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Biomedical subjects

Hans J Markowitsch

Publications and source records attributed to Hans J Markowitsch.

At least 19 recordsLinked to original sources
PubMed2006

Role of the amygdala in decisions under ambiguity and decisions under risk: evidence from patients with Urbach-Wiethe disease.

Various neuropsychological studies have shown that decision-making deficits can occur in a wide range of patients with brain damage or dysfunctions. Decisions under ambiguity, as measured with the Iowa Gambling Task, primarily depend on the integrity of the ventromedial prefrontal cortex and the amygdala, as well as on further brain regions such as the somatosensory cortex. However, little is known about the specific role of these structures in decisions under risk measured with tasks that offer explicit rules for gains and losses and winning probabilities, for example, the Game of Dice Task. We aimed to investigate the potential role of the amygdala for decisions under risk. For this purpose, we examined three patients with Urbach-Wiethe disease--a rare syndrome associated with selective bilateral mineralisation of the amygdalae. Neuropsychological performance was assessed with the Iowa Gambling Task (decisions under ambiguity), the Game of Dice Task (decisions under risk), and an extensive neuropsychological test battery focussing on executive functions. Furthermore, previous studies found relationships between generating skin conductance responses and deciding advantageously in the Iowa Gambling Task. Accordingly, we recorded skin conductance responses during both decision tasks as a measure of emotional reactivity. Results indicate that patients with selective amygdala damage have lower scores in both decisions under ambiguity and decisions under risk. Decisions under risk are especially compromised in patients who also demonstrate deficits in executive functioning. In both gambling tasks, patients showed reduced skin conductance responses compared to healthy comparison subjects. The results suggest that deciding advantageously under risk conditions involves both the use of feedback from previous trials, as required by decisions under ambiguity, and in addition, executive functions.

Adolescent↗
PubMed2006

Neuropsychological correlates of decision-making in ambiguous and risky situations.

Decision-making situations in real life differ regarding their explicitness of positive and negative consequences as well as regarding the directness of probabilities for reward and punishment. In neuropsychological research, decisions under ambiguity and decisions under risk are differentiated. To assess decisions under ambiguity the Iowa Gambling Task (IGT) is one of the most frequently used tasks. Decisions under risk can be measured by a task that offers explicit rules for gains and losses and stable winning probabilities, as the Game of Dice Task (GDT) does. In this contribution we firstly summarize studies that investigated decision-making in various groups of patients using the IGT or the GDT. We also propose a new model of decision-making in risky situations and describe differences between decisions under ambiguity and decisions under risk from a theoretical and clinical perspective.

Animals↗
PubMed2006

Functional MRI correlates of the recall of unresolved life events in borderline personality disorder.

BACKGROUND: Patients with borderline personality disorder (BPD) frequently report unresolved life events but it is still poorly understood, how these experiences are represented in the brain. Using functional magnetic resonance imaging (fMRI), the present study aimed at investigating the neural correlates of the recall of unresolved life events in patients with BPD and healthy controls. METHOD: Twenty female BPD patients and 21 healthy control subjects underwent fMRI. During measurement subjects recalled unresolved and resolved negative life events. Individual cue words were used to stimulate autobiographical memory. After scanning, subjects rated their emotional states during the recall of both types of memories. RESULTS: When contrasting unresolved and resolved life events, patients showed significant bilateral activation of frontotemporal areas including the insula, amygdala, and the anterior cingulate cortex, the left posterior cingulate cortex, right occipital cortex, the bilateral cerebellum and the midbrain. In healthy subjects, no differential brain activation was related to these conditions. The 2 x 2 factorial analysis (DeltaBPD - Deltacontrols) revealed similar results with bilateral activation of the frontal cortex including parts of the insula and of the orbitofrontal cortex, temporal activation including the amygdala, activation of the right occipital cortex, and parts of the cerebellum. Patients but not controls reported higher levels of anxiety and helplessness during the unresolved versus resolved memory condition. CONCLUSIONS: The activation of both, the amygdala and prefrontal areas, might reflect an increased effortful but insufficient attempt to control intensive emotions during the recall of unresolved life events in patients with BPD.

Adult↗
PubMed2005

Vestibular loss causes hippocampal atrophy and impaired spatial memory in humans.

