Chapter 2

Neural Communication & The Brain

Psychology 101

Sara J. Buhl

Phrenology (1800s)Phrenology (1800s)

Neural CommunicationNeural Communication Biological Psychology

branch of psychology concerned with the links between biology and behavior

Neuron a nerve cell the basic building block of the nervous system

Neural CommunicationNeural Communication

Neural CommunicationNeural Communication Dendrite

the branching extensions of a neuron that receive messages and conduct impulses toward the cell body

Axon the extension of a neuron, through which messages

are sent to other neurons or to muscles or glands

Myelin Sheath a layer of fatty cells covering the axon of some

neurons greatly increases the speed of neural impulses

How do neurons How do neurons communicate?communicate?

Synapse junction between the axon tip of the sending neuron

and the dendrite or cell body of the receiving neuron tiny gap at this junction is called the synaptic gap or

cleft

Neurotransmitters chemical messengers that cross the synaptic gaps

between neurons when released by the sending neuron,

neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse

NeurotransmissionNeurotransmission

NeurotransmittersNeurotransmitters

Acetylcholine – Enables muscle action, learning, and memory

Dopamine – Influences movement, learning, attention, and emotion

Serotonin – Affects mood, hunger, sleep, and arousal

Endorphins – opiatelike neurotransmitters linked to pain control and to pleasure

Neural CommunicationNeural Communication

Neural CommunicationNeural Communication

Serotonin pathways

The Nervous SystemThe Nervous System

Central Nervous System (CNS) the brain and spinal cord

Peripheral Nervous System (PNS)

the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

Peripheral Nervous Peripheral Nervous SystemSystem

Autonomic Nervous System the part of the peripheral nervous system that

controls the glands and the muscles of the internal organs (e.g., heart)

Two Parts: Sympathetic Nervous System

part of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

Parasympathetic Nervous System Part of the autonomic nervous system that calms the

body, conserving its energy

Central Nervous Central Nervous SystemSystem

Spinal Cord – information highway; connects the peripheral nervous system to the brain

The Brain – enables the mind – seeing, hearing, smelling, feeling, remembering, thinking, speaking, dreaming.

ReflexReflex

a simple, automatic, inborn response to a sensory stimulus

The BrainThe Brain 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 base of the brainstem controls heartbeat and breathing

The Brainstem and ThalamusThe Brainstem and Thalamus

The BrainThe Brain

Thalamus on top of brainstem the brain’s sensory switchboard

Reticular Formation a nerve network in the brainstem plays an important role in

controlling arousal

Electroencephalogram Electroencephalogram (EEG)(EEG)

an amplified recording of the waves of electrical activity that sweep across the brain’s surface

these waves are measured by electrodes placed on the scalp

MRI ScanMRI Scan

The BrainThe Brain

Cerebellum the “little brain” attached to the rear of the

brainstem it helps coordinate voluntary movement and

balance injury results in difficulty walking and keeping

balance; movements would be jerky and exaggerated

The BrainThe Brain

Limbic System a doughnut-shaped system of neural structures at

the border of the brainstem and cerebral hemispheres

associated with emotions such as fear and aggression and drives such as those for food and sex

includes the hippocampus (ch. 8), amygdala, and hypothalamus.

The Limbic System

The Limbic SystemThe Limbic System

Amygdala two almond-shaped neural

clusters that are part of the limbic system

linked to emotion influence aggression and fear

The Limbic SystemThe Limbic System

Hypothalamus neural structure lying below (hypo) the

thalamus directs several maintenance activities

eating drinking body temperature

helps govern the endocrine system via the pituitary gland

linked to emotion

The Limbic SystemThe Limbic System Electrode implanted in reward center of hypothalamus

The Cerebral CortexThe Cerebral Cortex

Cerebral Cortex (Cerebrum) the intricate fabric of interconnected neural cells

that covers the cerebral hemispheres the body’s ultimate control and information

processing center

Left & Right Hemispheres of the Cerebrum Left hemisphere receives input from & controls

the right side of the body Right hemisphere receives input from & controls

the left side of the body

The Cerebral CortexThe Cerebral Cortex

The Cerebral CortexThe Cerebral Cortex

Frontal Lobes Involved in speaking & muscle movements Important for planning and making judgments Damage can alter personality (e.g., Phineas

Gage)

Parietal Lobes Receives sensory input for touch and body

position

The Cerebral CortexThe Cerebral Cortex

Occipital Lobes

include the visual areas, each of which receives visual information from the opposite visual field

Temporal Lobes

include the auditory areas, each receives auditory information primarily from the opposite ear

The Cerebral CortexThe Cerebral Cortex

Functional MRI scan of the visual cortex activated by looking at faces

Brain ReorganizationBrain Reorganization

Plasticity the brain’s capability to

reorganize following damage (especially in children) and in experiments on the effects of experience on brain development

Brain ReorganizationBrain Reorganization

Corpus Callosum large bundle of neural fibers

connecting the two brain hemispheres and carrying messages between the hemispheres

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

Brain ReorganizationBrain Reorganization

Left visual field

Right visual field

Testing the divided Testing the divided brain:brain: