Task difficulty in mental arithmetic affects microsaccadic rates and magnitudes.
Microsaccades are involuntary, small-magnitude saccadic eye movements that occur during attempted visual fixation. Recent research has found that attention can modulate microsaccade dynamics, but few studies have addressed the effects of task difficulty on microsaccade parameters, and those have obtained contradictory results. Further, no study to date has investigated the influence of task difficulty on microsaccade production during the performance of non-visual tasks. Thus, the effects of task difficulty on microsaccades, isolated from sensory modality, remain unclear. Here we investigated the effects of task difficulty on microsaccades during the performance of a non-visual, mental arithmetic task with two levels of complexity. We found that microsaccade rates decreased and microsaccade magnitudes increased with increased task difficulty. We propose that changes in microsaccade rates and magnitudes with task difficulty are mediated by the effects of varying attentional inputs on the rostral superior colliculus activity map.
Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA.
Eva
E
Siegenthaler
Francisco M
FM
Costela
Michael B
MB
McCamy
Leandro L
LL
Di Stasi
Jorge
J
Otero-Millan
Andreas
A
Sonderegger
Rudolf
R
Groner
Stephen
S
Macknik
Susana
S
Martinez-Conde
D000328:Adult; D001288:Attention; D053483:Eye Movement Measurements; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D011340:Problem Solving; D012438:Saccades; D011795:Surveys and Questionnaires; D013647:Task Performance and Analysis; D013997:Time Factors
attention; fixational eye movements; microsaccades; task load