Determining effects of external stimuli on the brain using pet

Abstract

A method of evaluating the effects of administering an external stimuli or treatment such as a psychoactive compound, a drug, or an environmental influence like temperature, noise, vibration, light and similar sensory-perceived influences, on a subject's brain using imaging techniques with position emission tomography (PET). The method measures cerebral metabolism before and after administering the external stimuli or treatment, and employs a behavioral clamp to control behavioral influences on the subject's brain after administration of the external stimuli or treatment.

I claim:  
     
         1 . A method of evaluating the effects of administering an external stimuli to a subject on the subject's brain, comprising the steps of: 
 measuring cerebral metabolism of a subject's brain prior to any treatment with an external stimuli;    administering the external stimuli to the subject;    controlling behavioral influences on the subject's brain by subjecting the subject to a behavioral clamp;    measuring cerebral metabolism of the subject's brain after administering the external stimuli and during the behavioral clamp; and    determining any differences between cerebral metabolism prior to administering the external stimuli and cerebral metabolism after administering the external stimuli.    
     
     
         2 . The method of    claim 1    wherein said external stimuli is a psychoactive compound.  
     
     
         3 . The method of    claim 2    wherein the compound administered is a fragrance.  
     
     
         4 . The method of    claim 2    wherein the compound administered is fluoxetine.  
     
     
         5 . The method of    claim 2    wherein the compound administered is ethanol.  
     
     
         6 . The method of    claim 2    wherein the compound administered is pimizide.  
     
     
         7 . The method of    claim 2    wherein the compound administered is nimodopine.  
     
     
         8 . The method of    claim 1    wherein the step of measuring cerebral metabolism prior to any treatment utilizes position emission tomography.  
     
     
         9 . The method of    claim 1    wherein the step of measuring cerebral metabolism after administering the external stimuli utilizes position emission tomography.  
     
     
         10 . The method of    claim 1    wherein said behavioral clamp comprises a visual monitoring task performed by the subject.  
     
     
         11 . The method of    claim 1    further including the step of measuring a subject's mood both prior to and after administering the external stimuli.  
     
     
         12 . The method of    claim 1    wherein the step of measuring a subject's mood comprises administering a standard psychological test thereto.  
     
     
         13 . The method of    claim 12    wherein said standard psychological test is a profile of mood states.  
     
     
         14 . The method of    claim 1    further including the step of comparing the cerebral metabolism after administering the external stimuli to a reference cerebral metabolism.  
     
     
         15 . The method of    claim 1    wherein said external stimuli is a pharmaceutical drug.  
     
     
         16 . The method of    claim 1    wherein said external stimuli is an environmental influence.  
     
     
         17 . The method of    claim 16    wherein said environmental influence is selected from the group consisting of temperature, vibration, noise, and light.  
     
     
         18 . A method of evaluating the effects on a subject's brain of administering an external treatment to a subject comprising the following steps: 
 measuring cerebral metabolism of a subject's brain in the absence of any external treatment administration;    administering an external treatment to the subject;    controlling behavioral influences on the subject's brain by using a behavioral clamp, said behavioral clamp comprising a procedure that: 
 (a) maintains the subject in a standard and stable condition throughout a period of accumulation of cerebral metabolic information with and without said external treatment;  
 (b) is capable of being performed by the subject at comparable levels prior to as well as subsequent to administration of said external treatment;  
 (c) requires a non-stressful level of attention with no opportunity for the subject to develop a productive strategy;  
 (d) includes measurable variables capable of defining desired criteria; and  
 (e) minimizes subjective variables including extraneous ideation, motivation, and anxiety;  
   measuring cerebral metabolism to the subject's brain after administering the external treatment and during the behavioral clamp; and    determining any differences between cerebral metabolism in the absence of administering the external treatment and cerebral metabolism after administering the external treatment.    
     
     
         19 . The method of    claim 18    wherein said external treatment is selected from the group consisting of a psychoactive compound, a pharmaceutical drug and an environmental influence.