Exam 2 Flashcards
Ch 5-7
Describe all the major divisions of the nervous system, including their functions. (PERIPHERAL NERVOUS SYSTEM)
PNS: The rest of your nervous system (not brain and spinal cord); Connected to limbs and organs to relay information to and from CNS.
Splits off into two different systems, the Somatic nervous system (SNS) and Autonomic nervous system (ANS).
SNS is related to the external environment (mostly conscious), while ANS is related to internal environment (mostly unconscious). The SNS and ANS both consist of Efferent (motor; from the brain to the body) and Afferent (sensory) pathways.
The ANS’ Efferent pathway consists of the Sympathetic nervous system and Parasympathetic nervous system. Sympathetic mobilizes energy (“fight or flight”) and prepares you for action in stressful situations. The Parasympathetic conserves energy (“rest and digest”) and stimulates digestion and recovery.
Describe all the major divisions of the nervous system, including their functions. (DEFINITION OF NERVOUS SYSTEM + CENTRAL NERVOUS SYSTEM)
The nervous system is a network of neurons that conveys electrochemical information throughout the body. Comprised of both the Central nervous system (CNS) and Peripheral nervous system (PNS).
CNS: it is the brain and spinal cord; The control center of the body for processing and responding to information.
Describe the sensation of smell and how we perceive it
Olfactory information (sense of smell) enters frontal lobe, amygdala, hippocampus, etc. rather than connecting to the thalamus first, resulting in close relationship between smell, emotional/social behaviour, and memory
Olfactory epithelium (mucous membrane situated on top of nasal cavity) contains olfactory receptor neurons (ORN) that transduce odourant molecules into neural impulses
ORN sends axons from epithelium into bulb to process axons that form olfactory nerve
Smell is determined by bottom-up influences
What is a perceptual set?
Predisposition to perceiving one thing and not another (top-down processing) and is determined by schemas (ways that humans organize/categorize ambiguous information)
Schemas appear as:
- context effects (culture/pre-existing knowledge)
- motives can influence perception
- emotions (positive emotions alter our perceptions of how other people present themselves)
What is the physical stimulus that becomes the mental phenomenon of sound? How does this physical stimulus get transformed into sound?
Sound waves are physical stimulus that becomes sound. Sound waves compress and expand air molecules, creating areas of high and low density that ears detect as brief pressure changes
Sound waves from environment enter outer ear and travel along ear canal to eardrum (membrane that vibrates in response to different air densities) –> vibrations from eardrum pass to ossicles (bones connected to eardrum: hammer, anvil, and stirrup) that amplify sound vibrations and transfer to oval window –> oval window and cochlea (fluid-filled structure that stimulates hair cells, vibrations transduced into electrical signals) connected to brain
Differentiate the terms sensation and perception.
Sensation is how a physical stimulus is represented by the nervous system and sensory receptors - it is the registration of light, sound, pressure, odour or taste
Perception is how we organize, identify, and interpret sensory signals to form a mental representation
How do we perceive pain?
Tissue damage is transduced by free nerve endings that sense painful stimuli –> neural signals for pain travel to two distinct areas in the brain
- one sends to somatosensory cortex, identifying where pain is occurring and its intensity
- other sends signals to motivational and emotional centres of brain (hypothalamus, amygdala, and frontal lobe) –> aspect of pain that motivates us to escape or relieve pain
Referred pain: pain that originates internally but can be felt on the surface of the body (when sensory information from internal and external areas converge on the same nerve cells in spinal cord)
What is perceptual constancy? What are some notable examples?
Perceptual Constancy is the ability to perceive an object as the same regardless of the context (perceived as unchanging)
- Colour constancy: familiar objects will have consistent colour even if illumination changes around it (ex. banana is yellow under variety of lighting)
- Size constancy: recognizing that things remain the same size even though they take up more space in our retina
- Relative luminance: taking visual cues and building mental image of lightness and darkness based on context
How do we study selective attention? What does it tell us about unattended stimuli? What does it tell us about the value of attention?
We can conduct dichotic listening tasks where two different audio stimuli are present, one in each ear, and participants are told to attend to one ear, resulting in their ability to “shadow” the audio that is in the focused ear but filter out the audio in the other ear.
