David A. Magezi

Linear mixed-effects models for within-participant psychology experiments: an introductory tutorial and free, graphical user interface (LMMgui)

Linear mixed-effects models (LMMs) are increasingly being used for data analysis in cognitive neuroscience and experimental psychology, where within-participant designs are common. The current article provides an introductory review of the use of LMMs for within-participant data analysis and describes a free, simple, graphical user interface (LMMgui). LMMgui uses the package lme4 (Bates et al., 2014a,b) in the statistical environment R (R Core Team).

Cognitive control of language production in bilinguals involves a partly independent process within the domain-general cognitive control network: Evidence from task-switching and electrical brain activity

In highly proficient, early bilinguals, behavioural studies of the cost of switching language or task suggest qualitative differences between language control and domain-general cognitive control. By contrast, several neuroimaging studies have shown an overlap of the brain areas involved in language control and domain-general cognitive control. The current study measured both behavioural responses and event-related potentials (ERPs) from bilinguals who performed picture naming in single- or mixed-language contexts, as well as an alphanumeric categorisation task in single- or mixed-task context. Analysis of switch costs during the mixed-context conditions showed qualitative differences between language control and domain-general cognitive control. A 2 × 2 ANOVA of the ERPs, with domain (linguistic, alphanumeric) and context (single, mixed) as within-participant factors, revealed a significant interaction, which also suggests a partly independent language-control mechanism. Source estimations revealed the neural basis of this mechanism to be in bilateral frontal-temporal areas.

Binaural sluggishness precludes temporal pitch processing based on envelope cues in conditions of binaural unmasking

Binaural sluggishness refers to the binaural systems inability to follow fast changes in the interaural configuration of the incoming sound stream. Several studies have measured binaural sluggishness by measuring signal detection in conditions of binaural unmasking when the interaural configuration of the masker is changed over time. However, it has been shown that, in conditions of binaural unmasking, binaural sluggishness also affects the perception of temporal changes in the properties of the signal (i.e., its frequency or level) and not just in the interaural configuration of the masker. By measuring the temporal modulation transfer function for sinusoidally modulated noise presented in conditions of binaural unmasking, the first experiment of the current study showed that, due to binaural sluggishness, the internal representation of binaurally unmasked sounds conveys little or no information about envelope fluctuations with rates within the pitch range (i.e., above 30 Hz). The second experiment measured the masked detection threshold for musical interval recognition in binaurally unmasked harmonic tones and showed that, in conditions of binaural unmasking, pitch wanes when the harmonics become unresolved by the cochlear filters. These results suggest that binaural sluggishness precludes temporal pitch processing based on envelope cues in binaurally unmasked sounds.

Electrical neuroimaging during auditory motion aftereffects reveals that auditory motion processing is motion sensitive but not direction selective

Following prolonged exposure to adaptor sounds moving in a single direction, participants may perceive stationary-probe sounds as moving in the opposite direction [direction-selective auditory motion aftereffect (aMAE)] and be less sensitive to motion of any probe sounds that are actually moving (motion-sensitive aMAE). The neural mechanisms of aMAEs, and notably whether they are due to adaptation of direction-selective motion detectors, as found in vision, is presently unknown and would provide critical insight into auditory motion processing. We measured human behavioral responses and auditory evoked potentials to probe sounds following four types of moving-adaptor sounds: leftward and rightward unidirectional, bidirectional, and stationary. Behavioral data replicated both direction-selective and motion-sensitive aMAEs. Electrical neuroimaging analyses of auditory evoked potentials to stationary probes revealed no significant difference in either global field power (GFP) or scalp topography between leftward and rightward conditions, suggesting that aMAEs are not based on adaptation of direction-selective motion detectors. By contrast, the bidirectional and stationary conditions differed significantly in the stationary-probe GFP at 200 ms poststimulus onset without concomitant topographic modulation, indicative of a difference in the response strength between statistically indistinguishable intracranial generators. The magnitude of this GFP difference was positively correlated with the magnitude of the motion-sensitive aMAE, supporting the functional relevance of the neurophysiological measures. Electrical source estimations revealed that the GFP difference followed from a modulation of activity in predominantly right hemisphere frontal-temporal-parietal brain regions previously implicated in auditory motion processing. Our collective results suggest that auditory motion processing relies on motion-sensitive, but, in contrast to vision, non-direction-selective mechanisms.

Experience-based auditory predictions modulate brain activity to silence as do real sounds

Interactions between stimulis acoustic features and experience-based internal models of the environment enable listeners to compensate for the disruptions in auditory streams that are regularly encountered in noisy environments. However, whether auditory gaps are filled in predictively or restored a posteriori remains unclear. The current lack of positive statistical evidence that internal models can actually shape brain activity as would real sounds precludes accepting predictive accounts of filling-in phenomenon. We investigated the neurophysiological effects of internal models by testing whether single-trial electrophysiological responses to omitted sounds in a rule-based sequence of tones with varying pitch could be decoded from the responses to real sounds and by analyzing the ERPs to the omissions with data-driven electrical neuroimaging methods. The decoding of the brain responses to different expected, but omitted, tones in both passive and active listening conditions was above chance based on the responses to the real sound in active listening conditions. Topographic ERP analyses and electrical source estimations revealed that, in the absence of any stimulation, experience-based internal models elicit an electrophysiological activity different from noise and that the temporal dynamics of this activity depend on attention. We further found that the expected change in pitch direction of omitted tones modulated the activity of left posterior temporal areas 140–200 msec after the onset of omissions. Collectively, our results indicate that, even in the absence of any stimulation, internal models modulate brain activity as do real sounds, indicating that auditory filling in can be accounted for by predictive activity.

