up in long-term survivors

PURPOSE

Total body irradiation (TBI) in preparation for bone marrow transplantation (BMT) is a routine treatment of hematological malignancy. A retrospective and a prospective group study of long-term cerebral side effects was performed, with a special emphasis on neurobehavioral toxicity effects.

METHODS AND MATERIALS

Twenty disease-free patients treated with hyperfractionated TBI (14.4 Gy, 12 x 1.2 Gy, 4 days), 50 mg/kg cyclophosphamide, and autologous BMT (mean age 38 years, range 17-52 years; age at TBI 35 years, 16-50 years; follow-up time 32 months, 9-65 months) participated in a neuropsychological, neuroradiological, and neurological examination. Data were compared to 14 patients who were investigated prior to TBI. Eleven patients with renal insufficiencies matched for sex and age (38 years, 20-52 years) served as controls. In a longitudinal approach, neuropsychological follow-up data were assessed in 12 long-term survivors (45 years, 23-59 years; follow-up time 8.8 years, 7-10.8 years; time since diagnosis 10.1 years, 7.5-14.2 years).

RESULTS

No evidence of neurological deficits was found in post-TBI patients except one case of peripheral movement disorder of unknown origin. Some patients showed moderate brain atrophy. Neuropsychological assessment showed a subtle reduction of memory performance of about one standard deviation. Cognitive decline in individual patients appeared to be associated with pretreatment (brain irradiation, intrathecal methotrexate). Ten-years post disease onset, survivors without pretreatment showed behavioral improvement up to the premorbid level.

CONCLUSION

The incidence of long-term neurobehavioral toxicity was very low for the present TBI/BMT regimen.

Long-term exposure to wood-preserving chemicals containing pentachlorophenol and lindane is related to neurobehavioral performance in women

BACKGROUND

The adverse neurobehavioral effects of long-term low exposure to wood-preserving chemicals (WPC) containing solvents, pentachlorophenol (PCP) and gamma-hexachlorocyclohexane (gamma-HCH; lindane), and other neurotoxicants were investigated in a neuropsychological group study.

METHODS

Out of a population of 2,000 women visiting the outpatient practice of a gynecological department, a sample of 15 women aged 31-56 (mean 43) with long-term exposure to WPC verified by self-report, biological monitoring, and environmental samples was investigated. Fifteen controls aged 42 (31-56) years were drawn from the same population and pair-wise matched with respect to sex, age, education, and estimated intelligence.

RESULTS

For the exposed group, mean PCP serum level was 43.6 micrograms/l and mean gamma-HCH blood level was 0.085 microgram/l. Mean duration of exposure was 10 (5-17) years. Intellectual functioning, attention, memory, and visuo-motor performance were examined, suggesting significant group differences in visual short-term memory (Benton Test; d = 1.5, P = .005), verbal memory (paired associate learning and Peterson paradigm; d = 4.3 and 1.6, P < .001), and an incidental learning task (d = 2.3; P = .001). Frequent subjective complaints as assessed by questionnaire were attenuated motivation (d = 1.7; P = .001), increased fatigue (d = 1.6; P = .001), distractibility (d = 1.0; P = .003), and depressed mood (d = 1.9; P = .004). PCP blood level was significantly associated with paired-associate learning, Benton Test, and reading/naming speed.

CONCLUSIONS

Long-term low-dose exposure to WPC in the domestic environment could be related to subjective complaints (attention, mood, and motivation) and to subtle alterations of neurobehavioral performance (e.g., working memory) in women.

The decoding of emotional concepts in patients with focal cerebral lesions

The effects of focal brain lesions on the decoding of emotional concepts in facial expressions were investigated. Facial emotions are hierarchically organized patterns comprising (1) structural surface features, (2) discrete (primary) emotional categories and (3) secondary dimensions, such as valence and arousal. Categorical decoding was measured using (1) selection of category labels and selection of the named emotion category; (2) matching one facial expression with two choice expressions. Dimensional decoding was assessed by matching one face with two different expressions with regard to valence or arousal. 70 patients with well documented cerebral lesions and 15 matched hospital controls participated in the study. 27 had left brain damage (LBD; 10 frontal, 10 temporal, 7 parietal); 37 had right brain damage (RBD; 15 frontal, 11 temporal, 11 parietal). Six additional patients had lesions involving both frontal lobes. Right temporal and parietal lesioned patients were markedly impaired in the decoding of primary emotions. The same patients also showed a reduced arousal decoding. In contrast to several patients with frontal and left hemisphere lesions, emotional conceptualization and face discrimination was not independent in these groups. No group differences were observed in valence decoding. However, right frontal lesions appeared to interfere with the discrimination of negative valence. Moreover, a distraction by structural features was noted in RBD when facial identities were varied across stimulus and response pictures in matching tasks with differing conceptual load. Our results suggest that focal brain lesions differentially affect the comprehension of emotional meaning in faces depending on the level of conceptual load and interference of structural surface features.

Categorical and dimensional decoding of emotional intonations in patients with focal brain lesions

The present study attempts to elucidate whether cerebral brain lesions differentially affect the crossmodal decoding of emotional intonations in semantically meaningless sentences. Forty patients with well-documented lesions and 12 matched hospital controls participated in the study. Twenty-one had left brain damage (LBD: 12 with anterorolandic (anterior) and 9 with retrorolandic-infrasylvian (posterior) lesions); 19 had right brain damage (RBD: 12 anterior, 7 posterior lesions). The decoding of emotion categories was measured using (a) multiple choice of verbal labels and (b) matching one emotional vocalization (joy, fear, sadness, or anger) with two choice facial expressions. Crossmodal dimensional decoding was assessed by matching vocalizations with two facial expressions with regard to emotional valence or arousal. Results indicate that labeling was reduced in all lesion groups as compared to that in controls. Crossmodal categorical recognition was impaired in RBD, whereas LBD performance was comparable to controls. However, in the dimensional decoding task, a reduced recognition of valence in LBD and arousal in RBD was observed. An analysis of localizational subgroups revealed that subjects with left ventral frontal lesions, which in part extended into the adjacent right hemisphere, were predominantly impaired in the crossmodal identification of valence, whereas right temporoparietal lesions affected arousal decoding. Our results suggest that lateralized lesions may differentially affect the crossmodal recognition of dimensional concepts such as valence and arousal.

