Brain and Behaviour
Chapter 1: What are the Origins of Brain & Behaviour?
- Brain: a physical object, a living tissue, a body organ
- Behaviour: is action, momentarily observable, but fleeting
- Three reasons for linking brain to behaviour:
• #1: How the brain produces behaviour is a major unanswered question
• #2: brain is the most complex living organ on earth & is found in many diff.
groups of animals
• #3: a growing list of behavioural disorders can be explained & cured by
understanding the brain
- What is the brain?
• Brain —> tissue found within the skull
- body consists of organs —> organs consist of tissue —> tissue consist of
cells
- brain is an organ —> consist of nervous tissue —> nerve cells
- nervous system: central, peripheral
• Human brain comprises two major sets of structures:
- Cerebrum (Forebrain)
• two symmetrical halves —> hemispheres
• responsible for conscious behaviours (most)
• enfolds the brainstem: responsible for unconscious behaviour (most)
- Cerebellum: second major brainstem structure
• specialised for learning & coordinating skilled movements
• Term “brain” refers to: exerts control over behaviour, signifies both:
- the organ & the fact that this organ produces behaviour
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,- Gross Anatomy of the Nervous System:
• major divisions of the human nervous system —> composed of cells
- nerve cells: neurons, most directly control behaviour
• neurons: communicate w each other in the brain, sensory receptors in the
skin, w muscles, & w internal organs
- most connections between brain an the rest of the body: spinal cord
• depends from the brainstem through a canal in the backbone
• Brain & Spinal cord: central nervous system (CNS)
- encased in bone: brain (skull), spinal cord (vertebrae)
- “central” bc: physically located to be the core of the NS & bc it’s the core
structure mediating behaviour
• Peripheral nervous system (PNS):
- processes radiating out beyond the brain & spinal cord
- as well as the neutrons outside the brain & spinal cord
• Embodied language:
- proposes: movements we make & the movements w perceive in others are
central to communication w others
- understand each other not only by words BUT by observing gestures & other
body language
- we think not only w silent language BUT also w overt gestures & body
language
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, - Finding #1: CNS needs ongoing sensory stimulation from the world & from its
own body’s movements
- #2: brain communicates by producing movement & observing the movement
of others
- thus: refer to an active brain, connected to the rest of the NS & engaged in
doing its job of producing behaviour
- What is Behaviour?
• useless def. in book: “patterns in time”
• e.g.: Movement, speech, attitude, but also blushing (colour change) are
thoughts behaviour?
• usable def.: any form of movement in a living organism
- observable, measurable
- Perspectives on Brain & Behaviour
• three classic theories: mentalism, dualism, materialism
• mind-body problem: dualistic vs. monistic phil. views
• spiritualistic vs. materialistic views
• Aristotle: all human intellectual functions are produced by a person’s psyche
- responsible for life & its departure from the body results in death
- behaviour no role for the brain
- nonmaterial psyche responsible for human consciousness, perceptions, &
emotions for processes
- entity independent of the body
- mind: “memory”, “psyche” got translated into eng. —> “mind”
- person’s mind (psyche) responsible for behaviour —> mentalism
• Descartes: placed seat of the mind in the brain & linked it to the body
- nonmaterial mind is responsible for rational behaviour
- entity called mind directs a machine called the body
• dualism
- mind works through a small structure in the centre of the brain: pineal gland
- located beside fluid-filled cavities called ventricles
- Today: pineal gland related to bio. rhythms, doesn’t govern human behaviour
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, • Wallace & Darwin: materialism
- idea that rational behaviour can be fully explained by the workings of the
brain & the rest of the NS, w/o immaterial mind
- all living things are related
- natural selection: expl. how new species evolve & how existing species
change over time
- species: group of organisms that can breed among themselves, but not w
other members of other species
- phenotype: characteristics we can see & measure
• Mendel: heritable factors —> genes
- related to various physical traits displayed by the species
- genotype: members of a species that have a particular genetic makeup, will
express that trait
- Exp. w white & purple flower
- individuals inherit two factors for each trait, one factor may hide the other
- new traits appear bc new gene combinations are inherited from parents
• existing genes change/ mutate, suppressed genes are reexpressed,
suppressed
- Thus, unequal ability of ind. organisms to survive & reproduce is related to
the diff. genes the inherit from their parents & pass on to their offspring
- environment plays a role in how genes express traits & exp.
- epigenetics: study of diff. in gene expression related to environment &
experience
• epigenetic factors do not change genes BUT influence how your genes
express the traits u inherited
• epigenetic changes can persist throughout a lifetime & the cumulative
effects can make dramatic diff. in how your genes work
• Summary:
• bc all animal species are related, so too must be their brains
• bc all species of animals are related, so too must be their behaviour
• both brain & behaviour in complex animals such as humans evolved from
the brain & behaviour of simpler animals but also depend on learning
- Recovering Consciousness:
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