Another way to study selective attention is to use a cueing paradigm, which allows the participant to have enhanced detection to stimuli in the directed area but decreased ability to detect stimuli when pointed to a wrong spot.
These examples show that attention is a very limited resource and fixed by its capacity. As such, attention is important in order to filter out unimportant information so that our brains are storing only the critical details in our short-term and long-term memories.
Describe the organs and brain areas related to sound.
Electrical signals from the hair cells transmitted through auditory nerve, carrying sound information from cochlea to the brain.
Auditory signals pass through several processing centers (including brainstem and midbrain) where brain interprets information about sound location and timing
Auditory signals reach primary auditory cortex in temporal lobe to interpret and recognize sounds
What is priming? How is it related to the idea of subliminal messaging? Does subliminal
messaging work?
Subliminal Threshold: stimulus (that we experience less than half of the time) that reaches the brain but not the consciousness, could affect behaviour without our awareness
Priming is when we see things in our environment but were focused on other things, so it only has a weak activation in our brain (unconscious activation in mind)
Subliminal messaging does work but effects are very brief and weak and not enough to have an enduring influence on behaviour
Have a fundamental understanding of how visual information reaches the brain.
Cornea –> pupil –> iris –> lens –> retina –> bipolar/retinal ganglion cells (optic nerve)
- Cornea bends the light wave, reversing it and turning it upside down
- Pupil is where the light travels
- Iris controls the size of the pupil and amount of light that can enter the eye
- Lens stretches and relaxes muscles to bring things in and out of focus (process is called accommodation)
- Light information travels through fluid and blood vessels (inefficient machinery blurs image)
- Retina is where photoreceptors (rods and cones) are located and then travels to optic nerve to thalami before being sorted and reconstructed in the occipital lobe (primary visual cortex)
Describe all the major divisions of the brain, including the functions we discussed. (FOREBRAIN)
Forebrain: Consists of the Telencephalon and Diencephalon.
The Telencephalon (cerebral hemispheres) is the largest division of the human brain with the cerebral cortex and other underlying structures.
The cortex is the most prominent feature of the brain, having lots of convolutions as it is important for human behaviour and cognitions.
The Diencephalon is comprised of two structures, the thalamus and hypothalamus:
The thalamus includes inputs from sensory systems, motor systems, cerebellum, and basal ganglia. This region is called the “relay station/centre” for sensory information as most info stops and the thalamus before entering the cortex (all senses except smell).
The hypothalamus is a key intersection with the endocrine system via the pituitary gland (the master gland). The endocrine system is a junction of systems with organs and glands to produce hormones. It has diverse functions related to sex, sociality, aggresion, feeding, sleeping/waking, circadian rhythm, etc.
Describe the Limbic “System” and Basal Galglia
It is not a real system. The word “limbic” simply means on the edge/border between the cortex and deeper brain structure.
The Limbic “System” contains the amygdala, hippocampus, cingulate cortex, hypothalamus, mammillary body, fornix, septum, and olfactory bulb. The amygdala is related to emotions, learning, and decision-making, while the hippocampus is important for memory formation and spatial awareness. The cingulate cortex is critical for decision-making, pain, and autobiographical thoughts.
The Basal Ganglia is other structures (made of striatum and globus pallidus) in your brain nearby the Limbic “System” which are responsible for muscle memory, movement, skills, habits, motivation, and addiction.
Describe ten key features of consciousness.
Subjectivity: personally felt from experience and not immediately accessible to others
Intentionality: thoughts/experiences are always regarding something (can’t be empty)
Unity: cannot bring multiple information into awareness, resistant to division
Selectivity: brain fills in gaps in world and filters things out (attentional mechanism)
Transience: consciousness shifts and moves between states (can switch from topic to topic)
Body Awareness: tendency to know where your body begins and ends (note not all beings can recognize their body parts
Agency: recognizing that you have an influence over the world and have control over yourself (schizophrenia may cause people to act outside of their control)
Theory of Mind: recognize mind, knowledge, and more are separate from someone else’s
Self-awareness: carrying our own identity/idea of “I”
Metacognition: cognition about cognition
What is psychophysics? What major discoveries has it revealed?
