"Everyman, I will go with thee and be thy guide , in thy most need to be by thy side

the agents in auditory 'voices' --Wilkinso

a French summary

Current views on auditory hallucinations:- Mitropoulos -

mitropoulos update

mitropoulos latest reflections

Babcock et al

Wilkinsin:- agents in hallucinations

tempero-parietal connections ..Verkammen

radcliffe reviewed

A new finding in brain science reveals that the voices in a schizophrenia patient's head can drown out voices in the real world - and provides hope that people with the disorder can learn to ignore hallucinatory talk.
The new research pulls together two threads in earlier schizophrenia studies. Many scientists have noticed that when patients hallucinate voices, neurons in brain regions associated with processing sounds spontaneously fire despite there being no sound waves to trigger this activity.
That's an indication of brain overload.
But when presented with real-world voices, other studies showed, hallucinating patients' brains often failed to respond at all, in contrast with healthy brains. These studies pointed to a stifling of brain signals. By analyzing all of these studies together, biological psychologist Kenneth Hugdahl of the University of Bergen in Norway found the simultaneous over-stimulation and dampening of brain signals to be two sides of the same coin. The findings help explain why schizophrenia patients retreat into a hallucinatory world.

Now, Hugdahl wants to use this knowledge to help patients reverse that tendency.
"What if one could train the patient to shift attention away from the inside voices to voices coming from outside?" Hugdahl said. Hearing voices that aren't there

Hugdahl and his colleagues decided to work toward understanding just one of these symptoms: hallucinations, the most universal mark of schizophrenia (about 70 percent to 80 percent of schizophrenia patients hallucinate).

In research published in 2009, the scientists asked hallucinating patients to listen to sounds through headphones while in a functional magnetic resonance imaging (fMRI) scanner.
These scanners measure oxygenated blood flow to different brain regions. More blood flow suggests more activity in a given region.
The headphones played two syllables simultaneously, one in the left ear and one in the right ear. For example, the right ear might hear "pa," while the left heard "ta." Patients weren't told the tones were different, but were asked to report what they heard.

Healthy patients generally report hearing the syllable played in the right ear, because the brain is wired for fast transmission of signals from the right ear to the left temporal lobe where speech sounds are processed.
In the absence of outside sound, schizophrenia patients' left temporal speech regions showed hyperactivity, a testament to the real-seeming voices they were hearing in their heads. Hugdahl expected that the addition of real-world sound would only increase the activity in the left temporal lobe, given that more stimulus usually means more activation. But that's not what happened.

"We found, to my big surprise, that they didn't report hearing the right ear sounds when they were hallucinating " he said. "We didn't see activation in the left temporal lobe either."
A brain paradox

This was a paradox. How could the brain be overreacting to nothing and yet shutting down when real sounds came along?

To find out if this paradox was real, Hugdahl and University of Bergen researchers Kristiina Kompus and Rene Westerhausen (who is also affiliated with Bergen's Haukeland University Hospital) dug through earlier studies on schizophrenia to see if other researchers had found the same thing.
They found 11 studies that had compared the brains of schizophrenia patients with those of healthy people while listening to external sounds, and 12 studies that looked at the brains of hallucinating schizophrenia participants. No one had ever put two and two together, though - examining the brains of hallucinating patients while they listened to external sounds, for example.

The brain-scan results supported Hugdahl and his colleagues' earlier findings: The paradox appears to be real.

"It obviously must mean that when the hallucinations are taking place in the brain, they interfere with the perceptual system, the system which is there to perceive external stimuli," Hugdahl said.


bridge neurosciences Lutterfield et al :- magnetogram timing

The onset of Auditory Voice Hallucinations was accompanied by changes in theta-band power in the right hippocampus. Furthermore, AVH were associated with a decrease in alpha-band power in the right inferior frontal gyrus and with decreases in beta-band power in the left middle and superior temporal gyri, which are regions generally implicated in auditory and language processes.

