Biology subjects

Agopyan-Miu, A. H. C. W.

Publications and source records attributed to Agopyan-Miu, A. H. C. W..

3 recordsLinked to original sources

bioRxiv2024

Spectral-switching analysis reveals real-time neuronal network representations of concurrent spontaneous naturalistic behaviors in human brain

Despite abundant evidence of functional networks in the human brain, their neuronal underpinnings, and relationships to real-time behavior have been challenging to resolve. Analyzing brain-wide intracranial-EEG recordings with video monitoring, acquired in awake subjects during clinical epilepsy evaluation, we discovered the tendency of each brain region to switch back and forth between 2 distinct power spectral densities (PSDs 2-55Hz). We further recognized that this spectral switching occurs synchronously between distant sites, even between regions with differing baseline PSDs, revealing long-range functional networks that would be obscured in analysis of individual frequency bands. Moreover, the real-time PSD-switching dynamics of specific networks exhibited striking alignment with activities such as conversation and hand movements, revealing a multi-threaded functional network representation of concurrent naturalistic behaviors. Network structures and their relationships to behaviors were stable across days, but were altered during N3 sleep. Our results provide a new framework for understanding real-time, brain-wide neural-network dynamics.

neuroscience↗

bioRxiv2024

Cntnap2 loss drives striatal neuron hyperexcitability and behavioral inflexibility

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by two major diagnostic criteria - persistent deficits in social communication and interaction, and the presence of restricted, repetitive patterns of behavior (RRBs). Evidence from both human and animal model studies of ASD suggest that alteration of striatal circuits, which mediate motor learning, action selection, and habit formation, may contribute to the manifestation of RRBs. CNTNAP2 is a syndromic ASD risk gene, and loss of function of Cntnap2 in mice is associated with RRBs. How loss of Cntnap2 impacts striatal neuron function is largely unknown. In this study, we utilized Cntnap2-/- mice to test whether altered striatal neuron activity contributes to aberrant motor behaviors relevant to ASD. We find that Cntnap2-/- mice exhibit increased cortical drive of direct pathway striatal projection neurons (dSPNs). This enhanced drive is likely due to increased intrinsic excitability of dSPNs, which make them more responsive to cortical inputs. We find that Cntnap2-/- mice exhibit spontaneous repetitive behaviors, increased motor routine learning, perseveration, and cognitive inflexibility. Increased corticostriatal drive of the direct pathway may therefore contribute to the acquisition of repetitive, inflexible behaviors in Cntnap2 mice.

neuroscience↗

bioRxiv2019

Loss of Tsc1 from striatal direct pathway neurons impairs endocannabinoid-LTD and enhances motor routine learning

Tuberous Sclerosis Complex (TSC) is a neurodevelopmental disorder in which patients frequently present with autism spectrum disorder (ASD). A core diagnostic criterion for ASD is the presence of restricted, repetitive behaviors, which may result from abnormal activity in striatal circuits that mediate motor learning, action selection and habit formation. Striatal control over motor behavior relies on the coordinated activity of two subtypes of principle neurons, direct pathway and indirect pathway spiny projection neurons (dSPNs or iSPNs, respectively), which provide the main output of the striatum. To test if altered striatal activity is sufficient to cause changes to motor behavior in the context of TSC, we conditionally deleted Tsc1 from dSPNs or iSPNs in mice and determined the consequences on synaptic function and motor learning. We find that mice with loss of Tsc1 from dSPNs, but not iSPNs, have enhanced motor routine learning in the accelerating rotarod task. In addition, dSPN Tsc1 KO mice have impaired endocannabinoid-mediated long-term depression (eCB-LTD) at cortico-dSPN synapses in the dorsal striatum. Consistent with a loss of eCB-LTD, disruption of Tsc1 in dSPNs, but not iSPNs, results in a strong enhancement of corticostriatal synaptic drive. Together these findings demonstrate that within the striatum, dSPNs show selective sensitivity to Tsc1 loss and indicate that enhanced cortical activation of the striatal direct pathway is a potential contributor to altered motor behaviors in TSC.

neuroscience↗