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MR Studies: Brain MR Studies: Brain AbnormalitiesAbnormalities

• Decreased temporal lobe sizeDecreased temporal lobe size• Decreased frontal lobe sizeDecreased frontal lobe size• Decreased hippocampal sizeDecreased hippocampal size• Decreased thalamic sizeDecreased thalamic size• Gyral decreases (superior temporal Gyral decreases (superior temporal

gyrus, ventral frontal gyri)gyrus, ventral frontal gyri)• General and regional decreases in General and regional decreases in

gray matter volumegray matter volume

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A Neurodevelopmental A Neurodevelopmental Brain DiseaseBrain Disease

• Most brain abnormalities are present Most brain abnormalities are present at onset: e.g., decrease in total brain at onset: e.g., decrease in total brain tissuetissue

• Occasional evidence of defects in Occasional evidence of defects in neuronal migration: gray matter neuronal migration: gray matter heterotopiasheterotopias

• Midline abnormalities: cavum septi Midline abnormalities: cavum septi pellucidi, dysgenesis of the corpus pellucidi, dysgenesis of the corpus callosum, ventricular enlargementcallosum, ventricular enlargement

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Callosal DysgenesisCallosal Dysgenesis

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Imaging Studies of TwinsImaging Studies of Twins

• Initiated by the Maudsley Initiated by the Maudsley group using CTgroup using CT

• In discordant MZ pairs, the In discordant MZ pairs, the twin with schizophrenia had twin with schizophrenia had significantly larger ventriclessignificantly larger ventricles

• Similar results noted by the Similar results noted by the NIMH group using MRNIMH group using MR

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Increased Basal Ganglia SizeIncreased Basal Ganglia Size

• Jernigan et al, 1991Jernigan et al, 1991• Swayze et al, 1992Swayze et al, 1992• Breier et al, 1992Breier et al, 1992• Nasrallah et al, 1993Nasrallah et al, 1993• Elkashef et al, 1994Elkashef et al, 1994• Chakos et al, 1994Chakos et al, 1994• Keshavan et al, 1994Keshavan et al, 1994• Doriswaymy et al, 1995Doriswaymy et al, 1995• Rodriguez et al, 1997Rodriguez et al, 1997

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Increased Blood Flow in Striatum Increased Blood Flow in Striatum due to Chronic Dopamine due to Chronic Dopamine Blockade by HaloperidolBlockade by Haloperidol

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Functional Imaging Functional Imaging ToolsTools

• Single Photon Emission Single Photon Emission Computed Tomography (SPECT)Computed Tomography (SPECT)

• Positron Emission Tomography Positron Emission Tomography (PET)(PET)

• Functional Magnetic Resonance Functional Magnetic Resonance (fMR)(fMR)

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Visualizing the Working Mind Visualizing the Working Mind with Functional Imagingwith Functional Imaging

• Shows areas in Shows areas in which blood flow which blood flow is increased is increased during a mental during a mental tasktask

• Lets us see which Lets us see which parts of our parts of our brains are used brains are used for different kinds for different kinds of thinking and of thinking and feelingfeeling