NARSAD Grantees Link Altered Brain Activity to Schizophrenia Cognitive Symptoms

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Brain research, schizophrenia research
Brain Research

Many people with schizophrenia struggle to think clearly and remember information, and these problems prevent many from living and working independently. How these difficulties arise in the first place remains mysterious, but a new study by NARSAD Grantees and co-senior authors Christoph Kellendonk, Ph.D., and Joshua A. Gordon, M.D., Ph.D. (also a Brain & Behavior Research Foundation Scientific Council Member) of Columbia University, NY, and colleagues highlights a role for a region deep inside the brain called the mediodorsal (MD) thalamus. The study was published on March 21, 2013 in Neuron.

The MD thalamus makes many two-way connections with the prefrontal cortex, a brain region already well-known for complex thinking and memory. Brain scans have found that the MD thalamus seems underactive in people with schizophrenia.

To mimic this underactive MD thalamus signaling, the researchers dialed down the electrical signals in the MD thalamus in mice. This gave rise to problems with thinking and memory that are very similar to those seen in people with schizophrenia, and also interfered with communication between the MD thalamus and prefrontal cortex. The study illustrates that even a subtle disturbance in one part of the brain can substantially disrupt the flow of information throughout the brain, causing tangible problems with complex thinking and memory function.

Read the study announcement

Read more about the study on the website of the Schizophrenia Resource Forum, which is sponsored by the Brain & Behavior Research Foundation

Watch a video about this research:

Article comments

Professor Tim Crow's theory suggests that schizophrenia is the price we pay for language and I wonder if the exposure to stimulus (non-verbal) - stimulus (verbal) contingencies (classical conditioning) when you with a short delay are able to restore a verbal message or interpret what subjectively seems to be a verbal message can have such a profound effect that some people develop a mental illness.

Quote:"...classical conditioning is far more subtle and relevant to complex human cognitive-emotional behavior than one might first realize..." (p. 4) Source: The Imbalanced Brain: From Normal Behavior To Schizophrenia (2000) by Stephen Grossberg

