Thought Disorder
The ability to find and hold on to a thought, weakens after the illness, so that the direction given by the original connection wanders off line and canot be retrieved.
New experiences do not get matched to old ones and are not up-dated.
Other people mature in that way.
After schizophrenia experience does not seem to accumulate and fit in with what went before. The old memories are not adjusted.

'Voices'

If you put patients in an fMRI scanner and ask them to indicate when they are hearing voices, you see activation of Broca's area where speech is produced.
in normal individuals the production of inner speech somehow turns off the neural system that normally processes external speech
when patients are hallucinating they are activating temporal lobe areas that are normally involved in the processing of external speech
. The hearing bit of the brain is lit up before the inner spoken thoughts open, so they are registered as coming in from outside

To tell which areas of the brain become more active during a mental task, scientists compare brain activity during the task with activity when the person is at rest, either with eyes closed or while staring at a dot or cross.

Raichle, of Washington University in St. Louis, and others saw that every time a person engaged in a mental activity such as memorizing a list of words, a collection of brain regions consistently decreased activity compared with their resting levels.

Only when people recall autobiographical memories or imagine alternative situations is the network more active than it is at rest, scientists have since found. (In this context, "rest" refers to a state in which the brain is not engaged in a mental task but is still monitoring the body and the world around it.)

Raichle hypothesized that the network is more active when the brain is at rest and has to dial back its activity to let people concentrate on specific tasks.

Another account concerns the relationship between the default network and a set of regions commonly activated during task states In previous publications, we have noted that many of the regions that are negatively correlated with the default network belong to two separate networks (frontoparietal and cinguloopercular) proposed to implement task-level control of goal-oriented "external" behavior (refs. 21, 22, and 40; also see ref. 41 for review).

The frontoparietal network includes, among other regions, the dorsolateral prefrontal cortex (dlPFC) and intraparietal sulcus (IPS).

The cinguloopercular network includes the dorsal anterior cingulate/medial superior frontal cortex (dACC/msFC), anterior insula/frontal operculum (aI/fO), and anterior prefrontal cortex (aPFC).

Over age, these task-level control networks show significant developmental change in functional connectivity (22) that, in some ways, parallels the development of the default network described here.

In addition, recent work on the other end of the life span suggests that increased functional coherence between the regions of the default network is related to superior executive functions in healthy aging (42).

Thus, the parallel development and close relationship (albeit negative) between the default and task control networks may be important for the age-related improvements in control processes such as alerting, inhibition, set switching, and set maintenance observed over development (30, 43-48).

default again

The medial temporal lobe subsystem provides information from prior experiences in the form of memories and associations that are the building blocks of mental simulation. The medial prefrontal subsystem facilitates the flexible use of this information during the construction of self-relevant mental simulations. These two subsystems converge on important nodes of integration including the posterior cingulate cortex.

Our results indicated that the STPs-network regions, including the left precuneus (PCu, BA 7), the left angular gyrus/superior occipital gyrus (AG/SOG, BA 39/19), the left inferior parietal lobule (IPL, BA 40), the medial prefrontal gyrus (mPFG, BA 8/6) and the left hippocampus/parahippocampus (HIP/PHIP), showed significant correlations with the subjects' mind-wandering frequencies

Interestingly, we found that the functional connectivities associated with the HIP/PHIP tended to be weaker than other functional connectivities in both the N-Rest and in the M-Reprocess.

This result suggests that different STPs-network regions may contribute specialized functions that are organized into subsystems. In fact, previous studies have revealed that the brain's default network is comprised of at least two distinct, interacting subsystems: One is the medial temporal subsystem associated with the HIP/PHIP, and the other is a subsystem associated with the mPFG (for a review, see [37]).

This is consistent with our finding that the HIP/PHIP and other STPs-network regions are not highly correlated with each other. An explanation for such functional separation is that the HIP/PHIP is associated with receiving memory-related information and comparing/combining distinct memory representations [18], whereas the PCu, the IPL, the AG and the mPFG have been suggested as being associated with high-level offline memory processes, such as self-referential thought, or time-sequencing/organizing of recalled information [38]-[41].

Compared with the N-Rest, the functional connectivity between the PCu and the mPFG were significantly stronger during the M-Reprocess, suggesting the strengthened interaction between the two regions.

However, the functional connectivity between the HIP/PHIP and the PCu showed a tendency to be weaker (P<0.05, uncorrected) during the M-Reprocess than during the N-Rest.

Our ReHo analysis has found that both the HIP/PHIP and the PCu showed increased ReHo-reflected activity during the M-Reprocess than the N-Rest (Figure 2).

