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Jamie Ward

Publications and source records attributed to Jamie Ward.

17 recordsLinked to original sources
PubMed2007

Disruption of synaesthesia following TMS of the right posterior parietal cortex.

This study examines the role of four regions of the parietal lobe in grapheme-colour synaesthesia. TMS applied over a right parieto-occipital region disrupts performance on a synaesthetic priming task. TMS over the left parietal or a more anterior right parietal site did not have a reliable effect on synaesthesia even though one of the sites had been implicated in synaesthesia by previous fMRI studies. The same disruption is found for synaesthetes who experience colours in their "mind's eye" as well as those who project colours onto the inducing grapheme. This region may be important for binding graphemes and colours to different spatial reference frames.

Adult↗
PubMed2006

Varieties of grapheme-colour synaesthesia: a new theory of phenomenological and behavioural differences.

Recent research has suggested that not all grapheme-colour synaesthetes are alike. One suggestion is that they can be divided, phenomenologically, in terms of whether the colours are experienced in external or internal space (projector-associator distinction). Another suggestion is that they can be divided according to whether it is the perceptual or conceptual attributes of a stimulus that is critical (higher-lower distinction). This study compares the behavioural performance of 7 projector and 7 associator synaesthetes. We demonstrate that this distinction does not map on to behavioural traits expected from the higher-lower distinction. We replicate previous research showing that projectors are faster at naming their synaesthetic colours than veridical colours, and that associators show the reverse profile. Synaesthetes who project colours into external space but not on to the surface of the grapheme behave like associators on this task. In a second task, graphemes presented briefly in the periphery are more likely to elicit reports of colour in projectors than associators, but the colours only tend to be accurate when the grapheme itself is also accurately identified. We propose an alternative model of individual differences in grapheme-colour synaesthesia that emphasises the role of different spatial reference frames in synaesthetic perception. In doing so, we attempt to bring the synaesthesia literature closer to current models of non-synaesthetic perception, attention and binding.

Adolescent↗
PubMed2006

Synaesthesia: an overview of contemporary findings and controversies.

Research on synaesthesia is undergoing something of a renaissance, having initially been a hot topic in psychology and philosophy in the late 19th and early 20th centuries. One hundred years ago investigators failed to define an objective framework within which to characterise the phenomenon, and so interest in the topic waned. With the cognitive revolution and the rapid rise of new experimental techniques in human neuroscience, interest in synaesthesia as a legitimate topic for scientific investigation has been rekindled. Since the 1980s there has been rapid growth in scientific and media interest in synaesthesia, and there is now a sense that real progress is being made. This Special Issue of Cortex brings together the largest collection of empirical papers on the topic of synaesthesia to date. The 21 papers collected herein showcase the many significant advances that have been made in understanding the behavioural and neural bases of synaesthesia. The contributions reflect the work of more than 60 investigators from nine different countries. We are confident that the papers presented in this Special Issue will set the agenda for synaesthesia research for many years to come.

Association↗
PubMed2006

Sound-colour synaesthesia: to what extent does it use cross-modal mechanisms common to us all?

This study examines a group of synaesthetes who report colour sensations in response to music and other sounds. Experiment 1 shows that synaesthetes choose more precise colours and are more internally consistent in their choice of colours given a set of sounds of varying pitch, timbre and composition (single notes or dyads) relative to a group of controls. In spite of this difference, both controls and synaesthetes appear to use the same heuristics for matching between auditory and visual domains (e.g., pitch to lightness). We take this as evidence that synaesthesia may recruit some of the mechanisms used in normal cross-modal perception. Experiment 2 establishes that synaesthetic colours are automatically elicited insofar as they give rise to cross-modal Stroop interference. Experiment 3 uses a variant of the cross-modal Posner paradigm in which detection of a lateralised target is enhanced when combined with a non-informative but synaesthetically congruent sound-colour pairing. This suggests that synaesthesia uses the same (or an analogous) mechanism of exogenous cross-modal orienting as normal perception. Overall, the results support the conclusion that this form of synaesthesia recruits some of the same mechanisms used in normal cross-modal perception rather than using direct, privileged pathways between unimodal auditory and unimodal visual areas that are absent in most other adults.

Adult↗
PubMed2006

Crossmodal interactions: lessons from synesthesia.