Psychophysics looks at our relation between the physical experience and the psychological experience (literal amounts vs. perceived amounts)
Psychophysics established methods for quantifying how sensory experiences relate to physical stimuli via thresholds (absolute and difference)
Describe signal detection theory and the different thresholds
Signal Detection Theory: how we determine if and when an individual perceives anything at all based on response to a stimulus (depends on person’s sensitivity and decision criterion)
Absolute Threshold: smallest amount of stimulus that can be detected (50% may go undetected) - can be altered by alertness
Difference Threshold (JND): minimum difference that can be perceived between two stimuli (acuity is how well we can distinguish that)
Weber’s law: two stimuli must differ from some constant minimum percentage, not a constant amount, in order to be able to perceive
How is attention related to memory?
Attention controls the information that reaches our short-term (working memory) and strongly influences what is stored in the long-term memory.
Describe the sensation of taste and how we perceive flavour
Taste system contains 5 taste receptors (salt, sour, bitter, sweet, umami) and tongue is covered with papillae, which contain taste buds (organs of taste transduction)
Food molecules dissolved in saliva evoke specific, combined patterns of activity in receptor types - smell and taste (primary gustatory cortex) are connected and taste information is passed to primary olfactory cortex
Describe the mechanisms that support the brain’s healthy functioning (blood, meninges, cerebrospinal fluid). Why is damage to these support mechanisms so devastating?
The brain has four main arteries which are vertebral arteries and internal carotids.
There is also the two-step system with the blood-brain barrier that protects the brain from any viruses and bacteria.
Half of it is from the capillaries that have tight junctions to prevent harm from coming onto the brain, and the other half is from the feet of astrocytes that wrap around the arteries.
Chronic stress, aging, and diseases can weaken or loosen the blood-brain barrier.
The brain is concealed in 3 layers of protection: The Dura Mater (“tough mother”), Arachnoid Mater, and Pia Mater (“little mother”). These layers protect the brain alongside the skull and cerebrospinal fluid (CSF; layer of fluid with ventricles (pockets of fluid) converging together at an aqueduct. Without the CSF, traumatic brain injuries would be significantly more severe.
Describe monocular cues
Depth cues available to either eye (can be perceived with only one eye so information sent to brain still has depth information)
- Light and shadow
- Relative motion
- Relative size
- Linear perspective/Linearity
- Parallelism/parallelity
- Interposition
- Relative height
- Motion perception: humans are imperfect at motion perception, only get certain amount of information per second from photoreceptors, results in limited movement information about the world
Perception of movement as a result of alternating signals appearing in rapid succession in different locations = apparent motion
Biological motion perception = ability to perceive biological motion critical for identifying individuals and various socially relevant features, such as emotional state, personality characteristics, whether they are vulnerable to attack, or are engaging in deceptive actions
Region in back of temporal lobe strongly linked to this
§ Ie. Helicopter blades look like a blur
Beta movement/phi phenomenon makes us “see” things moving even though it’s just a lot of discrete images because of our limited frame rate of vision
§ Used in movies and video games
Describe all the major divisions of the brain, including the functions we discussed. (MIDBRAIN)
Midbrain: Consists of the Mesencephalon.
The Mesencephalon is comprised of a roof (tectum) and a floor (tegmentum).
The tectum receives visual information and generates eye and head movements. Has “automatic” orientation to stimuli and outside of conscious access (“Boston Pizza part of the brain” - part that always monitors environment for flashy and salient things; Ex. flashy TVs at B.P.). Also reacts to auditory stimuli too.
The tegmentum is important for movement related to emotions, motivation, and species-specific behaviours (ex. dog howling or a primate hooting). Dopamine neurons are found here.
What is attention? Why do we only attend part of the environment and not all?
Attention is the process of selectively focusing on certain pieces of information in our environment while ignoring other stimuli.
We only attend to parts of the environment and not all because we have limited capacity and the brain chooses to attend to the most important things while filtering out the least important information.
What is split brain and what are its implications on consciousness?
severing hemispheres by cutting the corpus callosum –> results in hemispheres operating independently on some tasks and intermanual conflict that suggests two different brains acting in the same body
left hemisphere controls speech and therefore only the right side of the world is communicated
patients cannot identify items in left visual field, but information is consciously available to the brain but not the part of brain responsible for speech
