Higher cortical functions higher cortical functions, language, visual perception, praxia, body image, etc., Are one of the most exciting chapters of neurology. To analyze this issue is required to define what is meant by the Act and major alterations. An Act is a voluntary activity, which may be intentional apparently very simple (close one eye) or passive (visual or auditory perception), but that is voluntary, we know that this activity is much more complex than the excitation of an afferent neuron and other efferent. Clinical observation shows that alterations of the acts may be three levels: psychological, psychiatric, neuropsychological and physiological level level. On the psychological level altering events is secondary to cerebral dysfunction, which may be purely functional or organic nature but diffuse, not focal. Among the former we can mention, as examples, the disturbance of speech or gait in a state of anxiety; alteration of the writing or the perception in schizophrenia and others.
In the second group, the Professional, mention the speech disturbance or motion in a dementia or an impairment of consciousness, the writing or alteration of perception in children with sequelae of perinatal encephalopathy. The physiological level is the most basic and best known. At this level the alteration of the acts attributed to a lesion of the primary areas, the peripheral organs or the connections between these areas and these bodies (including some subcortical structures). Examples include speech disturbances secondary to Parkinson’s disease, paralysis of the veil, or filing teeth. In these conditions, factors that alter the acts are relatively well known and the defect is relatively constant or predictable in contrast to the variability of returns that can be observed when compromise the psychological or neuropsychological level. At level Neuropsychological alterations include injuries acts from the areas of secondary or tertiary association.
At this level we find the aphasia, apraxia, agnosia, acalculia, etc. These entities have been classically defined as a defect in a specific performance (visual perception, aphasia) can not be explained as a psychological disorder or physiological level. We should note that the effect of injury to the secondary and tertiary cortical areas is only partially predictable. An injury does not always produce a certain type of aphasia. The severity of aphasia can vary from case to case depending on variables such as duration of symptoms, side of the subject, environmental, personal and others that are unknown. Psychological disturbance level of consciousness. From a neurological point of view, consciousness is defined as the individual’s ability to establish relationships with the environment and himself. Features of consciousness.