[ PHc selectively responsive to scene novelty ... Hippocampal novelty responses to changes in the spatial relationship between object and background context are maximal under conditions of associative match-mismatch .... favoring the operation of an associative match-mismatch, rather than a familiarity-based, mechanism ....the hippocampus supports representations that bind together the items and the contexts within which they occur, acting to detect changes in such relationships through its function as an associative match-mismatch detector. Importantly, no significant effects were observed in the PHc in any of the aforementioned contrasts, suggesting that a putative item-contextual binding function is specific to the hippocampus itself. ....a double dissociation between the hippocampus and PHc, with the former engaged specifically by changes in the spatial relationship between objects and their background context and the latter selectively by scene novelty. Together, our findings provide compelling support for recent proposals in which the PHc is viewed to support neural representations of the global context within which events occur, with the hippocampus playing a specific role in the rapid creation of item-context bindings. .... hippocampal activity was not observed in relation to scene novelty, nor could it be accounted for solely by changes in the egocentric position of objects on the screen, given that no significant effects were observed in a condition in which both object and background moved ....our data support theoretical predictions that the hippocampus operates as an associative match-mismatch detector ( a function perhaps subserved by the CA1 subregion based on receipt of dual inputs concerning both the external sensory environment (arriving from the entorhinal cortex) and past experience (from the CA3 subregion). Critically, according to such models, novelty signals are viewed to be contingent on the initial recall of stored information perhaps through an autoassociative mechanism (e.g., pattern completion), a process that only occurs under conditions (i.e., Object_move) when novel sensory inputs overlap sufficiently with existing representations (i.e., relating to the first presentation) ... Our results demonstrate that the PHc exhibited scene novelty responses and was not sensitive to changes in the spatial relationships between objects and the background in which they are presented, an opposite pattern to that observed in the hippocampus. ...the present findings are consistent with PHc responses being driven by stimulus novelty, given that both objects and background context were new in the Novel_scene condition, although, notably, the PHc has been found to be less responsive to changes in object identify than scene identity or scene viewpoint . It is also interesting to note that previous studies have observed that the PHc is engaged by object-location novelty, albeit typically in the setting of tasks involving explicit recognition memory judgements (Düzel et al., 2003; Köhler et al., 2005) or prefamiliarized object arrays
Furthermore, the PHc has been implicated in associating objects with navigational relevance ]

These results suggest that AVH are triggered by a short aberration in the theta band in the hippocampus, followed by activity in auditory areas accompanying the experience of hearing voices.

We speculate that these aberrations may disturb the coherency of thoughts and perception such that there is an increased focus on internal representations collected from memory.


I speculate that the loop between frontal cortex and hippocampus, which normally decides what perceived [ outside but also .. ?inside ... has to be attended to as salient, is interrupted, allowing recollected old memories- emotionally salient material- to be listened to as coming from outside.

< Auditory verbal hallucination (AVH) is a pathological hallmark of schizophrenia; however, their neural basis is unclear.
Voice identity is an important phenomenological feature of AVHs.
Certain voice identity recognition deficits are specific to schizophrenic patients with AVHs.

We tested our hypothesis that among schizophrenia patients with hallucination,
dysfunctional voice identity recognition is associated with poor functional integration in the neural networks involved in the evaluation of voice identity.

Using functional magnetic resonance imaging (fMRI) during a voice recognition task, we examined the modulation of neural network connectivity in 26 schizophrenic patients with or without AVHs, and 13 healthy controls.
Our results showed that the schizophrenic patients with AVHs had altered frontotemporal connectivity compared to the schizophrenic patients without AVHs and healthy controls.
The latter two groups did not show any differences in functional connectivity.

In addition, the strength of fronto-temporal connectivity was correlated with the accuracy of voice recognition.
These findings provide preliminary evidence that impaired functional integration may contribute to the faulty appraisal of voice identity in schizophrenic patients with AVHs.


back to Front Page

Hugdahl

A new finding in brain science reveals that the voices in a schizophrenia patient's head can drown out voices in the real world — and provides hope that people with the disorder can learn to ignore hallucinatory talk.
The new research pulls together two threads in earlier schizophrenia studies. Many scientists have noticed that when patients hallucinate voices, neurons in brain regions associated with processing sounds spontaneously fire despite there being no sound waves to trigger this activity.
That's an indication of brain overload.
But when presented with real-world voices, other studies showed, hallucinating patients' brains often failed to respond at all, in contrast with healthy brains. These studies pointed to a stifling of brain signals. By analyzing all of these studies together, biological psychologist Kenneth Hugdahl of the University of Bergen in Norway found the simultaneous over-stimulation and dampening of brain signals to be two sides of the same coin. The findings help explain why schizophrenia patients retreat into a hallucinatory world.

