Biology and Behaviour Flashcards
Franz Gall
Earliest theories in neuropsychology
- behaviour, intellect and personality could be linked to brain anatomy
- if a trait was well developed, the part of the brain responsible would expand (creating bumps on the head)
Pierre Flourens
first person to study the major sections and functions of the brain
- performed extirpations/ablations on rabbit and pigeons + removing parts of the brain and observing the behavioural consequences
- asserted that parts of the brain had specific functions and removing parts weakened the whole brain
William James
Known as the father of american psychology
- important to study how the mind functioned in adapting to the environment
- among one of the theories that formed functionalism = system of thought that studied how mental processes help individuals adapt to their environments
John Dewey
Wrote an article leading to the inception of functionalism
- it criticized the concept of the reflex arc (breaks the process of reaction to a stimulus into discrete parts)
- Dewey thought that psychology should focus on the study of the organism as a whole
Paul Broca
Examined the behavioural deficits of people with brain damage
- specific functional impairments could be linked to specific brain lesions
- discovered Broca’s area in the left side of the brain -> damage there leads to inability to speak
Herman von Helmholtz
First to measure the speed of a nerve impulse in terms of reaction time
-credited with the transition of psychology into the field of the natural sciences
Sir Charles Sherrington
First person to infer the existence of synapses
Sensory neurons/afferent neurons
transmit sensory information from receptors to the spinal cord and brain
Motor/efferent neurons
transmit motor information from the spinal cord and brain to muscles and glands
Interneurons
- most numerous of the 3 types of neurons
- located mainly in the brain and spinal cord
- often linked to reflexive behaviour
Reflex arcs
neural circuits that allow muscle action to occur before sensory information has reached the brain
-ex: interneurons of the spinal cord sending pain signals to the legs if you step on a nail
Central nervous system (CNS)
brain and spinal cord
-also the olfactory and optic nerves are the 2 pairs of cranial nerves in the CNS
Peripheral Nervous System (PNS)
Nerve tissue and fibres outside of the brain and spinal cord
-divided into the somatic and autonomic nervous systems
Somatic Nervous system
sensory and motor neurons throughout the skin, joints and muscles
Autonomic nervous system (ANS)
Regulates heartbeat, breathing, digestion, and glandular secretions
- involuntary muscle control
- regulates body temp by activation sweating or piloerection
- divided into the sympathetic and parasympathetic branches
Parasympathetic Nervous System
Main role is to conserve energy
- resting and sleeping states
- reduces heart rate and constricts bronchi
- increases peristalsis and exocrine secretions as well as bile release
*key neurotransmitter = acetylcholine
Sympathetic nervous System
Activted by stress
- increases heart rate and blood glucose levels
- relaxes bronchi and dilates pupils
- redistributes blood to muscles
- decreases digestion and peristalsis
*key neurotransmitter = epinephrine
Meninges: function
- protect the brain
- keep brain anchored within the skull
- resorb cerebral spinal fluid
Meninges: layers
- Pia mater: closest to the brain
- Arachnoid mater
- Dura mater: closest to the skull bone
Cerebrospinal fluid
aqueous solution in which the brain and spinal cord rest
-produced by specialized cells lining the ventricles of the brain
3 basic subdivision of the human brain
- hindbrain
- midbrain
- forebrain
Brainstem
formed of the hindbrain and the midbrain
- more primitive region of the brain
- contains the brain structures associated with basic survival
Limbic system
group of neural structures that are associated primarily with emotion and memory
- eg. aggression, fear, pleasure, pain
- developed later along with the forebrain
Cerebral cortex
Most recent evolutionary development
- outer covering of the cerebral hemispheres
- language processing, problem solving, impulse control and long-term planning
Midbrain: Structures & Functions
receives sensory information and motor information from the rest of the body
Colliculi = sensorimotor reflexes
- superior : visual sensory input
- inferior : auditory sensory input
Hindbrain: Structures & Functions
Cerebellum - refined motor movements
Medulla - vital functions : breathing and digestion
Reticular formation - arousal and alertness
Forebrain: Structures & Functions
cerebral cortex - complex perceptual, cognitive, and, behavioural processes
Basal ganglia - movement
Limbic system - emotion and memory
Thalamus - sensory relay station
Hypothalamus - hunger and thirst; emotion
The brain develops from the ____ in prenatal life?
