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Biomedical subjects

J Panksepp

Publications and source records attributed to J Panksepp.

At least 55 records · Page 3Linked to original sources
PubMed1990

Perinatal decortication impairs performance on an 8-arm radial maze task.

Two experiments evaluate the role of the neocortex in rodent spatial learning. In Experiment 1, perinatally decorticated rats and sham-operated controls began ten training sessions at day 200 on an 8-arm radial maze. Decorticated rats made more errors than controls, but showed improvement by the tenth session. In the second experiment, training was extended to determine whether decorticates could eventually match control performance levels if given sufficient training. Spontaneous activity levels were also recorded and compared to maze performance to investigate the relationship between poor performance on the radial maze and activity. More than half of the decorticates reached criterion performance. Decorticates had significantly elevated spontaneous activity levels when compared to controls, and the magnitude of this hyperactivity was related to performance deficits on the radial maze. These results suggest that with extended training decorticates can learn a spatial task. Performance deficits may reflect the hyperactive tendency of decorticates rather than a specific impairment of spatial learning abilities.

Animals↗
PubMed1990

Nimodipine alters acquisition of a visual discrimination task in chicks.

Chicks 5 days old received intraperitoneal injections of nimodipine 30 min before training on either a visual discrimination task (0, 0.5, 1.0, or 5.0 mg/kg) or a test of separation-induced distress vocalizations (0, 0.5, or 2.5 mg/kg). Chicks receiving 1.0 mg/kg nimodipine made significantly fewer visual discrimination errors than vehicle controls by trials 41-60, but did not differ from controls 24 h later. Chicks in the 5 mg/kg group made significantly more errors when compared to controls both during acquisition of the task and during retention. Nimodipine did not alter separation-induced distress vocalizations at any of the doses tested, suggesting that nimodipine's effects on learning cannot be attributed to a reduction in separation distress. These data indicate that nimodipine's facilitation of learning in young subjects is dose dependent, but nimodipine failed to enhance retention.

Age Factors↗
PubMed1989

Opiate effects on social behavior of juvenile dogs as a function of social deprivation.

The relationship between opioids and social behavior was examined by administering morphine (an opioid agonist) and naloxone (an opioid antagonist) to juvenile dogs and measuring various social behaviors (e.g., tail wagging) in a large room. Drugs were administered following social deprivation and nondeprivation. It was hypothesized that morphine would ease effects of social deprivation while naloxone would result in behavior typical of untreated socially-deprived dogs. Social deprivation (24 hr) resulted in more contact with the experimenter and increased tail wagging relative to nondeprivation. Morphine (0.25 mg/kg) resulted in more contacts with the experimenter and entrances into the "experimenter's area" relative to vehicle injections. Further, morphine decreased and naloxone increased tail wagging in the dog's area and there was a significant social condition X drug interaction for that measure. Naloxone (0.25 mg/kg) increased wagging following nondeprivation while morphine decreased wagging following deprivation. These data support the hypotheses that social deprivation can increase social behaviors, and that social behavior is regulated by activity in brain opioid systems.

Animals↗
PubMed1989

Effect of chronic neonatal morphine and naloxone on sensorimotor and social development of young rats.

Chronic morphine treatment of newborn Long-Evans rat pups between 3-26 days of age (thrice daily starting with 0.5 mg/kg, increased daily by 0.5 mg/kg to 10 mg/kg) led to lags of 1 to 3 days in physical development (body weights and eye opening times) and motor coordination (catalepsy test, grasping, swimming). Chronic naloxone treatment (5 mg/kg administered thrice daily from day 3-26), in contrast, led to modest gains in development on a number of measures (body weights, vaginal opening). Morphine animals also lagged behind controls and naloxone-tested animals in social behaviors, such as homing and play. Chronic naloxone did not block or retard social development; in fact naloxone-treated animals exhibited more rapid acquisition of homing behavior than controls.

Animals↗
PubMed1987

Sensory modulation of juvenile play in rats.

A series of experiments was conducted to determine the extent to which somatosensory stimulation is necessary for the elaboration of juvenile play in rats. Anesthetization of the dorsal body surface of juvenile rats with xylocaine reduced the frequency of pinning, an indicator variable for play, by 35% to 70%, while motivation to play, as measured by dorsal contacts, an index of play solicitation, remained largely intact. These data suggest that dorsal body surface anesthetization impairs the ability of juvenile rats to perceive and/or respond to playful gestures. When untreated animals were paired with xylocaine-treated animals, the xylocaine-treated animals consistently pinned the untreated pups more than vice versa, further suggesting that somatosensation may be involved in the establishment and/or maintenance of play dominance relations. A preliminary examination assessing potential involvement of other modalities in the play of rats was also conducted, with the data suggesting a possible role for audition in the play of this species.

Agonistic Behavior↗
PubMed1987

Brain opioids and autism: an updated analysis of possible linkages.

