The phonological similarity effect in short-term memory serial recall in schizophrenia (2023)

Working memory is one of the central constructs in cognitive science and has received enormous attention in the theoretical and empirical literature. Similarly, working memory deficits have long been thought to be among the core cognitive deficits in schizophrenia, making it a ripe area for translation. This article provides a brief overview of the current theories and data on the psychological and neural mechanisms involved in working memory, which is a summary of the presentation and discussion on working memory that occurred at the first Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) meeting (Washington, D.C.). At this meeting, the consensus was that the constructs of goal maintenance and interference control were the most ready to be pursued as part of a translational cognitive neuroscience effort at future CNTRICS meetings. The constructs of long-term memory reactivation, capacity, and strategic encoding were felt to be of great clinical interest but requiring more basic research. In addition, the group felt that the constructs of maintenance over time and updating in working memory had growing construct validity at the psychological and neural levels but required more research in schizophrenia before these should be considered as targets for a clinical trials setting.

Work with individuals with lesions to specific brain regions has long been used to test or even generate theories regarding the neural systems that support specific cognitive processes. Work with individuals who have neuropsychiatric disorders that also involve neurobiological disturbances may be able to play a similar role in theory testing and building. For example, schizophrenia is a psychiatric disorder thought to involve a range of neurobiological disturbances. Further, individuals with schizophrenia are known to suffer from deficits in working memory, meaning that examining the work on the neurobiology of working memory deficits in schizophrenia may help to further our understanding of the cognitive neuroscience of working memory. This article discusses the pros and cons of extrapolating from work in schizophrenia to models of healthy working memory function, and reviews the literature on working memory function in schizophrenia in relationship to existing human and non-human primate models of the cognitive neuroscience of working memory.

Neuroscience, Volume 256, 2014, pp. 230-241

In this study we were interested in the neural system supporting the audiovisual (AV) integration of emotional expression and emotional prosody. To this end normal participants were exposed to short videos of a computer-animated face voicing emotionally positive or negative words with the appropriate prosody. Facial expression of the face was either neutral or emotionally appropriate. To reveal the neural network involved in affective AV integration, standard univariate analysis of functional magnetic resonance (fMRI) data was followed by a random-effects Granger causality mapping (RFX-GCM). The regions that distinguished emotional from neutral facial expressions in the univariate analysis were taken as seed regions. In trials showing emotional expressions compared to neutral trials univariate analysis showed activation primarily in bilateral amygdala, fusiform gyrus, middle temporal gyrus/superior temporal sulcus and inferior occipital gyrus. When employing either the left amygdala or the right amygdala as a seed region in RFX-GCM we found connectivity with the right hemispheric fusiform gyrus, with the indication that the fusiform gyrus sends information to the Amygdala. These results led to a working model for face perception in general and for AV-affective integration in particular which is an elaborated adaptation of existing models.

Neuropsychologia, Volume 140, 2020, Article 107382

Languages may differ in their proximate units of phonological encoding in spoken word production. The roles of syllables and phonemes when Mandarin Chinese speakers prepare spoken words remain controversial. In the present study, native Chinese speakers named disyllabic pictures that were preceded by briefly presented and masked prime words while electroencephalogram signals were recorded. Prime words were syllabically or phonemically related to the first syllable of targets or were unrelated. Variables of prime type (syllable overlap or phoneme overlap) and relatedness (related or unrelated) were manipulated in the experiment. Behavioral results demonstrated a critical interaction between prime type and relatedness, with a facilitation effect relative to unrelated primes appearing only in the syllable overlap condition. Spatio-temporal segmentation analysis indicated that syllable relatedness shortened the duration of Map 6 (around 285–410ms), whose time window is associated with the phonological encoding stage. Comparatively, phoneme relatedness shortened the duration of Map 7 (around 410–480ms) in a later time window. Onset latency analysis suggested an earlier onset for the syllable effect (284ms) and a chronologically later onset for the phoneme effect (396ms). Traditional waveform analysis revealed that the syllable overlap condition exerted significant effects on event-related potentials in the time window of 280–440ms, whereas the phoneme overlap condition produced a weak effect in the time window of 400–440ms in a few electrodes. Taken together, these findings substantiate the primacy of abstract syllables in producing Mandarin spoken words and provide initial topographic evidence that Mandarin speakers mentally represent subordinate phonemes at a later stage of word-form encoding.

