bioRxiv Subject Collection: Neuroscience's Journal
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Sunday, August 25th, 2024
| Time |
Event |
| 9:18a |
Musicality enhances selective attention: spatiotemporal insights from precise separation of simultaneous neural responses
We precisely resolved simultaneous neural responses to their driving stimuli and classified them to different selective attention conditions towards specific melodies within mixtures. Magnetoencephalographic findings reveal the influence of participants' musicality and task performance on the recruitment of cortical regions in bottom-up and top-down attentional processes. Across parietal regions, musicality and performance correlated positively with top-down attention at the left hemisphere, but negatively with bottom-up attention at the right. In the right prefrontal cortex, individuals who maintained selective attention over the tone duration performed better and were more musical. These results suggest that musical training boosts performance by enhancing top-down attention, reducing bottom-up distractions, and sustaining selective attention overtime, with these effects mediated by the frontoparietal cortex. This work advances our understanding of neural selective attention mechanisms in complex soundscapes and underscores the potential of musical training for cognitive enhancement. Our breakthrough approach effectively captures cognitive effects with frequency-tagging, creating new possibilities for scientific applications. | | 9:18a |
Structural Development of Speech Networks in Young Children at Risk for Speech Disorder
Characterizing the structural development of the neural speech network in early childhood is important for understanding speech acquisition. To investigate speech in the developing brain, 94 children aged 4-7-years-old at risk for early speech disorder were scanned using diffusion weighted imaging (DWI) magnetic resonance imaging (MRI). Additionally, each child completed the Syllable Repetition Task (SRT), a validated measure of phoneme articulation. The DWI data were modeled using multi-compartment restriction spectrum imaging (RSI) to measure restricted and hindered diffusion properties in both grey and white matter. Consequently, we analyzed the diffusion data using both whole brain analysis, and automated fiber quantification (AFQ) analysis to establish tract profiles for each of six fiber pathways thought to be important for supporting speech development. In the whole brain analysis, we found that SRT performance was associated with restricted diffusion in bilateral inferior frontal gyrus, pars opercularis, right pre-supplementary and supplementary motor area (pre-SMA/SMA), and bilateral cerebellar grey matter (p < .005). Age moderated these associations in left pars opercularis and frontal aslant tract (FAT). However, in both cases only the cerebellar findings survived a cluster correction. We also found associations between SRT performance and restricted diffusion in cortical association fiber pathways, especially left FAT, and in the cerebellar peduncles. Analyses using automatic fiber quantification (AFQ) highlighted differences in high and low performing children along specific tract profiles, most notably in left but not right FAT. These findings suggest that individual differences in speech performance are reflected in structural gray and white matter differences as measured by restricted and hindered diffusion metrics, and offer important insights into developing brain networks supporting speech in very young children. | | 9:18a |
Gesture encoding in human left precentral gyrus neuronal ensembles
Understanding the cortical activity patterns driving dexterous upper limb motion has the potential to benefit a broad clinical population living with limited mobility through the development of novel brain-computer interface (BCI) technology. The present study examines the activity of ensembles of motor cortical neurons recorded using microelectrode arrays in the dominant hemisphere of two BrainGate clinical trial participants with cervical spinal cord injury as they attempted to perform a set of 48 different hand gestures. Although each participant displayed a unique organization of their respective neural latent spaces, it was possible to achieve classification accuracies of ~70% for all 48 gestures (and ~90% for sets of 10). Our results show that single unit ensemble activity recorded in a single hemisphere of human precentral gyrus has the potential to generate a wide range of gesture-related signals across both hands, providing an intuitive and diverse set of potential command signals for intracortical BCI use. | | 9:18a |
Brain structure and activity predicting cognitive maturation in adolescence
Cognitive abilities of primates, including humans, continue to improve through adolescence. While a range of changes in brain structure and connectivity have been documented, how they affect neuronal activity that ultimately determines performance of cognitive functions remains unknown. Here, we conducted a multilevel longitudinal study of monkey adolescent neurocognitive development. The developmental trajectory of neural activity in the prefrontal cortex accounted remarkably well for working memory improvements. While complex aspects of activity changed progressively during adolescence, such as the rotation of stimulus representation in multidimensional neuronal space, which has been implicated in cognitive flexibility, even simpler attributes, such as the baseline firing rate in the period preceding a stimulus appearance had predictive power over behavior. Unexpectedly, decreases in brain volume and thickness, which are widely thought to underlie cognitive changes in humans 5 did not predict well the trajectory of neural activity or cognitive performance changes. Whole brain cortical volume in particular, exhibited an increase and reached a local maximum in late adolescence, at a time of rapid behavioral improvement. Maturation of long-distance white matter tracts linking the frontal lobe with areas of the association cortex and subcortical regions best predicted changes in neuronal activity and behavior. Our results provide evidence that optimization of neural activity depending on widely distributed circuitry effects cognitive development in adolescence. | | 9:18a |
State modulation in spatial networks with three interneuron subtypes
Several inhibitory interneuron subtypes have been identified as critical in regulating sensory responses. However, the specific contribution of each interneuron subtype remains uncertain. In this work, we explore the contributions of cell-type specific activity and synaptic connections to dynamics of a spatially organized spiking neuron network. We find that the firing rates of the somatostatin (SOM) interneurons align closely with the level of network synchrony irrespective of the target of modulatory input. Further analysis reveals that inhibition from SOM to parvalbumin (PV) interneurons must be limited to allow gradual transitions from asynchrony to synchrony and that the strength of recurrent excitation onto SOM neurons determines the level of synchrony achievable in the network. Our results are consistent with recent experimental findings on cell-type specific manipulations. Overall, our results highlight common dynamic regimes achieved across modulations of different cell populations and identify SOM cells as the main driver of network synchrony. | | 10:32a |
Oxtyocin and vasopressin 1a receptor alterations in the superior temporal sulcus and hypothalamus in schizophrenia
Schizophrenia is a chronic, severe psychiatric condition characterized in part by social impairments. As social cognitive functioning is a major predictor of successful life outcomes in schizophrenia, there is a critical need to determine the neurobiological basis of social impairments in schizophrenia. The current study used receptor autoradiography to examine vasopressin 1a (AVPR1a) and oxytocin receptor (OXTR) densities in the postmortem brain tissue of individuals who had schizophrenia (N=23) relative to unaffected matched controls (N=18). We analyzed the superior temporal sulcus, a brain region that is highly implicated in social perception and shows aberrant functioning in schizophrenia. Greater AVPR1a binding densities were observed relative to OXTR. Increases in AVPR1a densities with advanced age in females who had schizophrenia were also observed. This finding in the superior temporal sulcus may explain a shift in positive symptom severity(paranoia/suspiciousness) that has been observed with advanced age in women with schizophrenia. In addition, increased OXTR and a trend toward increased AVPR1a densities were observed in the hypothalamus in schizophrenia. The hypothalamus synthesizes oxytocin and vasopressin in the brain and is the initiator of the hypothalamic-pituitary-adrenal axis, which facilitates the fight or flight stress response. These receptor systems may be upregulated to compensate for possibly low exogenous oxytocin and vasopressin release from the hypothalamus in schizophrenia. Our findings show age- and sex-dependent effects on nonapeptide receptor binding that shed light onto the neurobiology of the social brain in the progression of schizophrenia. |
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