Mihály Racsmány

Coronary artery bypass surgery provokes alzheimer's disease-like changes in the cerebrospinal fluid

Several biomarkers are used in confirming the diagnosis of cognitive disorders. This study evaluates whether the level of these markers after heart surgery correlates with the development of cognitive dysfunction, which is a frequent complication of cardiac interventions. Concentrations of amyloid-β peptide, tau, and S100β in the cerebro-spinal fluid were assessed, as well as cognitive functions were evaluated before and after coronary artery bypass grafting, utilizing immuno-assays and psychometric tests, respectively. A drastic rise in the level of S100β was observed one week after the surgery, a mark of a severe generalized cerebral injury. The level of amyloid-β peptide significantly decreased, whereas the concentration of tau markedly increased six months postoperatively. Gradual cognitive decline was also present. These findings clearly demonstrate post-surgical cognitive impairment associated with changes in biomarkers similar to that seen in Alzheimers disease, suggesting a unifying pathognomic factor between the two disorders. A holistic approach to coronary heart disease and Alzheimers type dementia is proposed.

Disrupted memory inhibition in schizophrenia

A feature of schizophrenia is disrupted executive function leading to learning difficulties and memory problems. In two experiments we measured the ability of patients with schizophrenia to suppress irrelevant parts of acquired information by intentional (executive) and autonomic (non-executive) strategies. In the first experiment using directed forgetting by lists patients were found to be unable to intentionally suppress recently acquired episodic memories. In a second experiment using a procedure that induces inhibition automatically schizophrenic patients showed levels of inhibition comparable to those of normal controls. These findings indicate that in schizophrenia memory is most impaired in tasks that load heavily on control or executive processes.

Correlations between clinical symptoms, working memory functions and structural brain abnormalities in men with schizophrenia.

Thirteen male patients with schizophrenia and thirteen male normal control subjects were compared by magnetic resonance imaging (MRI) on volumes of the straight gyrus (SG), anterior cingulate gyrus, middle frontal gyrus, hippocampus, third ventricle, cavum septi pellucidi, total brain volume and intracranial volume. In addition, neuropsychological tasks were used to measure working memory and executive functions. Healthy volunteers and schizophrenic patients showed no significant differences in mean values for volumes of regions of interests. In the case of the SG, we found a significant difference in laterality: the tendency toward left dominance in healthy volunteers changed to significant right dominance in patients. The schizophrenic patients showed lower performance in working memory tasks, and strongly significant group differences were observed in measures of neurological signs assessed by the Neurological Evaluation Scale (NES). Negative symptoms correlated with the level of spatial working memory and executive functions. Negative symptoms also correlated with the volume of the right hippocampus, while the rate of anhedonia negatively correlated with the relative volume of the left SG.

Morphological patterns in Hungarian children with Williams syndrome and the rule debates.

Williams syndrome (WMS), a rare neurogenetic disorder, has been in the forefront of research in cognitive psychology for the last 10 years. Studies of grammatical development in 14 Hungarian WMS children are presented: they were examined on tasks testing regular and irregular morphology; measures of digit span were also obtained. Results on the production of accusative and plural forms confirmed for Hungarian that regardless of the frequency of the item, inflected forms of irregulars are harder to produce, and often regularized in WMS, revealing a dissociation between the rules of grammar vs. the mental lexicon. Overall performance on the morphology task is associated with the capacity of phonological short-term memory: subjects with higher span perform better on both tasks. The specification of the surprisingly close relation of phonological short-term memory with the linguistic measures awaits further study.

Consolidation of Episodic Memories During Sleep Long-Term Effects of Retrieval Practice

Two experiments investigated the long-term effects of retrieval practice. In the retrieval-practice procedure, selected items from a previously studied list are repeatedly recalled. The typical retrieval-practice effects are considerably enhanced memory for practiced items accompanied by low levels of recall, relative to baseline, for previously studied items that are associated with the practiced items but were not themselves practiced. The two experiments demonstrated that the former effect persisted over 12 hr; the latter effect also persisted over 12 hr, but only if a period of nocturnal sleep occurred during the retention interval. We propose that consolidation processes occurring during sleep, and possibly featuring some form of off-line rehearsal, mediate these long-term effects of retrieval practice.

Testing Promotes Long-Term Learning via Stabilizing Activation Patterns in a Large Network of Brain Areas

The testing effect refers to the phenomenon that repeated retrieval of memories promotes better long-term retention than repeated study. To investigate the neural correlates of the testing effect, we used event-related functional magnetic resonance imaging methods while participants performed a cued recall task. Prior to the neuroimaging experiment, participants learned Swahili-German word pairs, then half of the word pairs were repeatedly studied, whereas the other half were repeatedly tested. For half of the participants, the neuroimaging experiment was performed immediately after the learning phase; a 1-week retention interval was inserted for the other half of the participants. We found that a large network of areas identified in a separate 2-back functional localizer scan were active during the final recall of the word pair associations. Importantly, the learning strategy (retest or restudy) of the word pairs determined the manner in which the retention interval affected the activations within this network. Recall of previously restudied memories was accompanied by reduced activation within this network at long retention intervals, but no reduction was observed for previously retested memories. We suggest that retrieval promotes learning via stabilizing cue-related activation patterns in a network of areas usually associated with cognitive and attentional control functions.

