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T J Marczynski

Publications and source records attributed to T J Marczynski.

At least 37 records · Page 2Linked to original sources
PubMed1979

Pulvinar and lateral geniculate neuronal activity in the cat during operantly conditioned appetitive behavior.

Cats were trained to press a lever for 0.5--1.0 ml of milk reward both in the presence and absence of ambient light. 'Floating' microelectrodes were implanted in the pulvinar and lateral geniculate nuclei to allow chronic recording from single or multiple neurons over a period of 1--16 days. Thirty-one of 36 pulvinar neurons (86%) showed a consistent periodicity in the firing rate that was clearly related to certain phases of operant behavior. In the presence of ambient light, the firing rate was maximal shortly prior to or immediately after a rewarded bar press, particularly during the animal's initial contact with reward (the first lap). This burst of activity was followed by an abrupt and strong inhibition of firing which was, in most instances, associated with high voltage slow wave (6--9 c/sec) postreinforcement synchronization (PRS) of the electroencephalogram over the visual and association cortices as well as in the pulvinar. Postreinforcement inhibition of neuronal activity was also observed in the lateral geniculate. Neuronal firing in both nuclei dropped significantly below the respective mean rate observed for each nucleus during relaxed wakefulness. In the dark, however, the reward-induced inhibition was abolished in both nuclei. Moreover, some pulvinar neurons in the dark showed a conspicuous and significant increase in firing during the consummatory response (dark reversal pattern). These findings suggest that a transient but powerful inhibitory process triggered by positive reinforcement depends on visual input. Firing patterns of some pulvinar neurons were noted to be entrained not only by the rhythm of PRS oscillations (inhibitory phasing and postinhibitory discharges) but also by the much slower 3--4 c/sec rhythm of lapping and licking. Furthermore, the patterns of entrainment by initial lapping appear to be different from those observed during the later phase of the consummatory response, thus indicating that the pulvinar may receive information regarding the content of the delivery cup. No entrainment of neuronal activity was observed in the lateral geniculate. These findings reveal remarkable plasticity in the pulvinar neurons that is consistent with their role in polysensory integration.

Action Potentials↗
PubMed1978

Electrical activation of visual pathways substitutes for tonic light input in triggering EEG correlates of food reward during conditioned behavior in cats.

Cats trained to press a lever for 1 cc of milk reward normally show during the consummatory response high voltage 6--8 c/sec EEG synchronization associated with epicortical positive steady potential shift over the primary and secondary visual projections. The emergence of this postreinforcement synchronization (PRS) and Reward Contingent Positive Variation (RCPV) is known to depend upon appropriate gustatory input and presence of ambient light, although visual perception of reward and/or environment is not essential as shown in cats wearing translucent "milky" contact lenses. Training the animals in a paradigm in which a "light-off" cue signaled the availability of reward, and thus assigned positively reinforcing quality to the dark condition, also failed to restore the PRS-RCPV phenomenon in the absence of light. However, brief electrical stimuli applied to either the optic tract or the lateral geniculate nucleus substituted for unpatterned light input and fully restored the PRS-RCPV in the dark. The suprathreshold stimuli were effective only during the consummatory response. Maximum effect could be produced during a brief time period between 0.8 and 1.5 sec after the onset of consummatory response as judged by lapping activity, thus showing the specificity of the effect of visual input. Even during a relaxed wakefulness after satiation or during slow wave sleep or REM sleep the same electric stimuli were ineffective although they produced well-developed evoked potentials with all characteristic wave components. The results indicate that brain pathways utilize unpatterned i.e. noisy visual input in complex integrative processes involving gustatory input.

Animals↗
PubMed1977

Temporal patterns, their distribution and redundancy in trains of spontaneous neuronal spike intervals of the feline hippocampus studied with a non-parametric technique.