Synesthesia is a condition in which stimulation in one modality also gives rise to a perceptual experience in a second modality. In two recent studies we found that the condition is more common than previously reported; up to 5% of the population may experience at least one type of synesthesia. Although the condition has been traditionally viewed as an anomaly (e.g., breakdown in modularity), it seems that at least some of the mechanisms underlying synesthesia do reflect universal crossmodal mechanisms. We review here a number of examples of crossmodal correspondences found in both synesthetes and nonsynesthetes including pitch-lightness and vision-touch interaction, as well as cross-domain spatial-numeric interactions. Additionally, we discuss the common role of spatial attention in binding shape and color surface features (whether ordinary or synesthetic color). Consistently with behavioral and neuroimaging data showing that chromatic-graphemic (colored-letter) synesthesia is a genuine perceptual phenomenon implicating extrastriate cortex, we also present electrophysiological data showing modulation of visual evoked potentials by synesthetic color congruency.

Animals↗
PubMed2006

Synaesthesia: the prevalence of atypical cross-modal experiences.

Sensory and cognitive mechanisms allow stimuli to be perceived with properties relating to sight, sound, touch, etc, and ensure, for example, that visual properties are perceived as visual experiences, rather than sounds, tastes, smells, etc. Theories of normal development can be informed by cases where this modularity breaks down, in a condition known as synaesthesia. Conventional wisdom has held that this occurs extremely rarely (0.05% of births) and affects women more than men. Here we present the first test of synaesthesia prevalence with sampling that does not rely on self-referral, and which uses objective tests to establish genuineness. We show that (a) the prevalence of synaesthesia is 88 times higher than previously assumed, (b) the most common variant is coloured days, (c) the most studied variant (grapheme-colour synaesthesia)--previously believed most common--is prevalent at 1%, and (d) there is no strong asymmetry in the distribution of synaesthesia across the sexes. Hence, we suggest that female biases reported earlier likely arose from (or were exaggerated by) sex differences in self-disclosure.

Adult↗
PubMed2006

Placing events in time: the role of autobiographical recollection.

Episodic experience is argued to be rich in temporal information, but it remains unclear whether temporal information is directly coded in the event memory or is reconstructed at retrieval. The two experiments reported here emphasise the role of reconstructive processes of autobiographical context in establishing the date of memories. Younger and older participants were presented with famous public events, although only the latter had actually lived through them. Participants were asked to make forced-choice judgements about the date of the event and other event-related facts. Overall, while the older group showed better fact knowledge of the events, this did not translate into better dating performance. This older group showed similar dating performance across events with high and low factual knowledge. In contrast, the younger group's dating accuracy was determined by their level of knowledge. This suggests that older individuals who have direct episodic experience of an event may perform the task in a qualitatively different manner, eschewing semantic facts in favour of other sources of information. Crucially, this process does not appear to enhance performance. A second experiment addressed the issue of whether older participants date events based on general qualities of the event memory (e.g., vividness), the availability of other event-related semantic facts, or autobiographical context. It was found that the ability to place an event in autobiographical context is related to dating accuracy, but not to other aspects of memory.

Adult↗
PubMed2006

Synaesthesia for reading and playing musical notes.

This study reports three cases of synaesthesia who experience colors in response to written musical notation, graphemes and heard music. The synaesthetes show Stroop-like interference when asked to name the colour of graphemes but not for written musical notes. However, reliable interference is found in two further studies that require deeper processing of the musical notation (namely playing music from colored notation, and naming the synaesthetic color of the notes whilst suppressing the veridical color). This is the first empirical demonstration of synaesthesia for musical notation. The fact that synaesthetic color influences music playing/reading (a sensory-motor transformation) but not verbal color naming suggests that synaesthetic Stroop effects can arise from processing the meaning of a stimulus and not just as a result of verbal response interference. However, it is likely that the color associations themselves have a developmental origin in the names assigned to them. In all three cases, the colors of the written notes are related to the graphemes that arbitrarily denote them (e.g., 'A' may be "red" both as a letter and when written in musical notation). The results suggest that synaesthetic associations may migrate from one representational format (e.g., graphemes) to another (e.g., musical notation).

Acoustic Stimulation↗
PubMed2005

What is the relationship between synaesthesia and visuo-spatial number forms?

