Elastic attention: enhanced, then sharpened response to auditory input as attentional load increases

Abstract

A long debate in selective attention research is whether attention enhances sensory response or sharpens neural tuning by suppressing response to non-target input. In fact, both processes may occur as a function of load: an uncertain listener might use a broad attentional filter to enhance responses to all inputs (i.e., vigilance), yet employ sharpened tuning to focus on hard to discriminate targets. The present work used the greater signal gain, anatomical precision, and laterality separation of intracranial electrophysiological recordings (electrocorticograms) to investigate these competing effects. Data were recorded from acoustically-responsive cortex in the perisylvian region of a single hemisphere in five neurosurgery patients. Patients performed a dichotic listening task in which they alternately attended toward, away from, or completely ignored (silent reading) tones presented to designated ears at varying presentation rates. Comparisons between the grand-averaged event-related potential (ERP) waveforms show a striking change in the effect of selective auditory attention with attentional load. At slower presentation rates (low-load), ERPs were overall enhanced in response to both input channels and regardless of attended ear, including a significant enhancement of ipsilateral input. This result supports a broadly enhancing model of attention under low perceptual load conditions. At the fastest rate, however, only responses to attended inputs contralateral to grid location remained enhanced. This result supports an increasing suppression, or “sharpening,” of neural responses to non-targets with increasing attentional load. These data provide support for an elastic model of attention in which attentional scope narrows with increasing load.

Modulation of response patterns in human auditory cortex during a target detection task: An intracranial electrophysiology study

“…However, there was a markedly enhanced ERBP response both in magnitude and duration when the 0.5 kHz tone was the target stimulus. Surprisingly, there was no significant increase in the AEP amplitude when the 0.5 kHz tone was the target as suggested by previous studies (Kiehl et al, 2001; Neelon et al, 2006, 2011). …”

“…This failure included examination of AEPs recorded from HG and PLST. In contrast, selective attention tasks have been shown to modulate AEP components recorded directly from grid electrodes located on PLST (Neelon et al, 2006, 2011). During the performance of behavioral tasks in the auditory modality, enhancements of exogenous AEP components such as N1 and generation of endogenous components such as processing negativities and the target-specific N2 component are routinely observed (e.g.…”

Effect of Water Immersion on Dual-task Performance: Implications for Aquatic Therapy

“…Certainly, the postural motor task in the current study (double‐leg stance) was not difficult as evidenced by the minimal CoP sway areas in the elderly single‐case patient. However, the rate of the letter sequences in the cognitive task (1.6 Hz) approached maximal frequency for perceptual sensitivity in young adult participants (Neelon et al ., ). Moreover, participants in our study verbally expressed the cognitive task by itself as being ‘challenging’.…”

Temporal regularity facilitates higher‐order sensory predictions in fast auditory sequences

“…Interestingly, in our control experiment temporal regularity appears to shift ERPs in the MMN/N2 latency range to more negative values, similarly to the effects of attention to sounds (negative difference, Näätänen, ; Alho et al ., ). Speculatively, it could be argued that both temporal regularity and attention translate into sharpened neuronal responses (Neelon et al ., ).…”