Behavioural Health

What does CNS stand for?

Central Nervous System

What does CNS consist of?

Brain and spinal cord

Spinal Cord

A long bundle of nerves that extend from the medulla to the brain down to the middle of the back to transfer messages between the brain and body.

What does CSF stand for?

Cerebrospinal fluid

What is the role of CSF

Protects CNS

What does PNS stand for

Peripheral Nervous System

Role of PNS

Nerve cells that exit the CNS that carry sensory and motor information to and from the rest of the body and not incased in the bone.

Spinal Cord is how much (%) of the weight of the entire CNS?

2%

Spinal Reflexes

Initiated by the spinal cord without assistance from the brain

Name the three types of nerve cells

Sensory neurons, Motor neurons, Interneurons

Sensory neuron

• Carries info from external environment/body back to CNS

Motor Neurons

• Carry commands from the CNS back to the muscles and glands of the body

Interneurons

Neurons that have neither sensory or motor functions and travel throughout the spinal cord.

Brainstem

• Responsible for critical survival functions such as heartrate and breathing

• Consists of the midbrain, pons, and medulla

Medulla

• Also known as Medulla Oblongata

• Responsible for breathing, respiration, heartrate, blood pressure

• Located just above the spinal cord

• Has large bundles of nerve fibres that travel to and from higher brain levels

• Damage results in immeadiate death

Pons

• Located between the medulla and midbrain

• Involved with sleep, arousal, and facial expression

• Connects cerebellum to the rest of the brain

Cerebellum

• Manages belance

• Motor Control

• Coordination

• Affected by alcohol

Midbrain

• Lies between pons and the cerebral hemispheres

• Involved in sensory reflexes, movement, and pain

• Part of reticular formation

• Promotes arousal and alertness

Reticular Formation

• Collection of structures located along the midline of the brainstem

• Participates in mood, arousal, and sleep

Subcortical

Located below the cortex

Thalamus

• Processes sensory information (Hearing, taste, sight, touch)

• States of arousal, learning, and memory

Basal Ganglia

• Collection of subcortical structures participating in the control of voluntary movement

• Connected to Parkinson’s disease

Hypothalamus

• Involved in motivation and homeostasis

• Done through regulating hunger, thirst, temprature, sexual behaviour, and agression

Hippocampus

Important for formation of long-term memory

Cingulate cortex

• Above the corpus callosum

• Anterior segment - decision making and emotion

• Posterior segment - memory and visual processing

Amygdala

• Located in temporal lobe

• Participates in emotional processing (specifically in fear and aggression)

Nucleus Accumbens

• Participates in reward and addiction

• Active during eating, sex, gambling addictive behaviours

Corpus Callosum

Wide band of nerve fibres connecting the right and left cerebral hemispheres

Cerebral Cortex

• Thin layers of neurons covering the outer surface of the cerebral hemispheres

• Localised in the cerebral cortex

Name the four lobes the cerebrum is divided into

Frontal, Parietal, Temporal, Occipital

Frontal Lobe

• Most forward lobe

• Location of primary motor cortex

• Prefrontal cortex

• Orbitofrontal cortex

• Broca’s area

• responsible for complex cognitive processes

• such as decision making, speech, higher level cognition

Parietal Lobe

• Lies at the top of the head between the frontal and occipital lobes

• Location of the primary somatosensory cortex (processes touch)

• Spatial awareness

Occipital Lobe

• Lobe located at the back of the brain

• Located at the primary visual cortex (processes vision)

Temporal Lobe

• Lobe that curves around the side of the hemisphere

• Location of the primary auditory cortex (processes hearing)

• Wernicke’s area

When was the mirror neurons experiment conducted and by who?

Giacommo Rizzolati and a team of italian scientists

What is processed by the left hemisphere?

Movement and sensation on the right side of the body

What is processed by the right hemisphere?