This study compares the tendency for numerals to elicit spontaneous perceptions of colour or taste (synaesthesia) with the tendency to visualise numbers as occupying particular visuo-spatial configurations (number forms). The prevalence of number forms was found to be significantly higher in synaesthetes experiencing colour compared both to synaesthetes experiencing taste and to control participants lacking any synaesthetic experience. This suggests that the presence of synaesthetic colour sensations enhances the tendency to explicitly represent numbers in a visuo-spatial format although the two symptoms may nevertheless be logically independent (i.e. it is possible to have number forms without colour, and coloured numbers without forms). Number forms are equally common in men and women, unlike previous reports of synaesthesia that have suggested a strong female bias. Individuals who possess a number form are also likely to possess visuo-spatial forms for other ordinal sequences (e.g. days, months, letters) which suggests that it is the ordinal nature of numbers rather than numerical quantity that gives rise to this particular mode of representation. Finally, we also describe some consequences of number forms for performance in a number comparison task.

Adult↗
PubMed2005

Is synaesthesia an X-linked dominant trait with lethality in males?

In previous research the inheritance patterns of synaesthesia (eg experiencing colours from graphemes) has been studied and it was concluded that synaesthesia is most likely to be the outcome of a single gene passed on the X chromosome in a dominant fashion. In addition, it has been reported that the female-male ratio of synaesthetes is as high as 6:1 and the families of synaesthetes contain more female than male members. This raises the possibility that the gene may be associated with lethality in males. In this study we replicate and extend previous research by investigating the female-male ratio and inheritance patterns in a large sample of synaesthetic families (N = 85). We were able to verify the authenticity of grapheme-colour associates in at least one proband from each family using internal consistency. As before, our results show a female-male bias and are broadly consistent with an X-linked dominant mode of inheritance. However, there was no evidence of male lethality (eg synaesthetes are just as likely to give birth to sons as to daughters). Moreover, our female-male ratio of synaesthetes within families was 2:1--considerably lower than previous estimates. We speculate that men may be more reluctant to disclose synaesthesia than women (indeed, our female-male ratio based on self-referral was 3.7: 1). Finally, we discuss how the genotype may give rise to the phenotype in terms of changes in synaptogenesis or plasticity extending into childhood, to be subsequently shaped by the environment.

Adolescent↗
PubMed2003

Lexical-gustatory synaesthesia: linguistic and conceptual factors.

This study documents an unusual case of developmental synaesthesia, in which speech sounds induce an involuntary sensation of taste that is subjectively located in the mouth. JIW shows a highly structured, non-random relationship between particular combinations of phonemes (rather than graphemes) and the resultant taste, and this is influenced by a number of fine-grained phonemic properties (e.g. allophony, phoneme ordering). The synaesthesia is not found for environmental sounds. The synaesthesia, in its current form, is likely to have originated during vocabulary acquisition, since it is guided by learned linguistic and conceptual knowledge. The phonemes that trigger a given taste tend to also appear in the name of the corresponding foodstuff (e.g. /I/, /n/ and /s/ can trigger a taste of mince /mIns/) and there is often a semantic association between the triggering word and taste (e.g. the word blue tastes "inky"). The results suggest that synaesthesia does not simply reflect innate connections from one perceptual system to another, but that it can be mediated and/or influenced by a symbolic/conceptual level of representation.

Adult↗
PubMed2003

Inappropriate association of semantics and context to novel stimuli can give rise to the false recognition of unfamiliar people.

This paper reports further experiments with a patient (MR) who has a tendency to claim that unfamous people are familiar together with good ability at identifying truly famous people. The first experiment examines the role that the typicality of stimuli plays in his false recognition. Although, typicality may have some influence over false recognition (as it does for normal controls) there is little evidence to suggest that MR is over-reliant on such information. It is unlikely that perceptual fluency can entirely explain his deficit. This is bolstered by a further study using morphed images of famous and unfamous faces, suggesting that false recognition is associated with inappropriate retrieval of semantic-biographical information. It is argued that MR's judgement of 'fame' is subjectively appropriate, given the information that he retrieves. This information is thought to derive from currently activated, or recently activated, contextual information which becomes inappropriately bound to the novel stimulus, giving rise to a false sense of familiarity. These findings underscore the importance of viewing memory as an attributional process, whereby current mental constructions/processes are attributed to some event(s) in the past.

