Expression of FoxP2 in the Basal Ganglia Regulates Vocal Motor Sequences in the Adult Songbird

Abstract

14Production of learned vocalizations requires precise selection and accurate sequencing of appropriate 15vocal-motor actions. The basal ganglia are essential for the selection and sequencing of motor actions, 16but the cellular specializations and circuit mechanisms governing accurate sequencing of vocalizations 17 are unknown. Here, we use single-nucleus RNA sequencing and genetic manipulations to map basal 18 ganglia cell types and circuits involved in the production of songbird vocal sequences. We identify cell-19 type specializations in direct-like and indirect-like basal ganglia pathways, including evolutionary 20 expansion of striatal and arkypallidal cell-types that could facilitate vocal sequencing. Surprisingly, we 21find that FoxP2, a gene important for vocal development, can potently and reversibly control accurate 22 sequencing of adult birdsong, and that phasic dopamine selectively regulates repetition of syllables 23 independent of its role in reinforcement-based learning of how they are sung. These findings identify key 24 evolutionary specializations and circuits essential for selection and sequencing of vocal-motor actions 25 necessary for vocal communication. 42and circuit specializations to these core or ancestral basal ganglia circuits. For example, human genetic 43 disruptions of the transcription factor FOXP2, which is selectively enriched in direct-pathway medium spiny 44 neurons (MSN)s, cause selective language development deficits marked by difficulties in controlling and 45 accurately sequencing appropriate vocal-motor actions (childhood apraxia of speech), but do not disrupt 46 the precise sequencing of non-vocal behaviors (Fisher et al.

An underlying motor bias shapes individuality during vocal learning

“…In agreement with previous reports in ZFs [60][61][62], we identi ed marker genes representing speci c cell types reported for the song nuclei, such as Area X medium spiny neurons (MSNs), Area X pallidal-like neurons, RA glutamatergic projecting neurons, GABAergic neurons, astrocytes, microglia, oligodendrocytes, oligo precursor cells, and RA surrouding arcopallium glutamatergic neurons (Fig. 5A).…”

“…The expression of established marker genes was used to assign identities for each cluster: SLC17A6 for glutamatergic neurons; GAD1 and GAD2 for GABAergic neurons; PPP1R1B for medium spiny neuron (MSN); SLC15A2, SLC1A2, and ASPA for astrocytes; PDGFRA and NKX2.2 for oligodendrocyte precursor cells (OPCs); PLP1 and ST18 for oligodendrocytes; and CSF1R and IKZF1 for microglia [92][93][94][95]. Subclusters in MSNs and pallidal-like neurons were identi ed with FOXP2, FOXP4, MTNR1A, and PENK based on a previous report [62]. Subclusters in glutamatergic neurons in RA were identi ed based on a previous report [60,61] and in situ hybridization database, ZEBrA [96]; SRD5A2 and SCUBE1 for the glutamatergic neurons in RA projecting to the nucleus of cranial nerve XII; CACNA1H, MGAT4C, and ADYAP1 for RA surrounding arcopallial neurons.…”

Wings of Change: aPKC/FoxP-dependent plasticity in steering motor neurons underlies operant selflearning inDrosophila

“…Our results (Fig. 6) suggest a role for adult FoxP expression in maintaining operant self-learning capabilities after development, analogous to the role of FoxP2 in songbird vocal learning (8,170). There are three possible explanations for this result: For one, the genes regulated by FoxP ( 171) may continue to exert their functions for this amount of time also without the FoxP protein present.…”

“…The result that adult knockout of FoxP had no immediate effect on operant self-learning (Figure 6A) seemed to corroborate this hypothesis. In contrast, supporting a continued role of FoxP genes in motor learning also after development are data from songbirds where FoxP2 gene expression is not only regulated by singing (15,(167)(168)(169), but where normal FoxP2 expression is necessary in adults to maintain learned song (8,170). To also test the second hypothesis, we aged the flies after the FoxP knockout and tested them 7 and 14-days later.…”

Autism-linked gene FoxP1 selectively regulates the cultural transmission of learned vocalizations

“…HVC X neurons project onto medium spiny neurons in Area X, and it has recently been shown that FoxP1 is also expressed in medium spiny neurons in both the direct and indirect pathways traversing the vocal basal ganglia (14,58). A recent study demonstrated that FP1-KD in Area X of juvenile zebra finches causes song learning deficits characterized by incomplete imitation of tutor songs (15).…”