Movement and sensation on the left side of the body

Lateralization

• Lateralization: A special type of localization of function in the cerebral cortex

• Refers to functions being specialized in either the right or left hemisphere of the brain

Effects of brain lateralization

• Enhances multitasking abilities in organisms

• May have contributed to the development of language in humans

• Could be linked to schizophrenia and autism spectrum disorder vulnerabilities

Structure of spinal cord

• Continous with the brainstem

• Large white matter pathways

• Reflexes

Structure of brainstem and cerebellum

• Large white matter pathways (arousal, reflexes, body functions like heart rate)

• Midbrain

• Pons

• Cerebellum

• Medulla

• Reticular formation

Subcortical structures

• Embedded in the white matter of the cerebral hemispheres

• Thalamus

• Basal ganglia

• Hypothalamus

• Hippocampus

• Cingulate cortex

• Amygdala

• Nucleus accumbens

Cerebral cortex

• Thin layer of gray matter enveloping the hemispheres

• Divided into four lobes

• Areas with sensory, motor, or association functions

• Same localized and lateralized functions

What two systems does the PNS consist of?

Somatic NS and Autonomic NS

Somatic NS

• Division of the PNS

• Brings sensory info to the CNS

• Transmits commands to the muscles

Autonomic NS

• Division of PNS

• Directs the activity of glands, organs, and smooth muscles

• Can be further divided into three systems

Name the three systems under the Autonomic NS

• Sympathetic NS

• Parasympathetic NS

• Enteric NS

Sympathetic NS

• Coordinates arousal and stress response

• Basically activating the fight v.s. flight response

Parasympathetic NS

• Associated with rest, repair, and energy storage

• Activating rest and digest response

Enteric NS

• Division of the Autonomic NS

• Consisting of nerve cells embedded in the lining of the GI tract

What does the Endocrine System do?

It releases hormones into blood and helps with body functions such as metabolism, growth, and sex.

What does the pineal gland control?

• Sleep-wake cycle

• Releases melantonin

• Released early evening

What hormones do the pituitary gland release, and what are their functions?

Oxytocin: Breastfeeding (also linked to love, bonding, and social connection)

Vassopressin: Fluid balance

Growth Hormone: Growth and regeneration

Controls sex hormones from ovaries and testes

What is the function of the thyroid gland

• Regulates metabolism rate

• Low levels contribute to depression

• Releases thyroxine (T4)

When are the Adrenal Glands activated and what hormone do they release?

• Activated during stress

• Releases cortisol

• Helps wake the body

Where are the Islets of Langerhans located and what hormone do they produce?

• Location: Pancreas

• produce insulin

• Essential for digestion

Neurons

• Cells of the nervous system

• Sends/recieves neural messages

Cell body

• Soma

• Large

• Center mass of neuron

• Contains nucleus

Axon

• Branch of a neuron

responsible for transmitting info to other neurons

Dendrites

• Branch from the nerve cell body that recieves info from other neurons

Myelin Sheath

• Insulating material covering axons

• Speeds up the process of transfering info

Glia

• Important cells in the nervous system

• Provide structural support for neurons

• Form tight connections with blood vessels, creating the blood-brain barrier (prevents toxins from entering the brain)

• Some glia myelinate neurons to speed up signals

Neural Communication

• 2-step process

  1. Electrical Signaling: Action potential travels down the axon

  2. Chemical Signaling: Action potential triggers neurotransmitter release

• Neurotransmitters act on the receiving neuron to produce an effect

Electrical Signaling

• Resting potential: The electrical charge when the neuron is inactive

• Action potential: An electrical signal in a neuron’s axon

  • Generated at the axon hillock when the membrane reaches a threshold

Synapse

A point of communication between two neurons

Neurotransmitter

Chemical messenger communicating thru a synapse

Receptor

• Special channel in the membrane of the neuron

• Interacts with neurotransmitters released by other neurons

Reuptake

• A process in which molecules of a neurotransmitter in the synaptic gap returned to the axon terminal from which they were released

