Temporal Processing Asymmetries Between the Cerebral Hemispheres: Evidence and Implications

Abstract

This paper reviews a large body of research which has investigated the capacities of the cerebral hemispheres to process temporal information. This research includes clinical, non-clinical, and electrophysiological experimentation. On the whole, the research supports the notion of a left hemisphere advantage for temporal resolution. The existence of such an asymmetry demonstrates that cerebral lateralisation is not limited to the higher-order functions such as language. The capacity for the resolution of fine temporal events appears to play an important role in other left hemisphere functions which require a rapid sequential processor. The functions that are facilitated by such a processor include verbal, textual, and fine movement skills. The co-development of these functions with an efficient temporal processor can be accounted for with reference to a number of evolutionary scenarios. Physiological evidence favours a temporal processing m echanism located within the left temporal cortex. The function of this mechanism may be described in terms of intermittency or travelling moment models of temporal processing. The travelling moment model provides the most plausible account of the asymmetry. IN T R O D U C T IO NTh e inherent bipartite nature of the cerebral hem ispheres has prom pted many researchers to portray hem ispheric psychological functions in terms of a dichotom ous or bipolar variable. One of the simplest and most intuitive dichotom ies describes the functions of the left and right hem ispheres in terms of their predispo sitions for the processing of verbal and non-ve rbal m aterial, respectively. Dax first noted an association between the left hem isphere (LH) and language function in the early half of the nineteenth century. This finding , published and popula rised independently by Broca in the latter half of the same LATERALITY, 1996, 1 (2), 97±137Requests for reprints should be sent to M ichael Nicholls,

Modelling rhythmic function in a musician post-stroke

“…In terms of cerebral lateralisation, Peretz and Morais [43] suggested that metric organisation may be ascribed to the right hemisphere, whilst smaller rhythmic groupings are encoded by the left hemisphere. This notion is consistent with research findings from normal subjects [12,18,52] and brain-damaged patients [11,30,44], as well as data supporting left hemispheric specialisation of temporal processing relevant to speech perception [33,34,51,54]. Neuropsychological studies of groups of patients, however, have generally shown more variable lateralisation effects, particularly in recent research [25,36,46].…”

Specific Language Impairment is not Specific to Language: the Procedural Deficit Hypothesis

“…Behavioral and fMRI evidence also closely ties the basal ganglia to the processing of temporal discrimination thresholds (the perception of rapidly presented stimuli as either simultaneous or sequential) (Fiorio et al, 2003); to motor timing (Grasso et al, 1999;Harrington et al, 1998;Malapani et al, 2002) and to duration estimation (Ferrandez et al, 2003;Harrington et al, 1998; 14 Nenadic et al, 2003). Moreover, just as the left hemisphere is particularly important for procedural memory, so it also appears to be crucial for rapid temporal processing: Evidence suggests that the left hemisphere has better temporal resolution than the right, and may be specialized for much shorter periods of temporal integration (Allard and Scott, 1975;Hickok and Poeppel, 2000;Ivry and Robertson, 1998;Nicholls, 1996;Zatorre et al, 2002). Intriguingly, the timing and rapid processing functions of the brain structures underlying the procedural system appear to be linked to other functions of this system.…”

Laterality in the perception of temporal cues of musical timbre

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