Memory awareness following episodic inhibition

Three experiments used directed forgetting (DF) and retrieval practice (RP) to investigate the relation of inhibited items to states of memory awareness occurring at test. In Experiment 1 using list DF robust inhibitory effects were present in cued recall, but in a recognition test these effects were only present in responses accompanied by recollective experience. In Experiments 2 and 3 using RP reliable effects of inhibition were found but these did not relate systematically to states of memory awareness. It is suggested that in DF the to-be-forgotten items are tagged at study as not to be recollectively experienced and so have a specific, inhibitory, relation to states of recollective experience occurring during test. In RP no tagging takes place, and inhibition is automatic or nonintentional and consequently does not have a specific relation to states of memory awareness at test.

Long-term follow-up of patients with obsessive-compulsive disorder treated by anterior capsulotomy: A neuropsychological study

BACKGROUND For treatment-refractory Obsessive-Compulsive-Disorder (OCD) patients, anterior capsulotomy is a potential therapy. We investigated what kinds of cognitive deficits treatment-refractory patients have and how anterior capsulotomy modifies their clinical and cognitive profiles. METHODS Ten treatment-refractory OCD patients were examined in two groups (operated and non-operated) with 5 participants in each group, matched for symptom severity, gender, age and education. The operated group was treated with anterior capsulotomy; the non-operated group was treated only with pharmaco- and psychotherapy. The Yale-Brown Obsessive-Compulsive Rating Scale (Y-BOCS) was used to measure OCD symptoms, and ten neuropsychological tests were used to measure cognitive functioning. RESULTS In the operated group, the score of Y-BOCS score significantly decreased during the two-year follow-up period. Additionally, we found a significant increase in neuropsychological test scores on the Wechsler Intelligence Test (MAWI), California Sorting Test Part A (CST-A), Stroop Test Interference Score (STR-I), Verbal Fluency Test and Iowa Gambling Test. As a negative result, we observed intrusion errors in the Category Fluency Test. In the non-operated group significant improvement was found in Y-BOCS scores. At follow-up, we found significant differences between the operated and non-operated groups on three neuropsychological tests: Trail Making Test Part B, Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Attention Index and RBANS Language Index, with better performance in the non-operated group. CONCLUSIONS Both treatment methods (i.e. anterior capsulotomy and pharmaco- and psychotherapy) seem effective in reducing OCD symptoms and cognitive deficits, but, importantly, to different degrees. The clinical and neuropsychological improvements were more impressive in the operated group.

Numerical abilities in Williams syndrome: Dissociating the analogue magnitude system and verbal retrieval

Two numerical systems—the analogue magnitude system and verbal retrieval—were investigated in Williams syndrome (WS) with three numerical tasks: simple addition, simple multiplication, and number comparison. A new matching technique was introduced in selecting the proper control groups. The WS group was relatively fast in the addition and multiplication tasks, but was slow in number comparison. No reverse numerical effect was observed in the comparison task, and the distance effect was stronger than that in the control groups. The findings indicate a profile with an impaired analogue magnitude system and less impaired verbal retrieval in Williams syndrome.

Vocabulary and morphological patterns in Hungarian children with Williams syndrome: a preliminary report

Williams syndrome (WMS), a rare neurogenetic disorder, has been inthe forefront of research in cognitive psychology for the last ten years.WMS is characterized by a distinctive cognitive prole: mild to moderate mentalretardation with relatively and surprisingly good linguistic abilities, whileperformance on spatial tasks is extremely poor. Concentrating on the linguisticabilities of children and adolescents with WMS, studies of vocabulary developmentand grammatical development in 15 Hungarian WMS children are presented: childrenwere tested on tasks testing vocabulary, regular and irregular morphological;measures of nonword repetition and digit span were also obtained. In contrastto previous observations, results on the vocabulary task do not show thatuncommon words activated as easily for a WMS child as common ones. Resultsin a picture-naming task support that conforming to the normal pattern, uncommonwords are harder to retrieve. Results on the production of accusative andplural forms conrmed for Hungarian as well that regardless of the frequencyof the item, inected forms of irregulars are harder to produce, and oftenoverregularized in WMS, revealing a dissociation between the rules of grammarvs. the mental lexicon. Performance on rare words in the vocabulary task,and overall performance on the morphology task is associated to the capacityof phonological short-term memory: subjects with higher span perform betteron both tasks. The specication of the close relation between the capacityof phonological short-term memory and their linguistic measures awaits furtherstudy.