Differences in MEG gamma oscillatory power during performance of a prosaccade task in adolescents with FASD

Abstract

Fetal alcohol spectrum disorder (FASD) is characterized by a broad range of behavioral and cognitive deficits that impact the long-term quality of life for affected individuals. However, the underlying changes in brain structure and function associated with these cognitive impairments are not well-understood. Previous studies identified deficits in behavioral performance of prosaccade tasks in children with FASD. In this study, we investigated group differences in gamma oscillations during performance of a prosaccade task. We collected magnetoencephalography (MEG) data from 15 adolescents with FASD and 20 age-matched healthy controls (HC) with a mean age of 15.9 ± 0.4 years during performance of a prosaccade task. Eye movement was recorded and synchronized to the MEG data using an MEG compatible eye-tracker. The MEG data were analyzed relative to the onset of the visual saccade. Time-frequency analysis was performed using Fieldtrip with a focus on group differences in gamma-band oscillations. Following left target presentation, we identified four clusters over right frontal, right parietal, and left temporal/occipital cortex, with significantly different gamma-band (30–50 Hz) power between FASD and HC. Furthermore, visual M100 latencies described in Coffman etal. (2012) corresponded with increased gamma power over right central cortex in FASD only. Gamma-band differences were not identified for stimulus-averaged responses implying that these gamma-band differences were related to differences in saccade network functioning. These differences in gamma-band power may provide indications of atypical development of cortical networks in individuals with FASD.

Fetal Alcohol Spectrum Disorders: Recent Neuroimaging Findings

“…This magnitude escalation may reflect increases in local field potential synchrony, amplitude (power) or both [41]. In FASD, relative increases in gamma oscillations were seen in right frontal clusters, while relative decreases occurred in right parietal and left temporal/occipital clusters [42]. These gamma-band power changes occurred despite a lack of difference in task performance in these groups.…”

“…These gamma-band power changes occurred despite a lack of difference in task performance in these groups. In addition, in adolescents with FASD there was a positive relationship between M100 peak latency and gamma oscillatory power in a cluster located around the medial frontal eye field region [42]. No such relationship was apparent in controls, and gamma-band power was not correlated with saccadic reaction time in either group.…”

Altered Neural Oscillations During Multisensory Integration in Adolescents with Fetal Alcohol Spectrum Disorder

“…In fact, PAE rats showed a loss of GABA A receptor mediated long-term potentiation, which can result in an imbalance between excitatory and inhibitory synaptic transmission (Zucca and Valenzuela, 2010). These imbalances in synaptic transmission can lead to the irregularities in neural oscillations found in studies like our own, which reported alterations in gamma band oscillations in children with FASD compared to controls during a prosaccade task (Stephen et al, 2013). When combined, the prior results provide evidence of deficits in neural oscillations and a possible deficit in multisensory integration in individuals with FASD.…”

“…Data for this study were collected as part of a larger, multimodal neuroimaging study (see Coffman et al, 2013, Stephen et al 2013). Participants’ brain responses were recorded using MEG during passive auditory and somatosensory stimulation.…”

“…Rats with PAE also demonstrate altered response to tactile stimuli in social situations (Lawrence et al, 2008). Finally, children with FASD demonstrate behavioral patterns of sensory over-responsivity to tactile, auditory, and visual stimuli, as well as patterns of sensory under-responsivity, sensation-seeking behaviors, and poor auditory filtering (Jirikowic et al, 2008; Coffman et al, 2013; Stephen et al, 2012; Stephen et al, 2013). Sensory processing is vital to development, and necessary for individuals to interact appropriately with the environment (Schaaf and Miller, 2005).…”