Carl J Hodgetts

• PhD
• Lecturer at Royal Holloway University of London

Recent “representational” accounts suggest a key role for the hippocampus in complex scene perception. Due to limitations in scanner field strength, however, the functional neuroanatomy of hippocampal-dependent scene perception is unknown. Here, we applied 7 T high-resolution functional magnetic resonance imaging (fMRI) alongside a perceptual oddit...

Functional neuroimaging studies have identified several "core" brain regions that are preferentially activated by scene stimuli, namely posterior parahippocampal gyrus (PHG), retrosplenial cortex (RSC), and transverse occipital sulcus (TOS). The hippocampus (HC), too, is thought to play a key role in scene processing, although no study has yet inve...

Autobiographical memory (AM) is multifaceted, incorporating the vivid retrieval of contextual detail (episodic AM), together with semantic knowledge that infuses meaning and coherence into past events (semantic AM). While neuropsychological evidence highlights a role for the hippocampus and anterior temporal lobe (ATL) in episodic and semantic AM,...

The fornix is the major white matter tract linking the hippocampal formation with distal brain sites. Human and animal lesion studies show that the connections comprising the fornix are vital for specific attributes of episodic and spatial memory. The fornix, however, interconnects the hippocampal formation with an array of subcortical and cortical...

Although several studies have demonstrated that perceptual discrimination of complex scenes relies on an extended hippocampal posteromedial system, we currently have limited insight into the specific functional and structural properties of this system in humans. Here, combining electrophysiological (magnetoencephalography) and advanced microstructu...

How we judge the similarity between stimuli in the world is connected ultimately to how we represent them. Because of this, decisions about how we model similarity, either in terms of human behavior or patterns of neural activity, can provide key insights into how representations are structured and organized. Despite this, psychology and cognitive...

This paper introduces the Welsh Advanced Neuroimaging Database (WAND), a multi-scale, multi-modal imaging dataset comprising in vivo brain data from 170 healthy volunteers (aged 18–63 years), including 3 Tesla (3 T) magnetic resonance imaging (MRI) with ultra-strong (300 mT/m) magnetic field gradients, structural and functional MRI and nuclear magn...

Cognitive maps are thought to arise, at least in part, from our intrinsic curiosity to explore unknown places. However, it remains untested how curiosity shapes aspects of spatial exploration in humans. Combining a virtual reality task with indices of exploration complexity, we found that pre-exploration curiosity states predicted how much individu...

Although the hippocampus and cerebellum are traditionally considered to support distinct memory systems, evidence from nonhuman species indicates a close bidirectional relationship during learning and navigational behaviour, with the hippocampus projecting to - and receiving input from - several cerebellar regions. However, little is known about th...

Although several studies have demonstrated that perceptual discrimination of complex scenes relies on an extended hippocampal network, distinct from an anterotemporal network supporting the perceptual discrimination of faces, we currently have limited insight into the specific functional and structural properties of these networks. Here, combining...

The medial temporal lobe (MTL) cortex, located adjacent to the hippocampus, is crucial for memory and prone to the accumulation of certain neuropathologies such as Alzheimer's disease neurofibrillary tau tangles. The MTL cortex is composed of several subregions which differ in their functional and cytoarchitectonic features. As neuroanatomical scho...

What happens once a cortical territory becomes functionally redundant? We studied changes in brain function and behavior for the remaining hand in humans (male and female) with either a missing hand from birth (one-handers) or due to amputation. Previous studies reported that amputees, but not one-handers, show increased ipsilateral activity in the...

Prior univariate functional magnetic resonance imaging (fMRI) studies in humans suggest that the anteromedial subicular complex of the hippocampus is a hub for scene-based cognition. However, it is possible that univariate approaches were not sufficiently sensitive to detect scene-related activity in other subfields that have been implicated in spa...

How we judge the similarity between objects in the world is connected ultimately to how we represent those objects. It has been argued extensively that object representations in humans are 'structured' in nature, meaning that both individual features and the relations between them can influence similarity. In contrast, popular models within compara...

