Download Introduction to Psychology

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
Most complex
structure in
known universe.
So how do you
study this thing?
Studying the brain
Surgical – can implant electrodes
Electrical 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
Neuroimaging
CT (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
Neuroimaging
MRI (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’ brain
Major 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 functions
Medulla [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 [sehruh-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 center
Glial 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 judgments
Parietal Lobes
include the sensory cortex
Occipital 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
Visual
cortex
Auditory
cortex
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 Cortex
Aphasia
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 speech
Wernicke’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
Corpus
Callosum
largest bundle
of neural fibers
connects the
two brain
hemispheres
carries
messages
between the
hemispheres
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
“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
 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
Cerebral cortex
Right hemisphere
Left hemisphere
Thalamus
Hypothalamus
Pituitary
Amygdala
Reticular
formation
Medulla
Hippocampus
Spinal
cord
Cerebellum
Cerebral cortex
Limbic system
Brainstem