Therefore, these results indicate that although both the HIP/PHIP and the PCu were more involved in the M-Reprocess, their activities showed a tendency to be de-coherent during the higher demanding state, further suggesting their different roles in the offline memory reprocessing. Taken together, the execution of offline memory reprocessing by the STPs-network would be expected to be a combined effect of functional integration and functional separation among its components.

January 20th, 2009 by Cathryn M. Delude

(PhysOrg.com) --

Schizophrenia may blur the boundary between internal and external realities by over-activating a brain system that is involved in self-reflection, and thus causing an exaggerated focus on self, a new MIT and Harvard brain imaging study has found.

The traditional view of schizophrenia is that the disturbed thoughts, perceptions and emotions that characterize the disease are caused by disconnections among the brain regions that control these different functions.

But this study, appearing Jan. 19 in the advance online issue of the Proceedings of the National Academy of Sciences, found that schizophrenia also involves an excess of connectivity between the so-called default brain regions, which are involved in self-reflection and become active when we are thinking about nothing in particular, or thinking about ourselves.

"People normally suppress this default system when they perform challenging tasks, but we found that patients with schizophrenia don't do this," said John D. Gabrieli, a professor in the McGovern Institute for Brain Research at MIT and one of the study's 13 authors. "We think this could help to explain the cognitive and psychological symptoms of schizophrenia."

Gabrieli added that he hopes the research might lead to ways of predicting or monitoring individual patients' response to treatments for this mental illness, which occurs in about 1 percent of the population. Schizophrenia has a strong genetic component, and first-degree relatives of patients (who share half their genes) are 10 times more likely to develop the disease than the general population. The identities of these genes and how they affect the brain are largely unknown.

The researchers thus studied three carefully matched groups of 13 subjects each: schizophrenia patients, nonpsychotic first-degree relatives of patients and healthy controls. They selected patients who were recently diagnosed, so that differences in prior treatment or psychotic episodes would not bias the results. The subjects were scanned by functional magnetic resonance imaging (fMRI) while resting and while performing easy or hard memory tasks. The behavioral and clinical testing were performed by Larry J. Seidman and colleagues at Harvard Medical School, and the imaging data were analyzed by first author Susan Whitfield-Gabrieli, a research scientist at the MIT Martinos Imaging Center at the McGovern Institute.

The researchers were especially interested in the default system, a network of brain regions whose activity is suppressed when people perform demanding mental tasks. This network includes the medial prefrontal cortex and the posterior cingulate cortex, regions that are associated with self-reflection and autobiographical memories and which become connected into a synchronously active network when the mind is allowed to wander.

Whitfield-Gabrieli found that in the schizophrenia patients, the default system was both hyperactive and hyperconnected during rest, and it remained so as they performed the memory tasks. In other words, the patients were less able than healthy control subjects to suppress the activity of this network during the task. Interestingly, the less the suppression and the greater the connectivity, the worse they performed on the hard memory task, and the more severe their clinical symptoms.

"We think this may reflect an inability of people with schizophrenia to direct mental resources away from internal thoughts and feelings and toward the external world in order to perform difficult tasks," Whitfield-Gabrieli explained. The hyperactive default system could also help to explain hallucinations and paranoia by making neutral external stimuli seem inappropriately self-relevant. For instance, if brain regions whose activity normally signifies self-focus are active while listening to a voice on television, the person may perceive that the voice is speaking directly to them.

The default system is also overactive, though to a lesser extent, in first-degree relatives of schizophrenia patients who did not themselves have the disease. This suggests that overactivation of the default system may be linked to the genetic cause of the disease rather than its consequences. The default system is a hot topic in brain imaging, according to John Gabrieli, partly because it is easy to measure and because it is affected in different ways by different disorders.

background material to thought disorder

default brain

default brain

G. H. Brans, MS, N E. M. van Haren, PhD, G. M. van Baal, PhD, W G. Staal, PhD, MD, HG. Schnack, PhD, R S. Kahn, PhD, MD and H E. Hulshoff Pol, PhD University Medical Center Utrecht, The Netherlands

The progressive decreases over time in whole brain and cerebral grey matter volume [ the cells ]
and less prominent increases in white matter [ the joining connecting lines ] observed in schizophrenia patients
but not in siblings may represent a (disease-related) non-genetic risk factor for the disease.

Our finding of progressive decrease over time is consistent with those of other longitudinal studies in schizophrenia.

The findings in siblings are consistent with the normalisation of cortical thickness
by the age of 20 in siblings of patients with childhood-onset schizophrenia.

