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-Our group, the Center for Astronomy Signal Processing and Electronics Research (CASPER), seeks to speed the development of radio astronomy signal processing instrumentation by designing and demonstrating a scalable, upgradeable, FPGA-based computing platform and software design methodology that targets a range of realtime radio telescope signal processing applications. This project relies on a small number of modular, connectible hardware components and open-source signal processing libraries which can be reused and scaled as hardware capabilities expand. We have demonstrated the use of 10 Gb Ethernet packetization and switches to manage high-bandwidth inter-board communication. Using these tools, we have built spectrometers, correlators, beamformers, VLBI data recorders, and many other applications. Future directions for the development include a fully packetized scalable correlator, additional library and toolflow development, and a next generation of modular FPGA-based hardware.

Whenever we move, speak, or play musical instruments, our actions generate auditory sensory input. the sensory consequences of our actions are thought to be predicted via sensorimotor integration, which involves anatomical and functional links between auditory and motor brain regions. the physiological connections are relatively well established, but less is known about how sensorimotor integration affects auditory perception. The sensory attenuation hypothesis suggests that the perceived loudness of self-generated sounds is attenuated to help distinguish self-generated sounds from ambient sounds. Sensory attenuation would work for louder ambient sounds, but could lead to less accurate perception if the ambient sounds were quieter. We hypothesize that a key function of sensorimotor integration is the facilitated processing of self-generated sounds, leading to more accurate perception under most conditions. the sensory attenuation hypothesis predicts better performance for higher but not lower intensity comparisons, whereas sensory facilitation predicts improved perception regardless of comparison sound intensity. A series of experiments tested these hypotheses, with results supporting the enhancement hypothesis. overall, people were more accurate at comparing the loudness of two sounds when making one of the sounds themselves. We propose that the brain selectively modulates the perception of self-generated sounds to enhance representations of action consequences.Many of our actions have auditory consequences, such as hearing our own speech or playing musical instruments. Predicting the auditory consequences of our actions is important for motor control, and there is evidence that sensorimotor networks in the brain generate these predictions 1,2 . Predictions about features of action-related sounds (e.g., frequency or amplitude) are conveyed from motor to auditory networks to help coordinate movements and correct errors 3-6 . The underlying cognitive process of sensorimotor integration is thought to be subtractive, where the brain dynamically compares predictions about self-generated sounds to the actual consequences of the actions 5,7 . This comparison is also thought to be important for establishing the sense of agency in human actions, which is a core feature of consciousness 8,9 . In this study we asked how sensorimotor integration affects the accuracy of auditory perception. We use term "active sounds" to refer to sounds that are generated by the participant. Active sounds are always a consequence of the participant's actions. By contrast, "passive sounds" are presented to participants and are never a direct consequence of their actions. Researchers typically study the processing of active vs. passive sounds by having people speak or press buttons to generate sounds and then asking them questions about their perceptions (e.g., 'Which sound was louder?').The neural basis of sensorimotor integration has been examined during spontaneous speech in humans and non-human primates. Electroencephalography (EEG), mag...

Objective Developmental stuttering is characterized by fluent speech punctuated by stuttering events, the frequency of which varies among individuals and contexts. Most stuttering events occur at the beginning of an utterance, suggesting neural dynamics associated with stuttering may be evident during speech preparation. Methods This study used EEG to measure cortical activity during speech preparation in men who stutter, and compared the EEG measures to individual differences in stuttering rate as well as to a fluent control group. Each trial contained a cue followed by an acoustic probe at one of two onset times (early or late), and then a picture. There were two conditions: a speech condition where cues induced speech preparation of the picture’s name and a control condition that minimized speech preparation. Results Across conditions stuttering frequency correlated to cue-related EEG beta power and auditory ERP slow waves from early onset acoustic probes. Conclusions The findings reveal two new cortical markers of stuttering frequency that were present in both conditions, manifest at different times, are elicited by different stimuli (visual cue, auditory probe), and have different EEG responses (beta power, ERP slow wave). Significance The cue-target paradigm evoked brain responses that correlated to pre-experimental stuttering rate.