- 4. Neuropsychological syndromes with lesions of the frontal brain.

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radical underlying it is a pronounced, increased inhibitory trail. Violations of selectivity are presented here in a very obliterated form, and dysfunction of trace formation can be seen only with a massive degree of severity of mnestic and clinical symptoms.
In this syndrome of memory impairment, a significant role is played by the level of semantic organization of the memorized material, which can be represented as a sequence of unrelated stimuli (words, figures, etc.), and also, as semantic material (phrases, stories).
Significant in the differential diagnostic plan are the forms of interfering effects (hetero-or homogeneous interference), and the qualitative specificity of their negative impact: a decrease in the volume of reproduction, the complete impossibility to recall the memorized material, forgetting the very fact of the previous interference of memorization.
The severity of the syndrome of mental disorders in the defeat of the hypothalamic-diencephalic region is determined by the following indicators.
1. Does only the mechanism of the pathological inhibitory traces act (mild and moderate degree) or do the other two, mentioned above, join it (massive amnesic syndrome).
2. Is the mnestic defect compensated for by the semantic organization of the material (mild and moderate degree) or pathological forgetting manifests itself, regardless of this characteristic of the memorized information (deep memory disturbances).
3. Does only homogeneous interference (mild degree) affect a decrease in productivity, or does heterogeneous one have a negative effect (medium and gross degree)?
4. Does the interference reduce the productivity of reproduction (mild and moderate degree) or does it completely forget the content of the stimulus material (medium and gross severity) or does it forget the fact that memorization took place (massive amnestic syndrome).
The most important distinctive feature of memory impairments in this localization of the pathological process is their occurrence against the background of a decrease in the level of activation, which, moreover, detects significant fluctuations in different time ranges. At the same time, memory disorders are fluctuating in nature and their severity can fluctuate on different days, during one study and even during the execution of one task. The range of fluctuations is associated with the stage of development of the pathological process and with its influence on the brain stem structures (Kiyaschenko et al., 1975). The decrease in the level of activation is also manifested in the emotional sphere in the form of a general flattening of affective processes, their monotony, lethargy, narrowing the field of emotionally significant stimuli. At later stages of development of the pathological process, symptoms of apathy can be seen.However, the patient remains "open" for the emotional impact on him; by additional instructions, indications of the significance of the survey and other forms of external stimulation, it is possible to temporarily increase the productivity of its activities and obtain adequate emotional responses.
With a significant decrease in the level of activation, characterized by the prevalence in the general status of the patient of prosonochny states, in combination with massive memory impairment, there are also disturbances of consciousness in the form of disorientation in place, time, and sometimes in the circumstances of one’s own life. As a rule, these disturbances of consciousness pass without confabulations, which, if they occur in some cases, are minimized unproductive and do not occur spontaneously in patients.
It is logical to assume, and the clinical and experimental data show that the function of attention is also deficient in these patients. With a general decline in both voluntary and involuntary attention, it, like memory impairment, has a fluctuating character, is unstable and can rise to a higher level with external, additional stimulation (E. Homskaya, 1972).
6. Split brain syndrome in lesions of the corpus callosum
The coordinated work of the cerebral hemispheres is provided by the commissural fibers, among which the corpus callosum (MT) plays the leading role in adults. When it is cut, each hemisphere begins to work as an isolated organ, the integration of the activity of the hemispheres is significantly impaired. The study of the symptoms of local MT lesion has received little attention so far. A disturbing reliable symptom of his dysfunction was considered to be a violation of reciprocal hand coordination. The lack of knowledge of the functions of the corpus collosum has objective reasons, consisting in the fact that its tumor lesion usually forms a complex syndrome of hemispheric, dislocation and cerebral disorders.
In recent years, thanks to the development of neurosurgery, the functions of the corpus callosum have become available to a differentiated study. In the United States, a full commissurotomy of epilepsy is carried out, which is not amenable to relief by other means of therapeutic treatment. The Institute of Neurosurgery. N.N. Burdenko performs a partial transection of the corpus callosum in connection with the removal of arteriovenous malformations from its anterior, middle or posterior regions. The development of postoperative symptoms of mental disorders arising from each of these types of surgical intervention can be associated with direct, local damage to the corpus callosum. At present, two main variants of syndromes due to a violation of interhemispheric interaction, the essential feature of which is their unilateral nature, are described.
The first syndrome is referred to as anomy syndrome. It manifests itself in violations of the naming of stimuli that enter the right hemisphere of the brain. If the patient feels the objects with his left hand or receives visual stimuli only in the left half-field of view, information enters the parietal or occipital parts of the right hemisphere of the brain. In case of preservation of interhemispheric connections, it is transferred to the left hemisphere, where the speech zones are located, and can be called. After commissurotomy such a transfer does not occur and the perceived objects can not be named.
The difference between anomie and violations of nomination in aphasia is that when the same information enters the left hemisphere (feeling the subject with the right hand, presenting stimuli in the right half-field of view), it can easily be called. It is important to note that the gnosis disorders are not the basis of the anomie, since a sensible object that can be identified by touch can be selected either by touch or visually from a group of other objects. The described phenomenon concerns naming not only objects, but also letters.
The second syndrome of lesion MT - syndrome "discopia-dysgraphia". It manifests itself in the fact that the patient becomes completely inaccessible letter with his left hand in combination with the inability to draw (draw) with his right hand. Diagnostic technique that allows to differentiate these symptoms from the usual violations of the letter and visual-constructive activity is a change of hand when performing tasks. Patients with commissurotomy can read the letter with the right hand and perform the drawing with the left hand.
The syndromes described here are most fully manifested in the surgical treatment of the posterior corpus callosum.
Damage to the anterior third of the corpus callosum does not lead to visible impairments of mental functions. Only in special studies - dichotomous listening and determining the time of the motor reaction - can we note some change in indicators, indicating a slowdown in the process of transmitting information from one hemisphere to the other.
In contrast, commissurotomy in the middle parts of the corpus callosum leads to dislocation of the skin-kinesthetic information from one hand to another in kraesthetic information when performing tests on praxis of the posture, samples for transferring the object to the other hand according to the shape detected in normal neuropsychological research presented in one hand, the other hand. When dichotomous presentation of verbal stimuli, the defeat of the middle parts of the corpus callosum leads to a pronounced phenomenon of ignoring the words placed on the left ear, i.e. entering the right brain.
Thus, the described symptoms of impaired mental functions with a lesion of the corpus callosum and the methods that allow them to be found give grounds for resolving issues of topical diagnosis not only with respect to the dysfunction of hemispheric connections in general, but also with regard to the localization of the pathological process in their posterior, middle or frontal departments.

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Часть 1 4. Neuropsychological syndromes with lesions of the frontal brain.
Часть 2 - 4. Neuropsychological syndromes with lesions of the frontal brain.