Paleostriatum Augmentatum Research Articles

Relations between dopaminergic and GABAergic mechanisms in avian brain

Summary In adult fowls and young chicks the relations between dopaminergic and GABAergic mechanisms in the paleostriatum augmentatum and brain-stem were studied. Intraventricular injection or infusion into the paleostriatum augmentatum of EOS, an inhibitor of GABA-transaminase (GABA-T) activity, at doses which increase GABA content, antagonized apomorphine-induced stereotyped behavior. In contrast, drugs inhibiting GABAergic transmission, i.e. bicuculline and tetanus toxin, given into the paleostriatum augmentatum or into the lateral ventricle produced an intense pattern of stereotyped movements. Subacute oral treatment with 1-DOPA produced concomitant with an increase in dopamine content in the paleostriatum augmentatum and brain-stem, a significant increase in glutamate decarboxylase (GAD) activity and a rise in the GABA content of these areas. GABA-T activity was inhibited in the paleostriatum augmentatum. In conclusion, the present experiments favour the existence of a strict relation between the dopaminergic and GABAergic mechanisms, i.e. an inhibitory GABAergic tone on dopaminergic neurons within the paleostriatum augmentatum seems to exist and a biochemical link between the two systems consisting in an increased GABA synthesis after a subacute treatment with 1-DOPA.

Projections of a telencephalic auditory nucleus-field L-in the canary.

Anterograde projections of a telencephalic auditory area - field L of the neostriatum - were traced in canaries, Serinus canarius. Field L was defined as the neostriatal projection of nucleus ovoidalis of the thalamus. Using amino acid autoradiography, two efferent projections of field L and adjacent neostriatum were observed: (1) a projection to the medial and ventral borders of nucleus hyperstriatum ventrale, pars caudale (HVc) and (2) a smaller projection to medial paleostriatum augmentatum (PA). When autoradiographic injection sites included neostriatum postero-ventral to field L, a projection to archistriatum outlining the anterior and ventral borders of the nucleus robustus archistriatalis (RA) resulted. Injection sites that included neostriatum antero-lateral to "L" gave rise to projections to the interior of HVc proper. Above background numbers of silver grains were consistently observed over caudal dorso-lateral portions of nucleus ovoidalis. Following lesion of field L and adjacent neostriatum, argyrophilic degeneration was traced to medial PA and to a shelf of neostriatum underlying HVc. All observed anterograde projections were ipsilateral. Two of the nuclei outlined by neostriatal projections in this study, HVc and RA, have important roles in the motor control of canary song (Nottebohm et al., '76). The development of song is dependent on auditory information. Auditory-vocal neural connections described here may be involved in song learning.

Prosencephalic pathways related to the paleostriatum of the pigeon ( Columba livia)

Afferent connections of the avian paleostriatal complex were traced by means of anterograde and retrograde transport of horseradish peroxidase (HRP). The paleostriatum augmentatum (PA), a cell field comparable to mammalian caudate nucleus and putamen, was found to receive projections from a distinct population of telencephalic neurons in the temporal-parietal-occipital (TPO) and lateral cortical (CDL) areas of the neostriatum. TPO neurons, in turn, were found to receive projections from the contralateral ventral archistriatum (Av) and from neurons in the ipsilateral frontal neostriatum adjacent to the rostal portion of the ectostriatum (E). The paleostriatum primitivum (PP), comparable to globus pallidus, receives projections from the small cells of PA, and from neurons in the anterior nucleus of the ansa lenticularis (ALa). ALa appears similar to the mammalian subthalamic nucleus of the basis of its afferent and efferent connections. In addition, PA was also found to receive extensive projections from the nucleus tegmenti pedunculopontinus of the midbrain, a dopamine-containing cell group. Evidence of projections from the nucleus dorsointermedius posterior (DIP), a cell group receiving both cerebellar and paleostriatal afferents, to the rostral telencephalon was also found.

Behavioural, electrocortical and body temperature effects of cholera toxin

In young chicks intrahypothalamic infusion of cholera toxin produced a dramatic and dose-dependent increase in motor activity. Similar effects were also obtained in adult fowls after injection of cholera toxin into the third cerebral ventricle, the hypothalamus or the paleostriatum augmentatum. Electrocortical changes consisted of a slight desynchronization during the hypermotor activity and were preceded, when the highest intraventricular doses were used, by a short period of slower frequency and higher amplitude potentials. Intraventricular and intrahypothalamic but not intrastriatal injection of cholera toxin produced a typical biphasic hyperthermic response.

Hormone concentrating cells in vocal control and other areas of the brain of the zebra finch ( Poephila guttata).

