Irving J. Goodman

Dopaminergic nature of feeding-induced behavioral stereotypies in stressed pigeons☆

Dopamine dependence of feeding-induced behavioral stereotypies (FIBS) was demonstrated by FIBS facilitation following chronic treatment with a dopamine (DA) agonist, apomorphine, and by FIBS inhibition following the administration of haloperidol, a DA antagonist. However, individuals that emitted FIBS were differentiated from those not emitting FIBS not by assayed telencephalic DA concentrations alone but by a higher stereotyping index (SI), a score positively related to the ratio of telencephalic DA-norepinephrine (NE) concentrations. These latter findings support the hypothesis of Antelman and Caggiula [3] which indicates that a catecholamine interaction in the brain serves to facilitate or inhibit some behavioral actions associated with stress.

Amphetamine and apomorphine induced stereotyped behavior in adult pigeons

Induced pecking by apomorphine has been reported in the past in pigeons. Research has supported the view that its mechanisms are, at least in part, dopaminergic in nature. This study tested the ability of amphetamine to induce stereotyped pecking. Amphetamine was found effective within a narrow dose range, displaying a relatively low potency for stereotyped pecking and high toxicity compared with apomorphine. The latter drug produced appreciable pecking rates that were proportional to dose over a wide range. The description of other stereotyped responses of the head and mouth, including swallowing, mandibulating and head shaking, which are produced by both of these drugs, supports the idea that common neural mechanisms are involved. It was suggested that the qualitative and quantitative measures afforded by pecking and non-pecking stereotyped behavior in the pigeon make this a useful animal model for the study of the mechanisms of stereotyped behavior.

Corticotropin-releasing factor and defensive withdrawal : Inhibition of monoamine oxidase prevents habituation to chronic stress

There is growing evidence for a role of extrahypothalamic corticotropin-releasing factor (CRF) in the pathogenesis of anxiety. A modified form of the defensive withdrawal test was used to test the anxiogenic effects of acute administration of intracerebroventricular (1 microg, i.c.v.) CRF in adult male rats. Habituation to the mild stress of daily handling and subcutaneous (s.c.) saline injection over 2-6 weeks abolished the anxiogenic effects of exogenous CRF. At 6 weeks this habituation also resulted in attenuation of baseline withdrawal behavior. CRF receptor binding was significantly decreased in the amygdala of chronically handled animals and may have been responsible for this habituation phenomenon. Comparison of rats treated with the monoamine oxidase (MAO) inhibitor, phenelzine [3 mg/kg, s.c., daily for 2-6 weeks] to the saline-treated groups revealed a failure to habituate to the chronic handling, as the baseline withdrawal (after injection of artificial CSF) by the phenelzine-treated animals was not different from the baseline withdrawal by unhandled rats. In comparison to rats treated chronically with saline, phenelzine treatment enhanced the anxiogenic effect of CRF. In summary, habituation to a mild chronic stress decreased baseline defensive withdrawal. Intraventricular administration of CRF produced an anxiogenic response as measured in the defensive withdrawal test, which was lost through exposure to mild chronic stress. Two or 6 weeks of daily handling and SC saline injection caused a downregulation of CRF receptors in the amygdala, which could account for the behavioral habituation and the loss of CRF-induced defensive withdrawal. Phenelzine treatment concurrent with mild chronic stress prevented habituation and maintained the anxiogenic effect of CRF in spite of the downregulation of CRF receptors in the amygdala.

Changes in locomotor activity following basal forebrain lesions in the pigeon

Adult male pigeons (Columba livia) were used to study the effects of basal forebrain lesions upon a measure of responsiveness to the environment, locomotor activity. Daily activity as well as food and water intake and body weight were recorded for Ss through various experimental test phases. Significant reductions occurred in activity scores of all but one experimental S following lesioning, with no changes occurring in controls during comparable test periods. Intrasession analyses of activity showed a tendency for lesion-produced activity depression to affect initial period scores most severely. Small lesions were identified in the parolfactory lobe and paleostriatum or anterior (ventral) thalamic and hypothalamic areas. A possible neuroanatomical explanation for these results was discussed.

Lesion-produced telencephalic catecholamine imbalances and altered operant pecking rates in pigeons.

