NEUR 2600 Lecture Notes - Lecture 1: Brain Injury, Brain Size, Smart People
CHAPTER 1: WHAT ARE THE ORIGINS OF BRAIN AND BEHAVIOUR
What is the brain?
●The brain and spinal cord make up the central nervous system (CNS)
●All of the processes radiating out beyond the brain and spinal cord constitute the
peripheral nervous system (PNS)
●Brain
refers to something other than the organ found inside the skull
○It refers to the brain as the body organ that exerts control over behaviour
●The term brain
then signifies both the organ itself and the fact that this organ produces
behaviour
●Nervous system is composed of cells called neurons
●Neurons in the brain communicate with one another and with
○Sensory receptors in the skin
○Muscles
○Internal body organs
●The CNS needs ongoing sensory stimulation from the environment and from its own
body’s movement
●The brain communicates by producing movement and observing others’ movements
●Thus the term brain
refers to an intelligent, functioning organ
○An active brain that is connected to the rest of the nervous system to produce
behaviour
●The brain can be conscious to a great extent in the absence of overt behaviour
●Locked-in syndrome: condition in which a patient is aware and awake but cannot move
or communicate verbally because of complete paralysis of nearly all voluntary muscles
Cerebral Cortex
●Heavily folded outer layer of brain tissue composed of neurons (cortex = bark)
● Forebrain: prominent in mammals and birds, responsible for most conscious behaviours
●Brainstem: source of behaviour in simpler animals, responsible for most of our
unconscious behaviours
Behaviour
●Irenäus Eibl-Eibesfeldt
○“Behaviour consists of patterns over time”
○Examples: movements, vocalizations, thinking
●Animals produce behaviours that are
○Inherited ways of learning
○Learned
●Most behaviours probably consist of a mix of inherited and learned actions
●Relatively fixed (innate) behaviours are dependant on heredity
●Relatively flexible behaviours depend on learning
●Most human behaviours retain some mixture of inheritance and learning
●Like other animals, we retain many inherited ways of responding
○The sucking response of a newborn human infant is an inherited eating pattern
●Later in life, eating is strongly influenced by learning and by culture
●Complexity of behaviour varies considerably from species to species
○Simple nervous system (eg. sea slug) = Narrow range of behaviour
○Complex nervous system (eg. human) = Wider range of behaviour
●Aristotle and Mentalism
○Mentalism: an explanation of behaviour as a function of the nonmaterial mind
○Ancient Greece: Aristotle
■Believed the brain cooled the blood; no role in producing behaviour
■Psyche: synonym for mind; an entity once proposed to be the source of
human behaviour
○The psyche was held responsible for, or thought to control human consciousness,
perceptions, and emotions
○Also processes such as imagination, opinion, desire, pleasure, pain, memory, and
reason
○The nonmaterial psyche was thought to be an entity independent of the body
■A nonmaterial entity governs our behaviour, and our essential
consciousness survives our death
■Also thought to be entirely independent of the body
○Mind
is an anglo-saxon word for memory
○When psyche
was translated into English, it became mind
■The philosophical position that a person’s mind (psyche) is responsible for
behaviour is mentalism
●Descartes and Dualism
○Dualism: both a nonmaterial mind and the material body contribute to behaviour
○Mind-body problem: How to explain a nonmaterial mind directing a material
body
○Rene Descartes:
■Nonmaterial mind directs rational behaviour
■Body and brain direct all other behaviour via mechanical and physical
principles
■Examples: sensation, movement, and digestion
■Believed that mind instructed the pineal gland of the brain, which sits
beside the ventricles, to direct fluid from them through nerves and into
muscles
●When the fluid expanded the muscles, the body would move
■Mind resides in the pineal gland, where it directs the flow of fluid through
the ventricles and into the muscles to move the body
○Problems with Descartes
■Pineal gland is involved in biological rhythms but not
in intelligence or
behavioural control
■Fluid is not
pumped from the ventricles to control movement
■Nonmaterial influences on the body would violate the law of conservation
of matter and energy
○The language and action tests
■To pass the language test, an organism must use language to describe and
reason about things that are not physically present
■The action test requires behaviour based on reasoning, not just an
automatic response to a particular situation
●Nonhuman animals and machines would be unable to pass the tests
because they lacked a mind
●Darwin and Materialism
○Materialism: behaviour can be explained as a function of the nervous system
without explanatory recourse to the mind
○Related to evolutionary theories of Alfred Wallace and Charles Darwin
■Both were struck at the many similarities among species
○Evolution by natural selection explains how
■New species evolve and existing species change over time
■Differential success in the reproduction of characteristics (phenotypes)
results from the interaction of organisms with their environment
○Natural selection
■The way new species evolve and existing species change over time
Document Summary
Chapter 1: what are the origins of brain and behaviour. The brain and spinal cord make up the central nervous system (cns) All of the processes radiating out beyond the brain and spinal cord constitute the peripheral nervous system (pns) refers to something other than the organ found inside the skull. It refers to the brain as the body organ that exerts control over behaviour. Nervous system is composed of cells called neurons. Neurons in the brain communicate with one another and with then signifies both the organ itself and the fact that this organ produces behaviour. The cns needs ongoing sensory stimulation from the environment and from its own body"s movement. The brain communicates by producing movement and observing others" movements. Thus the term brain refers to an intelligent, functioning organ. An active brain that is connected to the rest of the nervous system to produce behaviour.
