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Chapter 3

PSYC 1001 Chapter Notes - Chapter 3: Autonomic Nervous System, Cerebral Cortex, Muscle Tone


Department
Psychology
Course Code
PSYC 1001
Professor
Jennifer Pettalia
Chapter
3

Page:
of 4
Chapter 3: the Biological Bases of Behaviour Pg. 86-126
Divisions of the Brain
HINDBRAIN
Includes the cerebellum and 2 structures found in the lower part of the brainstem
Bottom of the brain
Medulla – attaches tot the spinal cord, In charge of unconscious, vital functions such as
circulating blood, breathing, maintain muscle tone;
o Regulating reflexes such as sneezing, coughing, salivating
Pons – “bridge” includes a bridge of fibres that connects the brainstem with the cerebellum.
oSleep and arousal
Cerebellum – “little brain”’ involves posture, coordinated movements and balance
MIDBRAIN
Between hindbrain and forebrain
Integrating sensory process – vision, hearing
Reticular Formation – muscle reflexes, breathing, pain perception
oRegulation of sleep and arousal
FOREBRAIN
Largest and most complex region of the brain, variety of structures
Top of the brain, higher function such as decision making
Major components:
Thalamus – sensory integration and acts as a relay station
oStructure in the forebrain through which all sensory info except smell must pass to get to
the cerebral cortex
Hypothalamus – structure found near the base of the forebrain that is involved in the regulation
of the basic biological needs
oMotivated behaviours
oControls the autonomic nervous system and endocrine system
oControls release of hormones
oRegulation of the basic biological drives
“Four F’s” –fighting, fleeing, feeding, mating
Limbic System – “edge”; emotion, memory, motivation
oHippocampus – memory
oAmygdala – emotions
Cerebrum – responsible for the most complex mental activity including remembering, learning,
thinking, and consciousness
oCerebral cortex: outer layer of the cerebrum
oSplit into 2 hemispheres – right and left, separated by a long fissure from front to back,
4 lobes
Frontal – most anterior region
“Executive control” (planning, decision-making)
Parietal – lies between the frontal and occipital lobes
Touch, bodily awareness
Occipital – posterior region, visual processing
Temporal – lateral region, auditory processing (language, music), memory
oCorpus Callosum – structure that connects the 2 cerebral hemispheres
Neurotransmitters
Nervous system relies on chemical couriers to communicate information between
neurons
Fundamental to behaviour, playing a key role in everything from muscle movements to
moods and mental health
Acetylcholine (Ach) – drives muscular contractions (typing, walking, breathing)
oBotox: releases the muscles
oInadequate supply is associated with memory loss (Alzheimers)
oNicotine acts at Ach receptors
oAgonist: a chemical that mimics the action of a neurotransmitter
oAntagonist: chemical that opposes the action of a neurotransmitter; acts like lock
Monoamines – Dopamine, Norepinephrine, and Serotonin
oDopamine (DA) – used by neurons that control voluntary movements
Implicated in movement, attention, learning, and reinforcing drugs
Over activation: Schizophrenia
Under activation: Parkinson’s Disease
oSerotonin – Implicated in regulation of mood, eating, sleep (dreaming), arousal,
sexual activity, anxiety, and pain
Under activation: depression
Eating disorders, OCD
oNorepinephrine – aka noradrenalin and adrenalin
oModulate mood, arousal, sexual behaviour
Mediate the “fight or flight” response
Amphetamines (speed) activate these neurons
Endorphins – involved in modulation of pain
oReleased after you play sports
oFeel the pain afterwards
oMorphine – painkiller
Amino Acids – produce only inhibitory postsynaptic potentials
oGABA: calms down, decreases anxiety
Primary inhibitory neurotransmitter in the brain
Glycine
oGlutamate: excites; involved in learning and memory
Organization of the Nervous System
Peripheral Nervous System – nerves that lie outside the brain and spinal cord
Nerves: bundles of neuron fibres (axons) that are routed together in the peripheral
nervous system
Somatic Nervous System – voluntary; made up of nerves that connect to voluntary
skeletal muscles and to sensory receptors.
oAfferent nerve -Bring sensory information from the environment to the brain
oEfferent nerve - Carry motor information from the brain to the body
Autonomic Nervous System – involuntary; nerves that connect to the heart, blood
vessels, stomach, lungs, smooth muscles, and glands
oRegulates internal environment
oTwo major divisions:
-Sympathetic nervous system: mobilizes the body’s resources for emergencies
(the 4 F’s); excitatory
-Parasympathetic nervous system: conserves energy (‘rest & digest’); inhibitory
The Central Nervous System – consists of the brain and spinal cord
oThe Brain – consists of 3 major divisions
oThe Spinal Cord -
Neurons – individual cells in the nervous system that receives, integrate, and transmit information
Soma or Cell Body – contains cell nucleus and much of the chemical machinery common to most cells
Dendrites – parts of a neuron that specialized to receive information
Axon – long thin fibre that transmits signals away from the soma to other neurons or to muscles/glands
Myelin sheath – insulating material, derived glial cells that encase some axons
The axon ends in a cluster of Terminal buttons – small knobs that secrete chemicals called
neurotransmitters.
Glia – cells found throughout the nervous system that provide various types of support for neurons.
Resting potential – its stable, negative charge when the cell is inactive.
Action potential – very brief shift in a neuron’s electrical charge that travels alone an axon,
Absolute refractory period – the minimum length of time after an action potential during which another
potential cannot begin. Must wait for a certain time Ex: flushing toilet
Relative refractory – if the signal is strong enough it will fire
Synapse – a junction where information is transmitted from one neuron to another; communication
between neurons
oPresynaptic neuron: sends the information,
oArrival of the action potential at an axon’s terminal buttons triggers the release of
neurotransmitters
Postsynaptic neuron – receives the signal
oReuptake – a process in which neurotransmitters are sponged up from the synaptic cleft by
the presynaptic membrane
Synaptic cleft – a microscopic gap between the terminal button of one neuron and the cell membrane of
another neuron.
Neuroscience Research Methods
Electroencephalograph (EEG) – device that monitors the electrical activity of the brain
over time by means of recording electrodes attached to the surface of the scalp
Lesioning – involves destroying a piece of the brain
Transcranial magnetic stimulation (TMS) – new technique that permits scientists to
temporarily enhance or depress activity in a specific area of the brain