What happens once a cortical territory becomes functionally redundant? We addressed brain and behavioural adaptations for the intact hand in individuals with a missing hand. Previous studies reported increased ipsilateral activity in the somatosensory territory of the missing hand (i.e., remapping) in acquired amputees, but not in individuals with...

The parahippocampal cingulum bundle (PHCB) interconnects regions known to be vulnerable to early Alzheimer's disease (AD) pathology, including posteromedial cortex and medial temporal lobe. While AD-related pathology has been robustly associated with alterations in PHCB microstructure, specifically lower fractional anisotropy (FA) and higher mean d...

The ability to effectively parse our experience into meaningful events is thought to be critical for structuring episodic memory, engaging in daily activities, and navigating the social and spatial environment. Despite this, little is known about how inter-individual variation in this ability emerges. Within a sample of 159 young adults, we found t...

The idea that objects can be represented within multi-dimensional ‘cognitive spaces’ remains popular within psychology and neuroscience, and yet the restrictive topology of such spaces is seldom considered. Here, we show that it is possible, even within a simple set of items, to break such models by imposing neighbourhood relations that are incompa...

How we judge the similarity between objects in the world is connected ultimately to how we represent those objects. It has been argued extensively that object representations in humans are ‘structured’ in nature, meaning that both individual features and the relations between them can influence similarity. In contrast, popular models of comparative...

The parahippocampal cingulum bundle (PHCB) connects regions known to be vulnerable to early Alzheimer's disease (AD) pathology, such as posteromedial cortex and medial temporal lobe. While AD-related pathology has been robustly associated with alterations in PHCB microstructure, specifically lower fractional anisotropy (FA) and higher mean diffusiv...

Neuropsychological and functional magnetic resonance imaging (MRI) evidence suggests that the ability to vividly remember our personal past, and imagine future scenarios, involves two closely connected regions: the hippocampus and ventromedial prefrontal cortex (vmPFC). Despite evidence of a direct anatomical connection from hippocampus to vmPFC, i...

Preclinical models of Alzheimer’s disease (AD) suggest APOE modulates brain function in structures vulnerable to AD pathophysiology. However, genome-wide association studies now demonstrate that AD risk is shaped by a broader polygenic architecture, estimated via polygenic risk scoring (AD-PRS). Despite this breakthrough, the effect of AD-PRS on br...

Experiments on rodents have demonstrated that transecting the white matter fibre pathway linking the hippocampus with an array of cortical and subcortical structures - the fornix - impairs flexible navigational learning in the Morris Water Maze (MWM), as well as similar spatial learning tasks. While diffusion magnetic resonance imaging (dMRI) studi...

Neuropsychological and functional magnetic resonance imaging (MRI) evidence suggests that the ability to vividly remember our personal past, and imagine future scenarios, involves two closely connected regions: the hippocampus and ventromedial prefrontal cortex (vmPFC). Despite evidence of a direct anatomical connection from hippocampus to vmPFC, i...

Across the lifespan, curiosity motivates us to learn, yet curiosity varies strikingly between individuals. Such individual differences have been shown for two distinct dimensions of curiosity: epistemic curiosity (EC), the desire to acquire knowledge about facts, and perceptual curiosity (PC), the desire for sensory information. It is not known, ho...

Precuneus/posterior cingulate cortex (PCu/PCC) are key components of a midline network, activated during rest but also in tasks that involve construction of scene or situation models. Despite growing interest in PCu/PCC functional alterations in disease and disease risk, the underlying neurochemical modulators of PCu/PCC's task‐evoked activity are...

Precuneus/posterior cingulate cortex (PCu/PCC) are key components of a midline network, activated during rest but also in tasks that involve construction of scene or situation models. Despite growing interest in PCu/PCC functional alterations in disease, the underlying neurochemical modulators of PCu/PCCs task-induced activity are largely unstudied...

Young adult APOE-ε4 carriers show increased activity in posterior regions of the default mode network (pDMN), but how this is related to structural connectivity is unknown. Thirty young adults (one half of whom were APOE-ε4 carriers; mean age 20 years) were scanned using both diffusion and functional magnetic resonance imaging. The parahippocampal...