The human hippocampal formation plays a crucial role in various aspects of memory processing. Most literature on the human hippocampus stresses its non-spatial memory functions, but older work in rodents and some other species emphasized the role of the hippocampus in spatial learning and memory as well. A few human studies also point to a direct relation between hippocampal size, navigation and spatial memory. Conversely, the importance of the vestibular system for navigation and spatial memory was until now convincingly demonstrated only in animals. Using magnetic resonance imaging volumetry, we found that patients (n = 10) with acquired chronic bilateral vestibular loss (BVL) develop a significant selective atrophy of the hippocampus (16.9% decrease relative to controls). When tested with a virtual variant (on a PC) of the Morris water task these patients exhibited significant spatial memory and navigation deficits that closely matched the pattern of hippocampal atrophy. These spatial memory deficits were not associated with general memory deficits. The current data on BVL patients and bilateral hippocampal atrophy revive the idea that a major--and probably phylogenetically ancient--function of the archicortical hippocampal tissue is still evident in spatial aspects of memory processing for navigation. Furthermore, these data demonstrate for the first time in humans that spatial navigation critically depends on preserved vestibular function, even when the subjects are stationary, e.g. without any actual vestibular or somatosensory stimulation.

Adult↗
PubMed2005

Decision-making impairments in patients with pathological gambling.

Pathological gambling (PG) is most likely associated with functional brain changes as well as neuropsychological and personality alterations. Recent research with the Iowa Gambling Task suggests decision-making impairments in PG. These deficits are usually attributed to disturbances in feedback processing and associated functional alterations of the orbitofrontal cortex. However, previous studies with other clinical populations found relations between executive (dorsolateral prefrontal) functions and decision-making using a task with explicit rules for gains and losses, the Game of Dice Task. In the present study, we assessed 25 male PG patients and 25 male healthy controls with the Game of Dice Task. PG patients showed pronounced deficits in the Game of Dice Task, and the frequency of risky decisions was correlated with executive functions and feedback processing. Therefore, risky decisions of PG patients might be influenced by both dorsolateral prefrontal and orbitofrontal cortex dysfunctions.

Adult↗
PubMed2005

Gender differences in the functional neuroanatomy of emotional episodic autobiographical memory.

Autobiographical memory is based on interactions between episodic memory contents, associated emotions, and a sense of self-continuity along the time axis of one's life. The functional neuroanatomy subserving autobiographical memory is known to include prefrontal, medial and lateral temporal, as well as retrosplenial brain areas; however, whether gender differences exist in neural correlates of autobiographical memory remains to be clarified. We reanalyzed data from a previous functional magnetic resonance imaging (fMRI) experiment to investigate gender-related differences in the neural bases of autobiographical memories with differential remoteness and emotional valence. On the behavioral level, there were no significant gender differences in memory performance or emotional intensity of memories. Activations common to males and females during autobiographical memory retrieval were observed in a bilateral network of brain areas comprising medial and lateral temporal regions, including hippocampal and parahippocampal structures, posterior cingulate, as well as prefrontal cortex. In males (relative to females), all types of autobiographical memories investigated were associated with differential activation of the left parahippocampal gyrus. By contrast, right dorsolateral prefrontal cortex was activated differentially by females. In addition, the right insula was activated differentially in females during remote and negative memory retrieval. The data show gender-related differential neural activations within the network subserving autobiographical memory in both genders. We suggest that the differential activations may reflect gender-specific cognitive strategies during access to autobiographical memories that do not necessarily affect the behavioral level of memory performance and emotionality.

Adult↗
PubMed2005

Decision-making deficits of korsakoff patients in a new gambling task with explicit rules: associations with executive functions.

Decision-making deficits reflected by risky decisions in gambling tasks have been associated with frontal lobe dysfunctions in various neurologic and psychiatric populations. The question remains whether decision-making impairments are related to executive functions. The authors developed a new gambling task, the Game of Dice Task, with explicit and stable rules for reinforcement and punishment, to investigate relations between executive functions and risk-taking behavior in an explicit decision-making situation. A sample of 35 alcoholic Korsakoff patients and 35 healthy controls was examined with the Game of Dice Task and a neuropsychological test battery. Results show that Korsakoff patients are strongly impaired in this explicit decision-making task and that these disturbances are correlated with specific executive functions.

Association↗
PubMed2005

Towards a bio-psycho-social model of autobiographical memory.

Self-awareness and identity are important cornerstones of thinking in social psychology. On the basis of current knowledge and theories from the social, cultural, and biological sciences, this paper attempts to outline an integrative approach to the phenomena of memory and reminiscence. Reference to psychodynamic argumentation is made in addition, where appropriate. The central topic to our argumentation is autobiographical memory, which we analyse according to evolutionary, neuroscientific, and cultural findings. The emotional context and the ontogenetic development of reminiscences (or memories directly relating to one's own self) provide the preliminary framework for an integrated view which includes interactions between the life span, brain development, the social and cultural environment, and genetic predispositions.

Brain↗
PubMed2005

A new test battery to assess aphasic disturbances and associated cognitive dysfunctions -- German normative data on the aphasia check list.