Now, Hugdahl wants to use this knowledge to help patients reverse that tendency.
"What if one could train the patient to shift attention away from the inside voices to voices coming from outside?" Hugdahl said. Hearing voices that aren't there

Hugdahl and his colleagues decided to work toward understanding just one of these symptoms: hallucinations, the most universal mark of schizophrenia (about 70 percent to 80 percent of schizophrenia patients hallucinate).

In research published in 2009, the scientists asked hallucinating patients to listen to sounds through headphones while in a functional magnetic resonance imaging (fMRI) scanner.
These scanners measure oxygenated blood flow to different brain regions. More blood flow suggests more activity in a given region.
The headphones played two syllables simultaneously, one in the left ear and one in the right ear. For example, the right ear might hear "pa," while the left heard "ta." Patients weren't told the tones were different, but were asked to report what they heard.

Healthy patients generally report hearing the syllable played in the right ear, because the brain is wired for fast transmission of signals from the right ear to the left temporal lobe where speech sounds are processed.
In the absence of outside sound, schizophrenia patients' left temporal speech regions showed hyperactivity, a testament to the real-seeming voices they were hearing in their heads. Hugdahl expected that the addition of real-world sound would only increase the activity in the left temporal lobe, given that more stimulus usually means more activation. But that's not what happened.

"We found, to my big surprise, that they didn't report hearing the right ear sounds when they were hallucinating " he said. "We didn't see activation in the left temporal lobe either."
A brain paradox

This was a paradox. How could the brain be overreacting to nothing and yet shutting down when real sounds came along?

To find out if this paradox was real, Hugdahl and University of Bergen researchers Kristiina Kompus and Rene Westerhausen (who is also affiliated with Bergen's Haukeland University Hospital) dug through earlier studies on schizophrenia to see if other researchers had found the same thing.
They found 11 studies that had compared the brains of schizophrenia patients with those of healthy people while listening to external sounds, and 12 studies that looked at the brains of hallucinating schizophrenia participants. No one had ever put two and two together, though — examining the brains of hallucinating patients while they listened to external sounds, for example.

The brain-scan results supported Hugdahl and his colleagues' earlier findings: The paradox appears to be real.

"It obviously must mean that when the hallucinations are taking place in the brain, they interfere with the perceptual system, the system which is there to perceive external stimuli," Hugdahl said.

the agents in auditory 'voices' --Wilkinso

a French summary

Current views on auditory hallucinations:- Mitropoulos -

mitropoulos latest reflections

Babcock et al

Wilkinsin:- agents in hallucinations

tempero-parietal connections ..Verkammen

radcliffe reviewed

A new finding in brain science reveals that the voices in a schizophrenia patient's head can drown out voices in the real world - and provides hope that people with the disorder can learn to ignore hallucinatory talk.
The new research pulls together two threads in earlier schizophrenia studies. Many scientists have noticed that when patients hallucinate voices, neurons in brain regions associated with processing sounds spontaneously fire despite there being no sound waves to trigger this activity.
That's an indication of brain overload.
But when presented with real-world voices, other studies showed, hallucinating patients' brains often failed to respond at all, in contrast with healthy brains. These studies pointed to a stifling of brain signals. By analyzing all of these studies together, biological psychologist Kenneth Hugdahl of the University of Bergen in Norway found the simultaneous over-stimulation and dampening of brain signals to be two sides of the same coin. The findings help explain why schizophrenia patients retreat into a hallucinatory world.

Now, Hugdahl wants to use this knowledge to help patients reverse that tendency.
"What if one could train the patient to shift attention away from the inside voices to voices coming from outside?" Hugdahl said. Hearing voices that aren't there

Hugdahl and his colleagues decided to work toward understanding just one of these symptoms: hallucinations, the most universal mark of schizophrenia (about 70 percent to 80 percent of schizophrenia patients hallucinate).

