Cost-effective device for locating and circumscribing superficial tumors with contrast enhancement and fluorescence quantification.

BACKGROUND: Two Bispectral contrast enhancement approaches for the fluorescence diagnosis with chlorine-e6 and a wide field-of-view imaging system with fluorescence excitation at 405 nm and time-resolved background suppression were analyzed and compared. METHODS: Two techniques for the contrast enhancement of a fluorescent video system (Red/Green (R/G) ratio and Red-Green (R-G)) with time-resolved background suppression for fluorescent diagnosis (FD) were tested in four patients with basal cell carcinoma (BCC). RESULTS: The results of both contrast enhancement methods were compared for the diagnostic efficiency for FD of BCC. Both techniques successfully determined the boundaries of the lesions and the fluorescence intensity. CONCLUSIONS: Both contrast enhancement modes have proven effective in identifying tumor borders in cases of low contrast in BCC FD with Ce6. While the Red/Green (R/G) mode provides sharper lesion borders, the Red minus Green (R-G) mode visualizes more fluorescent features and makes it easier to assess the lesion margins.

[Correlation between brain stem aminergic neuronal activity and EEG patterns in a wakeful cat].

There was carried out a correlation analysis for the frequency of the background impulse activity of the brain stem monoaminergic neurons and the spectral power of electroencephalogram frequency components in a wakeful cat. The frequency of the background impulse activity in the studied neurons was found to be reliably (p < 0.05) correlated with all basic electroencephalogram rhythms. Among the statistically significant correlations, there were most often observed the positive ones between the background impulse activity of the ventral tegmentum dopaminergic neurons and the locus coeruleus noradrenergic neurons, on the one hand, and the power spectral density of alpha-rhythm, on the other hand (40.3% and 48.0% respectively). Besides, 47.7% of the raphe nuclei serotoninergic neurons under study showed positive correlation between their impulse activity and the spectral power density of beta-rhythm. The results obtained let us assume the possibility of taking specific EEG patterns as markers of activity for the basic cerebral monoaminergic systems.

[Changes in the power of cat EEG rhythms during training with acoustic feedback signals].

Dynamics of power relation between beta and theta rhythms and activity of dopaminergic neurons in the ventral tegmentum were studied in chronic EEG biofeedback experiments in two waking cats. EEG biofeedback training was based on a developed scheme, in which the level of a presented sound signal decreased if the ratio of power of beta and theta rhythms recorded in the frontal area increased (due to the increase in the beta-rhythm power and decrease in the power of the theta rhythm). These changes were accompanied by the increase in the activity of tegmental neurons presumably dopaminergic.

Activity of substantia nigra neurons in the cat brain during a self-initiated behavioral act.

Cats were trained to perform a self-initiated behavioral act in the form of an operant food-obtaining reflex with defined time requirements. Activity was recorded from 50 dopaminergic neurons (identified in terms of their low frequency of background activity and long action potentials) and 67 nondopaminergic neurons of the substantia nigra and adjacent region. Dopaminergic neurons were the more responsive. Prior to EMG activation, the activity of 33 (66%) of these cells changed, and 44 (88%) showed changes in activity on movement. Dopaminergic neurons showed increased activity during the period of waiting for the conditioned stimulus, predicting the release of reinforcement or its absence. These cells were more frequently activated in response to a positive signal and reinforcement and were more frequently inhibited in the absence of reinforcement. The high reactivity of dopaminergic neurons during execution of a movement task could be explained by the involvement of a cognitive component, i.e., determining the point at which the movement should start.

Pre-movement activity of neurons in the parietal associative cortex of the cat during different types of voluntary movement.

Pre-movement activation of electromyographic spike activity of 201 neurons of field 5 was studied in cats trained to carry out a stereotypical act (lifting the anterior footpad to press a pedal) in response to a conditioned stimulus (experimental series 1) and without a conditioned stimulus (self-initiated movement, experimental series 2). In series 1, 69.2% of neurons were activated and 13.5% were inhibited before the movement. Prior changes in activity were also seen in intersignal movements, with activation of 40.6% and inhibition of 21.7% of neurons. The time parameters of excitatory and inhibitory responses in both situations were similar, with pre-movement intervals of 19-1640 msec. In series 2, pre-movement inhibition was seen rather more frequently than activation (36.7% and 33.7% respectively). The earliest changes were inhibitory, occurring some 1800 msec before movements, while excitatory changes occurred only 880 msec before movement. These data indicate the involvement of the parietal associative area in the can not only in executing, but also in preparing for different types of movement, including self-initiated movements, and that inhibition has an active role in this process.

[Substantia nigra neurons activity in cat brain during realization of self-initiation of behavioural action]. / Aktivnost' neironov oblasti chernogo veshchestva mozga koshki pri realizatsii samoinitsiiruemogo akta.

Activity of 50 dopamine and 67 non-dopamine neurons was studied during motivated behavioural actions in the cat brain black substance. 66% of former and 88% of latter neurons modified their activity before and during autoinitiated voluntary movements. The data obtained suggest that dopamine neurons are involved in organisation of movements in behavioural actions with cognitive components.

[Activity of neurons in the parietal associative cortex in the area of the substantia nigra in cats exposed to magnetic fields with an 8 Hz frequency]. / Aktivnost' neiropnov temennoi assotsiativnoi kory i oblasti chernoi substantsii u koshki pri vozdeistvii magnitnykh polei chastotoi 8 Gz.

The effects of magnetic field (frequency--8 Hz, induction--20 microI, exposition time--6 min) on movement--related activity of neocortex neurons and spontaneously firing nigral unit's of awake cats were studied. Exposure to field produced the modulation of the early neuronal activity preceding self-initiated arm movements in parietal cortex (area 5) and the increase of nigral cells firing rate.

[The corollary neuronal activity of the parietal associative cortex in the cat during different types of voluntary movements]. / Operezhaiushchaia aktivnost' neironov temennoi assotsiativnoi kory koshki pri raznykh vidakh proizvol'nykh dvizhenii.

Unit activity of 201 neurons was studies before the EMG activation in the area 5 in cats trained to perform a stereotypic movement in response to a triggering stimulus and without it. The data obtained suggest that the parietal associative cortex takes part both in triggering of different voluntary movements and in active inhibition of this process.