Brain Activation Patterns Characterizing Different Phases of Motor Action: Execution, Choice and Ideation.

Motor behaviour is controlled by a large set of interacting neural structures, subserving the different components involved in hierarchical motor processes. Few studies have investigated the neural substrate of higher-order motor ideation, i.e. the mental operation of conceiving a movement. The aim of this functional magnetic resonance imaging study was to segregate the neural structures involved in motor ideation from those involved in movement choice and execution. An index finger movement paradigm was adopted, including three different conditions: performing a pre-specified movement, choosing and executing a movement and ideating a movement of choice. The tasks involved either the right or left hand, in separate runs. Neuroimaging results were obtained by comparing the different experimental conditions and computing conjunction maps of the right and left hands for each contrast. Pre-specified movement execution was supported by bilateral fronto-parietal motor regions, the cerebellum and putamen. Choosing and executing finger movement involved mainly left fronto-temporal areas and the anterior cingulate. Motor ideation activated almost exclusively left hemisphere regions, including the inferior, middle and superior frontal regions, middle temporal and middle occipital gyri. These findings show that motor ideation is controlled by a cortical network mainly involved in abstract thinking, cognitive and motor control, semantic and visual imagery processes

Brain activation in Highly Superior Autobiographical Memory: The role of the precuneus in the autobiographical memory retrieval network

This is the first study to examine functional brain activation in a single case of Highly Superior Autobiographical Memory (HSAM) who shows no sign of OCD. While previous work has documented the existence of HSAM, information about brain areas involved in this exceptional form of memory for personal events relies on structural and resting state connectivity data, with mixed results so far. In this first task-based fMRI study of a normal individual with HSAM, dates were presented as cues and two phases were assessed during memory retrieval, initial access and later elaboration. Results showed that initial access was very fast, did not activate the hippocampus, and involved activation of predominantly posterior visual areas, including the praecuneus. These areas typically become active during later stages of elaboration of personal memories rather than during initial access. Elaboration involved a balanced bilateral activation of most of the autobiographical network areas, rather than the more typical shifts observed in people without HSAM. Overall, the pattern of brain activations, which rests on repeated observations in a single individual, highlights a strong involvement of the praecuneus and an idiosyncratic initial access to personal memory representations. Implications for the nature of personal memories in HSAM are discussed