Neural tube
total swellings in the mature neural tube
5
Rhombencephalon
subdivison of the embryonic brain that becomes the hindbrain
-subdivides into the:
myelencephelon => medulla
metencephelon => pons/cerebellum
Mesencephalon
subdivison of the embryonic brain that becomes the midbrain
Prosencephalon
subdivison of the embryonic brain that becomes the forebrain
-subdivides into the:
telencephalon => cerebral cortex, basal ganglia, limbic system
diencephalon => thalamus, hypothalamus, posterior pituitary gland and the pineal gland
Cortical maps
created by electrical stimulation of the cortex and observing the behavioural or perceptual result
Electroencephalogram (EEG)
Non-invasive method of measuring electrical activity produced by the brain
- electrodes placed on the subjects scalp
- measures electrical of large groups of neurons
- broad patterns of activity are detected
Regional cerebral blood flow (rCBF)
Non-invasive mapping procedure which detects broad patterns of neural activity based on the blood flow to different parts of the brain
- patient inhales radioactive gas
- images of the brain are obtained via MRI, PET or CT scans
Thalamus functions
Important relay station for incoming sensory information
- all senses except for smell
- sorts and transmits impulses to the appropriate areas of the cerebral cortex
Hypothalamus functions + Parts
Subdivided into the lateral, ventromedial, and anterior
Four F’s:
- Feeding
- Fighting
- Flighting
- (sex) Functioning
Lateral Hypothalamus functions
Hunger centre
- has special receptors to sense if the body needs more food or fluids
- triggers eating/drinking
- damage to this part results in loss of hunger
Ventromedial Hypothalamus functions
Satiety centre
- provides signals to stop eating
- damage usually results in overeating and obesity
Anterior Hypothalamus
Control of sexual behaviour + regulation of sleep and body temperature
*damage results in an inhibition of sexual activity
Posterior pituitary
Axonal projections from the hypothalamus
-releases hormones: Antidiuretic hormone (ADH) and oxytocin
Pineal gland
Important in control of several biological rhythms
- important is the circadian rhythm, regulated by melatonin
- receives direct signals from the retina for coordination with sunlight
Basal Ganglia
Group of structures in the middle of the brain
- coordinate muscle movement when signals are received from the cortex
- make movements smooth and posture steady
- relay information to the brain and the spinal cord via the extrapyramidal motor system
parkinson’s involves destruction of parts of the basal ganglia
Extrapyramidal motor system
gathers info about body position and carries this info to the CNS
Limbic system
Interconnected group of structures that loops around the central portion of the brain
- amygdala
- septal nuclei
- hippocampus
Septal Nuclei
One of the primary pleasure centres of the brain
-association with addictive behaviour
Amygdala
Role in defensive and aggressive behaviours (fear and rage for example)
damage = reduced fear and aggression reactions as well as docility and hypersexual states
Hippocampus
Learning and Memory processes
- consolidation of information & forming of long term memories
- connects with the limbic system via the fornix
Anterograde amnesia
Not being able to establish new long term memories
Retrograde amnesia
Loss of memories occurring before the brain injury
Cerebral cortex
Outer surface of the brain - also called neocortex
- convoluted gyri and sulci provide extra surface area
- whole cerebrum divided into 2 cerebral hemispheres
- cerebral cortex divided into 4 lobes
Gyri
Bumps in the cerebral cortex
Sulci
Folds in the cerebral cortex
Frontal lobe - 2 basic regions + 1 other
- Prefrontal lobe
- Primary motor area
* also contains Broca’s area
Prefrontal lobe
- manages executive function
- supervises/directs operations of other brain regions
- controls processes of perception, memory, emotion, impulse control, and long-term planning
- communicates with the reticular formation in the brain stem for wake/sleep alertness
damage to this area impairs overall supervisory function
example of an association area
Primary motor area
- located on the precentral gyrus (in front of the central sulcus that divides the frontal and parietal lobes)
- initiates voluntary motor movements
- neurons are arranged systematically according the the part of the body that they are attached to
example of a projection area
Association area
area that integrates input from diverse brain regions
*ex: prefrontal lobe
Projection area
areas that perform rudimentary or simple perceptual and motor tasks
*ex: visual cortex
motor homunculus
organizational pattern of the primary motor cortex that shows the relative area that each body part occupies in the PMA
Broca’s Area
Vitally important for speech production
-usually found in only one hemisphere (dominant one, usually left)
Parietal Lobe
Located to the rear of the frontal lobe (divided by the central sulcus)
-central region associated with spatial processing and manipulation
contains the somatosensory cortex (located on the postcentral gyrus) which is the destination for all incoming sensory signals for touch, pressure, temp, and pain
Occipital Lobe
Very rear of the brain
-contains the visual cortex (aka striate cortex due to striped appearance under a microscope)
Temporal lobe(s) - 2 parts and other functions
- Auditory cortex
- Wernike’s area
- also functions in memory processing, emotion, and language
- hippocampus is located deep within the temporal lobe
Auditory Cortex functions
primary site of most sound processing including speech, music, and other sound info
Wernike’s Area
