The role of the human anterior insular cortex in time processing

Abstract

The anterior portion of the human insula is implicated in a wide range of tasks that involve judgements of short periods of time (a few seconds or less). However, it is only one of several brain regions that share this property. We review the evidence for its involvement and discuss the nature of the contribution it might make to time judgements. The anterior insula is frequently identified in functional MRI studies that require participants to generate a time interval to match an internal or external template, or to discriminate between the durations of two stimuli. It is involved in many different timing tasks and is active irrespective of the stimulus modality used to present the stimuli. However, the role of the anterior insula in timing remains uncertain. Indeed, rather few studies have attempted to distinguish different possible contributions. The fact that it is active in a variety of tasks suggests that it may be involved in some indirect or general way. For example, during time discrimination, the anterior insula may be concerned more with discrimination than with time, as it is sometimes also active during other discrimination tasks. Other structures may be more strongly associated with core timing functions.

Distortion of time interval reproduction in an epileptic patient with a focal lesion in the right anterior insular/inferior frontal cortices

“…a higher variability) in a duration discrimination task using sub-and supra-second intervals (Gooch et al, 2011). This result further strengthens the notion that the right hemispheric AIC/IFC is preferentially recruited for explicit timing (Coull & Nobre, 2008;Coull, Davranche, Nazarian, & Vidal, 2013;Kosillo & Smith, 2010;Lewis & Miall, 2006;Wiener et al, 2010).…”

Anterior insula activations in perceptual paradigms: often observed but barely understood

“…In this patient, engagement in a visual discrimination task was associated with right AIC activation that was particularly strong in the unaware mode, i.e., when stimuli were presented in the blind hemifield (Sahraie et al 1997). This finding speaks of the possibility that AIC activation may reflect task difficulty rather than awareness per se (see also review on time perception by Kosillo and Smith (2010), in this issue). Such a view on the insula's role in perception may help to explain why several more studies than the one mentioned above (Kleinschmidt et al 2002) that compared awareness and unawareness of visual events failed to observe AIC activations.…”

Felt and Seen Pain Evoke the Same Local Patterns of Cortical Activity in Insular and Cingulate Cortex

“…Furthermore, brain regions showing shared emotional activations, such as AIns, have been associated with many other functions beside pain, emotion, and empathy (Kurth et al, 2010), including attention (Corbetta et al, 2008;Menon and Uddin, 2010), time perception (Kosillo and Smith, 2010), and motor agency (Karnath and Baier, 2010). It is therefore unclear whether shared activations in these regions reflect the activity of a unique population of bimodal neurons sensitive to one's and others' pain or distinct but intermingled neuronal groups each recruited by a different pain target, and whether these neurons code for somatic pain specifically or for other negative/aversive information more generally.…”