Impairments in learning by monetary rewards and alcohol-associated rewards in detoxified alcoholic patients.

Background: Excessive alcohol consumption has been linked to structural and functional brain changes associated with cognitive, emotional, and behavioral impairments. It has been suggested that neural processing in the reward system is also affected by alcoholism. The present study aimed at further investigating reward-based associative learning and reversal learning in detoxified alcohol-dependent patients.

Comorbid substance use disorder in schizophrenia: a selective overview of neurobiological and cognitive underpinnings.

Although individuals with schizophrenia show a lifetime prevalence of 50% for suffering from a comorbid substance use disorder, substance abuse usually represents an exclusion criterion for studies on schizophrenia. This implies that surprisingly little is known about a large group of patients who are particularly difficult to treat. The aim of the present work is to provide a brief and non-exhaustive overview of the current knowledgebase about neurobiological and cognitive underpinnings for dual diagnosis schizophrenia patients.

The involvement of the thalamus in semantic retrieval: a clinical group study.

There is increasing attention about the role of the thalamus in high cognitive functions, including memory. Although the bulk of the evidence refers to episodic memory, it was recently proposed that the mediodorsal (MD) and the centromedian-parafascicular (CM-Pf) nuclei of the thalamus may process general operations supporting memory performance, not only episodic memory. This perspective agrees with other recent fMRI findings on semantic retrieval in healthy participants.

Cortical processing of saccade-related efference copy signals in patients with cerebellar lesion.

The updating of visual space across saccades is thought to rely on efference copies of motor commands. In humans, thalamic lesions impair performance on a saccadic double-step task, which requires the use of efference copy information, and the altering of saccade-related efference copy processing. This deficit is attributed to disruption of a pathway from the superior colliculus to the frontal eye field.

Theory of mind and empathy in patients at an early stage of relapsing remitting multiple sclerosis.

Introduction: Early after having been diagnosed with relapsing remitting multiple sclerosis (RRMS), young patients coping with the new situation require good social support and interactions. Successful social interaction is critically dependent upon the ability to understand the minds of others and their feelings. Social cognition refers to the ability to understand the mind of others.

Perception of affective prosody in patients at an early stage of relapsing-remitting multiple sclerosis.

Cognitive dysfunction is well known in patients suffering from multiple sclerosis (MS) and has been described for many years. Cognitive impairment, memory, and attention deficits seem to be features of advanced MS stages, whereas depression and emotional instability already occur in early stages of the disease. However, little is known about processing of affective prosody in patients in early stages of relapsing-remitting MS (RRMS).

Recall deficits in stroke patients with thalamic lesions covary with damage to the parvocellular mediodorsal nucleus of the thalamus.

The functional role of the mediodorsal thalamic nucleus (MD) and its cortical network in memory processes is discussed controversially. While Aggleton and Brown (1999) suggested a role for recognition and not recall, Van der Werf et al. (2003) suggested that this nucleus is functionally related to executive function and strategic retrieval, based on its connections to the prefrontal cortices (PFC).

Neural representations of unfamiliar objects are modulated by sensorimotor experience.

Sensory/functional accounts of semantic memory organization emphasize that object representations in the brain reflect the modalities involved in object knowledge acquisition. The present study aimed to elucidate the impact of different types of object-related sensorimotor experience on the neural representations of novel objects. Sixteen subjects engaged in an object matching task while their brain activity was assessed with functional magnetic resonance imaging (fMRI), before and after they acquired knowledge about previously unfamiliar objects.

Updating of visual space across horizontal saccades in cerebellar and thalamic lesion patients.

Efference copies of motor commands are used to update visual space across saccades, ultimately ensuring transsaccadic constancy of space. Thalamic lesions have been shown to impair efference copy-based saccadic updating in an oculomotor context, i.e.

Learning from positive and negative monetary feedback in patients with alcohol dependence.

Background: Chronic and excessive consumption of alcohol is associated with structural, physiological, and functional changes in multiple regions of the human brain including the prefrontal cortex, the medial temporal lobe, and the structures of the reward system. The present study aimed to assess the ability of alcohol-dependent patients (ADP) to learn probabilistic stimulus-reward contingencies and to transfer the acquired knowledge to new contexts. During transfer, the relative preference to learn from positive or negative feedback was also assessed.

Mechanisms of cerebellar contributions to cognition in humans.

The role of the human cerebellum in cognitive processes is the subject of ongoing debate. On the basis of neuroanatomical findings of closed cerebro-cerebellar loops in monkeys, which originate not only in motor but also in nonmotor regions of the cerebral cortex, this article addresses mechanisms of the involvement of the human cerebellum in two well-studied cognitive domains, executive function, working memory in particular, and associative learning, with special emphasis on the nature of a potential cerebellar contribution to these cognitive processes. The uniform organization of cortico-cerebellar connections suggests parallels in cerebellar information processing in motor- and nonmotor contexts.

Human memory manipulated: dissociating factors contributing to MTL activity, an fMRI study.

Memory processes are mainly studied with subjective rating procedures. We used a morphing procedure to objectively manipulate the similarity of target stimuli. While undergoing functional magnetic resonance imaging, nineteen subjects performed a encoding and recognition task on face and scene stimuli, varying the degree of manipulation of previously studied targets at 0%, 20%, 40% or 60%.

Cerebellar lesions alter performance monitoring on the antisaccade task--an event-related potentials study.

