sensation and perception exam 1 (ch1-4)

methods of the perceptual process

methods of the perceptual process

1: thresholds

2: scaling

3: signal detection theory

4: sensory neuroscience

5: neuroimaging

stimulus and receptors

physical stimilus energy—-receptors— neurons to brain: perceptual experiences

transduction

process of converting energy into another form

neural processing and communication

Process by which neurons in the brain communicate and transmit information through electrical and chemical signals. Involves input (receiving sensory information), integration (analyzing and interpreting information), and output (sending signals to muscles and organs). Crucial for various cognitive functions, such as perception, learning, and memory.

perception

the act of giving meaning and purpose of detected sensations

perception as an active constructive process

consists of constructing internal representations of the world from multiple cues (depth, motion, size) representations are not always accurate

psychophysical approach

focuses on the relation between physical stimulus properties (light or sound intensity) and perceptual experience (brightness, loudness)

physiological approach

focuses on the relation between physical stimulus properties and how the brain represents those properties

absolute threshold

minimum amount of stimulation (stimulus intensity) necessary for a person to detect a stimulus 50% of the time

(Just Noticable) Difference Threshold/JND

the smallest detectable difference between two stimuli, or the minimum change in a stimulus that can be correctly judged as different from a reference stimulus

receptor

A molecule on the surface of a cell that binds to specific molecules, such as hormones or neurotransmitters, triggering a cellular response.

neuron

Cell responsible for transmitting electrical signals in the body; consists of a cell body, dendrites, and an axon.

action potential

Electrical signal that travels along a neuron, allowing for communication between cells. It consists of depolarization, repolarization, and hyperpolarization phases.

excitatory connection

synapse in which an action potential in a presynaptic neuron increases the probability of an action potential occurring in a post synaptic cell/prompt one neuron to share information with the next thru an action potential

inhibitory connection

inhibitory currents reduce the probability that such a transfer will take place

functional specialization

different areas in the brain are specialized for different functions

retina

a light sensitive membrane in the back of the eye that contains rods and cones, which receive an image from the lens and send it to the brain through the optic nerve

blind spot

the point of entry of the optic nerve on the retina insensitive to light

fovea

a small pit, near the center of the macula that contains the highest visual acuity

ganglion cells

a retinal cell that receives visual information from photoreceptors via two intermediate neuron types and transmits information to the brain and midbrain

two types of receptors

rods and cones

rods

photoreceptor specialized for night vision, 90million

cones

photoreceptor specialized for daylight vision, fine visual acuity and color 4-5m

neural convergence

convergence allows a neuron to receive input from many neurons in a network

receptive fields

the region within sensory stimuli cause increase or decrease in firing and the region within which stimuli modulate responses

lateral inhibition

the capacity of excited neurons to reduce the activity of their neighbors

receptor

molecule in the cell membrane able to respond specifically to a particular neurotransmitter hormone antigen or other substance

action potential

occurs when the membrane potential of a specific cell rapidly rises and falls

optic nerve

each of the second pair of cranial nerves transmitting impulses to the brain from the retina at the back of the eye

The Hermann Grid

an optical illusion in which the crossings of white grid lines appear darker than the grid lines outside the crossings

Mach Bands

exaggerates the contrast between edges of the slightly differing shades of grey

Simultaneous Contrast

two colors side by side interact with one another and change our perception accordingly

lateral geniculate nucleus (LGN)

nucleus in the thalamus that receives visual information from the retina and sends it to the visual cortex for processing

layers of LGN

six distinctive layers, the inner two layers are magnocellular layers, while the outer four layers are parvocellular layers

magnocellular system

magnocellular pathway carries information about large fast thing, low spatial frequency, high temporal frequency, is colorblind

parvocellular system

carries information about small, slow, colorful things/ high spatial frequency, low temporal frequency

retinal focus

the range of retinal defocus that can be tolerated without the perception of blur

retinotopic organization

neurons with receptive fields close together in visual space, has cell bodies close together in the cortex

primary visual cortex

primary cortical region of the brain that receives integrates, and processes visual information relayed from the retinas, is located in the occipital lobe

striate cortex

is part of the visual cortex that is involved in processing visual information, it is the first cortical visual area that receives input from the LGN in the thalamus

6 layers in V1

5 layers in the inferotemproral cortex(layer also), v12345

RF of simple cortical cells

simple cells respond to lines of particular width, orientation, angle and position within the visual field

inferotemporal cortex

plays an important role for the visual recognition of objects

retinotopic map

mapping of visual input from the retina to neurons, particularly neurons within the visual stream

feature detectors

process by which the nervous system sorts or filters complex natural stimuli in order to extract relevant cues that have a probability of being associated with important objects or organisms in their environment

tilt aftereffect

a visual illusion in which prolonged adaptation to an oriented stimulus causes shifts in perceived orientations

selective adaptation

the tendency to give a diminished response when faced with sustained stimuli

cortical magnification

refers to the fact that the number of neurons in the visual cortex responsible for processing the visual stimulus of a given size varies as a function of the location of the stimulus in the visual field

what makes object recognition difficult

an object viewed from different angles may look completely different

perceptual organization

refers to the way information is received by our senses and interpreted to make it meaningful

gestalt psychology

five principles of perceptual organization are proximity, similarity, continuity, closure, and connectedness

structuralism

a mode of knowledge of nature and human life that is interested in relationships rather than individual objects

FFA (fusiform face area)

region of the cortex in the inferior temporal lobe of the brain that has been shown to respond most strongly to faces

parahippocampal place area

V1 layer

4 layer compartments 2/3, 4ab. 4c. 5/6

Main visual input from the lgn of thalamus

Specialized for processing information aobut static and moving objects and is excellent in pattern recognition

V2 layer

visual association area

V3 layer

dorsal stream

V4 layer

divided into 4 layers, abcd

One of the visual areas in the extrastirate cortex

Shows strong attentional modulation

Tuned for orientation, spatial frequency, and color

how do rods and cones synapse with ganglion cells?

Bipolar cells from rods synapse with cone bipolar cells and make synaptic contacts to ganglion cells in the inner layer.

Rods and cones synapse with bipolar cells which then synapse with ganglion cells

what evidence proves that faces are a special category?

Face inversion suggest faces are special objects because when we see a distorted face it becomes much harder to process, we look at faces and see how features are configured with one another

what evidence proves that faces are a non-special category?

Some people can be experienced with perceiving other non-facial images, causing the same brain reaction

Visual expertise with a class of images

parietal lobe

Vital for sensory perception including taste, hearing, sight, touch, smell

frontal cortex

High cognitive functions like memory, impulse control, problem, solving, motor function, social interaction

medial temporal lobe

related to important cognitive and emotional functions/formation of memories and spatial cognition

occipital lobe

visuospatial processing, distance and depth perception, color determination, object and face recognition, memory formation