Summary 3.6C – The Brain (part 1)
Table of Contents
Theme 1: Brain Basics ............................................................................................................................................. 2
Breedlove & Watson (2017) - Chapter 6: Evolution of the brain and behaviour (pg 163 - 191) .........................................2
Breedlove & Watson (2013) - First part of Chapter 2 Functional Neuroanatomy (pg. 23-33) ..........................................7
Gazzaniga (2009) - Last part of chapter 2. Cellular Mechanisms and Cognition, (pg 44-53) ......................................... 12
Stahl (2013) - Part of Chapter 1, Chemical neurotransmission, (5-26) ........................................................................ 18
Breedlove & Watson (2013) - First part of Chapter 7, Lifespan development of the brain and behaviour, (pg 185-200) .. 27
Theme 2: Changing Brain ....................................................................................................................................... 34
Purves - Chapter 25: Experience-dependent plasticity in the developing brain (pg. 541 – 562) ..................................... 34
Purves - Chapter 26: Repair and Regeneration in the nervous system (pg. 563 – 590).................................................. 46
Carlson - Chapter 13: Learning and memory (p. 419 - 459)........................................................................................ 58
, 2
Theme 1: Brain Basics
Breedlove & Watson (2017) - Chapter 6: Evolution of the brain and behaviour (pg 163 - 191)
How did the enormous variety of species arise on earth?
Animal species are continually changing across generations (evolution), gradually gaining and losing features and
sometimes spinning off new species.
o Natural selection drives evolution (Darwin)
Darwin hypothesised that the variation among individuals affect the probability of their surviving long
enough to reproduce, thereby passing on their individual characteristics to their offspring. Individuals
who are better suited will have more success in reproduction and so their descendants will make up a
bigger portion of the successive populations --> these adaptations will eventually dominate the
population. Sexual selection is a principle in which members of each sex exert selective pressures on the
other in terms of both anatomical and behavioural features that favour reproductive success.
o Evolution may converge upon similar solutions
Convergent evolution is a process by which responses to similar ecological features bring about
similarities in behaviour or structure among animals that are only distantly related (body of a tuna and a
dolphin is similar since this is efficient for swimming but one is a fish and one a mammal). Such
resemblance is an example of homoplasy, a resemblance between physical or behavioural
characteristics that is due to convergent evolution. Homology on the other hand is a resemblance based
on common ancestry. Analogy refers to similarity in function, although structures may look different
(hand of a human and trunk of an elephant).
o Modern evolutionary theory combines natural selection and genetics
Darwin's theory suffered from uncertainty in some processes (the mechanisms by which something is
inherited and the source of individual variation). It was later found out how the formal laws of heredity
and genetics work and that occasionally a new feature arose spontaneously and was then passed on to
successive generations (mutations).
Beneficial mutations will give the individual a slight advantage in reproduction and pass it down
generations, to become more widespread. Evolution does not have a goal or an endpoint, it is
everchanging in a response to the environment.
Chromosomes are the supercoiled lengths of DNA, found within the cell nucleus, that contain genes that
encode the tens of thousands of proteins that make up the body. An individuals experience and
environment can also modify the expression of certain genes in a way that can be transmitted to an
offspring without changing the structure of the affected genes --> epigenetic modifications.
How closely related are two species?
Linnaeus proposed a basic classification system in which each species is assigned 2 names: first you have the
genus/genera, and then the name indicating the species (homo, sapiens).
The levels of classifications:
• Species
• Genus
• Family
• Order
, 3
• Class
• Phylum
• Kingdom
Similarities between some species of organisms reflect phylogeny (many species have given rise to other species,
kind of like a family tree). This is how we make inferences about the evolution of behaviours.
o Newer methods aid in classifying animals and inferring evolution
Taxonomy is the classification of organisms. With the proportion of differences between DNA samples
from two species can be used as a molecular clock to estimate how long ago they diverged from a
common ancestor. This shows that humans and chimpanzees are closer related than humans and
gorillas. But, these are all estimations, since it's a range of millions of years.
Why study other species?
This is based on a human-centred perspective, in which humans were the pinnacle achievement of evolution, where
animals were just sub-humans. Today we understand it more as a multi-branching set of radiations, using
comparisons of different species to gather clues about the evolutionary history.
