Browsing by Author "Pittman, Daniel J."

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    Gaze and motor control of ADHD adolescents and controls: the effects of temporal delays in goal parameter presentation
    (2004) Pittman, Daniel J.; Vickers, Joan Norma
    The gaze and motor performance of adolescent males with Attention-Deficit /Hyperactivity disorder (ADHD) and age-matched controls was determined in a computer-based simulation of a table tennis task used previously by Rodrigues et al (2002) and Vickers et al (2002). The Temporal Processing Task (TPT) was developed using the same time parameters and included visual cues that indicated two target locations to which a served ball was to be returned. During the long duration (LD) condition, the target was illuminated so that two seconds was available to prepare and respond, while in the short duration (SD) condition only 450 ms was available. Similarly to Vickers et al, the ADHD group was less accurate than the control group, and they also had irregular arm velocity at contact. However, contrary to Vickers et al, no group differences were found for gaze frequency, or the onset or duration of the quiet eye period. New findings were also found in the TPT that were not present in the previous studies. Movement time onset was significantly earlier for the ADHD group during successful LD trials, and participants from both groups tended toward a centralized fixation that was not apparent in the real task. The TPT did not appear to place the same pursuit tracking demands on the participants as did the actual task. The results cast some doubt upon the ecologically validity of computer-based tasks for testing ADHD participants, and suggest that ADHD research, particularly that which involves gaze behaviors, be performed using tasks with high ecological validity. The differences between the real task and the TPT are examined, and the results are discussed relative to disinhibitory models, as well as the potential implications of computer-based activities for those with ADHD.
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    Manipulating visual scanpaths during facial emotion perception modulates functional brain activation in schizophrenia patients and controls
    (2019-09) Spilka, Michael J.; Pittman, Daniel J.; Bray, Signe L.; Goghari, Vina M.
    Individuals with schizophrenia exhibit deficits in facial emotion processing, which have been associated with abnormalities in visual gaze behaviour and functional brain activation. However, the relationship between gaze behaviour and brain activation in schizophrenia remains unexamined. Studies in healthy individuals and other clinical samples indicate a relationship between gaze behaviour and functional activation in brain regions implicated in facial emotion processing deficits in schizophrenia (e.g., fusiform gyrus), prompting the question of whether a similar relationship exists in schizophrenia. This study examined whether manipulating visual scanpaths during facial emotion perception would modulate functional brain activation in a sample of 23 schizophrenia patients and 26 community controls. Participants underwent functional magnetic resonance imaging while viewing pictures of emotional faces. During the typical viewing condition, a fixation cue directed participants’ gaze primarily to the eyes and mouth, whereas during the atypical viewing condition gaze was directed to peripheral features. Both viewing conditions elicited a robust response throughout face-processing regions. Typical viewing led to greater activation in visual association cortex including the right inferior occipital gyrus/occipital face area, whereas atypical viewing elicited greater activation in primary visual cortex and regions involved in attentional control. There were no between-group activation differences in response to faces or interaction between group and gaze manipulation. The results indicate that gaze behaviour modulates functional activation in early face-processing regions in individuals with and without schizophrenia, suggesting that abnormal gaze behaviour in schizophrenia may contribute to activation abnormalities during facial emotion perception.