The Human Brain

Central Nervous System Spinal Cord Brain Brain and Spinal Cord key words: central nervous system; brain; spinal cord

Brain has 2 Hemispheres Left & Right sides are separate Corpus Callosum : major pathway between hemispheres Some functions are ‘lateralized’ language on left math, music on right Lateralization is never 100% Left Hemisphere Corpus Callosum Right key words: left hemisphere; right hemisphere

Each hemisphere is divided into 4 lobes Frontal Parietal Occipital Temporal key words: cerebral cortex; lobes; frontal; parietal; temporal; occipital

Sensory Information sent to opposite hemisphere Principle is Contralateral Organization Sensory data crosses over in pathways leading to the cortex Visual Crossover left visual field to right hemisphere right field to left Other senses similar Left visual field Right visual Optic nerves Corpus Callosum Left Visual Cortex Right Visual key words: left hemisphere; right hemisphere; visual infomation; touch information

Contralateral Motor Control Movements controled by motor area Right hemisphere controls left side of body Left hemisphere controls right side Motor nerves cross sides in spinal cord Somatosensory Cortex Motor Cortex

Corpus Callosum Major ( but not only) pathway between sides Connects comparable structures on each side Permits data received on one side to be processed in both hemispheres Aids motor coordination of left and right side Corpus Callosum Medial surface of right hemisphere Example : You read a geometry problem in a textbook. The words are seen and the visual forms translated into meaning by the language center in the left hemisphere. To solve the problem you have to imagine a cone shaped object. This is accomplished by centers in the right hemisphere. The solution is written down using language generated by the left hemisphere. What would happen in cases like this if the callosum was damaged ?

Lobes of the Brain key words: cerebral cortex; lobes; frontal; motor functions Frontal lobe is not directly involved in sensation or perception. Its functions are related to motor action (behavior). The motor cortex is the start of nerves that run through the spinal cord to the muscles. Broca’s area organizes sequences of speech movements. Damage leads to productive aphasia Dorsolateral Prefrontal Cortex is important in working memory. WM is short term memory for information needed to maintain a context, to prepare for the next step in a sequence of thought, and /or to inhibit irrelevant responses The wisconsin card sorting task illustrates the importance of working memory in maintaining context and inhibiting irrelevant responses © 1998-1999 Genentech Inc

Occipital Lobe Input from Optic nerve Contains primary visual cortex most is on surface inside central fissure Outputs to parietal and temporal lobes Occipital Lobe Visual Lobe

Temporal Lobe Inputs are auditory, visual patterns Contains primary auditory cortex Inputs are auditory, visual patterns speech recognition face recognition word recognition memory formation Outputs to limbic System, basal Ganglia, and brainstem Temporal Lobe Auditory Cortex Temporal Lobe

Parietal Lobe Inputs from multiple senses Somatosensory Cortex contains primary somatosensory cortex borders visual & auditory cortex Outputs to Frontal lobe hand-eye coordination eye movements attention

Frontal Lobe Contains primary motor cortex No direct sensory input Working Memory Motor Cortex Broca’s Area No direct sensory input Important planning and sequencing areas Broca’s area for speech key words: cerebral cortex; lobes; frontal; motor functions Frontal lobe is not directly involved in sensation or perception. Its functions are related to motor action (behavior). The motor cortex is the start of nerves that run through the spinal cord to the muscles. Broca’s area organizes sequences of speech movements. Damage leads to productive aphasia Dorsolateral Prefrontal Cortex is important in working memory. WM is short term memory for information needed to maintain a context, to prepare for the next step in a sequence of thought, and /or to inhibit irrelevant responses The wisconsin card sorting task illustrates the importance of working memory in maintaining context and inhibiting irrelevant responses Prefrontal area for working memory

Layers of the Cerebrum key words: cerebral cortex; lobes; frontal; motor functions Frontal lobe is not directly involved in sensation or perception. Its functions are related to motor action (behavior). The motor cortex is the start of nerves that run through the spinal cord to the muscles. Broca’s area organizes sequences of speech movements. Damage leads to productive aphasia Dorsolateral Prefrontal Cortex is important in working memory. WM is short term memory for information needed to maintain a context, to prepare for the next step in a sequence of thought, and /or to inhibit irrelevant responses The wisconsin card sorting task illustrates the importance of working memory in maintaining context and inhibiting irrelevant responses © 1998-1999 Genentech Inc

Control Centers of the Brain key words: cerebral cortex; lobes; frontal; motor functions Frontal lobe is not directly involved in sensation or perception. Its functions are related to motor action (behavior). The motor cortex is the start of nerves that run through the spinal cord to the muscles. Broca’s area organizes sequences of speech movements. Damage leads to productive aphasia Dorsolateral Prefrontal Cortex is important in working memory. WM is short term memory for information needed to maintain a context, to prepare for the next step in a sequence of thought, and /or to inhibit irrelevant responses The wisconsin card sorting task illustrates the importance of working memory in maintaining context and inhibiting irrelevant responses © 1998-1999 Genentech Inc