Chapter 3: The Biological
Bases of Behaviour (map 2
of 2)
The Brain and Behaviour
The brain can be divided into 3 major regions
Hindbrain
Cerebellum
literally means "little brain"
adjacent to the back surface of the
brainstem
Plays a key role in organizing the sensory
information. critical to the coordination of
movement and to the sense of equilibrium
damage to the cerebellum disrupts fine
motor skills
Medulla
attaches to the spinal cord
in charge of largely unconscious
but vital functions
Pons
literally means "bridge"
includes a bridge of fibres
that connects the brainstem
with the cerebellum.
Midbrain
is the segment of the brainstem that lies between the
hindbrain and the forbrain.
contains an area that is concerned with intergrating sensory
processes such as vision and hearing
Reticular formation runs through the hind and mind brain.
Contributes to modulation of muscle reflexes, breathing
and pain perception. Best know for regulation of sleep and
arousal.
Forebrain
Is the largest and most complex region of the brain.
Encompassing a variety of structures.
Thalamus
is the structure in the forebrain which all
sensory information (except smell) must pass
to get to the cerebral cortex
appears to play an active role in
integrating information from various
senses
Picture below taken from pg 100 of the 4th
edition of pychology themes and variations
Hypothalamus
Is found near the base of the
forebrain,laying beneath the thalamus.
involved in the regulation of basic
biological needs
Controls the autonomic nervous system
serves as a vital link between the brain and
endocrine system
Plays a major role in regulating the biological drives
related to survival
Anotações:
- 4 "F"'s fighting, fleeing, feeding and mating.
Contributes to the control of hunger, thrist and
temperature regulation and other basic biological processes
Limbic System
Anotações:
- Limbic system is a loosely connected network of structures located on the border between the cerebral cortex and deeper subcortical areas.
limbic means edge
Is NOT a well defined anatomical
system with clear boundaries
Involved in the regulation of emotion, memory and motivation
Cerebrum
Anotações:
-Seat of complex thought
The wrinkled surface of the cerebrum is
the cerebral cortex-the outer layer of the
brain which looks like a cauliflower
Responsible for the most
complex mental activities,
learning, remembering, thinking
and consciousness
Divided into two hemispheres right and left
Corpus callosum is the structure that
connects the 2 cerebral hemispheres.
Each hemisphere is divided into 4 lobes
OCCIPITAL LOBE
Anotações:
- Found at the back of the head, includes the cortical area where most visual signals are sent and the visual process is begun. this is called the VISUAL CORTEX
PARIETAL LOBE
Anotações:
- Is forward of the occipital lobe.
-includes the area that registers the sense of touch.
-Called the PRIMARY SOMATOSENSORY CORTEX
-Involved in integrating visual input and in monitoring the body's position in space.
TEMPORAL LOBE
Anotações:
-Means near the temples.
-lies below the parietal lobe
-contains an area devoted to auditory processing called the AUDITORY CORTEX
FRONTAL LOBE
Anotações:
-Largest lobe in the human brain
-Contains the principle areas that control the movement of muscles, called the MOTOR CORTEX
Mirror neurons
Anotações:
- are neurons that are activated by performing an action or by seeing another monkey or human perform the same action.
-Discovered by accident
Brain Plasticity
Refers to the brain's ability to change
structure and function
Neurogenesis is the formation of new neurons
Right Brain/Left brain: Cerebral Laterality
2 important parts of the brain dealing
with speech
Broca's area plays an important
role in PRODUCTION of speech
Wernicke's area found in the temporal lobe of
the left hemisphere. is used for
COMPREHENSION of language.
Split Brain Research
Split brain surgery
Anotações:
- The bundle of fibres that connects the cerebral hemispheres(corpus callosum) is cut to reduce the severity of epileptic seizures
- choosen only for the most severe cases.
- create a unique study opportunity
Each hemisphere's
primary connections
are to the opposite
side of the body.IE
left hemisphere
controls and
communicates with
the righht side of the
body
Information received by one hemisphere
is readily shared with the other via the
corpus callosum.
When the two hemispheres are
surgically disconnected, functional
specialization of the brain becomes
apparent.
Picture above taken from pg 108 of the 4th
edition of psychology themes and
variations
Hemispheric Specialization
Left
Better on tasks involving verbal
processing, such as language, speech,
reading, and writing
Right
Better on tasks involving
nonverbal processing,like spatial,
music, and visual recognition
tasks ans tasks involvingthe
perception of other's emotions.
The Endocrine System: Another Way to Communicate
Endocrine System
Consists of glands that release hormones into the
bloodstream; hormones help to control the bodily
functioning
hormonal messages travel to distant cells at slower speeds that
neural messages and tend to be less specific
Hormone release tends to be pulsatile
Anotações:
-Pulsatile means hormones tend to be released several times a day in brief bursts or pulses that last only minutes
Is controlled by the nervous system through the hypothalamus.
Pituitary gland is the "master gland" releasing a great variety of
hormones that stimulate actions in the other endocrine glands
Hormones help to modulate human physiological development.
Heredity & Behaviour: Is it All in the Genes?
Behavioural Genetics - an
interdisciplinary field that studies the
influence of genetic factors on
behavioural traits
HOMOZYGOUS CONDITION 2 genes
in a specific pair are the same.
HETEROZYGOUS CONDITION the
genes are different
GENOTYPE refers to a person's genetic makeup.
Is determined at conception and
is fixed forever.
PHENOTYPE
refers to the
ways in
which a
person's
genotype is
manifested
in
observable
characteristics.
Phenotypic characteristics (ie hair color) may change
over time and may also be modified by
environmental factors.
Researcher asses hereditary influence by examining
blood relatives to see how much they resemble one
another on a specific trait
Twin Studies
Researchers asses hereditary influence by
comparing the resemblance of identical
twins and fraternal twins with respect to a
trait
Adoption Studies
Asses hereditary influence by examining the resemblance between adopted children and both
their biological and their adoptive parents
The Evolutionary Bases of Behaviour
Darwin's Insights
Identified Natural selection as the mechanism that orchestrates the process of evolution
four crucial insights
#1 Organisms very in endless ways
#2 Some of these characteristics are heritable
#3 organisms tend to produce offspring at
a pace that out strips the local availability
of food supplies, living space and other
crucial resources
#4 if a specific heritable trait contributes to an
organism's survival or reproductive success, organisms
with that trait should produce more offspring and the
prevalence of that trait should gradually increase over
generations resulting in evolutionary change
Refinements to Evolutionary Theory
Mutation is a spontaneous, heritable change in a piece of DNA that occurs in an individual organism
Most mutations are NOT beneficial
Adaptation is an inherited characterisitc that increased in a population(through natural selection) because it helped solve a
problem of survival or reproduction during the time it emerged.
Behaviours as Adaptive Traits
Darwin recognized natural selection was
applicable to behavioural traits
Many behavioural adaptations are designed to improve an
organism's chances at reproductive sucess
Impact of genetic makeup depends on environment, and the impact of
environment depends on genetic makeup.