Hallucinations: Unintended or unexpected?

Hemsley, David R.

doi:10.1017/s0140525x00023943

Cited by 49 publications

(4 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although, to our knowledge, direct experimental investigation of this claim is lacking, the notion of ineffective inhibition of information from LTM on sensory processing is present in several related accounts of hallucinations in schizophrenia (e.g. Helmsley, 1987; George and Neufield, 1985; Rund, 1986). Further, results from Kopp (2007) suggest greater similarity-related intrusion of information from LTM into the contents of working memory in psychometrically-identified schizotypal individuals.…”

Section: Discussionmentioning

confidence: 99%

Visuospatial imagery and working memory in schizophrenia

Matthews

Collins

Thakkar

et al. 2013

Cognitive Neuropsychiatry

View full text Add to dashboard Cite

Introduction The ability to form mental images that reconstruct former perceptual experiences is closely related to working memory (WM) ability. However, while WM deficits are established as a core feature of schizophrenia, an independent body of work suggests that mental imagery ability is enhanced in the disorder. Across two experiments we investigated mental imagery in schizophrenia and its relationship with WM. Methods In Experiment 1, individuals with schizophrenia (SZ: N=15) and matched controls (CO: N=14) completed a mental imagery generation and inspection task and a spatial delayed-response WM task. In Experiment 2, SZ (N=16) and CO (N=16) completed a novel version of the mental imagery task modified to increase WM maintenance demand. Results In Experiment 1, SZ demonstrated enhanced mental imagery performance, as evidenced by faster response times relative to CO, with preserved accuracy. However, enhanced mental imagery in SZ was accompanied by impaired WM as assessed by the delayed-response task. In Experiment 2, when WM maintenance load was increased, SZ no longer showed superior imagery performance. Conclusions We found evidence for enhanced imagery manipulation in SZ despite their WM maintenance deficit. However, this imagery enhancement was abolished when WM maintenance demands were increased. This profile of enhanced imagery manipulation but impaired maintenance could be used to implement novel remediation strategies in the disorder.

show abstract

Section: Discussionmentioning

confidence: 99%

Visuospatial imagery and working memory in schizophrenia

Matthews

Collins

Thakkar

et al. 2013

Cognitive Neuropsychiatry

View full text Add to dashboard Cite

show abstract

“…Gray et al propose that a pigeon-holing defect is the primary cognitive disturbance in schizophrenia. It seems doubtful, however, that a pigeon-holing defect -which produces its ill effects by virtue of the unexpectedness of certain experiences -could have produced a symptom which was so frequent, so stereotypic, and so expected (for additional discussions see Hemsley 1987b;Hoffman 1986Hoffman , 1987.…”

Section: Department Of Psychiatry Yale University School Of Medicinementioning

confidence: 99%

The neuropsychology of schizophrenia

Gray¹,

et al. 1991

View full text Add to dashboard Cite

A model is proposed for integrating the neural and cognitive aspects of the positive symptoms of acute schizophrenia, using evidence from postmortem neuropathology and neurochemistry, clinical and preclinical studies of dopaminergic neurotransmission, anatomical connections between the limbic system and basal ganglia, attentional and other cognitive abnormalities underlying the positive symptoms of schizophrenia, specific animal models of some of these abnormalities, and previous attempts to model the cognitive functions of the septohippocampal system and the motor functions of the basal ganglia. Anatomically, the model emphasises the projections from the septohippocampal system, via the subiculum, and the amygdala to nucleus accumbens, and their interaction with the ascending dopaminergic projection to the accumbens. Psychologically, the model emphasises a failure in acute schizophrenia to integrate stored memories of past regularities of perceptual input with ongoing motor programs in the control of current perception. A number of recent experiments that offer support for the model are briefly described, including anatomical studies of limbic-striatal connections, studies in the rat of the effects of damage to these connections, and of the effects of amphetamine and neuroleptics, on the partial reinforcement extinction effect, latent inhibition and the Kamin blocking effect; and studies of the latter two phenomena in acute and chronic schizophrenics.

show abstract

“…In other words, the temporal dynamics by which mental representations emerge, on the order of a few hundred milliseconds, might be critical for distinguishing what is seen from what is remembered 42 . While speculative, such a perspective may be useful in studying states of disease or drug effects where the distinction of memories and percepts is blurred, e.g., during hallucinations 59,60 .…”

Section: Discussionmentioning

confidence: 99%

Prioritization of semantic over visuo-perceptual aspects in multi-item working memory

Kerrén

Linde-Domingo

Spitzer

2022

Preprint

View full text Add to dashboard Cite

Working Memory (WM) keeps information temporarily available for upcoming tasks. How the contents of WM are distinguished from perceptual representations on the one hand, and from long-term memories on the other, is still debated. Here, we leveraged recent evidence for a reversal of processing dynamics when retrieving episodic long-term memories as opposed to perceiving visual input. In two experiments (n=75 and n=103), we asked participants to hold one or more items in WM and to report their low-level perceptual and high-level semantic qualities. In both experiments, we found faster responses to the items' semantic qualities, indicating prioritization over visuo-perceptual aspects, when two or more items were held concurrently in WM. These dynamics of accessing information in multi-item WM were akin to those in retrieving episodic long-term memories and opposite to those in processing visual inputs. Little to no semantic prioritization was evident during single-item maintenance, consistent with a strictly capacity-limited focus of attention within which WM information can be transformed into a prospective action plan.

show abstract

Hallucinations: Unintended or unexpected?

Cited by 49 publications

References 40 publications

Visuospatial imagery and working memory in schizophrenia

Visuospatial imagery and working memory in schizophrenia

The neuropsychology of schizophrenia

Prioritization of semantic over visuo-perceptual aspects in multi-item working memory

Contact Info

Product

Resources

About