Moderate labeling was also seen throughout the hyperpallium and Mesopallium. 
We measured auditory responses to conspecific and heterospecific songs using ZENK protein expression within the caudomedial nidopallium (NCM) and the Mesopallium caudomedial (CMM).
Neurons in the song nuclei and in a secondary auditory area, the caudal medial Mesopallium (CMM), show selective responses to the BOS.
We illustrate our method by applying it both to simulated data and to data recorded from neurons in a forebrain region (intermediate medial Mesopallium, IMM) of the behaving domestic chick and simultaneously from the corresponding contralateral region.
Here we show by in situ hybridization that the mRNA for the microtubule-associated protein 2 (MAP2) gene was enriched in the Mesopallium and the hippocampus in the trained chick brain. In agreement with the gene expression, MAP2 protein was accumulated in the Mesopallium of the trained chick brain, but not in the brains of the controls.
By applying cDNA microarrays containing 13,007 expressed sequence tags, we examined the comprehensive gene expression profiling of the intermediate medial Mesopallium in the chick cerebrum, which has been shown to play a key role in filial imprinting.
We have identified roles for noradrenaline in the Mesopallium or 'avian cortex', the hippocampus, medial striatum or basal ganglia and teased out the different effects of noradrenaline in each of these areas based on the receptor subtypes activated by the transmitter and the stages on which they act.
With a species-specific probe for budgerigar androgen receptor mRNA, we found that the androgen receptor was expressed in the vocal areas, such as the central nucleus of the lateral nidopallium, the anterior arcopallium, the oval nucleus of the Mesopallium, the oval nucleus of the anterior nidopallium and the tracheosyringeal hypoglossal nucleus.
Songbirds rely on auditory processing of natural communication signals for a number of social behaviors,including mate selection,individual recognition and the rare behavior of vocal learning - the ability to learn vocalizations through imitation of an adult model,rather than by instinct.Like mammals,songbirds possess a set of interconnected ascending and descending auditory brain pathways that process acoustic information and that are presumably involved in the perceptual processing of vocal communication signals.Most auditory areas studied to date are located in the caudomedial forebrain of the songbird and include the thalamo-recipient field L (sub fields L1,L2 and L3),the caudomedial and caudolateral Mesopallium (CMM and CLM,respectively) and the caudomedial nidopallium (NCM).
Specifically, the number of ZENK-expressing cells in the caudomedial Mesopallium (CMM) was most affected by whether a song was directed or undirected, whereas the caudomedial nidopallium (NCM) was most affected by whether a song was familiar or unfamiliar.
We modeled auditory neurons in the caudal lateral Mesopallium (CLM) of adult male zebra finches under urethane anesthesia with linear filters convolved not with stimulus intensity, but with stimulus surprise.
To simulate variation in quality of the song environment, we exposed adult female starlings to 1 week of either long or short songs and then quantified several monoamines and their metabolites in the caudomedial Mesopallium and caudomedial nidopallium (NCM) using high performance liquid chromatography.
Proliferating cells were detected immunohistochemically on brain sections by incorporation of pre-training doses of 5-bromodeoxyuridine (BrdU) into DNA; numbers of new cells were counted in the intermediate medial Mesopallium, the intermediate arcopallium, the medial part of the Mesopallium and the nidopallium, the dorsocaudal nidopallium, the hippocampus, and the parahippocampal region 24 h and seven days after training. The intermediate medial Mesopallium showed an increase in the number of BrdU-positive cells 24 h after training. However, at seven days post-training, the number of BrdU-containing cells decreased in the medial nidopallium and Mesopallium, in the dorsocaudal nidopallium, and the right intermediate medial Mesopallium.
In the songbird, the secondary auditory telencephalic region caudal Mesopallium (CM) contains neurons that encode aspects of auditory experience.
Neural response to the stimulus was quantified by the amount of protein of the IEG ZENK (also known as zif-268, egr-1, ngf-Ia and krox-24) in the caudal medial nidopallium (NCM) and caudomedial Mesopallium (CMM).
We have used antibodies and western blotting to analyze subcellular fractions from the intermediate medial Mesopallium region of 14-day and 8-week chicken forebrain prepared 0, 45, and 120 min after learning a discriminative taste avoidance task.
Bead discrimination learning in day-old chicken was inhibited by bilateral injection into the intermediate medial Mesopallium (IMM), a homolog of the mammalian brain cortex, of the poorly metabolized enantiomer of L-lactate, D-lactate.