Multisensory self-referential stimulation : a contribution for the core-self

Whenever there is a decrease of the sensory function, whether due to a disease, trauma or to the normal aging process, a change occurs at the same time in the motor control, in body and emotions perception, in cognitive processing, in the functional activities and in the interpersonal relationships. The feeling that is generated is of loss of identity, of threat, and Self disintegration. This phenomenon of consciousness and identity is called the Self. There are many concepts of the Self but some more recent theories claim that there is only one Self. The human being is a whole and the greater this perception of the personal unit the greater physical, cognitive and emotional functionality can be reached. The Self may change when exposed to various health conditions but also due to sensory and relational experiences or due to the lack of stimulation. The stimulation we get through all sensory modalities helps build the representation we make of ourselves. However unisensory stimulation does not seem to be sufficient to promote perception of the Self as a whole. Multisensory stimulation, that it comprises meaningful and Self-referential stimuli, seems to trigger a more global consciousness of the Self. Self-referential stimuli are stimuli that are experienced as strongly related to one’s own person. The physiotherapist is a professional who distinguishes himself by the use of sensorial stimulation strategies, considered Self-referential stimulation, i.e., auditory-verbal stimulation liked to body parts and direct and prolonged manual contact with the patient´s body. But these approaches are rarely used in neurological Physiotherapy, for sensory and perceptual competences improvement and they are never used simultaneously. In reference to touch there is no concern to assess the perception that clients have about touch. Different meanings can be attributed to physical contact during therapeutic and social interactions and they may generate bonding or avoidant behaviours. If the loss of sensory function, namely the tactile sense, may lead to the disintegration of the Self, the study of this problem becomes more relevant in the elderly because it is proven that in this stage of life there is an important tactile sensory loss with implications in the motor function, in the activities of daily living and in interpersonal relationships. In this sense this thesis has as general objectives (1) to increase scientific evidence about the clinical practice of Physiotherapy; (2) to contribute to a reflection of clinical practice in Physiotherapy as it regards to the importance of sensory stimulation for the construction of the Self; (3) to allow for further understanding of the healthy aging process related to the functional and interpersonal relationships implications of tactile sensory decrease; (4) to make recommendations for enhancing the quality of provision of Physiotherapy services, specifically with regard to sensory assessment and sensory stimulation strategies. To achieve these objectives three studies were developed: (1) “Multisensory Self-referential stimulation of the lower limb – an fMRI study on healthy subjects”; (2) “Tactile Discrimination, Social Touch and Frailty criteria in elderly people”; (3) “Reliability and Validity of the European Portuguese version of the Social Touch Questionnaire”. The results and conclusions of the studies are: (1) unisensorial auditory-verbal and tactile-manual Self-referential stimulation and multisensory Self-referential stimulation elicits bilateral activations of the temporoparietal junction (TPJ), of the primary somatosensory cortex (S1), of the primary motor cortex (M1)-BA4 and of the premotor cortex (BA6). These sensorimotor areas were located in the lower-limb sensorimotor representation; Self-referential multisensory stimulation related to the body, more than unisensory one, produce a brain activation map in regions that are responsible for multisensory Self-processing. This process may represent the Core-Self. This brain map is composed of cortical and subcortical midline structures - BA7 (precuneus), left BA9 (medial prefrontal cortex), left BA30 (posterior cingulated), left thalamus, bilateral superior colliculum and left posterior cerebellum) and posterior lateral cortex (such as bilateral TPJ, bilateral posterior BA13 (insula), left BA19 and left BA37). Regarding all these structures, bilateral TPJ is the one that showed the biggest activation volume; (2) the decline of sensorial tactile discrimination of the hand is related to increasing age, to the decrease in grip strength and to higher avoidance behaviours and attitudes towards social touch. Sensorial tactile discrimination of the hand also explains frailty levels in the sample evaluated in the current study, i.e. frail elders have greater loss of sensorial discrimination then pre-frail elders. According to these results hand tactile discrimination should be used in assessment and intervention protocols in pre-frail and frail elders; (3) we produced an European Portuguese version of the Social Touch Questionnaire and is a reliable, valid and comprehensive measurement tool. It is an instrument that evaluates a range of behaviours and attitudes towards the touch and can be used by different health professionals, in clinical practice and for research purposes. Regarding the general conclusions of the studies supported by scientific evidence collected, such as: (1) brain areas activated by the multisensory stimulation performed in this study (auditory-verbal + tactile-manual) are those related to the Self processing; (2) decreased tactile sensitivity of the hand in the elderly has implications in the hand strength and in behaviour and attitudes towards social touch and can lead to difficulties in functional activities, decrease in interpersonal relations and the disorganization of the Self; (3) in case of elderly people, despite the deterioration of the sensory systems there is evidence of stabilization or increase of the multisensory integration processing; we recommend to contemplate multisensory Self-referential stimulation composed of unisensory auditory-verbal stimulus requesting to feel specific body parts and unisensory tactile-manual stimulation of the same body parts, when planning intervention strategies for healthy aging with the aim of maintaining the integrity of the elderly Self. According to the conclusions obtained in the developed studies some recommendations are presented for a more appropriate and comprehensive clinical reasoning that can lead to a more effective clinical practice in Physiotherapy.Sempre que ocorre uma alteração da função sensitiva, quer seja devida a uma doença, a um trauma ou ao processo normal de envelhecimento, surge simultaneamente uma alteração no controlo motor, na perceção do corpo e das emoções, na cognição, nas atividades da vida diária e na participação do individuo enquanto “ser” social. O sentimento que é gerado é de perda de identidade, de ameaça e de desintegração da perceção do