How do perception, cognition andbehavior arise from an amorphous blob?Cocaine induced fMRI signalincreases…And cocaine induced fMRI signaldecreasesThe Brain is Composed of DiscreteCells- Neurons, Glia and VasculatureÐÐGlia support and maintain neurons• Protect by surrounding and buffering• Speed transmission by forming myelin sheathsNeurons have specialized processes thatsupport neurochemical transmission.ÐÐÐÐÐNeurotransmitter systemshave unique properties• Excitatory Amino Acids- glutamate• Rapid point to point communication• Inhibitory Amino Acids- GABA• Focus response• Acetylcholine and Monoamines- NE, DA,5-HT, EPI, histamine• Widespread modulation• Neuropeptides- SubP, opioids, NPY & manymore• Slower, longer lasting action• More and More- NO, ….Inhibitory Amino Acids- GABA, glycine• Primarilyinterneurons• Projections include:Ð caudate, putamen,NAc, septum, SNr,cerebellar Purkinje• Metabolically active• Some co-expresspeptides (CCK, NPY)• 5 Receptor subtypes-A, B1a, B1δ, B2, CExcitatory Amino Acids-Glutamate, Aspartate• Rapid point-to-pointcommunication• Most prevalent• Place in cellular energetics• Receptor subtypes-ligandgated channels &metabotropic• Examples:Ð Cortical pyramidal cellsÐ Thalamic relay neuronsÐ Hippocampal granule andpyramidal neurons (CA1-3)Ð Cerebellar granule cellsExample of EAA mediatedtransmission: Visual perception“Between sensation andaction is cognition”• Memory• Emotion• Attention• Language• Thought• ConsciousnessS1Epicenters of large scale networks• Spatial awareness network• Posterior parietal and frontal eye fields• Language network• Wernike’s and Broca’s areas• Explicit memory/emotion network• Hippocampal-entorhinal complex and amygdala• Face-object recognition network• Midtemporal and temporopolar corticies• Working memory-executive function network• Lateral prefrontal and posterior parietalMultimodal network for sensory detectionExcerpt of stimulus-presentation protocolSurface rendering showingbrain regions activated bytransitions of unimodal andmultimodal stimulus transitionsAveragedevent-relatedhemodynamicresponses totransitionsModulation of Neuronal Activity• Norepinephrine• Dopamine• Serotonin• Histamine• AcetylcholineAscending Dopaminergic Pathways• Small clusters ofneurons withwidely ramifyingaxons• Tonically active• Firing rateregulated• Synchronously actson widespreadtarget areas• Receptor subtypes-G-proteinmediatedDopaminergic neurotransmission•Investigate the mediating neuroanatomy ofacute cocaine reward and cocaine cravingusing fMRI.VTANAccREWARD !!GABAGABAA ReceptorDopamine (DA)Kappa receptorDynorphinD1 DA Receptorµ opiate receptorRLLPFC (+ 39 mm)AC ( 0 mm)Insula (- 9 mm)Parahip (- 24 mm)• Concurrent ratingtask• Cardiorespiratoryactivation andreturn to baselineKnowledge of the underlying neurobiologyis critical to successful fMRI
View Full Document
Unlocking...