Aphasia, defined as an acquired impairment of linguistic abilities, can be accompanied by a diversity of neuropsychological dysfunction. Accordingly, the necessity to include cognitive testing in the diagnosis of aphasia is increasingly recognized. Here we present the Aphasia Check List (ACL), a new test battery for the assessment of aphasic and associated cognitive disorders. The language part of the battery provides a differentiated profile of important linguistic abilities. In addition, the ACL includes nonverbal screening tests for three neuropsychological domains: memory, attention, and reasoning. Dysfunctions in these domains have been observed in aphasic patients and can have an impact on language function. The ACL is applicable to patients with language disturbances of different etiologies, different stages of disease, and to patients with mild to severe aphasia. As the entire test duration is only about 30 minutes, the ACL is also economically valuable. It thus presents an adequate starting point in aphasia diagnosis for a wide range of patients. Here we describe the construction of the ACL, and the normative study of its original German version with 154 aphasic patients and 106 healthy comparison subjects. The ACL cognition part revealed additional neuropsychological dysfunction in the aphasia group. We present the patterns of these dysfunctions and their correlations with language deficits.

Adult↗
PubMed2005

Bi-hemispheric engagement in the retrieval of autobiographical episodes.

Functional magnetic resonance imaging (fMRI) was used to study the neural correlates of neutral, stressful, negative and positive autobiographical memories. The brain activity produced by these different kinds of episodic memory did not differ significantly, but a common pattern of activation for different kinds of autobiographical memory was revealed that included (1) largely bilateral portions of the medial and superior temporal lobes, hippocampus and parahippocampus, (2) portions of the ventral, medial, superior and dorsolateral prefrontal cortex, (3) the anterior and posterior cingulate, including the retrosplenial, cortex, (4) the parietal cortex, and (5) portions of the cerebellum. The brain regions that were mainly activated constituted an interactive network of temporal and prefrontal areas associated with structures of the extended limbic system. The main bilateral activations with left-sided preponderance probably reflected reactivation of complex semantic and episodic self-related information representations that included previously experienced contexts. In conclusion, the earlier view of a strict left versus right prefrontal laterality in the retrieval of semantic as opposed to episodic autobiographical memory, may have to be modified by considering contextual variables such as task demands and subject variables. Consequently, autobiographical memory integration should be viewed as based on distributed bi-hemispheric neural networks supporting multi-modal, emotionally coloured components of personal episodes.

Adult↗
PubMed2004

Posttraumatic stress disorder and fMRI activation patterns of traumatic memory in patients with borderline personality disorder.

BACKGROUND: Early traumatization and additional posttraumatic stress disorder are frequent in patients with borderline personality disorder (BPD). The purpose of this study was to investigate neural correlates of traumatic memory in BPD with and without posttraumatic stress disorder (PTSD) using functional magnetic resonance imaging (fMRI). METHODS: We studied 12 traumatized female patients BPD, 6 of them with and 6 without PTSD. According to an autobiographical interview key words (cues) were defined for traumatic and for negative but nontraumatic episodes. In a block-designed fMRI task patients recalled these episodes. Contrasts between trauma condition and nontrauma condition were analyzed. RESULTS: Analyses for all subjects revealed activation of orbitofrontal cortex areas in both hemispheres, anterior temporal lobes, and occipital areas. In the subgroup without PTSD, activation of orbitofrontal cortex on both sides and Broca's area predominated. In the subgroup with additional PTSD, we observed right more than left activation of anterior temporal lobes, mesiotemporal areas, amygdala, posterior cingulate gyrus, occipital areas, and cerebellum. CONCLUSIONS: Dependent on absence or presence of additional PTSD different neural networks seem to be involved in the traumatic memory of patients with BPD.

Adult↗
PubMed2004

[Neurocognition of psychiatric patients].

Cognitive, mnestic, and emotional disturbances can occur in a wide range of psychiatric patients. Both neurochemical alterations as well as structural brain abnormalities can be neural correlates of neuropsychological dysfunctions in these patients. In this paper, we give an introduction to neuropsychological domains with a focus on different kinds of memory and executive functions. Thereafter, we describe neurocognitive deteriorations in patients with schizophrenia, depression, alcohol addiction, and Korsakoff's syndrome. Brain alterations affect primarily parts of the frontal lobe, especially the dorsolateral prefrontal and the orbitofrontal cortex. This can be seen in volume reduction, glucose hypometabolism, or dysfunctions of dopaminergic fronto-striatal loops. Furthermore, structural or functional changes of hippocampal formation, anterior cingulate gyrus, amygdala, and different thalamic nuclei are also involved in neurocognitive disturbances of psychiatric patients.

Affective Symptoms↗
PubMed2004

Organic and psychogenic factors leading to executive dysfunctions in a patient suffering from surgery of a colloid cyst of the Foramen of Monro.

