Mark W. Geisler

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The Trail Making Test (TMT) is primarily a test of motor speed and visual attention. In Trail Making, Part A, the subject's task is to quickly draw lines on a page connecting 25 consecutive numbers. In Part B, the subject must draw the lines alternating between numbers and letters. To determine what makes Part B harder than Part A, variations of the(More)
The P300 or P3 component of the event-related brain potential (ERP) was obtained from five groups of 24 young adult subjects, with each group measured at a different time of day (8 a.m., 11 a.m., 2 p.m., 5 p.m., 8 p.m.). An activity-preference questionnaire was used to ensure that an equitable number of morning- and evening-preferring subjects were obtained(More)
BACKGROUND Amantadine hydrochloride and pemoline, both frequently used to treat the fatigue of multiple sclerosis (MS), may also improve attention and other cognitive functions in MS. To our knowledge, these agents have never been compared in a placebo-controlled trial of patients with MS. OBJECTIVE To evaluate the effects of amantadine and pemoline on(More)
This study examined mood-relevant emotion processing in depression using event-related potentials (ERPs). Cognition in depression has been characterized as having attention and memory biases for negative (or mood relevant) information and away from positive (or mood incongruent) information, however, the time course and specificity of this processing during(More)
The P300 (P3) event-related brain potential (ERP) was elicited with auditory and somatosensory stimuli using an easy discrimination task in two experiments. Experiment 1 manipulated target stimulus probability (0.20 vs. 0.80). Experiment 2 manipulated inter-stimulus interval (2 s vs. 6 s) for both stimulus modalities in different conditions while keeping(More)
Event-related brain potentials (ERPs) were recorded from 26 young adults, with equal numbers of male and female subjects, using attended and ignored, olfactory and trigeminal stimuli. The amplitudes and latencies of the N1, P2, and P3 components were recorded using a single-stimulus paradigm, with an inter-stimulus interval of 60 s, employing amyl acetate(More)
Olfactory event-related potentials (OERPs) were recorded monopolarly at the Fz, Cz, and Pz electrode sites in 16 young adults (8M/8F) and 16 older adults (8M/8F) with inter-stimulus intervals (ISI) of 45, 60 and 90 s using amyl acetate as the odorant stimulus. N1, P2, and N2 peak amplitudes and latencies were measured. Young participants demonstrated(More)
Unlike the clinical usages of evoked potentials (e.g. brain stem auditory evoked potentials for the assessment of auditory function), normative data for the olfactory event-related potential (OERP) have been unavailable. The principal objective was to establish normative data across the human life span for OERPs with a given set of parameters. Participants(More)
The use of bilateral eye movements (EMs) is an important component of Eye Movement Desensitization and Reprocessing (EMDR) therapy for posttraumatic stress disorder. The neural mechanisms underlying EMDR remain unclear. However, prior behavioral work looking at the effects of bilateral EMs on the retrieval of episodic memories suggests that the EMs enhance(More)
The effects of glucose ingestion on the P3(00) event-related brain potential (ERP) were investigated by using a visual stimulus oddball paradigm in which subjects discriminated between checkerboard (target) and horizontal line (standard) stimuli. Subjects were assessed for six consecutive trial blocks that were spaced 20 min apart on two different(More)