In research published in 2009, the scientists asked hallucinating patients to listen to sounds through headphones while in a functional magnetic resonance imaging (fMRI) scanner.
These scanners measure oxygenated blood flow to different brain regions. More blood flow suggests more activity in a given region.
The headphones played two syllables simultaneously, one in the left ear and one in the right ear. For example, the right ear might hear "pa," while the left heard "ta." Patients weren't told the tones were different, but were asked to report what they heard.

Healthy patients generally report hearing the syllable played in the right ear, because the brain is wired for fast transmission of signals from the right ear to the left temporal lobe where speech sounds are processed.
In the absence of outside sound, schizophrenia patients' left temporal speech regions showed hyperactivity, a testament to the real-seeming voices they were hearing in their heads. Hugdahl expected that the addition of real-world sound would only increase the activity in the left temporal lobe, given that more stimulus usually means more activation. But that's not what happened.

"We found, to my big surprise, that they didn't report hearing the right ear sounds when they were hallucinating " he said. "We didn't see activation in the left temporal lobe either."
A brain paradox

This was a paradox. How could the brain be overreacting to nothing and yet shutting down when real sounds came along?

To find out if this paradox was real, Hugdahl and University of Bergen researchers Kristiina Kompus and Rene Westerhausen (who is also affiliated with Bergen's Haukeland University Hospital) dug through earlier studies on schizophrenia to see if other researchers had found the same thing.
They found 11 studies that had compared the brains of schizophrenia patients with those of healthy people while listening to external sounds, and 12 studies that looked at the brains of hallucinating schizophrenia participants. No one had ever put two and two together, though - examining the brains of hallucinating patients while they listened to external sounds, for example.

The brain-scan results supported Hugdahl and his colleagues' earlier findings: The paradox appears to be real.

"It obviously must mean that when the hallucinations are taking place in the brain, they interfere with the perceptual system, the system which is there to perceive external stimuli," Hugdahl said.


The findings indicate that elevated dopamine synthesis capacity in the dorsal striatum is a robust feature of individuals at UHR for psychosis and provide further evidence that dopaminergic abnormalities precede the onset of psychosis.

recollection of object- and scene-related event details. Staresina BP , Davachi L Source Medical Research Council Cognition and Brain Sciences Unit, Cambridge CB2 7EF, United Kingdom. bernhard.staresina@mrc-cbu.cam.ac.uk Abstract How the different elements of our experiences are encoded into episodic memories has remained one of the major questions in memory research. Although the pivotal role of the medial temporal lobe as a whole for memory formation is well established, much controversy surrounds the precise contributions of the subregions in the medial temporal lobe cortex (MTLC), most notably the perirhinal cortex (PrC) and the parahippocampal cortex (PhC). Although one prominent view links PrC processes with familiarity-based memory and PhC with recollection, an alternative organizing principle is the representational domain critical for successful memory performance (e.g., object- versus scene-related information). In this functional magnetic resonance imaging study, we directly compared successful source encoding during object versus scene imagery, holding perceptual input constant across the two representational domains. Although the hippocampus contributed to associative encoding of both object and scene information, our results revealed a clear double dissociation between PrC and PhC for object- versus scene-related source encoding. In particular, PrC, but not PhC, encoding activation predicted later source memory for the object imagery task, whereas PhC, but not PrC, encoding activation predicted later source memory for the scene imagery task. Interestingly, the transitional zone between PrC and posterior PhC contributed to both object and scene source encoding, possibly reflecting a gradient in domain preference along MTLC. In sum, these results strongly point to representational domain as a key factor determining the involvement of different MTLC subregions during successful episodic memory formation.

the part of the brain lost among those who failed to perceive sarcasm The right parahippocampal gyrus must be involved in detecting more than just visual context it perceives social context as well in a part of the right hemisphere previously identified as important only to detecting contextual background changes in visual tests. "The right parahippocampal gyrus must be involved in detecting more than just visual context - it perceives social context as wel

the role of PRc in retrieval of item details and that of PHc and the hippocampus in retrieval of context details even when stimulus materials and test demands were held constant.