indivíduo como um todo. Este fenómeno de consciência pessoal é designado por Self. Na literatura são relatados vários conceitos do Self mas algumas teorias mais recentes afirmam que existe um único Self. O ser humano é um todo e quanto maior for a perceção de unidade pessoal maior funcionalidade física, cognitiva e emocional poderá ser alcançada. O Self pode alterar-se de acordo com a exposição a diferentes condições de saúde mas também devido a experiências sensoriais e relacionais que sejam relevantes para o indivíduo, ou ainda devido à falta de estimulação. A estimulação que recebemos através de todas as modalidades sensoriais ajuda a construir a representação que fazemos de nós próprios. No entanto a estimulação unisensorial parece não ser suficiente para promover a perceção do Self como um todo, sendo que, a estimulação multissensorial, desde que seja composta por estímulos significativos para o indivíduo e referenciados ao Self, parece desencadear uma consciência mais global do Self. Os estímulos referenciados ao Self são estímulos que estão relacionados fortemente com a própria pessoa, sobretudo com a perceção do seu corpo. O fisioterapeuta é um profissional que se diferencia pela utilização de estratégias de estimulação sensorial que podem ser consideradas referenciadas ao Self, tais como a estimulação verbal apelando para sentir partes do corpo e o contacto direto e prolongado das suas mãos com o corpo do utente. No entanto estas estratégias raramente são usadas na Fisioterapia com o objetivo de melhoria das competências sensoriais e percetivas e quando são aplicadas nunca são usadas em simultâneo. No que se refere a estratégias de avaliação e de intervenção que utilizam o toque, verifica-se também que não existe um cuidado sistemático em avaliar a perceção que os utentes fazem do contacto físico que é estabelecido. No entanto, diferentes significados poderão ser atribuídos a esse contacto físico durante as interações terapêuticas, podendo gerar atitudes e comportamentos de evitamento ao toque. Isto pode inviabilizar a relação terapêutica e afetar os resultados esperados. Se a perda de função sensorial, nomeadamente a função sensorial tátil pode conduzir a uma desintegração do Self, o estudo deste problema torna-se mais relevante nos idosos pois a evidência aponta para a existência de uma perda sensorial importante nesta etapa de vida, com implicações na função motora, nas atividades do dia-a-dia e nas relações interpessoais. Face ao exposto esta tese possuiu como objetivos gerais (1) aumentar a evidência científica acerca da prática clínica da Fisioterapia; (2) contribuir para uma reflexão acerca da prática clínica da Fisioterapia no que se refere à importância da estimulação sensorial na construção do Self; (3) permitir uma melhor compreensão do processo de envelhecimento saudável relacionado com as implicações do declínio da sensibilidade tátil na funcionalidade e nas relações interpessoais; (4) efetuar um conjunto de recomendações para o aumento da qualidade da prestação de serviços prestados pela Fisioterapia, especificamente relacionados com a avaliação da função sensorial e com as estratégias de estimulação sensorial. Para alcançar estes objetivos foram realizados três estudos: (1) “Multisensory Self-referential stimulation of the lower limb – an fMRI study on healthy subjects”; (2) “Tactile Discrimination, Social Touch and Frailty criteria in elderly people”; (3) “Reliability and Validity of the European Portuguese version of the Social Touch Questionnaire”. Os principais resultados e conclusões dos estudos são: (1) a estimulação unisensorial auditiva-verbal e tátil-manual referenciada ao Self, assim como a estimulação multisensorial (auditiva-verbal + tátil-manual) referenciada ao Self promovem ativações bilaterais da Junção Temporo Parietal (JTP), do córtex somatosensorial primário (S1), do córtex motor primário (M1)-BA4 e do córtex prémotor-BA6. Estas áreas sensoriomotoras foram localizadas na representação sensoriomotora dos membros inferiores; a estimulação multisensorial referenciada ao Self, comparada com a estimulação unisensorial, produz um mapa de ativação cerebral constituído por regiões que, segundo a literatura, são responsáveis pelo processamento multisensorial do Self. Este processo poderá representar o Core-Self (também designado por Eu nuclear). O mapa cerebral encontrado é composto por estruturas corticais e subcorticais da linha média do cérebro - BA7 (precuneo), BA9 esquerda (córtex pré-frontal medial), BA30 esquerda (cíngulo posterior), tálamo esquerdo, colículo superior bilateral e cerebelo posterior esquerdo, assim como pelo córtex lateral posterior - JTP bilateral, BA13 (insula posterior bilateral), BA19 esquerda e BA37 esquerda. Em relação a todas estas estruturas, a JTP bilateral foi a que mostrou maior volume de ativação; (2) o declínio da sensibilidade discriminativa da mão está relacionado com o aumento da idade, com a diminuição da força de preensão e com maior quantidade de comportamentos e atitudes de evitamento relacionados com o toque. A sensibilidade discriminativa da mão também constitui uma variável explicativa dos níveis de fragilidade da amostra de idosos selecionada para o estudo, ou seja, os idosos frágeis possuem maior perda da sensibilidade discriminativa da mão do que os idosos pré frágeis. De acordo com estes resultados recomendamos que a sensibilidade discriminativa da mão seja usada nos protocolos de avaliação e de intervenção em idosos frágeis ou em risco de se tornar frágeis; (3) produzimos uma versão Portuguesa-Europeia do “Social Touch Questionnaire” e demonstrámos que é um instrumento de medida confiável, válido e de fácil compreensão. É um instrumento que avalia uma variedade de comportamentos e atitudes relacionados com o toque social e que poderá ser utilizado por diferentes profissionais de saúde, tanto na prática clínica como na investigação. Tendo em conta as conclusões gerais dos estudos e tomando como suporte a evidência científica recolhida, tais como: (1) as áreas cerebrais ativadas com a estimulação multisensorial realizada neste trabalho (auditiva-verbal + tátil-manual) são as relacionadas com o processamento do Self, (2) a diminuição da sensibilidade tátil da mão no idoso tem implicações na força da mão e nos comportamentos e atitudes face a toque podendo conduzir a dificuldades nas atividades funcionais, a uma diminuição nas relações interpessoais e à desorganização do Self; (3) no caso dos idosos, apesar do declínio dos sistemas sensoriais, existe evidência que o processamento multisensorial cerebral estabiliza ou pode mesmo aumentar; propomos que no planeamento da intervenção para um envelhecimento saudável, cujos objetivos sejam a manutenção ou o aumento da funcionalidade e a manutenção da integridade do Self, seja contemplada a estratégia de estimulação multisensorial referenciada ao Self proposta nesta tese. De acordo com as conclusões obtidas nos estudos desenvolvidos são feitas algumas recomendações para um raciocínio clínico mais adequado e abrangente que possa conduzir a uma prática clínica em Fisioterapia mais eficaz