Different kinds of animals have evolved specific behaviours and neural mechanisms that allows them to exploit
specific sets of environmental opportunities (ecological niches). Species with varying biological histories show
different solutions to the challenges of survival. In many cases, these pressures to adapt have led to changes in brain
structure. One important adaptation is to learn and remember, in order to predict where, when and how to obtain
food and mates and avoid danger.
o Complicated lives require complicated brains
Researchers have found that the strategies that different species use to obtain food are correlated with
brain size and structure --> species that eat foods that are difficult to find (ripe foods) have larger brains
that those who eat food that is more uniformly distributed and easy to find (grass or leaves). Finding
novel ways of getting food is related to the size of the forebrain in different orders of birds. In bats, the
auditory centre (inferior collicus) is much larger for bats that depend on hearing than for bats who
depend on vision --> they'll have a bigger visual centre (superior collicus).
Birds that store food for later have bigger hippocampi relative to the forebrain than birds who do not
store food. Also in birds, song repertoire size is correlated with the volume of a brain regions called the
HPV (higher vocal centre). It is the females that are exerting the evolutionary pressure by choosing
males with larger repertoires and thereby selecting larger HPVs. This is therefore an example of sexual
selection. In general, relative size of a brain region is a rough guide to the importance of the function of
that region for the adaptations of the species
, 4
o Simpler invertebrate nervous systems provide models of neural function
Most animals on earth as invertebrates (animals without backbones), and they far exceed vertebrates in
many ways, including diversity of appearance, variety of habitat and overall numbers (insects for
example). The gross anatomy of the nervous systems of some representative animals is illustrated in
figure 8. The study of invertebrates are much easier to study since those of vertebrates are extremely
complex.
Yet, we are primarily interested in understanding human behaviour. So we focus on brains more similar
to our owns.
All vertebrate brains share the same basic structures
o The main brain structures are the same in all mammals
While most mammals share most of the same regions, the relative sizes, proportions and anatomical
locations of these brain regions have been subject to evolutionary modification.
The comparison can be extended in great detail to include nuclei, fibre tracts and types of cells. Most
differences are mainly quantitative (mass, area, proportions).
All vertebrate nervous systems share certain main features but differ in others
The nervous systems share many characteristics: (1) the development from a hollow neural tube, (2) bilateral
symmetry, (3) segmentation, (4) hierarchical control, (5) separate systems, (6) localisation of function. In general,
Table of Contents
Theme 1: Brain Basics ............................................................................................................................................. 2
Breedlove & Watson (2017) - Chapter 6: Evolution of the brain and behaviour (pg 163 - 191) .........................................2
Breedlove & Watson (2013) - First part of Chapter 2 Functional Neuroanatomy (pg. 23-33) ..........................................7
Gazzaniga (2009) - Last part of chapter 2. Cellular Mechanisms and Cognition, (pg 44-53) ......................................... 12
Stahl (2013) - Part of Chapter 1, Chemical neurotransmission, (5-26) ........................................................................ 18
Breedlove & Watson (2013) - First part of Chapter 7, Lifespan development of the brain and behaviour, (pg 185-200) .. 27
Theme 2: Changing Brain ....................................................................................................................................... 34
Purves - Chapter 25: Experience-dependent plasticity in the developing brain (pg. 541 – 562) ..................................... 34
Purves - Chapter 26: Repair and Regeneration in the nervous system (pg. 563 – 590).................................................. 46
Carlson - Chapter 13: Learning and memory (p. 419 - 459)........................................................................................ 58
, 2
Theme 1: Brain Basics
Breedlove & Watson (2017) - Chapter 6: Evolution of the brain and behaviour (pg 163 - 191)
How did the enormous variety of species arise on earth?
Animal species are continually changing across generations (evolution), gradually gaining and losing features and
sometimes spinning off new species.
o Natural selection drives evolution (Darwin)
Darwin hypothesised that the variation among individuals affect the probability of their surviving long
enough to reproduce, thereby passing on their individual characteristics to their offspring. Individuals
who are better suited will have more success in reproduction and so their descendants will make up a
bigger portion of the successive populations --> these adaptations will eventually dominate the
population. Sexual selection is a principle in which members of each sex exert selective pressures on the
other in terms of both anatomical and behavioural features that favour reproductive success.
o Evolution may converge upon similar solutions
Convergent evolution is a process by which responses to similar ecological features bring about
similarities in behaviour or structure among animals that are only distantly related (body of a tuna and a
dolphin is similar since this is efficient for swimming but one is a fish and one a mammal). Such
resemblance is an example of homoplasy, a resemblance between physical or behavioural
characteristics that is due to convergent evolution. Homology on the other hand is a resemblance based
on common ancestry. Analogy refers to similarity in function, although structures may look different
(hand of a human and trunk of an elephant).
o Modern evolutionary theory combines natural selection and genetics
Darwin's theory suffered from uncertainty in some processes (the mechanisms by which something is
inherited and the source of individual variation). It was later found out how the formal laws of heredity
and genetics work and that occasionally a new feature arose spontaneously and was then passed on to
successive generations (mutations).
