Brain and Behaviour E-Test 2

Receptive field

An area that responds to a specific stimuli and selectively activates cells 

Rod characteristics

light sensitive, optimal in dim light, more of them

Cone characteristics

colour vision, optimal in high light, less of them 

Iris

has an adjustable circular opening (pupil) which can expand or contract to control the amount of light entering the eye

Cornea

transparent structure at the front of the eye that helps to focus incoming light

Crystalline lens

behind pupil, a colourless, transparent structure, refracts light to be focused on the retina by changing shape, changes the focal distance of the eye allowing for a sharp image

Ciliary muscles

surround the lens - hold the lens in place

Vitreous humor

Interior chamber of the eyeball filled with a jelly-like tissue

Retina

light sensitive tissue

Optic nerve

transmits signals from the retina to the visual cortex

Horizontal (retinal) cells

link photoreceptors (rods, cones) with bipolar cells

Amacrine (retinal) cells

link bipolar cells with 2nd layer (retinal ganglion cells)

Retinal ganglion cells

collect at the optic disc and form the optic nerve

parvocellular cells input

midget retinal ganglion cells in the retina

Magnocellular cells input

primarily from rods

range of light visible to humans

A typical human eye will respond to wavelengths from about 390 to 700 nanometers

ventral stream

The ‘what stream,’ runs downward from the primary visual cortex into the temporal lobe, and is associated with object recognition and form representation

dorsal stream

The ‘where’ stream, stretches from the primary visual cortex in the occipital lobe forward into the parietal lobe, is involved in the guidance of actions and recognizing where objects are in space

Visual form agnosia

An impairment without a deficit in intellect or vision of visually presented objects, where a person cannot copy or discriminate the shapes of objects

Frequency

The number of occurrences of a repeating event per unit of time

range of sound for humans

20,000 Hertz

Timbre

The quality of complex tones produced

Pure tones

A single frequency, wave and shape remain unchanged

Complex tones

A mix of frequencies, wave and shape change

Overtones

set of higher frequency sound waves that vibrate at multiples of the fundamental frequency

Decibels (Db)

Measure the maximum displacement of vibrating particles from a rest position when the sound is produced

Amplitude (loudness) changes

Greater amplitude waves have more energy and greater intensity, so they sound louder

Inner hair cells

Specialized sensory receptor cells in the cochlea that convert sound vibrations into electrical signals for the brain

Movement of hair-cell cilia

Movement toward the tallest cilia depolarizes, movement toward the shortest cilia hyperpolarizes

Ventral auditory pathway

The brain's "what" system that processes sound recognition, meaning, and identification

Broca’s area

Located in the left frontal lobe of the brain and is primarily responsible for producing spoken and written language.

Wernicke’s area

Located in the posterior part of the superior temporal gyrus near the auditory cortex, responsible for language comprehension, word meaning and speech planning

Prosody

Melodical tone of the spoken voice

Language critical period

ages 3-4

What age children begin to combine words 

2 years old

Broca’s area damage in language

Langauge loss / brocas aphasia

Broca’s aphasia

Caused by damage to the frontal lobe of the brain, which affects a person's ability to speak and write while generally preserving their ability to understand language.

Wernicke’s aphasia

A language disorder that makes it hard to understand spoken and written words, even though a person can still speak fluently

Symptoms of left temporal lobe damage

Difficulty recognising faces- prosopagnosia, visual agnosia, Wernicke’s aphasia, hearing difficulties

Results of left hemisphere removal

Weakness / paralysis on the right side of the body and major language loss

Auditory cortex

Part of the brain responsible for discriminating between speech sounds

Simple auditory stimuli analysis

Primary auditory cortex

Complex auditory stimuli analysis

adjacent secondary auditory areas

Wilder Penfield

Used electrical stimulation to map the cortices of conscious human patients who were about to undergo neurosurgery, confirmed that movements in humans are triggered mainly in response to stimulation of the primary motor cortex.

Arcuate fasciculus

Connects Wernicke’s and Broca’s areas

Stimulation of the primary auditory cortex

produces basic, elementary auditory percepts such as simple tones, clicks, buzzes, or isolated sinusoidal sounds

Music perception

The left hemisphere plays at least some role in certain aspects of music processing, especially those that have to do with making music.

Rods location

peripheral vision

Cones location

the fovea

Macular degeneration

Caused by weakening of the elasticity of the lens in people over 50

Music in left hemisphere removal

Can still be understood regardless of language

Understanding of speech rates per second

30

Auditory route to the cortex

cochlear nucleus, olivary complex, inferior colliculus, medial geniculate, auditory cortex

What melodies activate

the area in front of Heschl’s gyrus on the right hemisphere

Photoreceptor and colour receptor sensitivity

Black and white are more sensitive than colour

Neuron layers in the retina from outermost to innermost

ganglion cell layer, bipolar cell layer, photoreceptor layer

Fundamental frequency

The rate at which a complex waveform repeats

Increases in loudness are coded by

an increased rate of firing in bipolar cells

Order of the middle ear bones from nearest to the eardrum to nearest the oval window

hammer, anvil, stirrup

Where photoreceptors are most densely packed

the fovea