Case-Control Studies↗
PubMed2003

Understanding oral spelling: a review and synthesis.

This article reviews a number of studies that report discrepancies between written and oral spelling that cannot easily be explained in terms of deficits to modality-specific output routines. For instance, some patients appear to be 'surface dysgraphic' for oral spelling but 'phonological dysgraphic' for written spelling (e.g. Lesser, 1990). A model is proposed to account for these findings which contains the basic premise that the mappings between phonemes and letter names (in oral spelling) is generally non-arbitrary, whereas the mappings between phonemes and letter shapes (in written spelling) is entirely arbitrary. For example, the phoneme /t/ sounds similar to the oral letter name "Tee" but is arbitrarily related to the written letter 'T' or 't'. An important consequence of this is that oral spelling, in normal spellers, may be more biased by phonological correspondences than written spelling. Other discrepancies between written and oral spelling are reviewed and accommodated within this model, and the model is extended to include recognition of oral spellings and transcoding between spoken and written letter forms.

Agraphia↗
PubMed2002

Formal lexical paragraphias in a single case study: how "masterpiece" can become "misterpieman" and "curiosity" "suretoy".

Formal lexical errors are relatively rare in the production of aphasic patients. In this study, we report the case of DW, who makes a high proportion of these errors. A few other cases have previously been reported, but DW shows a number of distinguishing characteristics. First, formal lexical errors are made in spelling and not in spoken speech. Second, they are associated with morphological errors and not with semantic errors. Third, they often combine lexical units in ways which are semantically and morphologically illegal. Finally, the majority of morphological errors involve the insertion, rather than the deletion, of suffixes. This pattern can be explained by hypothesizing that DW's errors arise because of confusions among a cohort of lexical neighbors activated top-down from a phonological input and bottom-up from shared letters. One possible cause of the confusions is lack of proper inhibition among lexical competitors.

Aged↗
PubMed2002

DNA tests in prolific sheep from eight countries provide new evidence on origin of the Booroola (FecB) mutation.

Recent discoveries that high prolificacy in sheep carrying the Booroola gene (FecB) is the result of a mutation in the BMPIB receptor and high prolificacy in Inverdale sheep (FecX(I)) is the result of a mutation in the BMP15 oocyte-derived growth factor gene have allowed direct marker tests to be developed for FecB and FecX(I). These tests were carried out in seven strains of sheep (Javanese, Thoka, Woodlands, Olkuska, Lacaune, Belclare, and Cambridge) in which inheritance patterns have suggested the presence of major genes affecting prolificacy and in the prolific Garole sheep of India, which have been proposed as the ancestor of Australian Booroola Merinos. The FecB mutation was found in the Garole and Javanese sheep but not in Thoka, Woodlands, Olkuska, Lacaune, Belclare, and Cambridge sheep. None of the sheep tested had the FecX(I) mutation. These findings present strong evidence to support historical records that the Booroola gene was introduced into Australian flocks from Garole (Bengal) sheep in the late 18th century. It is unknown whether Javanese Thin-tailed sheep acquired the Booroola gene directly from Garole sheep from India or via Merinos from Australia. The DNA mutation test for FecB will enable breeding plans to be developed that allow the most effective use of this gene in Garole and Javanese Thin-tailed sheep and their crosses.

Animals↗
PubMedDate not supplied

Encoding and the frontal lobes: a dissociation between retrograde and anterograde memories.

Recent functional neuroimaging studies have suggested that different neural substrates within the frontal lobes are associated with memory encoding, retrieval and monitoring. If this is the case, then it should be possible to find frontal patients with selective deficits to these processes. However, most laboratory based memory tests (e.g. Wechsler Memory Scale) require a combination of all these processes making it hard to find clear dissociations between patients. Using tests of everyday memory, this study documents a clear dissociation between a frontal patient's (JB) impaired ability to retrieve events from the anterograde period relative to spared ability to retrieve events from the retrograde period. This is consistent with specific disruption to frontal mechanisms associated with encoding which disrupts the formation of new episodic memories. The defective mechanism may be related to more general aspects of cognitive processing (e.g. selection demands), but it is unlikely to reflect damage to working memory (as assessed by the n-back task) as there is a clear dissociation between spared performance on this task and impaired performance on a comparable episodic recognition memory task.

Amnesia, Anterograde↗