The Central Nervous System Spinal cord Interface between
The Central Nervous System Spinal cord - Interface between the peripheral and central nervous systems - Carries reflexes, sensory, and motor information - 31 pairs specialized nerves (brain has 12 pairs – the cranial nerves)
The Brain z. Squishy z. Weighs about 3 pounds z. Most complex structure in known universe. z So how do you study this thing?
Studying the brain z. Surgical – can implant electrodes z. Electrical and imaging Electrical – y. Electroencephalography (EEG) y. Electromyography (EMG)
Electroencephalogram (EEG) y recording of the waves of electrical activity that sweep across the brain’s surface ymeasured by electrodes placed on the scalp
Neuroimaging z CT (computed tomograph) Scan ya series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body. Also called CAT scan for Computerized Axial Tomography. z PET (positron emission tomograph) Scan ya visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.
PET Scan
Neuroimaging z MRI (magnetic resonance imaging) ya technique that uses magnetic fields and radio waves to produce computer – generated images that distinguish among different types of soft tissue; allows us to see structures within the brain. y. Also known as f. MRI (functional magnetic resonance imaging) x. Can do real-time scans to see the brain at work.
MRI Scan
Da’ brain z. Major parts : y. Hindbrain y. Midbrain y. Subcortical forebrain y. Cerebral cortex
The Hindbrain z. Brainstem ythe oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull yresponsible for automatic survival functions z. Medulla [muh-DUL-uh] (aka Medulla Oblongata) ybase of the brainstem ycontrols heartbeat and breathing
The Hindbrain y. Pons z“switchboard” connecting cerebral cortex to cerebellum z. Reticular Formation(extends into midbrain) za nerve network that plays an important role in controlling alertness
The Hindbrain (pons & medulla plus some other junk…)
The Hindbrain z. Cerebellum [sehruh-BELL-um] ythe “little brain” attached to the rear of the brainstem yit helps coordinate voluntary movement and balance
The Midbrain y. Involved in vision and hearing y. Parts of reticular formation, eye & body movement y. Includes the substantia nigra that produces dopamine.
The Subcortical Forebrain z. Thalamus [THAL-uh-muss] ythe brain’s sensory switchboard, located on top of the brainstem ydirects messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla z. Basal ganglia y. Near the thalamus y. Movement, posture, also certain types of judgments
The Subcortical Forebrain z. Electrode implanted in reward center in hypothalamus
The Cerebral Cortex z. Cerebral Cortex ythe intricate fabric of interconnected neural cells that covers the cerebral hemispheres ythe body’s ultimate control and information processing center z. Glial Cells ycells in the nervous system that are not neurons but that support, nourish, and protect neurons
The Cerebral Cortex z Frontal Lobes yinvolved in speaking and muscle movements and in making plans and judgments z Parietal Lobes yinclude the sensory cortex z Occipital Lobes yinclude the visual areas, which receive visual information from the opposite visual field z Temporal Lobes yinclude the auditory areas
The Cerebral Cortex
The Cerebral Cortex z. Motor Cortex yarea at the rear of the frontal lobes that controls voluntary movements (aka primary motor area) z. Sensory Cortex yarea at the front of the parietal lobes that registers and processes body sensations (aka primary somatosensory area)
The Cerebral Cortex
The Cerebral Cortex z. Functional MRI scan of the visual cortex activated by light shown in the subject’s eyes`
Visual and Auditory Cortex Visual cortex Auditory cortex
Association Areas z areas of the cerebral cortex that are not involved in primary motor or sensory functions z involved in higher mental functions such as learning, remembering, thinking, and speaking
The Cerebral Cortex z. Aphasia yimpairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding) z. Broca’s Area yan area of the left frontal lobe that directs the muscle movements involved in speech z. Wernicke’s Area yan area of the left temporal lobe involved in language comprehension
Specialization and Integration
Specialization and Integration z Brain activity when hearing, seeing, and speaking words
Brain Reorganization z. Plasticity ythe brain’s capacity for modification as evident in brain reorganization following damage (especially in children) and in experiments on the effects of experience on brain development
Our Divided Brain z. Hemispheric specialization (or “cerebral lateralization”) z. Found in lots of species (even beta fish!) z. True, and important, but don’t overdo it…
What most people believe. . .
Our Divided Brain Corpus callosum z Corpus Callosum ylargest bundle of neural fibers yconnects the two brain hemispheres ycarries messages between the hemispheres
Our Divided Brain z. The information highway from the eyes to the brain
Split Brain za condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them
Split Brain “What word did you see? ” or “Look at the dot. ” Two words separated by a dot are momentarily projected. “Point with your left hand to the word you saw. ”
Disappearing Southpaws z The percentage of left-handers decreases sharply in samples of older people (adapted from Coren, 1993). Percentage of 14% left-handedness 12 The percentage of lefties sharply declines with age 10 8 6 4 2 0 10 20 30 40 50 Age in years 60 70 80 90
Corpus callosum Right hemisphere Left hemisphere Cerebral cortex Thalamus Hypothalamus Pituitary Amygdala Reticular formation Medulla Hippocampus Spinal cord Cerebellum Cerebral cortex Limbic system Brainstem
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