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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. Squishy Weighs about 3 pounds - PowerPoint PPT Presentation
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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 BrainSquishyWeighs about 3
poundsMost complex
structure in known universe.
So how do you study this thing?
Studying the brainSurgical – can implant electrodesElectrical and imaging Electrical –
Electroencephalography (EEG) Electromyography (EMG)
Electroencephalogram (EEG)
recording of the waves of electrical activity that sweep across the brain’s surface
measured by electrodes placed on the scalp
NeuroimagingCT (computed tomograph) Scan
a 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.
PET (positron emission tomograph) Scan a visual display of brain activity that detects where a
radioactive form of glucose goes while the brain performs a given task.
PET Scan
NeuroimagingMRI (magnetic resonance imaging)
a 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.
Also known as fMRI (functional magnetic resonance imaging) Can do real-time scans to see the brain at work.
MRI Scan
Da’ brainMajor parts :
Hindbrain Midbrain Subcortical forebrain Cerebral cortex
The Hindbrain
Brainstem the oldest part and central core of the brain,
beginning where the spinal cord swells as it enters the skull
responsible for automatic survival functionsMedulla [muh-DUL-uh] (aka Medulla
Oblongata) base of the brainstem controls heartbeat and breathing
The Hindbrain
Pons
“switchboard” connecting cerebral cortex to cerebellum
Reticular Formation(extends into midbrain)
a nerve network that plays an important role in controlling alertness
The Hindbrain (pons & medulla plus some other junk…)
The Hindbrain
Cerebellum [sehr-uh-BELL-um] the “little brain”
attached to the rear of the brainstem
it helps coordinate voluntary movement and balance
The Midbrain
Involved in vision and hearing Parts of reticular formation, eye & body
movement Includes the substantia nigra that
produces dopamine.
The Subcortical Forebrain
Thalamus [THAL-uh-muss] the brain’s sensory switchboard, located on
top of the brainstem directs messages to the sensory receiving
areas in the cortex and transmits replies to the cerebellum and medulla
Basal ganglia Near the thalamus Movement, posture, also certain types of
judgments
The Subcortical Forebrain
Electrode implanted in reward center in hypothalamus
The Cerebral Cortex
Cerebral Cortex the intricate fabric of interconnected neural
cells that covers the cerebral hemispheres the body’s ultimate control and information
processing centerGlial Cells
cells in the nervous system that are not neurons but that support, nourish, and protect neurons
The Cerebral Cortex
Frontal Lobes involved in speaking and muscle movements
and in making plans and judgmentsParietal Lobes
include the sensory cortexOccipital Lobes
include the visual areas, which receive visual information from the opposite visual field
Temporal Lobes include the auditory areas
The Cerebral Cortex
The Cerebral Cortex
Motor Cortex area at the rear of the frontal lobes that
controls voluntary movements (aka primary motor area)
Sensory Cortex area at the front of the parietal lobes that
registers and processes body sensations (aka primary somatosensory area)
The Cerebral Cortex
The Cerebral Cortex
Functional MRI scan of the visual cortex activated by light shown in the subject’s eyes`
Visual and Auditory Cortex
Auditorycortex
Visualcortex
Association Areas
areas of the cerebral cortex that are not involved in primary motor or sensory functions
involved in higher mental functions such as learning, remembering, thinking, and speaking
The Cerebral CortexAphasia
impairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding)
Broca’s Area an area of the left frontal lobe that directs the muscle
movements involved in speechWernicke’s Area
an area of the left temporal lobe involved in language comprehension
Specialization and Integration
Specialization and Integration
Brain activity when hearing, seeing, and speaking words
Brain Reorganization
Plasticity the 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
Hemispheric specialization (or “cerebral lateralization”)
Found in lots of species (even beta fish!)
True, and important, but don’t overdo it…
What most people believe...
Our Divided Brain
Corpus Callosum largest bundle
of neural fibers
connects the two brain hemispheres
carries messages between the hemispheres
Corpus callosum
Our Divided Brain
The information highway from the eyes to the brain
Split Brain
a 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
“Look at the dot.” Two words separatedby a dot are momentarily projected.
“What worddid you see?”
or
“Point withyour left hand to theword you saw.”
Disappearing Southpaws
The percentage of left-handers decreases sharply in samples of older people (adapted from Coren, 1993).
The percentage of lefties sharplydeclines with age
10 20 30 40 50 60 70 80 90Age in years
14%
12
10
8
6
4
2
0
Percentage ofleft-handedness
Cerebral cortex
Left hemisphere
Right hemisphere
Corpuscallosum
Thalamus
Hypothalamus
Pituitary
Reticularformation
Medulla
Spinalcord
Cerebellum
Amygdala
Hippocampus
Cerebral cortex Limbic system Brainstem