Cytochalasin B inhibited memory when injected into the Mesopallium (avian cortex) either close to or between 25 and 45 min after training, whereas phloretin and phlorizin only inhibited memory at 30 min.
Inside the telencephalon, Mesopallium, nidopallium (+ entopallium + arcopallium) and septum are smaller as well.
The intermediate arcopallium is recipient of input from intermediate and caudal nidopallium, Mesopallium and densocellular hyperpallium.
the Mesopallium intermediomediale and the striatum mediale.
This BOS selectivity is not a general property of neurons in primary and secondary auditory forebrain regions, field L and caudolateral Mesopallium (CLM).
Imprinting object is recognized and processed in the visual wulst, and the memory is stored in the intermediate medial Mesopallium in the dorsal pallium of the telencephalon. These results suggest that the activation of CCK cells in the visual wulst as well as in the intermediate medial Mesopallium by visual stimuli is indispensable for the acquisition of visual imprinting..
Cell proliferation was examined in the intermediate medial Mesopallium (IMM), arcopallium intermedium (AI), medial part of nidopallium and Mesopallium (MNM), nidopallium dorso-caudalis (Ndc), hippocampus (Hp) and area parahippocampalis (APH), as well as in corresponding ventricular zones.
To understand the neural mechanisms of how non-singing female songbirds perceive behaviorally relevant vocalizations, we recorded responses of single neurons to acoustic stimuli in two auditory forebrain regions, the caudal lateral Mesopallium (CLM) and Field L, in anesthetized adult female zebra finches (Taeniopygia guttata).
Telencephalic auditory areas, including field L subfields L1, L2a and L3, as well as the caudomedial nidopallium (NCM) and Mesopallium (CMM), contained GABAergic cells at particularly high densities.
Analysis of the expression pattern of this gene after passive-avoidance training revealed clear induction of eIF2Bepsilon in both the Mesopallium intermediomediale (IMM) and in the striatum mediale (StM).
In adult songbirds, auditory neurons in the primary auditory forebrain region of field L and a secondary auditory forebrain region of caudal Mesopallium (CM) are highly responsive to natural sounds, such as conspecific song.
CONCLUSION: These results indicate that the thalamofugal pathway is critical for learning the imprinting stimulus and that the visual wulst shows learning-related plasticity and may relay processed visual information to indicate the color of the imprint stimulus to the memory storage region, e.g., the intermediate medial Mesopallium..
Male zebra finches (Taeniopygia guttata) show differential ZENK expression to conspecific and heterospecific songs by day 30 posthatch in auditory perceptual brain regions such as the caudomedial nidopallium (NCM) and the caudomedial Mesopallium (CMM).
The lateral forebrain of zebra finches that comprises parts of the lateral nidopallium and parts of the lateral Mesopallium is supposed to be involved in the storage and processing of visual information acquired by an early learning process called sexual imprinting.
In adult brain, DCX mRNA was detected mainly in the Mesopallium (M), medial striatum (MSt), septum, Area X, diencephalon, telencephalic subventricular zone (SVZ), and Purkinje cells in the cerebellum.
Orexin-ir projections extended from the paraventricular nucleus rostrally to the preoptic area, laterally towards the medial striatum, nidopallium, and dorsally along the lateral ventricle towards the Mesopallium.
The involvement of tenascin-C in this juvenile learning task was tested by injections of monoclonal antibodies directed to distinct domains of the tenascin-C molecule into the avian prefrontal cortex analog, the medio-rostral nidopallium/Mesopallium (formerly termed medio-rostral neostriatum/hyperstriatum ventrale), a forebrain area which has been shown to be critically involved in auditory filial imprinting.
Furthermore, a novel division was identified (CB-rich, CR-rich), interposed between hyper- and Mesopallium and related to the lamina separating both, termed laminar pallial nucleus.