The authors report a 41-year-old female patient who had suffered from colloid cyst of the Foramen of Monro. After surgical intervention in which the cyst was completely removed, her hydrocephalus decreased to normal ventricle size measured by MRI. However, the patient became depressive and reported vast difficulties in everyday life decision-making. An examination twenty months after surgery indicated psychiatric symptoms and abnormalities in personality. Neuropsychological investigation revealed average to above average performance in anterograde memory, attention, information processing, and intelligence. In contrast, the patient was severely impaired in decision-making, complex executive functions, and social cognition. In 18F-2-fluoro-2-deoxy-D-glucose (18FDG-PET) hypometabolism in bilateral dorsolateral prefrontal cortex, cingulate cortex and left fusiform gyrus was observed. The authors conclude that in this case decision-making deficits and executive dysfunctions are influenced by both organic and psychogenic factors.

Adult↗
PubMed2004

Decision-making impairments in patients with Parkinson's disease.

A high percentage of Parkinson's disease (PD) patients show cognitive impairments in addition to the cardinal motor symptoms. These deficits primarily concern executive functions most probably linked to dysfunctions in prefrontal regions due to decreased dopaminergic transmission in fronto-striatal loops. To investigate possible associations between decision-making and executive functions in PD, we examined 20 non-demented PD patients and 20 healthy control subjects with a neuropsychological test battery and the Game of Dice Task. In this computerised decision-making task, the rules for gains and losses and the winning probabilities are obvious and stable. Thus, strategic components besides feedback processing might influence decision-making in this task. We found that PD patients were impaired in the Game of Dice task performance and that the frequency of disadvantageous choices correlated with both executive functions and feedback processing. We suggest that decision-making deficits of PD patients in explicit gambling situations might be associated with dysfunctions in two different fronto-striatal loops: the limbic-orbitofrontal-striatal loop, involved in feedback processing, and the dorsolateral prefrontal-striatal loop, involved in executive functions.

Aged↗
PubMed2003

Amygdala, affect and cognition: evidence from 10 patients with Urbach-Wiethe disease.

Patients with Urbach-Wiethe disease constitute a unique nature experiment as more than half have bilaterally symmetrical damage in the amygdaloid region. Ten such patients were studied neuropsychologically and, nine of them, neuroradiologically with static (CT) and functional imaging techniques [single-photon emission computed tomography (SPECT) and PET]. Their principal bilateral amygdala damage was confirmed. Neuropsychologically, the patients showed cognitively little deviation from normal subjects, while they differed emotionally. This was evident in their judgement of all emotions in facial expressions, in an odour-figure association test as well as in remembering negative and positive pictures. This suggests that the human amygdala influences both negative and positive emotional processing.

Adolescent↗
PubMed2003

Psychogenic amnesia.

Time- and content-based memory systems are briefly described so that their importance for a refined analysis of memory disturbances becomes evident. These memory systems are then related to their brain instantiation, emphasizing that there are limbic circuits for encoding different forms of memories, largely cortical networks for memory storage, and a combined temporofrontal network acting to trigger information retrieval. The terms functional amnesias and psychogenic amnesias are discussed and their symptomatology is compared to that of organic amnesias. The term "mnestic block syndrome" is introduced and defined as a syndrome of its own. Experimental data, obtained especially with functional imaging methods, are presented to elucidate changes in neural activation during functional amnesic states. It is concluded that functional amnesic states, confined to a patient's biography, can be triggered by environmentally induced stress and trauma, leading to lasting inability to retrieve autobiographical events. Such an impairment may be identified at the brain level using functional imaging techniques.

Amnesia↗
PubMed2003

Cognitive estimation in patients with probable Alzheimer's disease and alcoholic Korsakoff patients.

Cognitive estimation is an important function in daily living. In early studies it was proposed that estimation deficits are associated with frontal lobe damage and executive dysfunctions. In this study, we assessed Alzheimer patients and patients with alcoholic Korsakoff's syndrome with a newly developed cognitive estimation task. We compared their performance with respect to different dimensions of estimation ('size', 'weight', 'quantity', and 'time') and to various error types. Compared to healthy controls, both patient groups were strongly impaired in all tested estimation dimensions, with Alzheimer patients performing generally worse than Korsakoff patients, except for the dimension "time". Alzheimer as well as Korsakoff patients produced so-called 'bizarre errors' and errors in the choice of the correct unit of measurement. In both patient groups cognitive estimation correlated highly with general knowledge. The production of bizarre errors and unit errors correlated with general knowledge as well as with working memory and executive functions. Results support the main assumptions of a model of cognitive estimation, described in the discussion, that specific parts of the semantic memory system as well as executive functions, in form of a plausibility check of the generated answer, are involved in the process of cognitive estimation.

Aged↗