Anatomical Correlate of Impaired Covert Visual Attentional Processes in Patients with Cerebellar Lesions

Abstract

In the past years, claims of cognitive and attentional function of the cerebellum have first been raised but were later refuted. One reason for this controversy might be that attentional deficits only occur when specific cerebellar structures are affected. To further elucidate this matter and to determine which cerebellar regions might be involved in deficits of covert visual attention, we used new brain imaging tools of lesion mapping that allow a direct comparison with control patients. A total of 26 patients with unilateral right-sided cerebellar infarcts were tested on a covert visual attention task. Eight (31%) patients showed markedly slowed responses, especially in trials in which an invalid cue necessitated reorienting of the focus of attention for target detection. Compared with the 18 patients who performed within the range of healthy control subjects, only the impaired patients had lesions of cerebellar vermal structures such as the pyramid. We suggest that these midcerebellar regions are indirectly involved in covert visual attention via oculomotor control mechanisms. Thus, specific cerebellar structures do influence attentional orienting, whereas others do not.

Visuohaptic convergence in a corticocerebellar network

“…In contrast to our study, previous VH convergence studies have used matching tasks, in which participants were required to match inputs from the same or different modalities. In the case of different modalities, this might have imposed additional processing load regarding memory processes or attention which might have influenced the mechanisms of VH convergence (Holdstock et al, 2009; see also van Atteveldt et al, 2007;Baier et al, 2010). Our study suggests that in the absence of such task effects VH convergence can be found not only in the LOC but also in bilateral regions of the anterior cerebellum.…”

Network-targeted cerebellar transcranial magnetic stimulation improves attentional control

“…Indeed, the physiology of the cerebellum suggests that translated to the attentional system, this same internal model system may be responsible for predictive deployment and maintenance of attention. There is evidence of the cerebellum contributing to attentional processes from imaging, transcranial magnetic stimulation and lesion studies (Brissenden et al, 2016; Arasanz et al, 2012; Baier et al, 2010). Thus, it is plausible that the iTBS-induced improvement in sustained attention may arise from improved functioning of the cerebellum’s role in attention.…”

Deployment of spatial attention without moving the eyes is boosted by oculomotor adaptation

“…The ineffectiveness of VS adaptation in boosting covert exogenous attention is also consistent with VS adaptation-dependent recruitment of a more dorsal parietal network, centred over the intra-parietal sulcus (Gerardin et al, 2012 ; Panouillères et al, 2014 ), which has been previously involved in endogenous attention [Lateral Intra-Parietal area in monkey (Wardak et al, 2004 ; Balan and Gottlieb, 2009 ); Intra-Parietal Sulcus in humans (Jerde et al, 2012 )]. In summary, this model provides a parsimonious framework for linking these behavioral findings to their possible neural underpinnings, which by no means excludes the contribution of other brain areas involved both in covert attention [e.g., Frontal Eye Fields (Moore and Fallah, 2001 ); Superior Colliculus (Zénon and Krauzlis, 2012 ; Katyal and Ress, 2014 ); cerebellar vermis (Baier et al, 2010 )] and saccadic adaptation (see Hopp and Fuchs, 2004 ; Iwamoto and Kaku, 2010 ; Jenkinson and Miall, 2010 ; Pélisson et al, 2010 ; Prsa and Thier, 2011 ).…”