EEG Biometrics: On the Use of Occipital Cortex Based Features from Visual Evoked Potentials

The potential of using Electro-Encephalo-Gram (EEG) data as a biometric identifier is studied. This is the first study that assesses looming stimuli for the creation of biometrically useful Visual Evoked Potentials (VEP), i.e. EEG responses due to visual stimuli. A novel method for the detection of VEP responses with minimal expert interaction is introduced. The EEG data, segmented based on the VEP, are used to create a reliable feature vector. In contrast to previous studies, we provide a publicly available evaluation dataset based on infants which is therefore not biased due to unhealthy individuals. Only data from the occipital cortex are used (i.e. about 3 of the many possible electrode positions in the scalp), making the potential EEG biometric capture devices relatively simpler

A high-density EEG study of differences between three speeds of ecological forward motion in adult participants

A high-density EEG study was conducted to investigate evoked and oscillatory activity in response to three different stimulus speeds of simulated forward motion in adult participants. Participants were shown an optic flow stimulus consisting of a virtual road with moving poles at either side of it simulating forward motion at three different speeds (low, medium, and high) with a static control condition between each motion condition. The aim was to analyse the N2 component of visual motion and the evoked oscillatory activity in occipital and parietal areas. A significant difference in N2 latencies and peak amplitudes between the three stimulus speeds were found in parietal channels P3 and P4. The peak latency significantly increased as the simulated speeds increased, while the peak amplitudes decreased at increasing speeds. The latency differences were thought to indicate that the low simulated speed was easier to process than the faster medium and high simulated speeds, while the change in peak amplitude seemed to be the result of a greater number of neurons being attuned to the lower as opposed to the higher stimulus speeds. Theta-band synchronizations and alpha-band de-synchronizations in the three different speeds were observed, but no significant differences between the speeds were found. The static condition, in contrast, showed theta-band de-synchronizations and alpha-band synchronizations. Significant differences between the alpha de-synchronizations in the three different speeds and the alpha synchronizations in the static condition were found in the parietal midline source, while no significant differences were found between conditions in the theta oscillations. It was suggested that the alpha de-synchronizations reflect an activated state, possibly related to the visual processing of the three speeds, whereas the alpha synchronizations in response to the static condition reflect a deactivated resting period

A high-density EEG study of differences between three high speeds of simulated forward motion from optic flow in adult participants

A high-density EEG study was conducted to investigate evoked and oscillatory brain activity in response to high speeds of simulated forward motion. Participants were shown an optic flow pattern consisting of a virtual road with moving poles at either side of it, simulating structured forward motion at different driving speeds (25, 50, and 75 km/h) with a static control condition between each motion condition. Significant differences in N2 latencies and peak amplitudes between the three speeds of visual motion were found in parietal channels of interest P3 and P4. As motion speed increased, peak latency increased while peak amplitude decreased which might indicate that higher driving speeds are perceived as more demanding resulting in longer latencies, and as fewer neurons in the motion sensitive areas of the adult brain appear to be attuned to such high visual speeds this could explain the observed inverse relationship between speed and amplitude. In addition, significant differences between alpha de-synchronizations for forward motion and alpha synchronizations in the static condition were found in the parietal midline (PM) source. It was suggested that the alpha de-synchronizations reflect an activated state related to the visual processing of simulated forward motion, whereas the alpha synchronizations in response to the static condition reflect a deactivated resting period

A high-density EEG study of differences between three high speeds of simulated forward motion from optic flow in adult participants

A high-density EEG study was conducted to investigate evoked and oscillatory brain activity in response to high speeds of simulated forward motion. Participants were shown an optic flow pattern consisting of a virtual road with moving poles at either side of it, simulating structured forward motion at different driving speeds (25, 50, and 75 km/h) with a static control condition between each motion condition. Significant differences in N2 latencies and peak amplitudes between the three speeds of visual motion were found in parietal channels of interest P3 and P4. As motion speed increased, peak latency increased while peak amplitude decreased which might indicate that higher driving speeds are perceived as more demanding resulting in longer latencies, and as fewer neurons in the motion sensitive areas of the adult brain appear to be attuned to such high visual speeds this could explain the observed inverse relationship between speed and amplitude. In addition, significant differences between alpha de-synchronizations for forward motion and alpha synchronizations in the static condition were found in the parietal midline (PM) source. It was suggested that the alpha de-synchronizations reflect an activated state related to the visual processing of simulated forward motion, whereas the alpha synchronizations in response to the static condition reflect a deactivated resting period

A high-density EEG study of differentiation between two speeds and directions of simulated optic flow in adults and infants

A high‐density EEG study was carried out to investigate cortical activity in response to forward and backward visual motion at two different driving speeds, simulated through optic flow. Participants were prelocomotor infants at the age of 4–5 months and infants with at least 3 weeks of crawling experience at the age of 8–11 months, and adults. Adults displayed shorter N2 latencies in response to forward as opposed to backward visual motion and differentiated significantly between low and high speeds, with shorter latencies for low speeds. Only infants at 8–11 months displayed similar latency differences between motion directions, and exclusively in response to low speed. The developmental differences in latency between infant groups are interpreted in terms of a combination of increased experience with self‐produced locomotion and neurobiological development. Analyses of temporal spectral evolution (TSE, time‐dependent amplitude changes) were also performed to investigate nonphase‐locked changes at lower frequencies in underlying neuronal networks. TSE showed event‐related desynchronization activity in response to visual motion for infants compared to adults. The poorer responses in infants are probably related to immaturity of the dorsal visual stream specialized in the processing of visual motion and could explain the observed problems in infants with differentiating high speeds of up to 50 km/h

Towards a cellular food future: Final recommendations from the Protein 2.0 project to Norwegian policy makers and food system actors

publishedVersio

Towards a cellular food future: Final recommendations from the Protein 2.0 project to Norwegian policy makers and food system actors

publishedVersio