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Trusel, M.

Publications and source records attributed to Trusel, M..

5 recordsLinked to original sources

Holistic Motor Control of Zebra Finch Song Syllable Sequences

How brain circuits are organized to skillfully produce learned sequences of behaviors is still poorly understood. Here, we functionally examine how the cortical song premotor region HVC, which is necessary for zebra finch song, controls the sequential production of learned song syllables. We find that HVC can generate the complete sequence of learned song syllables independently of its main synaptic input pathways. Thalamic input to HVC is permissive for song initiation but it is not required for transitions between syllables or completing song. We show that excitation of HVC neurons during song reliably causes vocalizations to skip back to the beginning of song, reminiscent of a skipping record. This restarting of syllable sequences can be induced at any moment in song and depends on local circuits within HVC. We identify and computationally model a synaptic network including intratelencephalic premotor and corticostriatal neurons within HVC that are essential for completing song syllable sequences. Together, our results show that the learned zebra finch song is controlled by a cortical sequence-generating network in HVC that, once started, can sustain production of all song syllables independent of major extrinsic input pathways. Thus, sequential neuronal activity can be organized to fuse well-learned vocal-motor sequences, ultimately achieving holistic control of this naturally learned behavior.

neuroscience↗

Synaptic Connectivity of Afferent Inputs onto Projection Neurons in the Songbird HVC

Sensorimotor computations for learning and behavior rely on precise patterns of synaptic connectivity. Yet, we typically lack the synaptic wiring diagrams for long-range connections between sensory and motor circuits in the brain. Here we provide the synaptic wiring diagram for sensorimotor circuits involved in learning and production of male zebra finch song, a natural and ethologically relevant behavior. We examined the functional synaptic connectivity from the 4 main sensory afferent pathways onto the 3 known classes of projection neurons of the song premotor cortical region HVC. Recordings from hundreds of identified projection neurons reveal rules for monosynaptic connectivity and the existence of polysynaptic ensembles of excitatory and inhibitory neuronal populations in HVC. Circuit tracing further identifies novel connections between HVCs presynaptic partners. Our results indicate a modular organization of ensemble-like networks for integrating long-range input with local circuits, providing important context for information flow and computations for learned vocal behavior.

neuroscience↗

Bidirectional synaptic changes in deep and superficial hippocampal neurons following in vivo activity

Neuronal activity during experience is thought to induce plastic changes within the hippocampal network which underlie memory formation, although the extent and details of such changes in vivo remain unclear. Here, we employed a temporally precise marker of neuronal activity, CaMPARI2, to label active CA1 hippocampal neurons in vivo, followed by immediate acute slice preparation and electrophysiological quantification of synaptic properties. Recently active neurons in the superficial sublayer of stratum pyramidale displayed larger post-synaptic responses at excitatory synapses from area CA3, with no change in pre-synaptic release probability. In contrast, in vivo activity weakened both pre- and post-synaptic excitatory weights onto pyramidal cells in the deep sublayer. In vivo activity of deep and superficial neurons within sharp-wave ripples was bidirectionally changed across experience, consistent with the observed changes in synaptic weights. These findings reveal novel, fundamental mechanisms through which the hippocampal network is modified by experience to store information.

neuroscience↗

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

Autism spectrum disorders (ASD) are characterized by impaired learning of culturally transmitted behaviors like social skills, speech, and language1-3. These behaviors are learned by copying parents and other social models during development, a two-stage process that involves forming memories of appropriate behaviors during social experiences and then using those memories to guide imitation. How ASD-linked genes impair these often-intertwined aspects of learning is not known, thereby limiting our understanding of the developmental progression of ASD and the targeting of therapeutic interventions. Here we show that these aspects of learning are dissociable and that the ASD-linked gene FoxP1 selectively impairs learning from social experience, but not behavioral imitation. Haploinsufficiency of FOXP1 in humans causes FOXP1 syndrome, a neurodevelopmental disorder typified by severe disruptions in speech and language development, and other ASD-associated symptoms4,5. We tested how knockdown of FoxP1 (FP1-KD) affects the cultural transmission of vocal behaviors in zebra finches, a songbird that learns by memorizing and vocally copying the song of an adult song-tutor. We find that FP1-KD blocks song learning in juvenile birds by selectively impairing their ability to encode a memory during social experiences with a songtutor. These learning deficits are linked to disruptions in experience-driven structural and functional plasticity. However, if birds are exposed to tutor-song prior to FP1-KD, their ability to imitate that song during development is unaffected. Thus, FP1-KD impairs cultural transmission of vocalizations by disrupting the ability to form appropriate vocal memories, yet spares the ability to use previously acquired memories to guide vocal learning. This indicates that learning from social experience may be particularly vulnerable in FOXP1 syndrome.

neuroscience↗

The autism and schizophrenia-associated protein CYFIP1 regulates bilateral brain connectivity

Copy-number variants of the CYFIP1 gene in humans have been linked to Autism and Schizophrenia, two neuropsychiatric disorders characterized by defects in brain connectivity. CYFIP1 regulates molecular events underlying post-synaptic functions. Here, we show that CYFIP1 plays an important role in brain functional connectivity and callosal functions. In particular, we find that Cyfip1 heterozygous mice have reduced brain functional connectivity and defects in white matter architecture, typically relating to phenotypes found in patients with Autism, Schizophrenia and other neuropsychiatric disorders. In addition, Cyfip1 deficient mice present deficits in the callosal axons, namely reduced myelination, altered pre-synaptic function, and impaired bilateral-connectivity related behavior. Altogether, our results show that Cyfip1 haploinsufficiency compromises brain connectivity and function, which might explain its genetic association to neuropsychiatric disorders.

neuroscience↗