Cognitive models propose that auditory verbal hallucinations arise through inner speech misidentification. However, such models cannot explain why the voices in hallucinations often have identities different from the hearer 'voice'
Auditory verbal hallucinations in patients with a psychotic disorder are consistently preceded by deactivation of the parahippocampal gyrus.

The parahippocampus has been hypothesized to play a central role in memory recollection, sending information from the hippocampus to the association areas.

Dysfunction of this region could trigger inadequate activation of right language areas during auditory hallucinations.[Diederen KJ Cambridge neurosciences

Lutterfield et al :- magnetogram timing

The onset of Auditory Voice Hallucinations was accompanied by changes in theta-band power in the right hippocampus. Furthermore, AVH were associated with a decrease in alpha-band power in the right inferior frontal gyrus and with decreases in beta-band power in the left middle and superior temporal gyri, which are regions generally implicated in auditory and language processes.

[ PHc selectively responsive to scene novelty ... Hippocampal novelty responses to changes in the spatial relationship between object and background context are maximal under conditions of associative match-mismatch .... favoring the operation of an associative match-mismatch, rather than a familiarity-based, mechanism ....the hippocampus supports representations that bind together the items and the contexts within which they occur, acting to detect changes in such relationships through its function as an associative match-mismatch detector. Importantly, no significant effects were observed in the PHc in any of the aforementioned contrasts, suggesting that a putative item-contextual binding function is specific to the hippocampus itself. ....a double dissociation between the hippocampus and PHc, with the former engaged specifically by changes in the spatial relationship between objects and their background context and the latter selectively by scene novelty. Together, our findings provide compelling support for recent proposals in which the PHc is viewed to support neural representations of the global context within which events occur, with the hippocampus playing a specific role in the rapid creation of item-context bindings. .... hippocampal activity was not observed in relation to scene novelty, nor could it be accounted for solely by changes in the egocentric position of objects on the screen, given that no significant effects were observed in a condition in which both object and background moved ....our data support theoretical predictions that the hippocampus operates as an associative match-mismatch detector ( a function perhaps subserved by the CA1 subregion based on receipt of dual inputs concerning both the external sensory environment (arriving from the entorhinal cortex) and past experience (from the CA3 subregion). Critically, according to such models, novelty signals are viewed to be contingent on the initial recall of stored information perhaps through an autoassociative mechanism (e.g., pattern completion), a process that only occurs under conditions (i.e., Object_move) when novel sensory inputs overlap sufficiently with existing representations (i.e., relating to the first presentation) ... Our results demonstrate that the PHc exhibited scene novelty responses and was not sensitive to changes in the spatial relationships between objects and the background in which they are presented, an opposite pattern to that observed in the hippocampus. ...the present findings are consistent with PHc responses being driven by stimulus novelty, given that both objects and background context were new in the Novel_scene condition, although, notably, the PHc has been found to be less responsive to changes in object identify than scene identity or scene viewpoint . It is also interesting to note that previous studies have observed that the PHc is engaged by object-location novelty, albeit typically in the setting of tasks involving explicit recognition memory judgements (Düzel et al., 2003; Köhler et al., 2005) or prefamiliarized object arrays
Furthermore, the PHc has been implicated in associating objects with navigational relevance ]

These results suggest that AVH are triggered by a short aberration in the theta band in the hippocampus, followed by activity in auditory areas accompanying the experience of hearing voices.

We speculate that these aberrations may disturb the coherency of thoughts and perception such that there is an increased focus on internal representations collected from memory.


I speculate that the loop between frontal cortex and hippocampus, which normally decides what perceived [ outside but also .. ?inside ... has to be attended to as salient, is interrupted, allowing recollected old memories- emotionally salient material- to be listened to as coming from outside.

Tragedies

Aftercare and Recovery

Carers and
Caring

Mental Health
Service Delivery

Schizophrenia

Coroner

Police













10









20












30












40


>








50












60












70










80










90










100<

Auditory verbal hallucination (AVH) is a pathological hallmark of schizophrenia; however, their neural basis is unclear.
Voice identity is an important phenomenological feature of AVHs.
Certain voice identity recognition deficits are specific to schizophrenic patients with AVHs.

