No description available.

No description available.

No description available.

To date, only one study has situationally bolstered attentional resources in an effort to improve P300-BCI performance. The current study implements a 4-week Mindfulness Meditation Training Program (MMTP) as a nonmedicinal means to increase concentrative attention and to reduce lapses of attention; MMTP is expected to improve P300-BCI performance by enhancing attentional resources and reducing distractibility. A second aim is to test the efficacy of the checkerboard paradigm (CBP) against the standard row-column paradigm (RCP). Online results show that MMTP had greater accuracies than CTRL and that CBP outperformed the RCP. MMTP participants provided greater amplitude positive target responses, but these differences were not statistically significant. CBP had greater positive amplitude peaks and negative peaks than RCP. The discussion focuses on potential benefits of MMTP for P300-based BCIs, provides further support for the construct validity of mindfulness, and addresses future directions of the translational applicability of MMTP to in-home settings.

BACKGROUND: Food-related visual cues may affect eating behavior and energy intake. The purpose of this study was to determine the neural response to pictures of food and whether or not the neural responses were associated with energy intake. METHODS: Using a cross-sectional design, 60 adults participated in this study. Each participant reported to the laboratory in a fasted state, were fitted with a 128-electrode electroencephalogram (EEG) net, and were shown pictures grouped into three categories: high-calorie foods, low-calorie foods, and distractor pictures. These pictures were shown in random order. Furthermore, participants were shown these pictures in one passive condition and two active conditions (also in random order). The passive condition required participants to view pictures in a relaxed state while neural responses were recorded. The active conditions required participants to be actively engaged with the picture by pressing or withholding a specified button on a keyboard (go/no go task). The active conditions included only high- and low-calorie foods. Event Related Potentials (ERP) of interest were the N2, P300, and late positive potential (LPP). The National Cancer Institute's Automated Self-administered 24-hour Dietary Recall (ASA24) was used to assess energy and macronutrient intake. RESULTS: The N2 amplitude, when amplitude for high-calorie pictures is subtracted from the amplitude of low-calorie pictures, was significantly different for each active condition (F = 41.23; p < 0.0001). However, neural responses to picture-type for the N2, P300 and LPP were not different (p > 0.05). The difference in N2 amplitude, for the high-calorie no go condition that results from the amplitude for low and high-calorie pictures being subtracted from each other, was significantly associated with carbohydrate intake (r = -0.263) and significantly predicted carbohydrate intake (regression coefficient = -56.821; p = 0.043) but not energy, fat, or protein intake (p > 0.05). Neither the P300 nor the LPP was correlated with or predicted energy and macronutrient intake (p > 0.05). CONCLUSION: The N2 differentiates depending on the no go stimulus. The difference in N2 amplitude, for the high-calorie no go condition, may be an index of carbohydrate intake. The P300 and LPP do not appear to differentiate between pictures of high- and low-calorie foods, nor do they correlate with energy or macronutrient intake.

A biological marker of the addictive state would be a major breakthrough in objectively assessing the efficacy of treatment outcomes. Given its role in the mesolimbic system and drug reward, most biological marker studies for addiction focus on measures related to dopamine (DA). Dopamine is also implicated in some disorders of visual attention and plays a modulatory role in the processing of color in the retinal DA pathway. For example, visual processing in the retina has been shown to co-vary with DA levels during cocaine withdrawal. In this electroencephalographic (EEG) study, we studied event related potentials (ERPs) and reaction time (RT) in opiate addicts—recruited from a community-based high intensity residential substance abuse and detoxification treatment program—and their age- and gender- matched controls. Using a visual color recognition Go/NoGo task with three similar blocks, participants responded in each block to a "Relevant" stimulus of one of three randomly-presented Red, Green or Blue light stimuli as instructed, while ignoring the other two "Irrelevant" stimuli. This simple task produced robust ERPs that were well-differentiated in the visual evoked potentials (VEPs) obtained by the Relevant stimulus compared to the VEPs from Irrelevant distractor stimuli. P300 ERP amplitudes from the color recognition task were significantly higher in males than females. Similar results were obtained with the frontal late positive (LP) potentials (i.e., 700 msec after stimulus onset), which occurred 200-300 msec after the average participant response/RT. While there were no significant RT differences between controls and addicts in the task, male controls had significantly greater P300 and LP potentials than female controls, suggesting sex differences in visual color processing. However, there were also significant differences in P300 amplitudes male controls and addiction participants—suggesting a difference in retinal DA production in opiate addiction. Further to the hypothesis of sex differences in visual color processing, P300s and LPs were not significantly different in female controls compared to female addicts. Changing the color wavelength of the Relevant stimulus did not significantly affect ERPs in males or females, controls or addicts at P300 but did at LP, particularly when the color blue was relevant. These findings suggest that there are significant sex differences in retinal DA production for opiate addicts and controls in visual processing for a simple Go/NoGo color recognition task.

