Cognitive fluctuations are a core symptom in dementia with Lewy bodies (DLB) and may relate to pathological alterations in distributed brain networks. the left fronto-parietal temporal and sensory-motor networks. Desynchronization of a number of cortical and subcortical areas related to the left fronto-parietal network was associated with the severity and frequency of cognitive fluctuations. Our findings provide empirical evidence for the potential role of attention-executive networks in the aetiology of this core symptom in DLB. Keywords: Cognitive fluctuations Visual hallucinations Resting state network Lewy bodies Dementia ADL5859 HCl 1 Dementia with Lewy bodies (DLB) accounts for approximately 4-8% of dementia cases (McKeith et al. 2007 It is characterized by complex visual hallucinations (VHs) cognitive fluctuations and parkinsonism. These three core features help differentiate DLB from other dementias such as Alzheimer’s disease (AD) with the presence of at least two out of the three required to make a diagnosis of probable DLB (McKeith et al. 2005 Out of the three core features probably the least understood is usually that of cognitive fluctuations and this lack of knowledge has hampered the development of appropriate treatment for this deleterious symptom in DLB (Bostr?m et al. 2007 As a core feature cognitive fluctuations may be more specific to DLB than parkinsonism (Tiraboschi et al. 2006 Quantitatively and qualitatively cognitive fluctuations ADL5859 HCl appear to relate to intrinsic brain processes rather than environmental or situational factors (Bradshaw et al. 2004 Walker et al. 2000 may associate with attentional impairments and?often co-occur with visual hallucinations. Their presence can have significant functional impacts upon patients and their carers (Ballard et al. 2001 Ballard et al. 2001 Neurobiologically cognitive fluctuations are likely to arise from distributed functional network perturbations rather than specific structural abnormalities (Taylor et al. 2013 on electroencephalography (EEG) increased and fluctuating slow wave activity occurs in posterior regions in DLB patients compared to Alzheimer’s disease (AD) patients and these changes have been correlated with the frequency and severity of clinically observed cognitive fluctuations (Bonanni et al. 2008 Walker et al. 2000 Similarly relative decreases in cerebral perfusion in posterior parietal areas covariant with relative increases in perfusion in distributed motor networks have been observed in fluctuating DLB patients (Taylor et al. 2013 Another approach which may be sensitive to Rabbit Polyclonal to BCL2 (phospho-Ser70). cortical network disturbances associated with cognitive fluctuations is usually resting state blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) as this allows the characterization of resting state networks (RSNs) that are task free and thus are not confounded by task dependent differences in cognitive ADL5859 HCl or motor function which may be compromised in patients with dementia and/or parkinsonism. Current research on RSNs and dementia has focussed mainly on AD where the current consensus points to a disconnection of the default mode network (DMN) as intrinsic to this type of dementia (see for instance?Greicius et al. 2004 Binnewijzend et al. 2012 and Mevel et al. 2011 This network is usually highly related to consciousness and memory (Andrews-Hanna et al. 2010 Raichle et al. 2001 which are primarily affected in AD. In DLB recent work by Galvin et al. (2011) Kenny et al. (2012) and Franciotti et al. (2013) has examined the DMN although findings on how it is altered in ADL5859 HCl DLB have been inconsistent which may in part relate to methodological and cohort differences between studies. Given the intimated role of the DMN in internal mentation and its role in attentional/ behavioural performance (Wen et al. 2013 it has been speculated that alterations in the DMN may relate to cognitive fluctuations in DLB. However resting fMRI data on this is usually limited. A report by Franciotti et al. (2013) focussed around the role of the DMN in DLB cognitive fluctuations and they found contrary to expectation that this DMN in DLB patients with cognitive.