We tested our hypothesis that among schizophrenia patients with hallucination,
dysfunctional voice identity recognition is associated with poor functional integration in the neural networks involved in the evaluation of voice identity.

Using functional magnetic resonance imaging (fMRI) during a voice recognition task, we examined the modulation of neural network connectivity in 26 schizophrenic patients with or without AVHs, and 13 healthy controls.
Our results showed that the schizophrenic patients with AVHs had altered frontotemporal connectivity compared to the schizophrenic patients without AVHs and healthy controls.
The latter two groups did not show any differences in functional connectivity.

In addition, the strength of fronto-temporal connectivity was correlated with the accuracy of voice recognition.
These findings provide preliminary evidence that impaired functional integration may contribute to the faulty appraisal of voice identity in schizophrenic patients with AVHs.


back to Front Page


The findings indicate that elevated dopamine synthesis capacity in the dorsal striatum is a robust feature of individuals at UHR for psychosis and provide further evidence that dopaminergic abnormalities precede the onset of psychosis.

recollection of object- and scene-related event details. Staresina BP , Davachi L Source Medical Research Council Cognition and Brain Sciences Unit, Cambridge CB2 7EF, United Kingdom. bernhard.staresina@mrc-cbu.cam.ac.uk Abstract How the different elements of our experiences are encoded into episodic memories has remained one of the major questions in memory research. Although the pivotal role of the medial temporal lobe as a whole for memory formation is well established, much controversy surrounds the precise contributions of the subregions in the medial temporal lobe cortex (MTLC), most notably the perirhinal cortex (PrC) and the parahippocampal cortex (PhC). Although one prominent view links PrC processes with familiarity-based memory and PhC with recollection, an alternative organizing principle is the representational domain critical for successful memory performance (e.g., object- versus scene-related information). In this functional magnetic resonance imaging study, we directly compared successful source encoding during object versus scene imagery, holding perceptual input constant across the two representational domains. Although the hippocampus contributed to associative encoding of both object and scene information, our results revealed a clear double dissociation between PrC and PhC for object- versus scene-related source encoding. In particular, PrC, but not PhC, encoding activation predicted later source memory for the object imagery task, whereas PhC, but not PrC, encoding activation predicted later source memory for the scene imagery task. Interestingly, the transitional zone between PrC and posterior PhC contributed to both object and scene source encoding, possibly reflecting a gradient in domain preference along MTLC. In sum, these results strongly point to representational domain as a key factor determining the involvement of different MTLC subregions during successful episodic memory formation.

the part of the brain lost among those who failed to perceive sarcasm The right parahippocampal gyrus must be involved in detecting more than just visual context it perceives social context as well in a part of the right hemisphere previously identified as important only to detecting contextual background changes in visual tests. “The right parahippocampal gyrus must be involved in detecting more than just visual context — it perceives social context as wel

the role of PRc in retrieval of item details and that of PHc and the hippocampus in retrieval of context details even when stimulus materials and test demands were held constant.

Cognitive models propose that auditory verbal hallucinations arise through inner speech misidentification. However, such models cannot explain why the voices in hallucinations often have identities different from the hearer 'voice'
Auditory verbal hallucinations in patients with a psychotic disorder are consistently preceded by deactivation of the parahippocampal gyrus.

The parahippocampus has been hypothesized to play a central role in memory recollection, sending information from the hippocampus to the association areas.

Dysfunction of this region could trigger inadequate activation of right language areas during auditory hallucinations.[Diederen KJ Cambridge neurosciences

Lutterfield et al :- magnetogram timing

The onset of Auditory Voice Hallucinations was accompanied by changes in theta-band power in the right hippocampus. Furthermore, AVH were associated with a decrease in alpha-band power in the right inferior frontal gyrus and with decreases in beta-band power in the left middle and superior temporal gyri, which are regions generally implicated in auditory and language processes.