The 40 Hz auditory steady state response (ASSR) is an EEG response of local neural synchrony that is evoked by the repeated presentation of a 40 Hz click train. While the principal cortical generators of this response appear to be the bilateral primary auditory cortices as they show the largest phase locking and evoked power, other regions across the cortical mantle synchronize too, including the prefrontal cortex (PFC) that receives input from the primary auditory cortex and is involved in higher order cognitive functions. In schizophrenia, it is hypothesized that NMDA-mediated disruption in PFC function contributes to cognitive deficits including working memory and executive function. In rodents, NMDA antagonists reliably disrupt set shifting, a working memory task linked to PFC function. It is however not known if NMDA antagonism would disrupt the 40 Hz ASSR in PFC. In the following study, we equipped a group of female SD rats with epidural electrodes targeting the PFC (2.5 mm anterior and 0.8 mm lateral to bregma) and the primary auditory cortex (4.5 mm caudal, 7.5 mm lateral and 3.5 mm ventral to bregma). Two epidural screw electrodes on cerebellum served as ground and reference. After recovery from surgery and acclimation, rats were pretreated with small to modest doses of the NMDA antagonist MK801 (0.025, 0.05 and 0.1 mpk) or saline (1 ml/kg, sc) in a cross-over design, tethered to EEG cables and the EEG signal was amplified and acquired (Signal 7.0; CED1401 Micro 3). Trains of square waves (~ 1 ms duration; 40/s) were generated and played through the house speakers at ~ 65 dB SPL. EEG was acquired as 4 s sweeps while the click train played between 1-2 s of each sweep; 75 trials were recorded from each subject. Sixty minutes after vehicle treatment, robust EEG entrainment was noted in both the temporal cortex as well as the PFC. As expected, the EEG signal power from the temporal cortex was notably larger compared to the PFC. Nevertheless, both regions showed clear 40 Hz entrainment to click trains. However, MK801 effect on the 40 Hz ASSR was disparate across the two regions. In the prefrontal cortex, the intertrial coherence (ITC) of the 40 Hz ASSR was strongly disrupted by MK801 at all doses (P<0.001; Dunnett’s test). Evoked power was significantly reduced only at the highest dose (P<0.0001). In primary auditory cortex, relative to vehicle treatment, evoked power showed a significant increase after 0.025 mpk and 0.05 mpk dose but declined significantly after the 0.1 mpk dose (P<0.05). However, ITC was unaffected (P>0.05). These results indicate that gamma neural synchrony in the PFC is more vulnerable to NMDA antagonist- mediated disruption, as compared to the primary auditory cortex. Moreover, it suggests that executive and cognitive functions may be more readily compromised by NMDA-mediated transmission disturbance even as auditory processing is enhanced or unaffected.

No description available.

Objective: An electroencephalographic brain-computer interface (BCI) can provide a non-muscular means of communication for people with amyotrophic lateral sclerosis (ALS) or other neuromuscular disorders. We present a novel P300-based BCI stimulus presentation - the checkerboard paradigm (CBP). CBP performance is compared to that of the standard row/column paradigm (RCP) introduced by Farwell and Donchin (1988). Methods: Using an 8 × 9 matrix of alphanumeric characters and keyboard commands, 18 participants used the CBP and RCP in counter-balanced fashion. With approximately 9-12 min of calibration data, we used a stepwise linear discriminant analysis for online classification of subsequent data. Results: Mean online accuracy was significantly higher for the CBP, 92%, than for the RCP, 77%. Correcting for extra selections due to errors, mean bit rate was also significantly higher for the CBP, 23 bits/min, than for the RCP, 17 bits/min. Moreover, the two paradigms produced significantly different waveforms. Initial tests with three advanced ALS participants produced similar results. Furthermore, these individuals preferred the CBP to the RCP. Conclusions: These results suggest that the CBP is markedly superior to the RCP in performance and user acceptability. Significance: The CBP has the potential to provide a substantially more effective BCI than the RCP. This is especially important for people with severe neuromuscular disabilities.

Objective: Brain-computer interface (BCI) technology can provide severely disabled people with non-muscular communication. For those most severely disabled, limitations in eye mobility or visual acuity may necessitate auditory BCI systems. The present study investigates the efficacy of the use of six environmental sounds to operate a 6 × 6 P300 Speller. Methods: A two-group design was used to ascertain whether participants benefited from visual cues early in training. Group A (N = 5) received only auditory stimuli during all 11 sessions, whereas Group AV (N = 5) received simultaneous auditory and visual stimuli in initial sessions after which the visual stimuli were systematically removed. Stepwise linear discriminant analysis determined the matrix item that elicited the largest P300 response and thereby identified the desired choice. Results: Online results and offline analyses showed that the two groups achieved equivalent accuracy. In the last session, eight of 10 participants achieved 50% or more, and four of these achieved 75% or more, online accuracy (2.8% accuracy expected by chance). Mean bit rates averaged about 2 bits/min, and maximum bit rates reached 5.6 bits/min. Conclusions: This study indicates that an auditory P300 BCI is feasible, that reasonable classification accuracy and rate of communication are achievable, and that the paradigm should be further evaluated with a group of severely disabled participants who have limited visual mobility. Significance: With further development, this auditory P300 BCI could be of substantial value to severely disabled people who cannot use a visual BCI.