A modification of the non-parametric technique for the analysis of temporal patterns in long trains of single neuronal spike intervals has been described and tested empiracally. The technique is based on inequality testing of sequential pairs of intervals. If the second interval in a pair is longer or shorter than or equal to the first interval, a(+), a(-), and a (0) is recorded respectively in sequential bins of the computer memory. Subsequently, the long sequences of signs are arranged into transition frequency matrices which are then converted into transition probability matrices of various complexity. In this manner, the sign permutations composed of 4, 5, 6, etc. signs were studied. First of all, the theoretical distribution of various sign permutations was derived, assuming that the arrangement of intervals that generate the signs is totally independent. The theoretical distribution of signs permutations in tetragrams, pentagrams and hexagrams constitute the 'controls' with which the empirical data can be compared. In this manner, using the chi-square test, the total deviation of a studied neuronal output from an independent state can be quantified. The empirical data showed a consistent deviation from the theoretical distribution of sign permutations during REM sleep, as compared to slow wave sleep which was characterized by an almost perfect theoretical distribution of sign permutations. This indicates that slow wave sleep is associated with relaxation of constraints that are responsible for the emergence of specific patterns. In addition, redundancies in the occurrence of sign permutations, and the linear relationships between them, have been defined and tested empirically. The apparent discrepancies between the redundancies, based on theoretical symmetry in sign distribution and the linear redundancy that fits the empirical data, have been defined and discussed.

Action Potentials↗
PubMed1976

Dependence of reward contingent positive variation (RCPV) and cortical synchronization on visual input in the cat.

Cats trained to press a lever for milk reward display high amplitude low frequency electrocorticographic post-reinforcement synchronization (PRS) associated with epicortical steady potential shift, termed Reward Contingent Positive Variation (RCPV), over the parieto-occipital cortex. Previously, it was found that the PRS-RCPV phenomenon depends on unpatterned light input devoid of any conceivable information or conditional property. Although training in the dark most likely eliminated the "novelty" factor and the resulting orienting reaction to "light off" as a cause of PRS-RCPV suppression, a possibility could not be excluded that the absence of light had a negatively reinforcing property preventing the emergence of PRS-RCPV. Hence, in the present study an experimental paradigm was used in which "light off" and/or "tone on" cues signalled the availability of reward, the "light off" periods extending through the consummatory response. Seven out of 9 cats, despite 2-4 months of daily training, and 85% correct timing of bar press performance, never showed a PRS-RCPV response (one animal showed only sporadic and poorly developed patterns.) However, when the light was turned on during consumption, in 85% of such tests a fully developed PRS-RCPV emerged in a stimulus-bound manner. One animal was an exception and showed PRS-RCPV both in the absence and presence of light. It was concluded that light input plays a crucial role in the emergence of the PRS-RCPV phenomenon and therefore also participates in the integration of gustatory input.

Animals↗
PubMed1976

Dose-dependent dual effect of morphine on electrophysiologic correlates of positive reinforcement (reward contingent positive variation: RCPV) in the cat.

In cats trained to press a lever for milk reward, the postreinforcement EEG synchronization (PRS) and the associated epicortical steady potential shift, known as "Reward Contingent Positive Variation (RCPV) restricted to the occipital cortex, were studied prior to and after administration of morphine sulfate. Contrary to what has ordinarily been described as a typical feline response to morphine, such as restlessness, aggressiveness, rage, and exaggerated startle reaction to environmental stimuli, associated with an increased tonus of the brainstem-hypothalamic arousal system and desynchronized EEG patterns, doses of 0.1-0.4 mg/kg, IM, caused a strong monophasic enhancement of the PRS-RCPV phenomenon. Doses of 0.6-1.0 mg/kg, IM, had clearly a biphasic action: the initial enhancement of the PRS-RCPV responses was followed by their strong suppression. Chlorpromazine (0.1-1.6 mg/kg, i.e.) promptly restored the EEG responses. During the peak effect of the enhancing doses of morphine, the reward-related EEG phenomena also occurred prior to or after the nonrewarded bar press when the animals licked the empty cup. This dissociation of the PRS-RCPV from consumption was much more conspicuous in animals whose control frequency of the PRS oscillations was higher, and after morphine showed more significant slowing. Despite the strong facilitation of the PRS-RCPV in the presence of light, morphine, in contrast to LSD-25, was not able to restore the reward-induced phenomena in the dark.

Animals↗