The Lancet, Volume 392, Issue 10160, 2018, p. 2170

Cortex, Volume 63, 2015, pp. 317-351

The Stimulus Type Effect on Phonological and Semantic errors (STEPS) describes the phenomenon in which a person, following brain damage, produces words with phonological errors (fine→fige), but number words with semantic errors (five→eight). To track the origins of this phenomenon and find out whether it is limited to numbers, we assessed the speech production of six individuals with conduction aphasia following a damage in the left hemisphere, who made phonological errors in words. STEPS was found in all six participants, and was not limited to number words – several other word categories were also produced with semantic rather than phonological errors: function words, English letter names, and morphological affixes were substituted with other words within their category. This supports the building blocks hypothesis: when phonological sequences serve as building blocks in a productive process, they end up having pre-assembled phonological representations, ready for articulation. STEPS reflects a deficit that causes substitutions of one phonological unit with another. In the case of plain content words, this causes substitutions of one phoneme with another, but in the case of pre-assembled phonological units, this causes substitutions of number words with other number words, function words with function words, and morphological affixes with other affixes. An analysis of the participants' functional locus of deficit revealed that they all had a deficit in the phonological output buffer, and this was their only common deficit. We therefore concluded that the pre-assembled phonological units are stored in dedicated mini-stores in the phonological output buffer, which processes not only phonemes but also whole number words, function words, and morphemes. We also found that STEPS depends on the word's role: number words were produced with semantic errors only when they appeared in numeric context, and function words triggered semantic errors only in grammatical context. This suggests that the phonological representation of a word can be obtained either from the phonological output lexicon or from a store of pre-assembled representations in the phonological output buffer, depending on the word's role.

Epilepsy & Behavior, Volume 29, Issue 2, 2013, pp. 337-343

Cognitive deficits and psychological impairments are often associated with seizures. In order to describe the neuropsychological profiles of adult patients with epilepsy (PWEs) in Hong Kong China, a total of 186 PWEs were recruited with 102 being drug-responsive and 84 being drug-resistant. Symptoms of depression, anxiety, and epilepsy-specific quality of life (QOL) were measured. Cognitive assessments consisted of intelligence, memory, verbal and visual abilities, and executive function. Neurocognitive impairments were prevalent among PWEs, and patients with drug-resistant epilepsy had significantly more impaired psychological and cognitive profiles. Thirty-nine percent and 30% of patients with drug-resistant epilepsy reported moderate to severe levels of anxiety and depression, respectively, versus 16% and 7% of patients with drug-responsive epilepsy. The most commonly occurring cognitive deficit was memory. Thirty-five percent to 47% of patients with drug-resistant epilepsy and 26% to 35% of patients with drug-responsive epilepsy were compromised in verbal recall memory. Our findings also suggested significant correlations between psychological well-being and cognitive performance. Patients who reported more psychological symptoms tended to perform worse in neurocognitive tests. Identification and management of neuropsychological difficulties in PWEs are important and should be included in primary epilepsy care.

Cortex, Volume 90, 2017, pp. 88-102

Multiple levels of representation are involved in reading single words: visual representations of letter shape, orthographic representations of letter identity and order, phonological representations of the word's pronunciation, and semantic representations of its meaning. Previous lesion and neuroimaging studies have identified a network of regions recruited during word reading, including ventral occipital-temporal regions and the angular gyrus (AG). However, there is still debate about what information is being represented and processed in these regions. This study has two aims. The first is to help adjudicate between competing hypotheses concerning the role of ventral occipital cortex in reading. The second is to adjudicate between competing hypotheses concerning the role of the AG in reading. Participants read words in the scanner while performing a proper name detection task and we use a multivariate pattern analysis technique for analyzing fMRI data – representational similarity analysis (RSA) – to decode the type of information being represented in these regions based on computationally explicit theories. Distributed patterns of activation in the left ventral occipitotemporal cortex (vOT) and the AGshow evidence of some type of orthographic processing, while the right hemisphere homologues of the vOT supports visual, but not orthographic, information processing of letter strings. In addition, there is evidence of left-lateralized semantic processing in the lvOT and evidence of top-down feedback in the lvOT. Taken together, these results suggest an interactive activation theory of visual word processing in which both the lvOT and lAG are neural loci of an orthographic level of representations.