Investigating Semantic Alignment in Character Learning of Chinese as a Foreign Language: The Use and Effect of the Imagery Based Encoding Strategy

For learners of Chinese as a foreign language (CFL), character learning is frustrating. This research postulated that this difficulty may mainly come from a lack of semantic understanding of character-denoted meanings. Language theories support that when a learner’s semantic meaning increases, the orthographic structures that represent the underlying meanings also improve. This study aimed to reveal CFL learners’ cognitive abilities and processes in visual-semantic learning of Chinese characters. Particularly, this study investigated the process by which English-speaking adolescent CFL learners, at the beginning to intermediate level, made mental images of character-denoted meanings to visually encode and retrieve character forms. Quantitative and qualitative data were gathered from image making questionnaires, writing, and reading tests, after learning characters in three commonly-used teaching methods (i.e., English, pictorial, and verbal). The data were analyzed based on a triangulation of the literature from Neuro-Semantic Language Learning Theory, scientific findings in cognitive psychology, and neuroscience. The study found that participants’ semantic abilities to understand character-denoted meanings emerged, but were still restricted in familiar orthographic forms. The use of the imagery strategy as a semantic ability predicted better performances, most evidently in writing; however, the ability in using the imagery strategy to learn characters was still underdeveloped, and needed to be supported with sufficient contextual information. Implications and further research in visual-semantic learning and teaching characters were suggested

Different neuronal pathways support the generation of general and specific mental images

The aim of this functional magnetic resonance imaging (fMRI) study was to investigate the neural correlates associated with the generation of general (i.e., prototypical) and specific (i.e., exemplar) visual mental images from concrete nouns. The fMRI paradigm included a non-imagery baseline, and two activation conditions requiring the generation of either general or specific images. Image generation times and brain activation were recorded. Analysis of the behavioral results showed that generating general images took less than the specific ones. The comparison of each activation condition with the baseline showed significant increase in brain activation in left frontal areas in both kinds of images, with the additional involvement of the posterior cingulate cortex during the generation of specific images. When the two activation conditions were contrasted with each other and masked for their respective comparison with baseline, significant activation was found in right frontal areas for general mental images, whereas a significant increase in activation in the left superior frontal region and the right thalamus was detected during the generation of specific mental images. These findings suggest that general and specific mental images are generated with the support of two different neural pathways. The generation of general images seems to involve brain areas associated with the formation of global gestalt-like images (areas in the right hemisphere), while the generation of specific mental images appears to require additional support from areas involved in the retrieval of visual details (i.e., the right thalamus)

Kognitive und neuronale Korrelate von Halluzinationen bei der Schizophrenie : Wahrnehmungsstörungen bei Patienten mit Schizophrenie im Vergleich zu erstgradigen Verwandten und Kontrollpersonen - untersucht mit psychometrischen Messungen und Magnetresonanz-Tomographie (MRT)