Beneficial mutations will give the individual a slight advantage in reproduction and pass it down
generations, to become more widespread. Evolution does not have a goal or an endpoint, it is
everchanging in a response to the environment.
Chromosomes are the supercoiled lengths of DNA, found within the cell nucleus, that contain genes that
encode the tens of thousands of proteins that make up the body. An individuals experience and
environment can also modify the expression of certain genes in a way that can be transmitted to an
offspring without changing the structure of the affected genes --> epigenetic modifications.
How closely related are two species?
Linnaeus proposed a basic classification system in which each species is assigned 2 names: first you have the
genus/genera, and then the name indicating the species (homo, sapiens).
The levels of classifications:
• Species
• Genus
• Family
• Order
, 3
• Class
• Phylum
• Kingdom
Similarities between some species of organisms reflect phylogeny (many species have given rise to other species,
kind of like a family tree). This is how we make inferences about the evolution of behaviours.
o Newer methods aid in classifying animals and inferring evolution
Taxonomy is the classification of organisms. With the proportion of differences between DNA samples
from two species can be used as a molecular clock to estimate how long ago they diverged from a
common ancestor. This shows that humans and chimpanzees are closer related than humans and
gorillas. But, these are all estimations, since it's a range of millions of years.
Why study other species?
This is based on a human-centred perspective, in which humans were the pinnacle achievement of evolution, where
animals were just sub-humans. Today we understand it more as a multi-branching set of radiations, using
comparisons of different species to gather clues about the evolutionary history.
Different kinds of animals have evolved specific behaviours and neural mechanisms that allows them to exploit
specific sets of environmental opportunities (ecological niches). Species with varying biological histories show
different solutions to the challenges of survival. In many cases, these pressures to adapt have led to changes in brain
structure. One important adaptation is to learn and remember, in order to predict where, when and how to obtain
food and mates and avoid danger.
o Complicated lives require complicated brains
Researchers have found that the strategies that different species use to obtain food are correlated with
brain size and structure --> species that eat foods that are difficult to find (ripe foods) have larger brains
that those who eat food that is more uniformly distributed and easy to find (grass or leaves). Finding
novel ways of getting food is related to the size of the forebrain in different orders of birds. In bats, the
auditory centre (inferior collicus) is much larger for bats that depend on hearing than for bats who
depend on vision --> they'll have a bigger visual centre (superior collicus).
Birds that store food for later have bigger hippocampi relative to the forebrain than birds who do not
store food. Also in birds, song repertoire size is correlated with the volume of a brain regions called the
HPV (higher vocal centre). It is the females that are exerting the evolutionary pressure by choosing
males with larger repertoires and thereby selecting larger HPVs. This is therefore an example of sexual
selection. In general, relative size of a brain region is a rough guide to the importance of the function of
that region for the adaptations of the species
, 4
o Simpler invertebrate nervous systems provide models of neural function
Most animals on earth as invertebrates (animals without backbones), and they far exceed vertebrates in
many ways, including diversity of appearance, variety of habitat and overall numbers (insects for
example). The gross anatomy of the nervous systems of some representative animals is illustrated in
figure 8. The study of invertebrates are much easier to study since those of vertebrates are extremely
complex.
Yet, we are primarily interested in understanding human behaviour. So we focus on brains more similar
to our owns.
All vertebrate brains share the same basic structures
o The main brain structures are the same in all mammals
While most mammals share most of the same regions, the relative sizes, proportions and anatomical
locations of these brain regions have been subject to evolutionary modification.
The comparison can be extended in great detail to include nuclei, fibre tracts and types of cells. Most
differences are mainly quantitative (mass, area, proportions).
All vertebrate nervous systems share certain main features but differ in others
The nervous systems share many characteristics: (1) the development from a hollow neural tube, (2) bilateral
symmetry, (3) segmentation, (4) hierarchical control, (5) separate systems, (6) localisation of function. In general,
