Rethinking Knowledge

The view that the subject matter of epistemology is the concept of knowledge is faced with the problem that all attempts so far to define that concept are subject to counterexamples. As an alternative, this article argues that the subject matter of epistemology is knowledge itself rather than the concept of knowledge. Moreover, knowledge is not merely a state of mind but rather a certain kind of response to the environment that is essential for survival. In this perspective, the article outlines an answer to four basic questions about knowledge: What is the role of knowledge in human life? What is the relation between knowledge and reality? How is knowledge acquired? Is there any a priori knowledge?     

Object-centred orienting of attention

Abstract

In the present study two experiments are reported in which the subjects were presented on a computer screen with a two-dimensional line drawing that is perceived as a three-dimensionalobject (i.e. a cube). The cube could be seen as stationary, as rotating about the y-axis (Experiment 1A), or as rotating about the x-axis (Experiment 1B). The subject's attention was directed by a visual precue to a vertex of the cube. As the cube rotated, the precued location moved in viewer-centred co-ordinatesm, but the local feature of the cube that had been precued (i.e. a given vertex) did not move in object-centred co-ordinates. The imperative stimulus was presented at the precued location (valid trials) or at an uncued location (invalid trials). Precued and uncued locations were determined in object-centred coordinates. The subjects were required to signal detection of the imperative stimulus by pressing the space bar on the computer keyboard. There were also control conditions in which the procedure was identical, but the cube was not visible. When the cube was visible, valid trials were faster than invalid trials, regardless of whether it was seen as stationary or rotating. It was concluded that the subjects could allocate spatial attention in object-centred co-ordinates. There wer also indications that responses for invalid trials were faster when the imperative stimulus was presented on the same face as the precue than when it was presented on the opposite face.     

Delirium and isolated angiitis of the central nervous system: a case report and review

Central nervous system (CNS) vasculitis is a rare entity, especially when it occurs in isolation; it is seen more commonly as part of a multisystem vasculitis. Common presenting symptoms include persistent headache, encephalopathy, and multifocal signs. We discuss the case of a 68-year-old female who presented twice in 1 month with confusion and choreaform movements. Extensive workup was negative for a connective tissue disease or other conditions in the differential, including neurosarcoidosis, Creutzfeldt-Jakob disease, and neurosyphilis. The only significant findings were elevated erythrocyte sedimentation rate, inflammatory signs in the CNS, and diffuse slowing of the electroencephalogram. A presumptive diagnosis of isolated angiitis of the central nervous system (IACNS) was made and the patient was successfully treated with steroids. She recovered fully with no residual symptoms. The diagnosis of IACNS is often difficult given there are no definitive laboratory investigations or pathognomonic presentation. However, a series of signs, symptoms, and laboratory findings have been proposed that are helpful in making the diagnosis. To our knowledge, IACNS presenting primarily with delirium has not been previously reported in the literature. The diagnosis of IACNS is purely speculative for this case, as the gold standard for diagnosis, a leptomeningeal cortical biopsy, was not performed.     

Fear of The Mind. The Annihilating Power of the Gaze

The concern for the annihilating power of the gaze is not part of the Freudian discourse, but represents one of the most valuable contributions of phenomenology to psychoanalysis. When clear boundaries between the self and the others are not yet established, the gaze is experienced as a disembodied force that radiates from the eyes and can dangerously penetrate into the mind. In this regard, the body or parts of it can be used as a shelter. If the external body is not sufficiently cathected, its sheltering function is also decreased, to the point that the body is experienced as transparent, and the most intimate feelings and thoughts become dangerously available to the others. In primitive societies this situation is experienced as the danger of losing the soul. The unconscious fantasy of obstructing the sight can be used to neutralize the annihilating power of the gaze by introducing an artificial barrier between the minds. In dreams and in other expressions of the unconscious, the black color might hint at such an artificial barrier. What is then blackened are moments of the meeting of the mind that cannot be introjected. Blind spots in the perception of the mind of the other as well as in the perception of the self are a specific consequence of this kind of defense.     

Dopaminergic modulation of prospective memory in Parkinson's disease

Growing interest is present in literature on the study of prospective memory functioning in Parkinson's disease (PD). Current data indicate that prospective memory may be impaired in PD and a relationship with general executive dysfunctioning has been suggested. However, although the dopamine dependency of cognitive dysfunction in PD has been widely investigated, poor is known on the dopaminergic modulation of PM. In the present study we explored the effect of acute administration of levodopa on the performance of a PD sample (n=20) in a time-based prospective memory task. PD patients were evaluated in the morning after a 12-hour therapy wash-out in two experimental conditions: i) after levodopa assumption ("on"); ii) without drug administration ("off"). The experimental task required to execute three uncorrelated actions after 10' for three consecutive trials. Distinct scores for the spontaneous recall of the intention to perform the actions (prospective component) and for the correct execution of the actions (retrospective component) have been computed. Results showed that in the "off" condition PD patients were selectively impaired on the prospective component of the task. However, L-dopa administration significantly improved PD patients' performance actually restoring the prospective memory deficit. These results support a critical role of dopaminergic modulation in prospective memory processes in PD patients, possibly through the replacement of dopamine levels in fronto-striatal pathways.     

Right—left prevalence effect with horizontal and vertical effectors

We investigated the right-left prevalence effect in spatial compatibility tasks by assessing subjects’ performance on a two-dimensional task in which both the horizontal and vertical spatial dimensions were task relevant. Two experiments were performed, in which stimulus-response mappings were one-dimensional (Experiment 1) and two-dimensional (Experiment 2). The subjects responded by using either horizontal or vertical effectors to stimuli appearing in four possible locations. With the one-dimensional mapping, the spatial compatibility effect was present only in the dimension relevant to the mapping. With the two-dimensional mapping, the horizontal compatibility effect was always present, whereas the vertical compatibility effect was present only when vertical effectors were used. This pattern of results indicates that horizontal coding takes place with either horizontal or vertical effectors, whereas vertical coding takes place only when vertical effectors are used.