PSYC123 - Cog. Neuroscience EXAM #2

Tympanic membrane

Eardrum - air pressure pushes against the membrane, which in turn causes vibration of the ossicles.

Ossicles

Tiny drums connected to ear drum. Help in amplifying sound and transferring to the cochlea.

Cochlea

Fluid-filled spinal structure connected to the ossicles. Contains membrane that responds selectively to different frequencies.

Basilar membrane

Translates vibrations by responding selectively to different frequencies. Far end = apex, low frequencies. Near end = base, high frequencies

Place code

Different frequencies of sound are represented by the brain according to where along the basilar membrane is stimulated

Rate code

Different intensities (amplitude) of sounds are represented by the brain by the firing rate of auditory nerve neurons

Auditory transduction

Hair cells trigger the neurons of the auditory nerve which synapse onto brain stem structures, then the medial geniculate thalamus nucleus (in cortex), and finally the primary auditory cortex.

Tonotopy

In A1, similar pitches are represented near each other

Interaural timing difference

The difference in when a signal arrives to each ear.

Interaural intensity difference

The difference in the intensity of a signal at each ear

Delay lines

ITD. Cells A, B, and C send signals to each other horizontally (←→). Cells only activate when they recieve signals from the left and right at the same time. Respond best to the coinciding of imputs from the 2 ears.

Mechanoreceptors

Cells that detect touch, pressure, vibration of skin

Nocireceptors

Pain. Detect tissue damage and extreme temperatures

Thermoreceptors

Cells that detect ranges of temperature

Propioreceptors

Cells that detect different muscles stretching or relaxing

Olfactory system

Pathway begins in nose, with neural cells dangling into the nasal cavity. Olfactory receptor cells connect to the glomeruli (first layer of…) in the olfactory bulb, allowing for odor discrimination

Tonotopy is the organizational principle of primary auditory cortex. What does tonotopy refer to?

 

Nearby brain areas represent similar frequencies

Which step of the auditory pathway comes after the inferior colliculus?

Medial geniculate cortex

What does the delay-line model explain about sound processing?

Location

Which of the following describes the correct path from sound wave to auditory neuron?

Tympanic membrane, ossicles, cochlea/basilar membrane, hair cells/stereocilia, auditory neuron

Which of the following would be considered “somatosensation”?

Detection of: pressure on skin, pain, extreme temperature, heat, extent of muscle stretching/relaxation

What is the cribriform plate?

A part of the skull containing many holes allowing olfactory receptors to pass through

Do the olfactory bulbs send signals to the ipsilateral hemispheres, or cross over and send signals to the contralateral hemispheres?

 

Ipsilateral (same side)

Which cues can be used to help determine a sound’s general location?

 

Interaural timing difference and interaural intensity difference

The tympanic membrane is like a ___ and the basilar membrane is like a ___.

drum, spiral

What is something special about pain detection and response that allows it to be very fast?

 

It can be accomplished in the spinal cord without involving the brain

Parvocellular (foveal) pathway

Small, slow, colorful things. Carries information from cones.

Magnocellular (peripheral) pathway

Large, fast movement and colorblind. Carries information from rods

Parvo/magnocellular pathways to the lateral geniculate nucleus

Left eye: Left visual field = ipsilateral

Right visual field = contraletral

Right eye: Left visual field = contralateral

Right visual field = ipsilateral

Temporal area (ventral stream)

WHAT? Object discrimination based on shape, texture, color, detail, etc.

Parietal area (dorsal stream)

WHERE? Landmark discrimination, and how to interact with an object

Sparse coding theory

The idea that there are highly specialized cells that respond to different objects

Population encoding hypothesis

No “one neuron” that represents a concept. Concepts are the sum of a pattern of activation across a bunch of neurons.

Perceptual constancy

We are able to percieve and identify objects as being the same even when many of the visual cues are different (e.g. Eiffel tower from different angles, lighting, etc.)

Form-cue invariance

The brain can identify objects as belonging to the same category despite differences in visual cues across objects. E.g. whether the circle is defined by a change in brightness or a textured surface, we will still recognize it as a circle

Left hemisphere

Specialized for local/feature-based processing

Right hemisphere

Specialized for global, holistic, and configural processing

Fusiform face area

Faces / Exhibits a greater response to faces than to other objects

Parahippocampal place area

Locations / Processes visual information related to places in the local enviroment

Extrastriate body area

Human body / Responds to images of human bodies/body parts compared to inanimate object and object parts

Visual word form area

Words / Responsive to written words

Apperceptive agnosia

Fundamental difficulty in identifying objects based on vision. Cannot copy drawings, or process local elements. Caused by diffuse damage to occipital lobe

Associative agnosia

Can see and even reproduce objects, but can’t recognize them as what they are - no access to name, usage, or meaning. Caused by damage to ventral stream - specifically occipitotemporal regions of both hemispheres

Someone with apperceptive agnosia would have deficits with which of the following:

Holistic processing

Prosopagnosia is a selective inability to visually recognize or differentiate…

Faces

The grandmother cell theory relates to the coding of cells in the ventral stream. What type of coding is it an example of?

Sparse coding

What feature best describes the sensitivity of the magnocellular pathway?

 Luminance detection

What is a “greeble”?

A complex visual stimulus designed to study differentiation among members of a category

Senses must determine and distinguish ‘what’ and ‘where’. In the visual system which pathways tend to do what?

 What: ventral stream, Where: dorsal stream

The brain’s ability to recognize the different instances of the same object as shown in a photo, a painting, and a drawing is an example of ___ and is related to activation in the ___.

Form-cue invariance, lateral occipital cortex

There is support that the fusiform face area is specialized for processing faces as well as being an area related to what?

Expertise in object recognition

The anterior parietal lobe is concerned primarily with…

Somatosensory representations

Within the PPC the superior parietal lobule and the inferior parietal lobule are separated by…

Intraparietal sulcus

Susan has sustained damage to the pathway connecting her parietal cortex to her prefrontal cortex. She would have deficits in which of the following areas?

Spatial working memory

Egocentric reference codes spatial information with respect to:

Yourself

The retrosplenial cortex…

Is thought to contribute to the integration between different reference frames, such as egocentric (self-centered) and allocentric (object-centered) perspectives

Anterograde disorientation is when a patient is unable to construct new representations of environments, and is due to damage to…

Parahippocampal gyrus, which is crucial in forming new representations of environments