RESUMEN
In adults, partial damage to V1 or optic radiations abolishes perception in the corresponding part of the visual field, causing a scotoma. However, it is widely accepted that the developing cortex has superior capacities to reorganize following an early lesion to endorse adaptive plasticity. Here we report a single patient case (G.S.) with near normal central field vision despite a massive unilateral lesion to the optic radiations acquired early in life. The patient underwent surgical removal of a right hemisphere parieto-temporal-occipital atypical choroid plexus papilloma of the right lateral ventricle at four months of age, which presumably altered the visual pathways during in utero development. Both the tumor and surgery severely compromised the optic radiations. Residual vision of G.S. was tested psychophysically when the patient was 7 years old. We found a close-to-normal visual acuity and contrast sensitivity within the central 25° and a great impairment in form and contrast vision in the far periphery (40-50°) of the left visual hemifield. BOLD response to full field luminance flicker was recorded from the primary visual cortex (V1) and in a region in the residual temporal-occipital region, presumably corresponding to the middle temporal complex (MT+), of the lesioned (right) hemisphere. A population receptive field analysis of the BOLD responses to contrast modulated stimuli revealed a retinotopic organization just for the MT+ region but not for the calcarine regions. Interestingly, consistent islands of ipsilateral activity were found in MT+ and in the parieto-occipital sulcus (POS) of the intact hemisphere. Probabilistic tractography revealed that optic radiations between LGN and V1 were very sparse in the lesioned hemisphere consistently with the post-surgery cerebral resection, while normal in the intact hemisphere. On the other hand, strong structural connections between MT+ and LGN were found in the lesioned hemisphere, while the equivalent tract in the spared hemisphere showed minimal structural connectivity. These results suggest that during development of the pathological brain, abnormal thalamic projections can lead to functional cortical changes, which may mediate functional recovery of vision.
Asunto(s)
Plasticidad Neuronal , Corteza Visual/lesiones , Adolescente , Mapeo Encefálico , Neoplasias del Plexo Coroideo/cirugía , Sensibilidad de Contraste , Imagen de Difusión Tensora , Femenino , Humanos , Imagen por Resonancia Magnética , Pruebas Neuropsicológicas , Papiloma del Plexo Coroideo/cirugía , Complicaciones Posoperatorias/diagnóstico por imagen , Complicaciones Posoperatorias/psicología , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Temporal/lesiones , Corteza Visual/diagnóstico por imagen , Pruebas del Campo Visual , Vías Visuales/diagnóstico por imagen , Vías Visuales/lesionesRESUMEN
The authors consider that the Freudian theory of dreams is not directly applicable to psychotic and borderline patients with their constantly varying states of mental integration. Because these patients' dreams lack associations, the usual psychoanalytic approach cannot be used to ascertain their meaning. After reviewing the literature on the specific quality of dreams in the psychotic state, the authors point out that such dreams have nothing to do with the metaphorical language of the dream work but instead express the concreteness of the hallucinatory construction. For this reason, a dream's meaning may fail to be understood by the patient even if it seems clear to an observer. Yet the analyst's reception of a 'psychotic dream' is a unique and essential source of valuable information on the manner of construction of the delusional system, allowing analytic work on the psychotic nucleus. In the authors' view, such dreams may help the analyst and the patient--while still lucid--to acquire insight, thus affording a stable foundation for emergence from psychosis. The paper includes some case histories, in one of which a psychotic female patient is enabled by work on dreams to reconstruct a psychotic episode and thereby to ward off an imminent fresh lapse into psychosis.
Asunto(s)
Sueños/psicología , Terapia Psicoanalítica , Trastornos Psicóticos/psicología , Trastorno de Personalidad Limítrofe/psicología , Femenino , Teoría Freudiana , Humanos , MasculinoRESUMEN
The author contends that the various psychoanalytic theories and techniques employ different models of the unconscious, each relating to a different unconscious reality describable in terms of specific mental functions. He reviews in particular the Freudian dynamic unconscious, based on repression; the Kleinian unconscious, which adds the notions of unconscious fantasy and splitting of the object; Bion's conception of the unconscious as a mental function of which the subject is unaware but which can formulate thoughts and metabolise emotions; and the neuroscientific view of the unconscious as coinciding with that of which one is unaware and not with the Freudian repressed. The author thus distinguishes between the dynamic and the emotional unconscious and between 'unconscious' and 'unaware', and notes the role of distortion of the 'unaware' perceptions involved in the analytic relationship in the impasse situation. He is particularly concerned to show that, whereas neurosis involves the dynamic unconscious, psychosis alters the emotional unconscious, the entity underlying the sense of identity and the 'unaware' consciousness of existence. In psychosis the emotional unconscious is blinded, so that the patient is conscious but lacks awareness. The dynamic unconscious is also affected. After presenting two case histories, the author draws attention to the need for further clinical and theoretical research in this field.
Asunto(s)
Teoría Psicoanalítica , Trastornos Psicóticos/psicología , Inconsciente en Psicología , Adulto , Concienciación , Humanos , Masculino , Terapia Psicoanalítica , Trastornos Psicóticos/diagnósticoRESUMEN
On the basis of the development in the course of analytic treatment of a young male patient in a state of hallucinatory terror, the author discusses in this paper the nature of the psychotic superego. He shows how the process of recomposition of the self after a psychotic breakdown involves the transition from a terrorising and destructuring type of superego to one more reminiscent of that seen in depressive illness. The author describes this process against the background of the variations in the auditory hallucinations that began during the analysis. In the first phase of the analysis the patient is helped to free himself from the intimidating power of the hallucinatory superego, while the second phase centres on the patient's own involvement in producing the hallucinations. The author shows how the analysis mitigated the destructive hate resulting from unbearable psychic pain and describes how insight and transformation gradually ensued in the hallucinatory state. The resulting restoration of an internal psychic space is stated to be essential to the reconstitution of a whole and separate self. After drawing an interesting parallel between the psychotic superego and the attitude of God in the Old Testament story of Job, the author places his thesis in the context of the ideas of Klein, Bion and Rosenfeld.
Asunto(s)
Alucinaciones/psicología , Terapia Psicoanalítica , Trastornos Psicóticos/psicología , Trastornos Psicóticos/terapia , Superego , Adulto , Biblia , Alucinaciones/terapia , Humanos , Masculino , Modelos Psicológicos , Relaciones Profesional-Paciente , Religión y Psicología , Transferencia PsicológicaRESUMEN
An ultrastructural study has been carried out on the cells involved in the formation and ripening of tetraspores in the red alga Erythrocystis Montagnei. This organism is considered a parasitic species, although relationships with the host plant are not completely known. The work reveals a series of morphological changes in dictyosomes, which assume different dispositions of cisternae and produce different kinds of vesicles in the various stages of tetrasporogenesis. Plastids reach their complete differentiation when the cleavage furrows are nearly complete. Their complexity is comparable to that visible in autotrophic red algae. It is confirmed that during tetrasporogenesis the cytological changes are less profound than those which take place in the course of carposporogenesis.
Asunto(s)
Rhodophyta/ultraestructura , Diferenciación Celular , Rhodophyta/fisiología , Esporas Fúngicas/ultraestructuraRESUMEN
Erythrocystis montagnei lives as a symbiont on the thallus of another red alga, Laurencia paniculata. This electron microscope study carried out on its vegatative cells shows that the plastids have a fine structure adequate to perform photosynthesis, different from that observed in other parasitic red algae. Starch granules occur frequently in all the cells of the thallus except the large vacuolized basal cell, which joins together the symbionts. These features suggest that Erythrocystis lives on its host plant for reasons other than a lack of photosynthesis.