Psych 2NF3 – Chapter 1
Concussion is only a mild form of Traumatic Brain Injury (TBI)
Executive Function: mental skill related to attention, memory, everyday problem-solving and
Brain theory: brain is the source of behaviour
Neuron theory: the idea that the unit of brain structure and function is the neuron
THE BRAIN THEORY
Cerebro-spinal fluid (CSF): fluid in the brain. Cushions the brain and assists in removing metabolic
Gyri: folds/bumps of the brain
Sulci: creases between the bumps (gyri)
Fissures: large/long creases (sulci)
- Longitudinal fissure: divides the two hemispheres
- Lateral fissure: divides each hemisphere in half
Comissures: connect the brain's hemispheres
- Corpus Callosum: the largest comissures
Forebrain: in embryos; mainly cerebral cortex. Mediates cognitive function
- Brain stem mediates regulatory functions such as eating, drinking, moving
- Spinal cord conveys sensory information to/from brain to/from muscles
Central Nervous System (CNS): brain and spinal cord. Cannot regenerate.
PERIPHERAL NERVOUS SYSTEM
Nerve fibers that carry information from/to CNS. Can regenerate.
– includes Somatic Nervous System and Autonomic Nervous System
Somatic Nervous System:
---- Sensory Pathways: collection of fibers that carry specific sensory modalities. They carry
information from one side of the body mainly to the opposite side of the brain.
---- Motor Pathways: collection of fibers that carry information from the brain to body's muscles. Side
of brain sends information to opposite side of body.
Autonomic Nervous System:
Control internal organs (sensory and motor control)
PERSPECTIVES ON THE BRAIN AND BEHAVIOUR
First formal theory of behaviour
Psyche responsible for human thoughts, perceptions and emotions, imagination, opinion, desire, etc.
Nonmaterial (separate of the body) but works through the heart to produce behaviour. It was translated
into “mind”, thus mentalism began. Descartes: Dualism
Dualism: mind and body are separate but can interact
First Neurophysiology text
Brain has a prominent role: it has spatial extent, responds mechanically and reflexively to events
Mind: non-material and without spatial extent, different from the body. Body operated like machine
(brain) but mind decided what movements should be made.
- Located the pineal body (of pineal gland) as the site of action of the mind since it was the only place
in the brain that was not bilateral and also close to the ventricles
- Thought cortex was just a covering for pineal gland
- People argued against him as damage to pineal gland did not change behaviour much
Mind-body problem: how could a non-material mind produce movement through a material body?
- Language and reason indicate the presence of a mind (thus animal, children and mentally ill did not
Rational behaviour can be fully explained by the works of the nervous system
- nothing was non-materialistic
- similarities in anatomy could be explained if all animals had evolved from a common ancestor
- Natural selection explains how new species evolve and change over time
Gregor Mendel and heritable factors:
- Found that some traits are due to heritable factors (genes) and that genes expression can be affected
by the environment (epigenetics)
- Neuroplasticity: brains ability to form new connections/pathways. Enhances adaptability to new
environments and compensates for inury.
Materialistic and neutral to beliefs/religion
- “Mind” is a short term for brain functions, not an entity
BRAIN FUNCTIONS: INSIGHTS FROM BRAIN INJURY:
Gall and Spurzheim:
Cortex and its gyri are functional, not just coverings for the pineal gland
- corticospinal pathway (cortex and spine) sends movement to opposite side of body
- Corpus callosum connects the two hemispheres
Localization of function: specific brain areas control specific behaviours
- Bumps were well-developed, functional gyrus and depression an underdeveloped gyrus
Phrenology: they identified list of behavioural traits and assigned each trait to a particular bump
LATERALIZATION OF FUNCTION
One side of the brain is specialized in certain functions
Broca's area: left side of the frontal lobe, impairs making of speech movements
Broca's aphasia: the damage to broca's area. Often associated with paralysis of right side of body.
Wernicke's area: temporal lobe – Wernicke suspected a relation between hearing and speech
functioning since this area was so close to Broca's. He proposed that auditory information travels to the
temporal lobes from auditory receptors and that in Wernicke's area, sounds are processed into images or ideas of objects and stored.
Wernicke's aphasia/fluent aphasia: impairs understanding of language and production of meaning
- The auditory ideas flow from Wernicke's are to Broca's area through the arcuate fasciculus. In
Broca's area, representations of speech movements are stored.
conduction aphasia: Wernicke predicted this: a damage to the arcuate fasciculus (connecting broca's
and wernicke's area). Patient would be unable to repeat what is heard.
Alexia: inability to read due to disconnection of brain's visual area and Wernicke's area
Apraxia: inability to make sequences of movements due to disconnection of motor and sensory areas
-Goltz and Flourens experiments with dogs (removing parts of their brains)
HIERARCHICAL ORGANIZATION – by John Hughlings Jackson
Explains the disconnect between experiments that support functional localization and those that
observe recovery of a functional
- Information in brain is processed serially and organized as a functional hierarchy