[ PHc selectively responsive to scene novelty ... Hippocampal novelty responses to changes in the spatial relationship between object and background context are maximal under conditions of associative match–mismatch .... favoring the operation of an associative match–mismatch, rather than a familiarity-based, mechanism ....the hippocampus supports representations that bind together the items and the contexts within which they occur, acting to detect changes in such relationships through its function as an associative match–mismatch detector. Importantly, no significant effects were observed in the PHc in any of the aforementioned contrasts, suggesting that a putative item–contextual binding function is specific to the hippocampus itself. ....a double dissociation between the hippocampus and PHc, with the former engaged specifically by changes in the spatial relationship between objects and their background context and the latter selectively by scene novelty. Together, our findings provide compelling support for recent proposals in which the PHc is viewed to support neural representations of the global context within which events occur, with the hippocampus playing a specific role in the rapid creation of item–context bindings. .... hippocampal activity was not observed in relation to scene novelty, nor could it be accounted for solely by changes in the egocentric position of objects on the screen, given that no significant effects were observed in a condition in which both object and background moved ....our data support theoretical predictions that the hippocampus operates as an associative match–mismatch detector ( a function perhaps subserved by the CA1 subregion based on receipt of dual inputs concerning both the external sensory environment (arriving from the entorhinal cortex) and past experience (from the CA3 subregion). Critically, according to such models, novelty signals are viewed to be contingent on the initial recall of stored information perhaps through an autoassociative mechanism (e.g., pattern completion), a process that only occurs under conditions (i.e., Object_move) when novel sensory inputs overlap sufficiently with existing representations (i.e., relating to the first presentation) ... Our results demonstrate that the PHc exhibited scene novelty responses and was not sensitive to changes in the spatial relationships between objects and the background in which they are presented, an opposite pattern to that observed in the hippocampus. ...the present findings are consistent with PHc responses being driven by stimulus novelty, given that both objects and background context were new in the Novel_scene condition, although, notably, the PHc has been found to be less responsive to changes in object identify than scene identity or scene viewpoint . It is also interesting to note that previous studies have observed that the PHc is engaged by object–location novelty, albeit typically in the setting of tasks involving explicit recognition memory judgements (Düzel et al., 2003; Köhler et al., 2005) or prefamiliarized object arrays
Furthermore, the PHc has been implicated in associating objects with navigational relevance ]

These results suggest that AVH are triggered by a short aberration in the theta band in the hippocampus, followed by activity in auditory areas accompanying the experience of hearing voices.

We speculate that these aberrations may disturb the coherency of thoughts and perception such that there is an increased focus on internal representations collected from memory.


I speculate that the loop between frontal cortex and hippocampus, which normally decides what perceived [ outside but also .. ?inside ... has to be attended to as salient, is interrupted, allowing recollected old memories- emotionally salient material- to be listened to as coming from outside.

Tragedies

Aftercare and Recovery

Carers and
Caring

Mental Health
Service Delivery

Schizophrenia

Coroner

Police













10









20












30












40


>








50












60












70










80










90










100<

Auditory verbal hallucination (AVH) is a pathological hallmark of schizophrenia; however, their neural basis is unclear.
Voice identity is an important phenomenological feature of AVHs.
Certain voice identity recognition deficits are specific to schizophrenic patients with AVHs.

We tested our hypothesis that among schizophrenia patients with hallucination,
dysfunctional voice identity recognition is associated with poor functional integration in the neural networks involved in the evaluation of voice identity.

Using functional magnetic resonance imaging (fMRI) during a voice recognition task, we examined the modulation of neural network connectivity in 26 schizophrenic patients with or without AVHs, and 13 healthy controls.
Our results showed that the schizophrenic patients with AVHs had altered frontotemporal connectivity compared to the schizophrenic patients without AVHs and healthy controls.
The latter two groups did not show any differences in functional connectivity.

In addition, the strength of fronto-temporal connectivity was correlated with the accuracy of voice recognition.
These findings provide preliminary evidence that impaired functional integration may contribute to the faulty appraisal of voice identity in schizophrenic patients with AVHs.


back to Front Page

Licznik Odwiedzin, Licznik Wizyt