Chemical Signaling

• Action potential reaches the axon terminal

• Synaptic vesicles (carrying neurotransmitters) are released from protein anchors (triggered by calcium influx)

• Vesicles fuse with the axonal membrane at release sites

• Neurotransmitters are released into the synaptic cleft

• Vesicle material is recycled for future use

• Vesicles are refilled with neurotransmitters

Acetylcholine (ACh)

• Found in many systems linking to behaviour and in neurovascular junction the synapse at which the nervous system commands muscles, interference can result in paralysis and death

• Key neurotransmitter of the autonomic nervous system

• Involved in learning, memory, movement and linked to Alzheimer’s disease

Norepinephrine (Noradrenaline)

• Released in the brain leading to arousal and attentiveness

• Released by the sympathetic nervous system

• Connected to bipolar disorder and PTSD

Dopamine

• Involved with movement, planning, and reward

• Connected to Parkinson’s disease, schizophrenia, and ADHD

Seratonin

• Involved with sleep, apetite, and mood

• These three behaviours are tightly linked

Endorphins

Modify natural response to pain

Epinephrine (Adrenaline)

• Activates fight v.s. flight response

• Enables the brain to be more alert

• Involved in arousal

Glutamate

• Excitation of brain activity

• Links to learning and memory

• Too much of this contributes to migraines/seizures

GABA (Gamma-aminobutryic acid)

• Inhibition of brain activity

• Calms the nervous system (anxiety)

• Low levels contribute to seizures

Sensation

• Detecting environmental and body stimuli

• Evolved through natural selection for survival (e.g., humans, dogs, and horses have unique sensory systems)

• Subtle differences exist between individuals (e.g., need for corrective glasses)

Perception

• Interpreting sensory information

• More individual variation—stimulation may be the same, but perception is subjective

• Sensory systems are highly sensitive to change

Sensory Processing

Sensory processing begins with an interaction between a physical stimulus and our biological sensory systems

Stimulus

Anything that elicits a reaction from our sensory systems

Transduction

Converts incoming sensory information into neural signals sent to the brain

How does the brain construct perceptions?

It processes sensory information in the form of neural signals.

Why is perception important?

It allows us to organize, recognize, and use sensory input.

What is an important gateway to perception?

Attention.

What is sensory adaptation?

The tendency to pay less attention to unchanging stimuli.

Why do unfamiliar, changing, or intense stimuli get more attention?

They may have safety consequences and require quick responses.

Selective attention

• Prioritizing a specific amount of information while excluding the rest

• Can’t process all stimulus

Bottom up Processing

• Brain’s use of incoming perceptions to contruct perceptions

• Build simple input into more complex perceptions

Top-down Processing

• Impose structure on incoming information

• Memories and other cognitive processes and knowledge gained from prior experience interpret sensory information

Who developed psychophysics and what is it?

• Gustav Fechner (1801-1887)

• Studies the relationship between the physical qualities of the stimuli and subjective responses they produce

• Like absolute threshold and difference threshold

Absolute Threshold

Smallest amount of stimulus that can be detected

Difference Threshold

Smallest detectable difference between two stimuli

Signal Detection

• Analysis of sensory and decision making processes in the detection of faint uncertain stimuli

• Two-step process:

• A: the actual intensity of the stimulus

• B: Observer’s criteria for deciding whether the stimulus occured

Vision

The sense that allows us to process reflected light

How much (%) of our cerebral cortex processes visual information and how much for hearing, touch, and pain?

• 50% (cerbral cortex)

• 3% (Hearing)

• 11% (Touch and Pain)

Visual Stimulus

• Visible light/energy within electromagnetic spectrum to which our visual systems respond

• Type of radiation emitted by the Sun, other stars, and artificial sources as a light bulb

Cornea

The clear surface at the front of the eye that begins the process of bending/directing light into the retina

Pupil

An opening formed by the iris

Iris

• Brightly colored circular muscle surrounding the pupil of the eye

• Adjusts the opening of the pupil in response to the amount of light in the environment and to signals from the ANS