Our study focused on the eventual occurrence of dimorphism in the intermediate medial Mesopallium, an area associated with learning in non-singing birds. The ventricular zone, intermediate medial part of Mesopallium and lateral septal area was analyzed using stereological methods for cell counts. Short-term experiments revealed significantly higher numbers of newborn cells in male ventricular zone of Mesopallium compared to female at post-hatching day 1. Long-term survival until post-hatching day 20 showed significantly higher numbers of labeled cells in the male compared to female intermediate medial part of Mesopallium, which is the final destination of migrating cells born in the overlying ventricular zone. The vast majority of these early post-hatching newborn cells residing in the intermediate medial part of Mesopallium expressed a neuronal phenotype. In addition to neurogenesis, higher numbers of apoptotic figures were found in the male intermediate medial part of Mesopallium at post-hatching day 10, suggesting that cell death plays a role in the control of telencephalic regional cell density in males. Our findings indicate that sex-specific mechanisms possibly stimulate increased cell genesis and survival, as well as the counteracting event of increased apoptotic cell death that characterized the male intermediate medial part of Mesopallium..
Ten microliters of 10nM gp120 was bilaterally injected into the region of the intermediate medial Mesopallium of day-old chicks at various times before, or after, training using a single-trial passive avoidance task.
The physiological basis of this learning process is an irreversible reduction of dendritic spines in two forebrain areas, the LNM (lateral nido-Mesopallium) and the MNM (medial nido-Mesopallium).
However, when CLN was injected (i.c.) into a region known to be important in memory formation, the Mesopallium intermediomediale (IMM), prior to training with 10% MeA, chicks exhibited strong memory retention at 24 h, similar to those trained on 100% MeA.
Previous work has shown that exposure of males to their tutor song leads to increased expression of immediate early genes (IEGs) in the caudomedial nidopallium (NCM) and in the caudomedial Mesopallium (CMM).
We show that, in the context of song auditory stimulation, Arc expression is induced in several telencephalic auditory areas, most prominently the caudomedial nidopallium and Mesopallium, whereas in the context of singing, Arc is also induced in song control areas, namely nucleus HVC, used as a proper name, the robust nucleus of the arcopallium and the interface nucleus of the nidopallium.
The intermediate and medial hyperstriatum ventrale/Mesopallium (IMHV/IMM), a forebrain memory storage site, was removed together with a control brain region, the posterior pole of the neostriatum/nidopallium (PPN).
Outside of the song system, major areas of expression were in medial nidopallium (N), hyperpallium apicale (HA), Mesopallium ventrale (MV), taenial amygdala (TnA), cerebellar Purkinje cells, and nucleus isthmo-opticus (IO).
These connections can be compared with the rotundic fibers reaching the ventromedial part of the anterior dorsal ventricular ridge in reptiles/entopallium in birds (ventral pallium) and the dorsolateral part of the anterior dorsal ventricular ridge in reptiles (lateral pallium), and probably the Mesopallium in birds..
Most work on IEG expression in songbirds such as zebra finches has focused on playback of acoustic stimuli and its effect on auditory processing areas such as caudal medial Mesopallium (CMM) caudal medial nidopallium (NCM).
Thus, Ei, but not Ex, makes a reciprocal connection with a distinct nucleus in the ventrolateral Mesopallium and is a major source of projections to the lateral striatum.
In songbirds, parrots, and hummingbirds, which need to learn their songs, exposure to conspecific song leads to increased expression of the immediate early gene (IEG) ZENK in a number of forebrain regions, including the caudomedial nidopallium (NCM) and the caudomedial Mesopallium (CMM).
The present study examined expression of these IEGs in the caudomedial nidopallium (NCM), caudomedial Mesopallium (CMM; formerly cHV), and the hippocampus (HP) in both sexes at d45 in response to conspecific, heterospecific, or no songs.
After postnatal exposure to a novel 30-min auditory imprinting stimulus, Arc/arg3.1 mRNA was found to be significantly increased in two higher associative areas, the Mesopallium intermediomediale (P = 0.002) and the nidopallium dorso-caudale (P = 0.031), compared with naïve controls. In addition, increases were seen in the medio-rostral nidopallium/Mesopallium (P = 0.054), which is presumed to be the analog of the mammalian prefrontal cortex, and the hyperpallium intercalatum (P = 0.054), but these did not quite reach significance.
However, experiments using the expression of immediate early genes (IEGs) reveal the activation of brain regions outside the song control system, in particular the caudomedial nidopallium (NCM) and the caudomedial Mesopallium (CMM).
Whereas some telencephalic areas that have not been regarded as limbic were also LAMP-rich (e.g., the hyperpallium intercalatum and densocellulare of the Wulst, the Mesopallium, and the intrapeduncular nucleus), most nonlimbic telencephalic areas were LAMP-poor (e.g., field L, the lateral nidopallium, and somatic basal ganglia).
