40-Hz auditory steady-state responses and the complex information processing: An exploratory study in healthy young males

Abstract

Electroencephalographic (EEG) activity in the gamma (30–80 Hz) range is related to a variety of sensory and cognitive processes which are frequently impaired in schizophrenia. Auditory steady-state response at 40-Hz (40-Hz ASSR) is utilized as an index of gamma activity and is proposed as a biomarker of schizophrenia. Nevertheless, the link between ASSRs and cognitive functions is not clear. This study explores a possible relationship between the performance on cognitive tasks and the 40-Hz ASSRs in a controlled uniform sample of young healthy males, as age and sex may have complex influence on ASSRs. Twenty-eight young healthy male volunteers participated (mean age ± SD 25.8±3.3) in the study. The 40-Hz click trains (500 ms) were presented 150 times with an inter-stimulus interval set at 700–1000 ms. The phase-locking index (PLI) and event-related power perturbation (ERSP) of the ASSR were calculated in the 200–500 ms latency range, which corresponds to the steady part of the response. The Psychology Experiment Building Language (PEBL) task battery was used to assess five cognitive subdomains: the Choice response time task, the Stroop test, the Tower of London test, the Lexical decision task and the Semantic categorisation task. Pearson‘s correlation coefficients were calculated to access the relationships; no multiple-test correction was applied as the tests were explorative in nature. A significant positive correlation was observed for the late-latency gamma and the mean number of steps in the Tower of London task reflecting planning and problem-solving abilities. These findings support the concept that 40-Hz ASSR might highlight top-down mechanisms which are related to cognitive functioning. Therefore, 40-Hz ASSRs can be used to explore the relationship between cognitive functioning and neurophysiological indices of brain activity.

Gamma-Range Auditory Steady-State Responses and Cognitive Performance: A Systematic Review

“…Most of the studies examined multiple cognitive domains and used neuropsychological batteries: BACS [ 44 , 59 , 69 , 70 ], WAIS [ 75 ], ADAS-cog subscale [ 55 ], MATRICS MCCB [ 76 ], or different subtests from various batteries like WAIS [ 73 , 74 ] and PEBL [ 71 ]. Three of the studies evaluated only global cognitive functioning [ 59 , 61 , 69 ].…”

“…Rass et al, Sun et al, and Gaskins et al did not include the early response (0–100 ms) part [ 60 , 73 , 74 , 76 ]. Murphy et al, Tada et al, and Parčiauskaite et al evaluated only the late-latency gamma (starting at 200 ms after stimulus onset) activity [ 44 , 70 , 71 ]. Finally, Arrondo et al and Lehongre et al focused on the time window of the maximal gamma response occurrence [ 58 , 68 ].…”

“…In healthy participants, the gamma-range ASSR was related to cognitive flexibility and reasoning as measured by complex tasks such as Tower of London [ 71 ], Similarities [ 73 ], and the Mazes Test [ 76 ]. Additionally, the ASSR was related to behavioral indicators of processing speed, i.e., performance on the Trial making test [ 76 ] and Symbol coding [ 74 ].…”

“…Additionally, performance on several tasks tapping cognitive flexibility and reasoning correlated with measures of gamma-range ASSRs [ 71 , 74 , 76 ] in healthy controls [ 71 , 74 , 76 ] and patients with schizophrenia [ 74 , 76 ]. However, tasks evaluating cognitive flexibility and reasoning are defined by high versatility, and the functions they assess are intricately covering attentional control/executive functioning and memory processes [ 83 , 84 ].…”

“…This makes evaluation of a particular aspect that is contributing to the observed relationship difficult. For example, the moves on the Tower of London task (ToL), as assessed in reviewed papers, were positively correlated to the synchronization levels of gamma-range activity [ 71 ]. Cazalis et al proposed that standard performers on ToL might need to put the higher load on working memory to perform the task, compared to superior performers [ 85 ].…”