Can the binaural system extract fine-structure interaural time differences from noncorresponding frequency channels?

Due to the phase differences in the basilar membrane response between neighboring places along the cochlea, it is generally assumed that the processing of interaural time differences (ITDs) in the temporal fine structure relies on comparisons between corresponding frequency channels from the two ears. This study was aimed to test whether the auditory system is capable of extracting fine-structure ITDs from noncorresponding channels. For that, the ITD discrimination threshold was measured for a 500 Hz pure tone partially masked by a lowpass masker in one ear and a highpass masker in the other. The maskers were intended to obscure the apical or basal part of the tones excitation pattern, respectively, and thus force the listener to extract ITDs from disparate channels. While the results did not allow any definite conclusions as to whether or not ITD processing in these conditions was based on cross-channel comparisons, some aspects of the data suggest that it was. Modeling simulations showed that any cross-channel comparisons would have to be limited to a fairly narrow frequency range of little more than one auditory-filter bandwidth. However, the between-channel phase differences within even such a narrow range would be sufficient to explain ITD sensitivity in neurophysiological data.

Restricted left gyrus rectus hemorrhage with unusual frontal syndrome presentation.

and collaborating patient with a Glasgow Coma Scale of 14/15 and no neurological deficit or lateralizing signs. The brain CT scan showed a left inferior frontal sub-arachnoid hemorrhage secondary to an aneurysm rupture from the distal left ca-rotid artery bifurcation (M1; grade: Fisch-er IV, HH3, WFNS2), spread to both syl-vian fissures and in the perimesencephalic cistern, which was associated with a left GR parenchymatous hemorrhage. She was treated by cerebral arteriography with em-bolization of the aneurysm by placement of 3 Guglielmi detachable coils, with an ex-cellent result. There were no complications following this procedure. A bedside neuropsychological assess-ment performed 6 days after symptom on-set showed a preserved orientation to time, place, and person, fluent and informative spontaneous oral expression, very slight word-finding difficulties (Boston Naming Test 15/34) and impairment of verbal cate-gory-specific and literal fluency, maxi-mum name of animals (5) and a word be-ginning with M (3) in 1 min, but preserved comprehension (complex command 4 out of 4 correctly executed). There were also slight verbal memory deficits, and a major behavioral slowdown with lack of initia-tive in action and in language that impact-ed on other cognitive functions as oral cal-culation (prolonged thinking time, loss of her train of thought in the course of calcu- De, r Si ar The study of localized and well-cir-cumscribed brain lesions has contributed greatly to our understanding of the func-tion of single brain areas. The gyrus rectus (GR) is part of Brodmann’s area (BA) 11, which together with BA 10 and BA 47 form the orbito-frontal cortex. Lesions of this region are classically associated with dis-inhibition syndromes even if some reports described very few or no behavioral symp-toms after such lesions [1–3] . Here we re-port the case of a 59-year-old woman who suffered a subarachnoid hemorrhage asso-ciated with a restricted lesion of her left GR, with an unusual frontal syndrome presentation.

Auditory time perception in Huntington's disease

Background: Huntingtons disease (HD) is characterized by early involvement of the striatum. It affects the pace of repetitive motor activity, as motor timing depends on basal ganglia activity. However, data are lacking on the impact of this process on auditory time perception in motor non‐affected gene carriers. Objective: This work aims to test the performance in time perception of a group of mutation carriers, either without motor symptoms or at an early stage of motor involvement. This should allow designing therapies targeting compensation strategies and possibly be used as a disease progression marker. Method: Time was assessed using two different tasks. An absolute, duration‐based time perception was assessed in a first task and a relative, beat‐based time perception was assessed in a second one. HD‐mutation carriers with low‐to‐middle grades of motor involvement (HD‐motor, n = 10) or without motor signs (HD‐premotor n = 21), were compared with age‐ and sex‐matched healthy controls (control (n = 27)). Thresholds of time difference perception where assessed. Results: For both tasks, poorer performances were found in HD‐motor patients as compared with HD‐premotor and controls. Thresholds of time difference perception correlated positively with the CAP score for the whole group of HD‐gene carriers in both tasks. In a post‐hoc exploratory analysis performed by a multiple regression, a negative correlation was found between the thresholds in both tasks and the Stroop interference test. Furthermore, in the first task, a positive correlation was found between thresholds and a trail making B test and a negative one with a total functional score. Conclusion: Our data confirm that the impairment in time perception in persons affected by HD correlates with the advancing disease. They also suggest that time perception depends on similar cognitive mechanisms as the ones sub‐serving the Stroop interference test. HighlightsCortico‐striatal pathways are involved in time perception.Time perception is impaired in HD, in line with striatal involvement early in disease process.Impaired time perception is related to the disease burden.Assessment of time perception might be helpful in measuring disease progression.

Human cortical responses to change in sound lateralization suggest non‐topographical coding of interaural time differences

It is generally assumed that interaural time differences (ITDs) are coded by a parametric array of finely tuned ITD channels (topographic code). An alternative theory is that ITD is coded by a rate code, which involves only one channel in each hemisphere, broadly tuned to the contralateral hemispace. The aim of the current study was to investigate ITD coding in humans by using electroencephalography (EEG) with a continuous stimulation paradigm (CSP). In this paradigm, a test sound, with a given ITD, is immediately preceded by an appropriately matched control sound with a different ITD. At the transition from the test to the control sound, only neural elements that respond to the test but not the control ITD would be expected to be activated. Thus, the size of the transition response would be assumed to be determined by the degree of overlap between the neural responses to the control and test ITDs. The pattern of results was found to be inconsistent with the topographic model, and thus lend support to the...