Subcortical Structures Limbic System o Consists several subcortical areas o Important for emotion memory motivation and sense of smell o Cingulate Gyrus Serves as roadway for information from limbic system to other cortical areas Processes both social and physical pain Associated with Bipolar or Depression If dysfunctional impulsivity likely o Hypothalamus Underneath thalamus Controls autonomic nervous system Emotional response food intake water balance sleep cycles Attached to pituitary glad Hormone regulation o Hippocampus Also part of temporal lobe Important for converting short term memories into long term memories o Amygdala Important for making associations between different stimuli Influences emotional valence of stimuli Recognition of emotional faces May dysfunction in autism o Basal Ganglia Set of ganglia located around thalamus and hypothalamus Involved in suppression of unwanted motor activity Forms complex signaling loops with motor areas of cortex o Olfactory bulbs frontal lobe Underlies sense of smell sit on inf surface of Connect to amygdala anterior to hippocampus ant inf to thalamus emotional reaction to scents o Thalamus Top of brain stem process ALL sensory input Thalamus and anterior cingulate first to turn on other than smell upon awakening Often associated with seat of consciousness Switchboard of the brain Sensory input through here to cortex from the periphery Cortex projects back to thalamus Connections just as important as structures Connectome project started in 2005 Goal to map every neural connection in the brain Uses gross anatomy and functional magnetic resonance imaging fMRI techniques o Evolutionary limited in brain size due to size of birth canal limited in number of connects White vs Gray Matter White connects different parts of the brain o Axon Highways Grey contains neuron cell bodies o Neuron Homes Corpus Callosum white matter o Connects hemispheres to each other o Largest white matter tract in the brain 250mill axons o Some cortical functions are lateralized Contralateral motor control and sensation Rt nonverbal and spatial tasks Lt language tasks o Left handed patients have less laterilzation o Removal of corpus callosum used to treat epilepsy Arcuate Fasciculus o Important fiber pathway o Connects Broca s and Wernicke s areas o Both important for certain aspects of language o Damage on left causes conduction aphasia Understand language but make many errors Cant repeat back o Loss on right associated with tone deafness White Matter Drug abuse o Incr stop signal reaction time is associated w drug abuse o Associated with inherited neural connections n the infereior prefrontal cortex Incr drug addiction potential Cerebellum Important for balance motor learning and motor error correction Brain is organized over sizes that span 6 orders of magnitude slide 26 composed of a network of densely packed neurons and glia Brain Metabolism Into neurons o Oxygen o Carbs o Amino acids o Fats o Hormones o Vitamins Glucose is the brains primary source of energy and most of it is used to maintain a resting membrane potential critical for neuronal function Out of neurons o Carbon dioxide o Ammonia o Lactate o Hormones Neuronal Components Receiving o Dendrites o Cell body soma o Nucleus Transmitting o Myelin Sheath insulating fatty later that speeds transmission o Axons Conduction fiber o Nodes of Ranvier little cracks b t myelin o Presynaptic terminal o Schwann s Cells make myelin in PNS Neurons Neurons in brain germ cells use a great deal of DNA and therefore are very large o Neurons and Cancer cells are dependent on sugar glucose Neurons have a great deal of mitochondria but cannot store sugar o Materials used for growth repair and transmission are transported down the axon by a specialized protein Kinesin that walks along the microtubules at the expense of ATP Supporting glial cells o Formation of Myelin Sheath in CNS Done by oligodendrocytes Produce myelin in CNS reach out piece of themselves and produce electrical vehicle Schwann does same in peripheral Myelin sheath can remain intact after injury and help guide the regrowing nerve axon to correct site of action o Astrocytes Contribute to blood brain barrier look similar to oligodendrocytes Provide space b t neurons and blood vessels Cover everythin in brain 10 15 astrocytes neuron Functions Conduct nutrients from the blood to neurons Transport waste and products away to the blood and CNS 1 1 billion synapses cubic mm each astrocyte support and modulates the function of roughly 2 million Astrocytic network is organized in non overlapping domains o Microglia are least numerous brain s immune system Performs phagocytosis of synaptic structures and active remodeling of perisynaptic environment AKA protective and recovery units o Oligodendrocytes and astrocytes are most likely to form cancers Designed to divide Neurons never produce forms of cancer Synapses terminals Very close points of contact between neurons and axons axon Lined with synaptic vesicles containing neurotransmitter o Have complete array of proteins floating on surface that allow them to attach to pre synaptic membrane and eject contents Synaptic connections o Axosomatic Synapse to the cell body soma Most convincing and influential o Axodendritic o Axo axonic Synapse to spine of dendrite or shaft Synapse to terminal end of axo o Can occur in all places and cells pay attention to Neurons sensitive to sequence of activation of their synaptic connect site inputs Drugs take effect on you at synaptic cleft Acetylcholine example Brain wants sugar to make ATP glucose intake feeds production of acetylcholine if stop intake then feel foggy hard to concentrate o Similar to hypoglycemia Binding of a transmitter to its receptor activates Second messengers o A complex cascade of changes amplify the effects of the acetyl choline within the neuron Action of acetylcholine within the brain can alter the nature of how two neurons physically communicate with each other o Aceylcholine hippocampus temporal lobe