Studies in rodents have demonstrated that transecting the white matter pathway linking the hippocampus and anterior thalamic nuclei - the fornix - impairs flexible navigational learning in the Morris Water Maze (MWM), as well as similar spatial learning tasks. While diffusion MRI studies in humans have linked fornix microstructure to scene discrimi...

Young adult APOE -ε4 carriers show increased activity in posterior regions of the default mode network (pDMN), but how this is related to structural connectivity is unknown. Thirty young adults (half APOE -ε4 carriers, the other half APOE -ε3ε3/ε2ε3; mean age 20 years) were scanned using both diffusion and functional magnetic resonance imaging. Dif...

Ultra high-field 7T MRI offers sensitivity to localize hippocampal pathology in temporal lobe epilepsy (TLE), but has rarely been evaluated in patients with normal-appearing clinical MRI. We applied multimodal 7T MRI to assess if focal subfield atrophy and deviations in brain metabolites characterize epileptic hippocampi. Twelve pre-surgical TLE pa...

The Uncinate Fasciculus (UF) is an association fibre tract connecting regions in the frontal and anterior temporal lobes. UF disruption is seen in several disorders associated with impaired social behaviour, but its functional role is unclear. Here we set out to test the hypothesis that the UF is important for facial expression processing, an abili...

Apolipoprotein E (APOE) ε4 is a major genetic risk factor for Alzheimer's disease (AD), yet the mechanisms by which APOE-ε4 influences early-life brain function, and hence, in turn, risk for later-life AD, are poorly understood. Here, we report a novel, and selective, pattern of functional brain activity alteration in healthy young adult human APOE...

Raw values for the DTI metrics.DOI: http://dx.doi.org/10.7554/eLife.07902.008

Table of co-ordinates for the whole-brain tract-based spatial statistics (TBSS) analysis. DOI: http://dx.doi.org/10.7554/eLife.07902.016

Results of the mediation analyses across the three ROIs. DOI: http://dx.doi.org/10.7554/eLife.07902.017

Raw behavioural data from the oddity task.DOI: http://dx.doi.org/10.7554/eLife.07902.006

Individual percentage BOLD signal change values for the fMRI contrasts.DOI: http://dx.doi.org/10.7554/eLife.07902.013

Transection of the nonhuman primate fornix has been shown to impair learning of configurations of spatial features and object-in-scene memory. Although damage to the human fornix also results in memory impairment, it is not known whether there is a preferential involvement of this white-matter tract in spatial learning, as implied by animal studies...

Inspired by the principles used to market physical products, campaigns to promote pro-environmental behaviour have increasingly emphasized self-interested (for example, economic) reasons for engaging with a self-transcendent cause (that is, protecting the environment). Yet, psychological evidence about values and behaviour suggests that giving self...

Asymmetries, where response times differ depending on the order of two stimuli, have been widely used to explore fundamental aspects of perceptual processing. Given how much is made of asymmetries in the study of perception there has been surprisingly little research into the cognitive mechanisms that may underlie why comparing two objects in isola...

Book synopsis: A highly original new book that tackles one of the most mysterious and puzzling qualities of human nature - our ability to conceptualize, presenting views from a range of authorities in the area Considers the evolutionary origins of conceptual thinking, how and when it might develop in childhood, and whether animals have some kind of...

This paper contrasts two structural accounts of psychological similarity: structural alignment (SA) and Representational Distortion (RD). SA proposes that similarity is determined by how readily the structures of two objects can be brought into alignment; RD measures similarity by the complexity of the transformation that “distorts” one representat...

This paper investigates the role of transformations and similarity in a perceptual task, the same-different paradigm. Representational Distortion (RD) theory measures similarity by the complexity required to 'distort' compared object representations. In an experiment, participants compared pairs of geometric shapes that varied across two dimensions...

The transformational approach to similarity views similarity as a function of the complexity of the transformations required to 'distort' the representation of one object into another. These transformations may be more complex in one direction than the other, thus giving rise to asymmetric similarity relationships. Using the same-different paradigm...

This chapter reviews studies of rule-based category learning within the human adult literature, and contrasts these results with evidence for similarity-based accounts of category learning (e.g. exemplar and prototype models). Specifically, the chapter considers the contrast between rule-based versus similarity-based learning within research on uns...