Using the autoradiographic method in the zebra finch (poephila guttata), areas of the brain were identified which contain cells which accumulate testosterone. Among these areas are the caudal nucleus of the hyperstriatum ventrale, nucleus intercollicularis of the midbrain, and the tracheosyringeal portion of the hypoglossal nucleus of the medulla (nXIIts). These three are known to control or influence androgen dependent song and other vocalizations of passeriform birds, and nXIIts is composed of the motoneurons innervating the vocal (syringeal) muscles. Other areas containing hormone-concentrating cells are the medial preoptic area, nucleus periventricularis magnocellularis of the hypothalamus, dorsal infundibular layers, dorsomedial thalamus, lateral septum, magnocellular nucleus of the anterior neostriatum, periventricular medial neostriatum, nucleus taeniae of the archistriatum, and ventral paleostriatum augmentatum. Accumulation by cells in the preoptic area, hypothalamus, and limbic forebrain is consistent with a general vertebrate pattern of distribution of brain cells which accumulate sex steroids. Some of these same areas may be involved in the control of androgen dependent events such as courtship, copulation, aggression, and feedback regulation of the hypophysis.

The organization and projections of the paleostriatal complex in the pigeon (Columba livia).

AbstractThe paleostriatal complex (PC) of the pigeon lies in the basolateral wall of telencephalon, and consists of three major subdivisions: the paleostriatum augmentatum (PA), paleostriatum primitivum (PP), and nucleus intrapeduncularis (INP). The lobus parolfactorius (LPO) lies on the medial aspect of PA and has often been considered to be part of PA. The present study of afferent and efferent connections of the paleostriatal complex supports earlier previous suggestions that the PC is directly comparable to the basal ganglia of mammalia. High concentrations of acetylcholinesterase were found in the PA, LPO and INP. Intense yellowish green fluorescence, probably dopamine, was confined to the PA and LPO.Stereotaxic lesions were placed in either the dorsal ventricular ridge structures above the PC (neo‐ and hyperstriatum), PA, LPO or PP‐INP, and animals sacrificed from one to six days postoperatively. The brains were stained with the Fink‐Heimer methods for the demonstration of degenerating axons and terminals. The region of the neo‐ and hyperstriatum was found to project upon the PA, in a seemingly topographic manner. PA was found to project topographically upon the PP and INP. In contrast, the LPO contributed to the medial forebrain bundle, terminating in the rostral lateral hypothalamus. LPO does not appear to project to the PP or INP.Lesions of PP‐INP resulted in massive degeneration of a descending tract, the ansa lenticularis. Terminal degeneration was found in the anterior and posterior nuclei of the ansa lenticularis of the ventral diencephalon, nucleus dorsalis intermedius posterior and nucleus spiriformis lateralis of the dorsal thalamus, and the nucleus tegmenti pedunculopontinus pars compacta et disseminata of the isthmic tegmentum. In these several features of histochemical and hodological organization the PC alone appears similar to the caudate‐putamen and globus pallidus complex of mammalian brains.More specifically, the PA resembles the caudate‐putamen, whereas PP and INP resemble the external and internal divisions of the globus pallidus, respectively. Similarities and differences between avian and mammalian brains, and the relationship of the present study of the PC and previous studies of the dorsal ventricular ridge structures are discussed (Karten, '69; Nauta and Karten, '70).

Effects of catecholamines and adenosine derivatives given into the brain of fowls.

1. Adult fowls (Gallus domesticus) with cannulae chronically implanted into the IIIrd cerebral ventricle and various other sites of the brain received microinfusions or injections of catecholamines, adenosine, 3',5'-cyclic AMP or its dibutyryl derivative. The effects of these substances on behaviour, electrocortical activity and body temperature were studied.2. Behavioural and electrocortical sleep with fall in body temperature were obtained with intraventricular noradrenaline, alpha-methylnoradrenaline and isoprenaline; dopamine was ineffective. The doses required to elicit sleep were smaller than those affecting body temperature. Following mebanazine, the effects of noradrenaline were prolonged and doses of dopamine, previously ineffective, lowered body temperature and induced behavioural and electrocortical sleep.3. Noradrenaline, alpha-methylnoradrenaline, isoprenaline and dopamine infused into the hypothalamus induced sleep and lowered body temperature. Effective doses of noradrenaline, alpha-methylnoradrenaline and isoprenaline infused into the hypothalamus were one-twentieth to one-fifth those for intraventricular injection. Tachypnoea developed with isoprenaline and dopamine. Additionally with dopamine, there was deviation of the head to the contralateral side, together with repetitive jerking movements of the head. These effects were prolonged and intensified by mebanazine, whereas the involuntary movements with dopamine were greatly reduced by haloperidol.4. Involuntary movements, but without sleep, were induced by infusing dopamine into the paleostriatum augmentatum; noradrenaline infused into this site was ineffective.5. In three of five fowls pretreated with aminophylline, 3',5'-cyclic AMP infused into the hypothalamus induced behavioural and electrocortical sleep; without aminophylline pretreatment, 3',5'-cyclic AMP was ineffective. Adenosine infused into the hypothalamus, following pretreatment of fowls with aminophylline, consistently induced behavioural and electrocortical sleep. Dibutyryl cyclic AMP infused into the hypothalamus of intact fowls elicited behavioural arousal, followed by bursts of electrocortical spikes (6 Hz) over both cerebral hemispheres, spikes subsequently becoming regular at 1 Hz. Clonic limb and body movements occasionally accompanied the bursts of spike activity, infrequently developing into convulsions. In fowl encéphale isolé preparations, in which dibutyryl cyclic AMP was infused into the hypothalamus, spike activity was confined to the ipsilateral hemisphere.