Considerable clinical evidence suggests that autistic children lack the normal ability or desire to engage others socially, as indicated by their poor social skills and inappropriate use of language for communicative purposes. Specifically, these children seem to lack normal amounts of social-emotional interest in other people, leading perhaps to a decreased initiative to communicate. This paper summarizes experimental evidence supporting a neurological theory, which posits that autism, at least partially, represents in the brain, such as brain opioids. These substances modulate social-emotional processes, and the possibility that blockade of opioid activity in the brain may be therapeutic for early childhood autism is discussed.

Autistic Disorder↗
PubMed1987

Juvenile play in the rat: thalamic and brain stem involvement.

Discrete electrolytic lesions of the parafascicular area of the thalamus (PFA) or posterior thalamic area (TP) reduced the frequency of pinning, an indicator variable for rough-and-tumble play in juvenile rats, while largely sparing motivation to play. Similar sized lesions placed within the ventrobasal thalamic area (VBT) had minimal effects on both pinning and measures of play solicitation. Lesions placed within the ventrolateral aspect of the brain stem also markedly reduced pinning, while having no effect on indices of play motivation. Although tests designed to assess the extent to which the observed play deficits may be attributable to a loss of somatic acuity proved inconclusive, the overall pattern of results were not inconsistent with positing a role for these neural areas in relaying somatic stimuli relating to playful intent.

Age Factors↗
PubMed1987

Perinatal leupeptin retards subsequent acquisition of a visual discrimination task in chicks.

Recent discoveries that calcium sensitive proteases (calpains) may play an important role in memory led to investigation of the effects of leupeptin, a calpain inhibitor, on learning. Intracerebral injections of either 0.9% saline, 80 micrograms aprotinin, 306 micrograms glutamate, or 8 or 80 micrograms leupeptin were administered to 95 two-day-old chicks. On Day 10 posthatch, animals were then tested on a task requiring discriminations between pebbles and food pellets. Chicks receiving 8 or 80 micrograms leupeptin or 306 micrograms glutamate were found to be deficient in acquiring the task. Aprotinin, a control serine protease inhibitor, did not retard discrimination learning. None of the drugs tested altered body weight or gross visual skills. These results suggest that retardation produced by leupeptin is not due to nonspecific changes in protease activity, visual competency, or growth. The reported results confirm earlier reports of leupeptin-induced memory impairments in rats.

Animals↗
PubMed1985

Energy balance and play in juvenile rats.

These experiments systematically analyzed the relationship between energy balance and play in the juvenile rat. As expected, depriving pups of food for 24 hours or more resulted in a reliable reduction in levels of play, with a single meal being sufficient to return play to baseline levels. Consumption of saccharin did not reverse deprivation-induced reductions of play. It is proposed that the food-induced restoration of play in food-deprived pups is perhaps reflective of normal satiety and may be useful in screening putative "satiety agents." Naloxone, cholecystokinin and bombesin, all putative satiety agents, were tested for their ability to reverse deprivation-induced reduction of play. Only bombesin was marginally effective in increasing play of food deprived rats.

Adaptation, Physiological↗
PubMed1985

Effects of clonidine and yohimbine on the social play of juvenile rats.

The social play of juvenile rats was observed following administration of either the alpha-2-adrenergic agonist clonidine (0.1, 0.5, 1, 5, 10, and 50 micrograms/kg) or antagonist yohimbine (0.5, 1, 2, and 5 mg/kg). Using pins (one animal on its back with the other on top) as the dependent measure, we found that clonidine reliably reduced the amount of play at all but the lowest dose tested, while yohimbine had no effect at any but the highest dose. In addition, we tested a clonidine-yohimbine interaction to assess neurospecificity of the results. While yohimbine alone (0.5 mg/kg) had no effect on play, it partially reversed the clonidine-induced suppression, indicating that the effect may be mediated to some degree through an alpha-2-adrenergic mechanism.

Animals↗
PubMed1985

Effects of quipazine and methysergide on play in juvenile rats.

Social play of juvenile rats was analyzed following administration of either the serotonin receptor agonist quipazine (1, 2.5, 5 and 10 mg/kg) or the antagonist methysergide at the same doses. Quipazine reduced pinning at all doses, while methysergide did so at only the highest two. An interaction study using the lowest doses of the agents used above, indicated that methysergide could reverse quipazine induced reductions of play. Thus, the quipazine effect was probably mediated through a serotonin receptor; however, the role of serotonin in play appears to be a general modulatory one rather than a specific influence on play.

Animals↗
PubMed1985

The prolonged effects of naloxone on play behavior and feeding in the rat.

The effects of naloxone on social play and feeding behaviors of postweanling and adult Long-Evans hooded rats were studied. Administration of 1.0, 5.0, or 10.0 mg/kg naloxone reduced play in a dose-related fashion. The effects of a 5.0-mg/kg dose of naloxone could be detected at least 3 h after administration, in terms of both a decrease in social behavior and decreased food consumption, indicating that the behavioral time course of naloxone effects is greater than some reports in the pharmacokinetic literature suggest.