In addition, we demonstrated potential for neuronal synthesis of pregnenolone in the day-old chick brain, including in the intermediate medial Mesopallium, formerly known as intermediate medial hyperstriatum ventrale and the medial striatum..
We have previously shown that activation of beta2-, beta3- and alpha1-adrenoceptors (ARs) by injection into the multimodal forebrain association region (intermediate medial hyperstriatum ventrale [ IMHV] or intermediate medial Mesopallium [ IMM]) is involved in the consolidation of memory 30 min after training and that activation of alpha2-ARs in the caudate putamen plays a role in the reinforcement of memory leading to consolidation in the IMM (IMHV).
Converging evidence implicates the auditory forebrain regions caudal medial Mesopallium (formerly cmHV) and caudal medial nidopallium in the perceptual processing of conspecific vocalizations in songbirds. One hallmark of the caudal medial Mesopallium and caudal medial nidopallium, areas analogous to mammalian secondary auditory cortical structures, is their robust expression of the immediate-early-gene zenk in response to conspecific songs. Using European starlings operantly trained to recognize the songs of individual conspecifics, we show that the levels and patterns of zenk protein expression in the caudal medial nidopallium and caudal medial Mesopallium differ when song recognition demands are placed on the system. In the caudal medial Mesopallium, expression is significantly elevated above basal levels during the recognition of familiar songs, the acquisition of novel associations for familiar songs, and the acquisition of novel song discriminations. The results directly implicate the caudal medial nidopallium and caudal medial Mesopallium in at least a portion of the auditory processes underlying vocal recognition. Moreover, the observed differences between these regions imply the functional localization (or at least the concentration) of different auditory processing mechanisms within the caudal medial nidopallium and the caudal medial Mesopallium..
We found no significant differences in volume or the total number of neurons in the hippocampal formation between dominant and subordinate chickadees, but subordinate birds had significantly lower cell proliferation rates in the ventricular zone adjacent to both the hippocampus and Mesopallium compared to the dominants.
Here, we compared the experience-dependent modulation of ZENK with that of another IEG, FOS, and report that ZENK and FOS expression in the caudomedial Mesopallium and caudomedial nidopallium show different modulation properties that complement natural variation in song-bout length.
Cell proliferation rates, measured as the total number of BrdU-labeled cells in the ventricular zone adjacent either to the hippocampus or to the Mesopallium, were also not significantly different between corticosterone and placebo-implanted chickadees.
The results showed that field L2, the caudomedial nidopallium (NCM) and the caudomedial Mesopallium (CMM) contain a high number of GABAergic cells.
Recent data from single neurons in the caudal medial portion of the Mesopallium are then reviewed, showing that song recognition learning leads to explicit representation of acoustic features that correspond closely to specific motifs, but only to motifs in the songs that birds have learned to recognize.
These areas, which include field L subfields L1 and L3, as well as the adjacent caudomedial nidopallium (NCM) and caudomedial Mesopallium (CMM), are part of the central auditory pathway and constitute a lobule in the caudomedial aspect of the telencephalon.
Auditory neurons in the secondary auditory areas caudal nidopallium and caudal Mesopallium show specific responses to familiar songs or behaviorally relevant songs.
The sectors of the hyperstriatum composing the Wulst (i.e., the hyperstriatum accessorium intermedium, and dorsale), the hyperstriatum ventrale, the neostriatum, and the archistriatum have been renamed (respectively) the hyperpallium (hypertrophied pallium), the Mesopallium (middle pallium), the nidopallium (nest pallium), and the arcopallium (arched pallium).
To investigate the role of the auditory system in generating the selective responses observed in the song system, we recorded auditory responses in the zebra finch primary auditory forebrain, field L, and in a secondary auditory area, the caudal Mesopallium. Field L and caudal Mesopallium project directly or indirectly to the high vocal center and nucleus interface of the nidopallium and are presumed to provide substantial auditory input to the song system. We found that, on average, neurons in field L and caudal Mesopallium did not show positive selective responses for the bird's own song or tutor song relative to conspecific song.
We show that the entopallium projects laterally and diffusely to the perientopallium and nidopallium (formerly the neostriatum) and specifically and densely to a teardrop-shaped nucleus in the ventrolateral Mesopallium (formerly known as the hyperstriatum ventrale), here called MVL (abbreviation used as a proper name).
As laughing and weeping are motivated in the cerebral trunc they must have been projected through the Mesopallium (which includes the thalamus) to the facial nuclei.
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