Effect of oxotremorine on the acetylcholine content of whole brain and various brain regions in the pigeon.

Oxotremorine (0.125 mg/kg) produces a significant increase in total acetylcholine content in whole pigeon brain. The contribution of different regions to this increase varies. The largest increase occurs in the nucleus basalis (paleostriatum augmentatum), a region which is highly involved in motor control. The mechanism by which oxotremorine increases the acetylcholine content of brain and the causal relationship between the rise in acetylcholine content and tremor are discussed.

The accessory olfactory bulbs and the lateral telencephalic wall of the rat-fish, Chimaera.

AbstractThe lateral telencephalon of Chimaera possesses several unique features but also has nuclei and fiber systems homologous with those of other sub‐mammalian vertebrates. Ventricular ridges, similar to those of reptiles, are quite evident. Accessory olfactory bulbs are associated with the dorsal and ventral parts of each olfactory bulb. These contribute to the lateral olfactory tract.The internal granular layer caudal to the olfactory and the accessory bulbs blends with the anterior olfactory nucleus. Caudal to this nuclear area, the nuclei of the rostral telencephalon are well differentiated.Nuclear areas distinguishable in the lateral hemisphere include: the primordial dorsal pallium, the primordial piriform cortex, the primordial striatal and amygdaloid nuclei, and the lateral zone of the olfactory tubercle. These areas replace dorsal, dorsolateral, ventrolateral and ventral parts of the anterior olfactory nucleus, respectively. The primordial striatum is subdivided into hyperstriatum, neostriatum, paleostriatum augmentatum and paleostriatum primitivum. The amygdaloid area has anterior, corticomedial and basolateral nuclear groups. The basolateral area is best differentiated. The hyperstriatum forms a rostral ventricular eminence; the basolateral amygdaloid nucleus is present in a larger caudal ventricular ridge.Fiber tracts of the lateral wall include the lateral olfactory tract, the lateral corticohabenular tract, the lateral forebrain bundle and the stria terminalis. Nuclei of medial and lateral walls are interrelated through the hippocampal and the anterior commissures.

Spreading depression in the striatum and optic lobes of the chicken

The properties of spreading depression (SD) in cerebral hemispheres and the optic lobe were studied in 30 chickens under allobarbital anesthesia (40 mg/kg). Using multiple capillary electrodes the slow potential change of SD evoked by micro- injection of 25%KCI was recorded from the hyperstriatum, neostriatum, ectostriatum and paleostriatum. Whereas typical slow potential changes (11 mV negativity, 35 sec duration at 50% maximum) were found in the hyperstriatum and neostriatum, SD completely failed to enter the ectostriatum and paleostriatum primitivum, and appeared irregularly and with reduced amplitude in the border region between the above structures. Microinjections of 25% KCI into the paleostriatum augmentatum and optic lobe usually elicited a local negative potential, although spreading slow potential changes of the SD type were also observed exceptionally. It is proposed that the SD susceptibility of different regions of the chicken brain is directly proportional to the surface of somatodendritic membranes and indirectly proportional to the density of myelinated fibers per unit volume of tissue.

The ascending auditory pathway in the pigeon ( Columba livia) II. Telencephalic projections of the nucleus ovoidalis thalami

Summary 1. The nucleus ovoidalis of the pigeon is a major diencephalic terminus of the brachium of the inferior colliculus (nucleus mesencephali lateralis, pars dorsalis). 2. The fiber degenerations following stereotaxic lesions of the nucleus ovoidalis were studied with the Nauta-Gygax and Fink-Heimer methods for degenerating axons and boutons terminaux. 3. Efferent axons of the nucleus ovoidalis form the medial portion of the fasciculus prosencephali lateralis and pass through the medial part of the paleostriatum augmentatum to enter the overlying capsula occipitalis interna (CIO). 4. Some scattered ovoidalis axons terminate on the intercalated neurons of the CIO, and in the medial caudal neostriatum. By far the major distribution of the ovoidal projection, however, takes place in a sharply demarcated region of the medial caudal neostriatum, consisting of small, densely packed neurons. This region corresponds to Field L of Rose. 5. This study, taken in conjunction with an earlier report on the projections of the avian inferior colliculus, indicates the existence of a discrete and sharply segregated auditory projection pathway leading from the inferior colliculus over the thalamic nucleus ovoidalis to the forebrain. 6. The relationships between avian and mammalian ascending auditory pathways are discussed.

EFFECT OF ELECTRICAL STIMULATION OF TELENCEPHALON ON OVULATION AND OVIPOSITION IN THE HEN.

Electrical stimulation of the archistriatum and paleostriatum primitivum leads to a 2- to 4-hr delay of ovulation and generally to a delay of 2–48 hr of oviposition in White Leghorn hens. The optimal time for stimulation for obtaining these effects is 13–16 hr before ovulation. Electrical stimulation of the neostriatum, area septalis, or of the paleostriatum augmentatum affects neither ovulation nor oviposition. Possible explanations are offered for the effects observed.