The present study consists of two parts: The first part is made up of questions concerning the cognitive underpinnings of auditory verbal hallucinations in schizophrenia. As this thesis framed schizophrenia as a multivariate problem, neural correlates to auditory verbal and visual hallucinations were investigated in the second part. The main finding is that vividness of mental imagery was increased in all putative high-risk groups as well as the patients themselves, compared with low-schizotypy controls. Therefore, it seems that vivid imagery is a trait rather than a state marker, and may be related to the genetic liability to develop schizophrenia. However, no evidence was found for a linear relationship between vividness of mental imagery and predisposition to hallucinate. Self-reported imagery vividness and predisposition to hallucinate did not depend on psychomotor speed or intelligence. In addition, individual psychopathology ratings did not correlate significantly with the mental imagery scores. Furthermore, the analysis of the control orientation and the degree of dysfunctional psychopathological status across the schizophrenia spectrum, showed an independence of control orientation and dysfunctional status from each other, as well as from other markers of schizophrenia or schizophrenic-like individuals. As a conclusion, external control orientation seems to be a symptom or a trait marker of schizophrenia. The results lead to the assumption that, beside schizophrenic individuals, first-degree relatives and schizotypy controls have some impairments and visible signs without suffering from the illness directly. This would lead to the further assumption that the illness schizophrenia is not only genetic but also dependent on environmental factors. In the second part of the study, we investigated anatomical and functional brain abnormalities in the schizophrenia patients compared with first-degree relatives and healthy controls. Here, the results followed the continuum of healthy controls, first-degree relatives and schizophrenic patients in the functional and anatomical data sets, and in the language lateralization. The decrease of lateralisation correlated with the severity of symptoms in the patient group. The investigation of visual hallucinations showed activity in higher visual areas during the experience of visual hallucinations in a schizophrenia patient and in a blindfolded subject. The activity in higher visual areas followed the boundaries of category-selective areas in both subjects. In contrast to the memory-related areas found in the schizophrenic patient experiencing visual hallucinations, we did not observe memory-related areas during visual hallucinations induced by blindfolding. This suggests that the neural mechanisms underlying hallucinations in schizophrenia are at least partly distinct from those operational in cortical deafferentation. It is proposed that individual differences in psychopathology, as well as neuropsychological and psychosocial functioning may provide further means to understand the complex and highly dynamic aspects of hallucinations specifically and schizophrenia in general. The enlargement of the subject sample to high-schizotypy controls and first-degree relatives of patients allowed new insights into the mental imagery debate and the dysfunctional connectivity pattern known to be responsible for psychotic symptoms. Further topics of research are discussed.Die hier präsentierte Arbeit untersucht die Erkrankung Schizophrenie, und speziell das Phänomen der Halluzinationen, unter multivariaten (kognitiv, neuronal) Gesichtspunkten. In der ersten Teiluntersuchung wurde geprüft, ob sich die mentale Vorstellungskraft bei den verschiedenen Versuchspersonengruppen, schizophrene Patienten, erstgradige Verwandte der Patienten, hoch-schizotype Kontrollpersonen und normale Kontrollpersonen, signifikant unterscheidet, und ob diese potentiellen Unterschiede eine Verbindung zu Halluzinationen, aufweisen. Das Hauptergebnis ist, dass die Lebhaftigkeit der mentalen Vorstellung in allen potentiellen Risikogruppen, also Verwandten, hoch-schizotypen Personen und schizophrenen Patienten selbst, erhöht ist, wenn man sie mit der Lebhaftigkeit der mentalen Vorstellungskraft bei normalen Kontrollprobanden vergleicht. Die Ergebnisse zeigen Hinweise auf eine genetische Disposition zu einer vermehrten Lebhaftigkeit