associated with language reception and comprehension
Contralaterality
when one side of the brain communicates with the opposite side of the body
Ipsilaterally
cerebral hemispheres communicating with the same side of the body
-eg hearing
Dominant Hemisphere
More heavily stimulated during language reception and production
-Broca’s and Wernike’s areas are driven by the dominant side
usually the left side
- primarily analytic in function
- language, logic, and math skills
Nondominant Hemisphere
Associated with intuition, creativity, music cognition, spatial processing
- assembles the stimulus pieces into a holistic image
- usually the right side
- more sensitive to the emotional tone of language
Corpus callosum
connects the two hemispheres of the brain
Acetylcholine
Found in both the CNS and PNS
PNS: used to transmit nerve impulses to muscles
-used by the parasympathetic NS and slightly by the sympathetic (sweat glands)
CNS: attention and arousal
Epinephrine and Norepinephrine
Controlling alertness and wakefulness
Primary NT of the sympathetic nervous system
-promote fight or flight
Norepinephrine - acts more as a local NT
- low levels = depression
- high levels = mania
Epinepherine - secreted from adrenal medulla to act systematically as a hormone
Catecholamines
important role in the experience of emotions
Three closely related neurotransmitters
- Dopamine
- Epinephrine
- Norepinephrine
also classified as monoamines or biogenic amines
Dopamine
Important in movement and posture
- high concentrations in the basal ganglia
- loss of dopaminergic neurons is associated with Parkinson’s
Imbalances play a role in schizophrenia
-dopamine hypothesis: delusions, hallucinations, and agitation arise from too much or too little dopamine
Dopamine/Schizophrenia relationship
Treatment of both diseases can result in side effects of the other disease
- Dopamine blockers for schizophrenia can lead to parkinson’s like motor disturbances (extrapyramidal side effects)
- l-DOPA increases dopamine levels for Parkinson’s patients but an overdose can lead to psychotic symptoms
Serotonin
Regulation of mood, eating, sleeping, and dreaming
Is a monoamine or biogenic amine neurotransmitter like the catecholamines
low levels = depression
high levels = mania
GABA
Stabilizes neural activity in the brain by producing inhibitory post synaptic potentials
-does so by causing hyperpolarization of the post synaptic membrane
Glycine
Inhibitory NT in the CNS by increasing chloride influx into the neuron
-causes hyperpolarization like GABA
Glutamate
excitatory NT in the CNS
-acts opposing to Glycine
Neuromodulators
also called neuropeptides
- relatively slow, longer effects
- more complex chain of events in the postsynaptic neuron
*endorphins are an example
Endorphins
Natural pain killers
Brain structure linking the endocrine and nervous systems?
Hypothalamus
Hypophyseal Portal System
Connects the hypothalamus and the (anterior) pituitary gland
Pituitary gland : functions and divisions
“master” gland located at the base of the brain
Posterior pituitary: ADH and oxytocin release
Anterior pituitary: “master” part of the gland
-releases hormones that control endocrine glands
-controlled directly by the hypothalamus
Adrenal glands : functions and divisions
Located on top of the kidneys
Medulla (inside) : epinephrine and norepinephrine, part of the PNS
Cortex (outside) : corticosteroids (like stress hormone cortisol) as well as sex hormones
Gonads
Sex glands of the body that produce sex hormones in higher concentrations
-increase libido and mating behaviour/sexual function
Innate behaviour
genetically programmed as a result of evolution
Learned behaviour
due to experience and environment
Adaptive value
extent to which a trait/behaviour positively benefits a species
-increasing fitness, leads to adaptation through natural selection
Nature vs nurture
Nature = heredity and inherited behaviours Nurture = effects of environment/surroundings
Family studies limitation
families share both genes and environment which makes it hard to tell which influences a certain behaviour
Twin studies
compare concordance rates between monozygotic and dizygotic twins
*concordance rates = how likely both twins are to exhibit the same trait
Adoption studies
help to understand environmental influences and genetic influence on behaviour
Neurulation
occurs at 3-4 weeks gestational age
-ectoderm over the notochord begins to furrow, forming a neural groove surrounded by two neural folds
Neural crest
Cells at the leading edge of the neural fold
-disperse throughout the body to form disparate tissues
Neural tube
formed by the closure of the furrow
- ultimately becomes the CNS
- has an altar plate = becomes sensory neurons
- basal plate = motor neurons
*antiepileptic meds are linked to neural tube defects in babies
reflex
behaviour that occurs in response to a given stimulus without higher cognitive input
rooting reflex
automatic turning of the head in the direction of a stimulus touching the cheek
Moro reflex
infants react to abrupt movements of their head by quickly throwing up their arms and then slowly lowering them while crying
-usually disappears after 4 months
Babinski reflex
causes toes to spread apart automatically when the sole of the foot is stimulated
Grasping reflex
infants close fingers around objects placed in their hands
Stranger anxiety
fear/apprehension of unfamiliar people
-appears around 7 months
Separation anxiety
fear of being separated from parent
-appears around 1 year
Parallel play
children play alongside each other without influencing each other’s behaviour
-around age 2
Gross motor skill development
proceeds from head (lifting head) to toe (walking) and from core to periphery