http://www.cns.bu.edu/Profiles/Grossberg/Gro.BioPsy2000.pdf

Summary: Some people who hear their own thoughts as alien voices in response to non-verbal environmental or tinnitus like sounds are definitely able to generate the perception of an external voice "that retain certain acoustic features that were present in the original signal" and what if each and every one of us are able to use covert speech to generate the perception of an external voice "that retain certain acoustic features that were present in the original signal" when we need to restore and better distinguish a verbal message? (I am convinced that Alvin M. Liberman more than 50 years ago was correct in his assumption that “the articulatory movements and their sensory effects mediate between the acoustic stimulus and the event we call perception”... ) Alien covert speech must somehow operate on the environment in order to generate the event we call speech perception and the lost ability to control an operant behavior like covert speech may serve the purpose of not letting an act of will interfere with the ability to select the gestures you need to use in response to a verbal message. (Incentive motivational signals ("a type of motivationally-biased attention") may shift the allocation of processing resources from what generates the ability to consciously control covert speech (a self-monitoring or “corollary discharge” mechanism) to what you are able to attend with a corresponding top-down sensory expectation and the gesture you need to use (the one with the most equivalent sensory consequence you are able to produce) can be selected when what you are able to attend with a corresponding top-down sensory expectation (a competing task), more than what you are able to attend with any other to a lesser extent matching top-down sensory expectation, suppress the ability to control covert speech! To lose the ability to generate an act of will with which you are able to consciously control covert speech is to more or less lose the ability to inhibit the gesture you are about to produce and some people who lack the ability to inhibit a verbal response are able to hear the sensory consequence of covert speech in integration with what they were able to select with a corresponding top-down sensory expectation... ) To frequently reward a behavior which generates the exposure to stimulus (non-verbal) - stimulus (verbal) contingencies when you with a short delay are able to restore a verbal message or interpret what subjectively seems to be a verbal message may very well establish a tendency to interpret what people normally ignore. (Positive symptoms in all of our other senses (visual hallucinations etc) emerge when people frequently are able to reveal a verbal illusion and due to "unusual persistence of controlled information processing strategies" fail to simultaneously block a neutral stimulus in compound with CS (un-patterned noise). Visual hallucinations etc can like verbal auditory hallucination be established as the result of stimulus (ambiguous) - stimulus (informative) contingencies when you with a short delay are able to generate the event we call perception.) "Non-clinical populations usually experience voices with a neutral or even positive emotional content" and to selectively be able to avoid some voices expressed with a negative emotional content by paying more attention to what you are able to hear more objectively may eventually generate a more unpleasant voice hearing experience, disorganization and negative symptoms... (People who consistently avoid the event they fear will continue to expect a fearfull event (phobia) and people who selectively are able to avoid some of the voices they hear by revealing a mismatch will continue to expect to hear the voices they were able to avoid! To continue to expect to hear the voices you are able to avoid by revealing a verbal illusion may eventually generate negative symptoms like poverty of speech, affective flattening and avolition and to continue to expect to hear the voices you are trying to avoid will generate the voices you are trying to avoid whenever you are unable to reveal a verbal illusion. The allocation of processing resources from what generates the ability to consciously control covert speech to what you are able to attend with a corresponding top-down sensory expectation must be greater when you are trying to avoid a voice with a negative emotional content than when you are trying to restore a verbal message or interpret non-verbal environmental or tinnitus like sounds with no connection to a verbal message (not coexisting with or corresponding to a distorted verbal message) and avoidance may therefore also generate a more disorganized behavior. "Dopamine is released in order to achieve something good or to avoid something evil" and dopamine receptor antagonists are used to treat "schizophrenia"... Conditioned avoidance response (CAR) is a test with predictive validity for antipsychotic efficacy, but negative symptoms are very hard to treat and I wonder if this can be explained with the assumtion that negative symptoms predominantly depend on that you previously in avoidance were able to reveal a verbal illusion. ) The ability to frequently reveal a mismatch will allow you to inhibit a behavior which generates the event we call speech perception in response to non-verbal environmental or tinnitus like sounds and the occurrences of a conditioned response (CR - when a conditioned reinforcer triggers the need to access a verbal message!) will eventually decrease or disappear if a conditioned reinforcer (un-patterned noise) due to the ability to reveal a verbal illusion no longer is paired with a primary reinforcer (information brought to awareness when the event we call speech perception is generated in response to non-verbal environmental or tinnitus like sounds), but only in people who frequently are able to reveal a verbal illusion while they trying to hear the voice they are about to produce! (The ability to reveal a verbal illusion - a protector and the road to recovery in people who are trying to hear the voice they are about to produce? Any signal that consistently precedes a meal, such as a clock indicating that it is time for dinner or an appetizer, may cause us to feel hungrier than before the signal because we learn to expect a meal in response to CS (CS will eventually predict the arrival of food) and non-verbal environmental sounds that consistently precedes a verbal illusion (information) can like any signal that consistently precedes a meal become a conditioned reinforcer that can activate a drive representation D. What you learn to expect or predict in response to a signal that consistently precedes a reinforcer can motivate an operant behaviour which has been established and fine tuned because it satisfies the need to access what you learn to expect and the ability to reveal a verbal illusion while you are trying to hear the voice you are about to produce may prevent this from happening (non-verbal environmental or tinnitus like sounds will never start to motivate a verbal response by activating a drive representation corresponding to the need to access a verbal message) or lead to extinction (non-verbal environmental or tinnitus like sounds will cease to motivate a verbal response) by blocking the voice you are about to produce. To change the context you are exposed to and experience may generate a more positive voice hearing experience in some people who frequently are able to reveal a verbal illusion... Is the ability to reveal a verbal illusion prevented in people who are treated with a dopamine receptor antagonist and can this have a negative impact on their ability to recover or not?)

From lingforum.com

Post subject: Speech perception and some symptoms of schizophrenia

http://www.lingforum.com/forum/viewtopic.php?t=512

y son Has been diagnosed with schizophrenia, I need to know everything!

Amador has some good stuff on the web, and the book on medication avoidance discussing the "LEAP" method was very helpful for us when our son was diagnosed. This is a challenging illness, but the best think is to show empathy and not catastrophise. There will be ups and downs, but recovery can be attained with the help of a good treatment team and patience.

From my personal view,it is easy to explain everything as following:
1-If you know,there is no autologous defects in the anatomical structure or bio-chemical processes that prevent the mental processes from working as its usual
2-That is means,the original higher cognitive processes is remain normal
3-Processes that arise by schizophrenia cause,is in itself a new king of high knowledge processes (the phenomena so called hallucination )
4-Temporal and spatial interference between both processes( original and new) leading to the emergence of three possibilities incoming in any moment of time ,as following:
A-The original higher cognitive processes occur in its usual form
B-Or new cognitive processes occur by schizophrenia cause
C-Or both the original and new processes occur at the same time,hinder neither the other path
So,manifestation of schizophrenia disorder in thoughts and behavior (symptoms of SZ )appears only in the case of second and third possibility !!
-treatment of schizophrenia,is the way to deal with the interference processes ,to prevent it from working all time !!

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