Pigeons with bilateral neurotoxic or electrolytic lesions within ventral mesencephalon, in nucleus tegmenti pedunculo pontinus (TP) (equivalent to substantia nigra) or area ventralis of Tsai (AVT), were found to have catecholamine (CA) depletion in the telencephalon, including the paleostriatum augmentatum (PA) and lobus parolfactorius (LPO), avian basal ganglia rich in CA. Joint telencephalic concentrations of dopamine (DA) and norepinephrine (NE) within individuals were found to vary with sustained fixed interval (FI) pecking rate increases or decreases following surgery. Low (below 75% of controls) DA/normal NE concentrations were found in individuals showing a marked reduction in their key pecking rates; low DA/low NE concentrations were found in individuals showing a marked increase in their pecking rates. The fit of these data with the NE-DA interaction hypothesis of Antelman and Caggiula [2] was acknowledged but the nature of that interaction remains to be clarified.

Fixed interval responding by pigeons following damage to corpus striatal and limbic brain structures (paleostriatal complex and parolfactory lobe)

Abstract Twenty-three adult pigeons were trained on a fixed-interval 2 min schedule for grain reinforcement. After responding stabilized on the fixed-interval schedule, groups of animals were either lesioned bilaterally in paleostriatal complex (PC), parolfactory lobe (LPO), neostriatum and/or ectostriatum (N/E controls) or received no lesioning current at all (sham controls). Analysis of reponse timing patterns and response rates indicated significant declines only in experimental animals; PC group quarter life scores and rates returned to normal after 6 days, LPO group quarter life scores returned to preoperative levels after 16 days and response rates remained significantly depressed through 21 test days. PC pigeons exhibited short-lived postsurgical signs of somnolence with sustained docility. LPO pigeons, in contrast, exhibited early and sustained defensive behavior. It is hypothesized that subtelencephalic PC inputs and/or outputs may be more critical than neostriatal inputs in paleostriatal control of operant responding and/or arousability. The results suggest that the PC and LPO, two basal forebrain structures, are separable both anatomically and functionally.

Modified retention of punishment with unilateral, single-pulse stimulation of amygdala but not hippocampus

Following surgical preparation, male hooded rats were trained to descend from a platform and cross a grid floor for food. Upon reaching a performance criterion, a single treatment trial was administered. Upon descent from the platform on the treatment trial, the subjects received foot-shock, which was followed immediately by the delivery of a single.5-msec, 100-μA pulse of intracranial stimulation delivered unilaterally to either the amygdala or dorsal hippocampus. Performance on recall tests administered 24 and 48 h after the treatment trial revealed memory alteration in amygdala-stimulated subjects but not in hippocampus-stimulated or control subjects. These results suggest that the amygdala and hippocampus may have different roles in memory processing. The contribution of amygdala in memory processing may involve affective quality and quantity of specific events. A new interpretation of the nature of memory modification by electrical brain stimulation is discussed.

Correlated behavioral and cardiac activity: Amygdala mediated amnesia or fear gradients

Abstract Little information concerning specific brain structures that are involved in the formation of autonomic and skeletal indexes of memory can be gleaned from past electroconvulsive shock studies. The present study examined the effects of a single pulse, intracranial stimulation (ICS) delivered unilaterally to the amygdala at subseizure levels on skeletal and cardiac indexes of memory. Male rats were prepared with chronically implanted EKG and bipolar ICS electrodes. Food deprived subjects were trained to descend from a platform and cross a grid floor to approach food. After meeting a performance criterion, a treatment trial consisting of footshock followed by ICS was administered. Tests 24 and 48 hrs later revealed significant memory modification for skeletal and autonomic responses, but at a lower threshold for the former. There was a significant correlation between skeletal and cardiac indexes. The degree of memory modification observed was dependent upon ICS intensity. The role of the amygdala in the processing of aversive events was discussed, and an alternative interpretation of ICS intensity dependent amnesia gradients was proposed.

Attack-target attributes and pigeon aggression: Accessibility, vocalization, and body movements

Characteristics of the attack-target in laboratory tests appear to greatly influence the tendency for aggression to be initiated, maintained, and stopped. To address this question, accessibility, target movement, and vocalization among pigeon conspecifics were investigated in two different aggression tests: 1) paired aggression (PA); and 2) schedule-induced aggression (SI). In the PA test, dominant and subordinate roles formed quickly, and soon aggression episodes started to decline. In part, the subordinates yielding behavior appeared to discourage attack. The significance of the target birds behavior on attack frequency was borne out by the finding in the SI test that pigeons attacked a shielded, live, active target more often than a passive one. Furthermore, using a specially constructed stuffed pigeon in the SI test, results indicated that programmed, combined aggressive vocalization and body movement evoked most attacks with the VT schedule, vocalization alone evoked the next highest number of attacks, body movement alone the third most, and combined silence and immobility the least attacks. These findings provide a basis for explaining some past reported results associated with target features and a means for selecting other target features for future study.