Could it be disuse ? How otherwise to find late 'recoveries - unless another pathway is found to get round the grey matter loss ?

mica@jidgey.e7even.com

Time course of regional brain activation associated with onset of auditory/verbal hallucinations.

Hoffman, Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut : Anderson, M Varanko, JC. Gore,

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Two sites exhibiting positive BOLD [ blood oxygen up levels becasue of activity in local cells ] signal correlations with hallucination time course exclusively at negative time lags [ occuring so many seconds before hallucinating ] largely replicated pre-hallucination activation sites described previously.

Positive Blood Oxygen signal correlations with hallucination time course were detected selectively at negative time intervals ( time lags ranging from -4.5 s to -1.5 s) in the left insula and a right middle temporal region, as well as in left pre-central areas .

Positive correlations also emerged in the superior temporal gyrus bilaterally at negative time lags, ( then ) peaking approximately at zero time lag [ i.e. the same time as hallucinating ]
Negative blood oxygen signal correlations with hallucination time course were detected in the right ventral anterior cingulate , and left parahippocampal gyri at negative time lags.

Right middle temporal site

The right middle temporal site (Brodmann area 21) was located remarkably close to middle temporal gyrus sites of pre-hallucination activation reported by Lennox et al and Shergill et al.

Activation in the bilateral superior temporal gyrus (Brodmann area 22) emerged at negative time lags also [ i'e .. 'before ] , but peaked later and was broadly distributed over both positive and negative time lags.

Our correlation-based method for mapping BOLD signal time course will produce temporal smearing that broadens with increasing neural activation.
The temporal pattern of our data suggests therefore that the more robust bilateral activation in the superior temporal gyrus arose somewhat later - perhaps at hallucination onset - than the middle temporal gyrus activation.

Bilateral activation of the latter region has been associated with aspects of verbal comprehension during speech processing distinct from acoustic feature detection referable to the superior temporal gyrus, whereas non-dominant middle temporal gyral activation has been associated with detecting prosodic features of spoken speech.

One plausible account of our findings is that pre-hallucination activation in the middle temporal gyrus reflecting verbal content and/or prosody [ the study of poetic meters, metrics and versification - the stress and intonation patterns of an utterance ] is subsequently propagated to the superior temporal gyrus via top-down processing, which generates ( hallucinated) acoustic representations. [ 'voices' ]

Left anterior insula

The left anterior insula was close to a site of activation in the left inferior frontal gyrus 9 , prior to hallucination onset, identified by Shergill et al, who reported expanded activation incorporating the left insula at later times.
Left insula activation has been associated with speech articulation, imagining spoken speech of others, and focused auditory attention,
suggesting that pre-hallucination insula activation reflects inner speech
or auditory imagery generation as previously hypothesised, or enhanced auditory attention.

However, pre-hallucination insula activation might instead reflect motor movement required to signal these events.
This possibility is suggested by the fact that doing simple finger movements
is preceded by activation in the adjacent Broca's area, which has been postulated to reflect mental preparation.

Other sites

Evidence of right ventral anterior cingulate and left parahippocampal deactivation preceding hallucination onset was detected.
Co-occurring deactivations in these regions have also been linked to heightened vigilance/attention, suggesting a shift in cognitive state preceding auditory/verbal hallucinations.
Along these lines, Arieti described a `listening attitude' that predisposes people with schizophrenia to hear `voices'.

Pre-central activation emerging prior to hallucination onset in our study could reflect either inner speech generation or signalling hallucinations by finger movement.

In summary, activation detected as BOLD signal changes correlated with auditory/verbal hallucination time course at negative time lags may reveal complex brain processes triggering these experiences.

Future studies of this type would be advanced by controlling for effects of motor behaviour [ the other explanation preparing whatever motor required to signal hallucination occurrences.

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To me this means that activity goes on in the area of the brain dealing with 'hearing' hallucinatory voices before there is activity in the areas of the brain that do speech or silent speech ?

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People with autism are supposed not to do 'day dreaming'. What about people with schizophrenia - anybody know ??? How will day dreaming fit in with the above.

People in schizophrenia are often in a state of doing nothing - the default state of daydreaming.
Then, when actually 'paying attention' e.g at a professional interview
when it is important to be paying attention, because of the possible consequences ...
...that seems to be when the 'voices' are not there or are disregarded.
Similarly when taken up with concentrating on doing something connected with 'outside the person ' activities.

What about the 'fantasy dreaming that goes on ? when 'dozing' on the way to sleep,
or being half to waking up ?? Help ??

mica2@tiscali.co.uk

Why now ?

Recovery