[Electrophysiological analysis of septum-amygdala interaction at the level of the dorsomedial thalamic nucleus in the rat]. / Elecktrofiziologicheskii analiz septo-amigdaliarnogo vzaimodeistviia na urovne dorzomedial'nogo iadra talamusa krysy.

The characteristics were studied of focal potentials and impulse activity of 102 neurones of the thalamus dorsomedial nucleus (DMN) of anaesthetized rats under stimulation of the anterior periamygdalar cortex (APC) and septal lateral nucleus (SLN). The dominating type of impulse responses to APC and SLN stimulation recorded correspondingly in 31.4 and 12.8% of cells was expressed in a short latency (10-30 ms) phasic activation. It has been found that the convergence of these inputs, revealed in 9.8% of cells, is unidirected according to the genotype of the reaction. Neuronal complexes of DMN, organizing the responses to the stimulation of APC and SLN are characterized by a weak interaction testifying to a definite functional differentiation of the amygdalar and septal components of the lymbic-thalamic projection system.

[Thermovision monitoring of neurografts in the rat]. / Teplovizionnyi kontrol' neirotransplantata u krys.

By thermovision technique and images digital processing, thermal fields and reactions of dorsal cortical surface of 15 white rats were studied through the intact skull in various times after transplantation of the embryonal visual cortex, amygdala and hippocampus into the visual cortex. After operation significant thermoasymmetries arise outside transplantation area which in early periods (2-15 days) are dynamic, and in 5-5.5 months become stabilized. At successful implantation, transplantat area in background state in late terms is not thermodistinct, and in pseudo-transplanted animals--is cooled. In transplantat area, a changed thermoreaction to light stimulation is recorded, and in early terms it is connected with thermal flow from neighbouring cortical sites.

[Neuronal correlates of the functional reorganization of the dorsomedial thalamic nucleus in the rat after damage to the amygdala]. / Neironnye korreliaty funktsional'noi reorganizatsii dorsomedial'nogo iadra talamusa krysy posle povrezhdeniia amigdaly.

Activity of the thalamic dorso-medial nucleus (DMN) cells evoked by stimulation of the periamygdaloid cortex was recorded in anesthetized rats in various periods of time after the baso-lateral amygdala destruction. It was found that changes in functional characteristics of cells observed at the early postoperative period intensified and reached the highest expression 10-30 days after such a destruction. Both the number of responding cells and percentage rate of neurons with excitatory and inhibitory responses restored along with the prolongation of the postoperative period. The structure of evoked excitation differed from the normal in predominant long-lasting tonic activation. Some peculiar features of functional reorganization of the DMN neuronal network involved in processing of incoming afferentation are discussed.

[Processes of the survival of embryonic amygdala tissue after transplantation into different parts of the brain of adult rats]. / Issledovanie protsessov prizhivleniia émbrional'noi tkani amigdaly posle peresadki v razlichnye uchastki mozga vzroslykh krys.

Histological examination of the Nissl and Golgi stained neurons revealed that the amygdalar embryonic grafts survive in the adult rat brain. Some quantitative characteristics, such as index of the parenchymal integration, growth potential, neuronal density and vascularization index were used for objective estimation of the graft development. The qualitative and quantitative analysis have shown that the localization of the graft in the host brain is one of the main factors determining the survival success. The grafts revealed the least survival in the host cortex. The grafts which were placed in the ventricular cavity displayed better survival. Amygdalar grafts with subcortical localization gave the best results of survival. In the "good" grafts normally differentiated neurons and glial cells were observed. The ingrowth of capillaries in the grafts could be found. The Golgi impregnation revealed the formation of the common neuropile between the grafts and the host brain. Structural integration of donor and host brain tissues provides a good model for investigation not only of the functional recovery of the neural interconnections, but also of changes in the behavior controlled by amygdalar structures.

[Reorganization of the evoked neuronal activity of the dorsomedial nucleus of the thalamus in the rat shortly after destruction of the basolateral nuclei of the amygdala]. / Perestroika vyzvannoi neironnoi aktivnosti dorsomedial'nogo iadra talamusa krysy v rannie sroki posle razrusheniia bazolateral'nykh iader amigdaly.

Characteristics of the thalamic dorso-medial nucleus neuronal responses evoked by stimulation of the periamygdaloid cortex before and after the baso-lateral amygdala destruction were compared in anesthetized rats. Appearance of a new reaction in the form of a long rhythmic bursts and reliable decrease of phasic-active units and increase in the number of cells with tonic activation were found after such destruction. The number of units with spontaneous discharge increased without affecting the spontaneous discharge frequency. The mean duration of the tonic discharge increased from 142.5 +/- 42.4 ms to 375.4 +/- 53.8 ms but other parameters of the neuronal reactions did not differ significantly.