Error processing is associated with distinct event-related potential components (ERPs), i.e. the error-related negativity (ERN) which occurs within approximately 150 ms and is typically more pronounced than the correct-response negativity (CRN), and the error positivity (Pe) emerging from about 200 to 400 ms after an erroneous response.

Positivity effect in healthy aging in observational but not active feedback-learning.

The present study investigated the impact of healthy aging on the bias to learn from positive or negative performance feedback in observational and active feedback learning. In active learning, a previous study had already shown a negative learning bias in healthy seniors older than 75 years, while no bias was found for younger seniors. However, healthy aging is accompanied by a 'positivity effect', a tendency to primarily attend to stimuli with positive valence.

Eyeblink conditional discrimination learning in healthy young men is impaired after stress exposure.

Stress is known to influence the hippocampus. Eyeblink conditional discrimination learning is dependent on the hippocampus, but the effects of stress on the task are unknown. Male participants were allocated to a psychosocial stress condition (Trier Social Stress Test) or a control condition.

Cognitive and affective empathy in depression linked to executive control.

Depression has been linked to executive dysfunction and emotion recognition impairments, associated with abnormalities in fronto-temporal and subcortical brain regions. Little is known about changes of different empathy subcomponents during depression, with potential impairments being related to the interpersonal difficulties of depressed patients. Twenty patients treated for an episode of unipolar depression and 20 matched healthy controls were assessed.

The feedback-related negativity is modulated by feedback probability in observational learning.

The feedback-related negativity (FRN), an event-related potentials (ERPs) component reflecting activity of the anterior cingulate cortex (ACC), has been shown to be modulated by feedback expectancy following active choices in feedback-based learning tasks. A general reduction of FRN amplitude has been described in observational feedback learning, raising the question whether FRN amplitude is modulated in a similar way in this type of learning. The present study investigated whether the FRN and the P300 - a second ERP component related to feedback processing - are modulated by feedback probability in observational learning.

Face and body perception in schizophrenia: a configural processing deficit?

Face and body perception rely on common processing mechanisms and activate similar but not identical brain networks. Patients with schizophrenia show impaired face perception, and the present study addressed for the first time body perception in this group. Seventeen patients diagnosed with schizophrenia or schizoaffective disorder were compared to 17 healthy controls on standardized tests assessing basic face perception skills (identity discrimination, memory for faces, recognition of facial affect).

Altered error processing following vascular thalamic damage: evidence from an antisaccade task.

Event-related potentials (ERP) research has identified a negative deflection within about 100 to 150 ms after an erroneous response--the error-related negativity (ERN)--as a correlate of awareness-independent error processing. The short latency suggests an internal error monitoring system acting rapidly based on central information such as an efference copy signal. Studies on monkeys and humans have identified the thalamus as an important relay station for efference copy signals of ongoing saccades.

What comes first? Electrophysiological differences in the temporal course of memory and future thinking.

It is now widely accepted that remembering the past and imagining the future rely on a number of shared processes and recruit a similar set of brain regions. However, memory and future thinking place different demands on a range of processes. For instance, although remembering should lead to early associative retrieval of event details, event construction may be slower for future events, for which details from different memories are combined.

Processing of expected and unexpected monetary performance outcomes in healthy older subjects.

The feedback-related negativity (FRN), an event-related potential (ERP) component reflecting feedback processing in the anterior cingulate cortex (ACC), has consistently been found to be reduced in healthy aging, whereas behavioral findings regarding age-related changes in decision making and feedback-based learning are inconsistent. This study aimed to elucidate similarities and differences between healthy younger and older subjects in the processing of monetary performance feedback focusing on effects of reward expectancy. Eighteen younger and 20 older subjects completed a feedback learning task, in which a rule could be learned to predict the reward probabilities associated with particular stimuli.

Encoding/retrieval dissociation in working memory for human body forms.

The present study was conducted to investigate the effect of working memory (WM) load on body processing mechanisms by using event-related potentials (ERPs). It is well known that WM load modulates the P3b (amplitude decreases as WM load increases). Additionally, WM load for faces modulates earlier ERPs like the N170.

Differential impairment of remembering the past and imagining novel events after thalamic lesions.

Vividly remembering the past and imagining the future (mental time travel) seem to rely on common neural substrates and mental time travel impairments in patients with brain lesions seem to encompass both temporal domains. However, because future thinking-or more generally imagining novel events-involves the recombination of stored elements into a new event, it requires additional resources that are not shared by episodic memory. We aimed to demonstrate this asymmetry in an event generation task administered to two patients with lesions in the medial dorsal thalamus.

Differences between perception of human faces and body shapes: evidence from the composite illusion.

The present study aimed to investigate whether human body forms--like human faces--undergo holistic processing. Evidence for holistic face processing comes from the face composite effect: two identical top halves of a face are perceived as being different if they are presented with different bottom parts. This effect disappears if both bottom halves are shifted laterally (misaligned) or if the stimulus is rotated by 180°.

Levels-of-processing effects on recollection and familiarity during transient global amnesia and after recovery.

Objective: The aim of the present study was to investigate the pattern of recollection and familiarity deficits and the modulation of recognition memory performance by the depth of encoding (deep vs. shallow) in transient global amnesia (TGA).

Method: Ten patients with TGA and 11 control subjects were assessed during the acute stage and after recovery 7 to 19 days later.