Mood changes after surgery for tumors of the cerebral cortex

OBJECTIVE

To identify cortical lesion sites associated with particular mood states.

DESIGN

A prospective study of patients with tumors affecting the cerebral cortex. The patients were examined neuropsychologically 1 to 5 days preoperatively and 2 to 10 days, several months, and several years postoperatively. Only data from the preoperative and the first postoperative examination were considered in this report.

SETTING

Neurosurgical department of the University of Heidelberg (Germany).

PATIENTS AND SUBJECTS

A consecutive sample of 141 patients with brain tumors (84 female and 57 male) with cortical lesions caused by microsurgical tumor resection; 29 clinical control patients (having undergone surgery for slipped disks); and 18 normal control subjects.

MAIN OUTCOME MEASURE

Preoperative and postoperative mood state as measured with an adjective checklist.

RESULTS

(1) Patients with lesions of the ventral frontal cortex or lesions of the temporoparietal cortex reported postoperatively significantly (P < .01) worse mood states (anxiety/depression, irritability/anger, fatigue) than did patients in the other lesion and control groups. (2) A more detailed lesion analysis revealed that lesions of heteromodal frontal or parietal association cortexes, combined with paralimbic lesions, were responsible for the negative mood states. Lesions of the sensorimotor cortexes ameliorated the negative effects of heteromodal and paralimbic lesions. (3) Lesion laterality did not influence the mood states.

CONCLUSIONS

Heteromodal cortexes may be especially concerned with emotionally relevant operations. A loss of these functions deprives limbic structures of one of their main sources of input and is therefore likely also to produce changes in feelings, that is, emotional states.

Neuropsychological effects of chronic exposure to environmental dioxins and furans

The environmental contamination by dioxins and furans (PCDD/PCDF) of a local area in southwest Germany due to pyrolytic processes led to a survey of health consequences in the exposed population. 2,3,7,8-TCDD (8000 ng/kg TE (ppt)) was found in the soil and up to 585000 ng/kg TE in attic dust in private homes. In a randomized study group of definitively exposed persons, a neuropsychological test battery was applied and its value as a diagnostic tool investigated. A total group of 19 persons participated in a standard neuropsychological examination including common procedures to evaluate mnestic and attentional performance and psychomotor speed (e.g., WAIS, WMS-R, TMT, and symptom and mood checklists). The range of PCDD/PCDF between 16 and 80 (mean 31) ppt did not vary substantially from blood fat values in a national sample. Results of neuropsychological testing showed only slight deviations from the expected range. Nevertheless, in a high-level exposure group, a reduction of verbal conceptualization, mnestic organization of verbal and visual stimuli, and psychomotor slowing was found. Among other correlations visual exploration speed (TMT) was most directly related to TE. Affective symptoms (such as irritability and emotional instability) were also related to exposure. Results indicate that standard neuropsychological testing can be recommended for the routine evaluation of chronic dioxin exposure.

[Evaluation of the toxicity of particle-bound dioxins and furans in the environment of a metal plant]

During the last years increased PCDD/PCDF-levels were found in soil, dust and vegetables in a living area close to a metal reclamation plant in Southern Germany. 450 volunteers participated in a clinical and laboratory trial. In a randomised group of 22 persons PCDD/PCDF concentrations have been investigated from blood samples. The range of PCDD/PCDF between 16-80 (mean 31) did not vary substantially from values in non-exposed national samples. Results of clinical history and clinical and laboratory testing did not correlate with emission, time of exposure or PCDD/PCDF concentrations of blood samples. It is suggested that PCDD/PCDF of pyrolytic origin may be incorporated to a lesser extent in humans.

Colchicine myopathy and neuropathy

Although colchicine has been used for centuries, its neuromuscular toxicity in humans is largely unrecognized. In this report we describe a characteristic syndrome of myopathy and neuropathy and present 12 new cases of the condition. Colchicine myopathy may occur in patients with gout who take customary doses of the drug but who have elevated plasma drug levels because of altered renal function. It usually presents with proximal weakness and always presents with elevation of serum creatine kinase; both features remit within three to four weeks after the drug is discontinued. The accompanying axonal polyneuropathy is mild and resolves slowly. Electromyography of proximal muscles shows a myopathy that is marked by abnormal spontaneous activity. Because of these features, colchicine myoneuropathy is usually misdiagnosed initially, either as probable polymyositis or as uremic neuropathy. The myopathy is vacuolar, marked by accumulation of lysosomes and autophagic vacuoles unrelated to necrosis or to the mild denervation in distal muscles. The morphologic changes in muscle suggest that the pathogenesis involves disruption of a microtubule-dependent cytoskeletal network that interacts with lysosomes. Correct diagnosis may save patients with this disorder from inappropriate therapy.

Clinical experience with molindone hydrochloride in geriatric patients

Elderly patients (N = 28) with a variety of psychiatric disorders were treated with molindone in an 8-week open clinical trial. Many patients had concomitant medical illnesses, and many were on other medications in addition to molindone. Molindone appeared to be safe, clinically effective, and well-tolerated. The most common adverse effects were extrapyramidal side effects, but the occurrence of these symptoms was relatively low.