[Interaction of afferent inputs from structures of the amygdalar complex at the level of the dorsomedial nucleus of the thalamus in the rat]. / Vzaimodeistvie afferentnykh vkhodov ot struktur amigdaliarnogo kompleksa na urovne dorzomedial'nogo iadra talamusa krysy.

In acute experiments on rats, focal potentials characteristics were compared with responses of 63 neurones of the thalamic dorsomedial nucleus (DMN) to stimulation of the anterior amygdalar area (AAA), anterior periamygdalar cortex (APC) and basolateral amygdala (BLA). A resemblance was established of parameters of DMN evoked responses to APC and BLA stimulation. At DMN level, interaction of inputs from BLA and APC and to a lesser degree from AAA and BLA was discovered, expressed in suppression of the evoked activity to testing stimulation in the interval of 50-500 ms after conditioning stimulation. It is shown that the inputs from the structures of the amygdalar complex to DMN are of different effectiveness. 30% of tested neurones were characterized by convergence of the inputs from APC and BLA. APC coagulation was followed by a reduction of focal potentials evoked by BLA stimulation and by their complete disappearance in the ventral part of DMN. It is supposed, that APC in rats is the main relay structure between BLA and DMN.

[Effect of the destruction of the basolateral nuclei of the amygdala on the character of the electrical activity of the dorsomedial nucleus of the rat thalamus]. / Vliianie razrusheniia bazolateral'nykh iader amigdaly na kharakter élektricheskoi aktivnosti dorsomedial'nogo iadra talamusa krysy.

Characteristics of the thalamic dorsomedial nucleus slow and neuronal activity in different periods after the basolateral amygdala destruction were studied in semichronic experiments on anesthetized rats. Periodic spontaneous transformation of neuronal activity in rhythmic bursts and development of burst seizure activity were observed 1.5-2h after the destruction. Seizure activity was characterized by groups of 4-6 acute waves appearing at a frequency of 1.5 +/- 0.3 Hz. A change in the coefficient of correlation between the duration of seizure activity and its frequency was determined. Interference between seizure activity and orthodromic focal potentials caused by stimulation of the periamygdaloid cortex and anterior amygdaloid area was shown. Dorsomedial nucleus neurons with long (up to 1 s) responses in the form of impulse rhythmic bursts or tonic activation correlating with the appearance of rhythmic afterdischarge were described. Seizure activity was most expressed during 3-4 days after the amygdala destruction. A disorder of the dorsomedial nucleus transmitting and integrative function associated with seizure activity is supposed to be one of the mechanisms of the change of adaptive behaviour in amygdalectomized animals.

[Nature of evoked responses of the dorsomedial nucleus of the thalamus to stimulation of the periamygdaloid cortex and anterior amygdaloid region of the rat brain]. / Kharakter vyzvannykh otvetov dorsomedial'nogo iadra talamusa pri stimuliatsii periamigdaliarnoi kory i perednei amigdaliarnoi oblasti mozga krysy.

Focal evoked potentials (FEP) and unit activity characteristics of the thalamic dorsomedial nucleus were compared with the periamygdaloid cortex (PC) and area amygdaloidea anterior (AAA) stimulation in acute experiment with rats. Some pattern differences of the FEP as well as differences of the recovery period of both activities to the PC and AAA stimulations are established. AAA and PC stimulation was followed by electrical activity changes in 19.2% and 26.9% of the units in question, respectively. Four types of neurons are found: active ones (64.3% of all responding units); two-phase active units (14.3%); inhibitory or inhibitory-active units (14.3%) and complex units (7.1%). PC stimulation evokes both short (12-18 ms) and long latency (23-66 ms) phasic-active unit responses, while AAA stimulation led to appearance of responses with latencies not less than 20 ms (21-136 ms). Responses of the first two types were peculiar to 92.9% and 64.3% of units responding to PC and AAA stimulation, respectively.

[Interaction between auditory and trigeminal afferent volleys in the dorsal cochlear nucleus of rats]. / Vzaimodeistvie slukhovykh i trigeminal'nykh afferentnykh posylok v dorsal'nom kokhlearnom iadre krysy.

In chloralose anaesthetized rats preliminary electrical stimulation of the second branch of the trigeminal nerve diminished the amplitude of all component of the evoked potential produced by click, when the interval between conditioning and testing stimuli was up to 40 ms. Only late negative-positive component of the evoked potential was depressed when the interval between the stimuli was increased. The conclusion is made that the afferent inflow to the dorsal cochlear nucleus is controlled by peripheral mechanisms changing the sensory input and by central descending inhibitory influences on the nucleus.