visueller Vorstellungen im schizophrenen Spektrum. Jedoch zeigten die Ergebnisse nicht, wie von verschiedenen Autoren vermutet, einen direkten Zusammenhang zwischen der mentalen Vorstellungskraft und der Prädisposition zu halluzinieren. Beide Konstrukte scheinen darüber hinaus von psychomotorischer Verarbeitungsgeschwindigkeit und kristalliner Intelligenz unabhängig zu sein. Darüber hinaus besteht kein Zusammenhang zwischen der individuellen Ausprägung der psychopathologischen Symptome der schizophrenen Patienten und der subjektiven Einschätzung der mentalen Vorstellungskraft. Die Ergebnisse weisen darauf hin, dass die Lebhaftigkeit der Vorstellung eher etwas Überdauerndes (trait marker) als ein aktuell untersuchter Zustand (state marker) ist. Die Lebhaftigkeit der mentalen Vorstellungskraft scheint eine von Halluzinationen oder anderen psychopathologischen Symptomen unabhängige Auffälligkeit zu sein, die sich über das Schizophrenie-Spektrum erstreckt. Weiterhin konnten bei der Untersuchung weiterer möglicher Korrelate zu Halluzinationen andere kognitive Konstrukte mit den gleichen Probandengruppen untersucht werden: das Ausmaß an externaler Kontrollüberzeugung sowie an dysfunktionalen psychopathologischen Zustandsbild. Hier zeigte sich, dass schizophrene Patienten eher zu einer externalen Kontrollorientierung neigen, während Kontrollprobanden eine internal orientierte Kontrollüberzeugung hatten. Hoch-schizotype Personen sowie Verwandte der Patienten bildeten die Mitte zwischen den beiden anderen Probandengruppen. Auch bezüglich des dysfunktionalen Status konnte das eben beschriebene Kontinuum gezeigt werden. Beide Konstrukte zeigten sich unabhängig voneinander, wie auch von Halluzinationen. Jedoch zeigte sich ein Zusammenhang zwischen der externalen Kontrollüberzeugung und einem anderen psychopathologischen Symptom der Schizophrenie, den Wahnvorstellungen. Also scheint eine externale Kontrollüberzeugung ein Symptom oder ein Trait marker der des Schizophrenie-Spektrums zu sein. Diese Probandengruppen zeigen im Vergleich zu normalen Kontrollprobanden Auffälligkeiten, ohne dass sie an der Erkrankung direkt leiden. Dies könnte zu dem Schluss führen, dass gewisse Auffälligkeiten genetisch veranlagt sind, die Grenze zur Erkrankung Schizophrenie aber nur überschritten wird, wenn Umgebungs- oder andere Faktoren ungünstig dazu kommen. Im zweiten Teil der Studie untersuchten wir anatomische und funktionelle Auffälligkeiten des Gehirns. Die neurologischen Daten zeigen eine niedrigschwellige Aktivität im auditorischen Kortex außerdem eine reduzierte Sprachlateralisierung bei Schizophrenen und ihren Verwandten im Vergleich zu Normalpersonen. Sprache wird normalerweise stärker linksseitig im Gehirn verarbeitet, bei unseren Patienten scheint dieser Mechanismus jedoch gestört zu sein. Weitergehende Fragen zeigten, dass die Reduzierung der Sprach-Lateralisierung bei den Patienten in direkter Verbindung zu psychotischen Symptomen stehen. Je mehr psychotische Symptome die Patienten während des Zeitraums der Untersuchung aufwiesen, desto deutlicher gestaltete sich die Reduktion der Sprachlateralisierung. Diese Ergebnisse konnten auch für die Untersuchung des anatomischen Volumens des auditorischen Kortex gezeigt werden. Die hier vorliegenden Befunde sprechen für das schon zuvor beobachtete Kontinuum der Ergebnisse, von den Normalpersonen ohne Auffälligkeiten, zu den Verwandten mit leichten Auffälligkeiten, bis hin zu den Patienten mit deutlichen Auffälligkeiten in auditorischen und visuellen Verarbeitungsbereichen. Im weiteren Verlauf untersuchten wir das Phänomen der visuellen Halluzinationen bei einem schizophrenen Patienten sowie bei einer Probandin, die visuelle Halluzinationen durch sensorische Deprivation bewusst herbeigeführt hat. Wir konnten zeigen, dass höhere visuelle Areale während des Erlebens von visuellen Halluzinationen aktiviert sind, die direkt mit den Grenzen Kategorie-spezifischer Areale einhergingen. Während es gelungen ist, bei dem schizophrenen Patienten Gedächtnis-Areale zu finden, konnte dieser Befund für die Probandin mit den durch sensorische Deprivation herbeigeführten Halluzinationen nicht bestätigt werden. Dieser Befund bestätigt die Vermutung, dass die neuronalen Mechanismen, die den visuellen Halluzinationen bei schizophrenen Patienten zugrunde liegen, teilweise anders als bei operationaler kortikaler Deafferentation sind