Animals↗
PubMed1985

Opiates and play dominance in juvenile rats.

Social play between pairs of individually housed juvenile rats was studied by measuring pinning frequencies occurring during rough-and-tumble play. Low doses of morphine increased play, and opioid blockade with naloxone reduced play. Dominance, as measured by which pinned which most, was markedly reduced by naloxone and slightly increased by morphine. These effects were most apparent when animals were treated with these drugs continuously from the beginning of play testing. Although the respective drugs tended to reverse established dominance patterns (i.e., naloxone made dominant animals more submissive, and morphine made submissive animals more dominant), it was apparent that previously established social learning limited the effectiveness of these manipulations. In general, the results are consistent with the proposition that brain opioids are important in controlling the vigor of social relations.

Animals↗
PubMed1985

Dorsomedial diencephalic involvement in the juvenile play of rats.

Lesions of either the dorsomedial thalamus (DMT) or the parafascicular region of the thalamus (PFA) reduced rough-and-tumble social play in juvenile rats, as measured by frequency of pinning. Pinning was reduced by 33% in pups with DMT lesions and by 73% in pups with PFA lesions. Although PFA lesions had minimal effects on average pin durations, DMT pups had pins that were, on average, 105% longer than those of controls. Lesions of the PFA, but not DMT, also reduced play solicitation behaviors. Pups with PFA lesions were also insensitive to the play modulating effects of both naloxone and morphine. DMT pups were sensitive to the facilitatory effects of morphine, but naloxone was without effect in these animals. Control studies designed to evaluate general behavioral competence showed that the observed lesion effects were relatively specific to play.

Animals↗
PubMed1984

The psychobiology of play: theoretical and methodological perspectives.

The social play of pairs of juvenile rats can be brought under tight experimental control using social deprivation, and it can be objectively quantified by measurement of pinning behavior. Research and conceptual issues concerning this paired-encounter procedure are summarized, including issues related to measurement, gender differences (and the absence thereof), relations between play and aggression, the regulatory processes interacting with and underlying play, the neurochemical and neuroanatomical substrates of play, the functions of play in dominance and other adult behaviors. Existing results suggest the operation of a harmoniously operating brain process which generates a unique emotive brain process that is appropriately referred to as social play. Although the concept of play remains to be adequately defined, the position is advocated that rigorous psychobiological analysis will ultimately provide an empirical definition based upon neural circuit characteristics. Analysis of the underlying circuits may help reveal the manner in which more complex levels of behavioral competence arise ontogenically, and work in the area may yield clues to the genesis of several psychopathologies.

Age Factors↗
PubMed1983

The role of brain norepinephrine in clonidine suppression of isolation-induced distress in the domestic chick.

Distress vocalizations (DV) induced by social isolation were measured in 1-day-old domestic chicks after intracerebroventricular injections of drugs believed to exert their effects through the noradrenergic system. The alpha-adrenoreceptor agonist clonidine reliably suppressed DV rates at doses low as 0.08 micrograms. When given alone, phentolamine, phenoxybenzamine, propranolol, sotalol, and yohimbine (adrenoreceptor antagonists) did not reliably alter DV rates at doses that were not toxic. The clonidine DV suppression was reliably reversed by yohimbine (1.75 micrograms), but by none of the other adrenoceptor antagonists or naloxone. 6-Hydroxydopamine at doses as high as 120 micrograms, which essentially eliminated forebrain norepinephrine, failed to suppress DV rates reliably when given alone and, when given in combination with clonidine (0.1 micrograms) or morphine (0.05 micrograms), failed to reverse the severe DV suppression imposed by these drugs. The results suggest that clonidine suppresses DV rates in or by some means other than prejunctional alpha 2-adrenoreceptor stimulation.

Animals↗
PubMed1983

Fenfluramine anorexia: a peripheral locus of action.

In a series of feeding pattern studies, amphetamine was shown to produce a period of complete anorexia often followed by a broken nibbling pattern of eating. Fenfluramine produced a regular feeding pattern in which a depressed meal size was not compensated for by an increase in meal frequency. The disproportionate lengthening of the post-meal interval relative to meal size was accompanied by a decrease in the rate of gastric emptying. Fenfluramine was most effective in lengthening post-meal interval when administered immediately after a meal, and was progressively less effective when the injection was delayed, allowing time for gastric emptying to occur. Amphetamine was shown to have similar but less pronounced effects, corresponding to its weaker effects on gastric emptying. Midbrain raphe lesions that abolished the fenfluramine effect on short-term intake of food-deprived rats did not attenuate fenfluramine's effect on gastric emptying, nor did the lesions attenuate the anorectic effect of fenfluramine on ad lib food intake. Lateral intracerebroventricular administration of fenfluramine not reduce feeding. These results suggest that fenfluramine controls feeding primarily by short-term signals related to food in the upper gastro-intestinal tract.

Animals↗