Brain and behavior unit two

What are the six senses?

Vision, Audition(hearing), Somatosensation(touch), Gustation(taste), Olfaction(smell), Equilibrium(balance)

What are the four levels of processing? 

Sensory detection units

Receiving centers

Integration centers

Perception

What is a stimulus detector unit?

specialized sensory receptor neurons (primary sensory receptors) that convert sensory events from absolute, physical form into cellular signals (Action Potentials)

Where are each sense’s SDUs located? 

Vision (retina), audition (cochlea), Somatosensation(skin), Gustation(tounge), Olfaction(nose), Equilibrium(vestibular organ)

What is special about the retina?

It’s part of the CNS

What is transduction?

sensory receptors convert energy of a stimulus (e.g., light, air-pressure waves) into neural activity

What is a receptive field? 

a region of space in which the presence of a stimulus will alter the firing of that neuron

What senses have receptive fields? 

Touch and vision

What types of sensory information are encoded? 

type of stimulus, location, quantity, frequency and duration

What brain area is important for integration of sensory information?

Thalamus

Is there an exception to the types of information this brain area receives?

Smell goes to limbo cortex

What are the main structures of the eye? 

Cornea, Iris, Lens and retina

What do Cornea, Iris, Lens and retina do

• : clear outer coating; serves as barrier to external environment

• : small hole in iris, through which light passes 

• : colored portion of the eye; muscles connect to pupil to open/close in order to let more/less light in

• : curved structure that focuses light; bends to accommodate near and far objects

: where light energy initiates neural activit

What are the two types of photoreceptorsand what is each specialized for? 

Rods: sensitive to low levels of light (Used for night vision)

Cones: highly responsive to bright light (color vision and high visual acuity)

How does visual information leave the eye, and where does it go? 

leaves the retina via the retinal ganglion cells’ axons and converge to form optic nerve

What are the brain regions involved and type of information shared for the two main visual pathways? 

Dorsal Visual Stream: originates in the occipital cortex and projects to parietal cortex

“Where/How” pathway

Ventral Visual Stream: originates in the occipital cortex and projects to  temporal cortex

“What” pathway

What is an ataxia vs. an angnosia?

“without order” (coordination)

“not knowing”

What is an example of a specific agnosia? 

Prosopagnosia: inability to recognize faces

How is sound characterized?

Amplitude: Magnitude of change in air molecule density (Perceived as differences in loudness (dB))

Frequency:# of compressions per second (Perceived as differences in pitch (Hz))

1 cycle/second = 1 Hertz

Complexity: Pure tones = sounds with a single frequency, Complex tones = sounds with a mixtures of frequencies (Perception of timbre or uniqueness)

What are the main parts of the ear?

Outer Ear: Pinna, auditory canal, eardrum

Middle Ear: Air-filled chambers that comprises tiny bones, the ossicles

Inner Ear: Cochlea, semicircular canals, vestibule

What area is most important for hearing (i.e., where are the primary sensory detectors)?

Organ of Corti: auditory receptor cells (hair cells)

What is unique about the basilar membrane? 

Different parts of the basilar membrane respond to different frequencies

What are the major types of hearing loss/deafness?

Conduction hearing loss: caused by structural damage to the mechanical system that conducts sound waves to the cochlea

Sensorineural hearing loss/nerve deafness: damage to hair cells or the auditory nerve

What are some ways to treat the various types of hearing loss (discuss why they may be effective with one type of hearing loss but not another) 

hearing aids ( not effective for sensorineural)

Cochlear implant: a device for converting sounds into electrical signals and stimulating the auditory nerve

What do chemosignals (chemical signals) help us to do?

Chemosignals (chemical signals) play a central role in motivated and emotional behavior

What are the five basic tastes that have been identified to date?

Sweet, Sour, Salty, Bitter, Umami

What are pheromones?

biochemical signals released by one animal that acts as chemosignals to affect the physiology or behavior of another animal

What four senses are included in somatosensation?

–Bodily sensations (touch and balance)

–Auditory sensations (hearing)

–Visual sensations (sight)

–Chemical sensations (taste and olfaction)

 Where are somatosensory receptors located? How is this unique from other senses? 

Receptors are distributed throughout the body (as opposed to being concentrated at small, specialized locations)

Respond to many kinds of stimuli

4 senses: Touch, body position, temperature, pain

Describe the difference between an area with high sensitivity and an area with low sensitivity (what is the difference in receptor density/number?) 

Receptive fields are smaller in sensitive areas because there are more touch SDUs there

–Receptive fields are larger in non-sensitive areas because there are fewer touch SDUs there

How can you get a general idea of a body area’s sensitivity?

two-point discrimination test

What brain areas process touch/pain information? 

Medulla, Thalamus, somatosensory cortex

What neurotransmitter is used in the pain pathways?

Substance p

Describe three different pain pathways, and list what each is important for. 

Withdrawal reflex pathway: within spinal cord; no perception

Fast pain pathway: direct to somatosensory cortex; for pain location

Slow pain pathway: indirect through hypothalamus and limbic system to prefrontal regions; for emotional reactions

What is the gate-control theory of pain? 

non-pain signals coming into the spinal cord (or higher brain signals descending from the cortex to the spinal cord) can close a “spinal gate” to effectively blunt the perception of pain

What are the important frontal regions for motor control? 

Prefrontal cortex, premotor cortex, primary motor cortex

What is the role of the cerebellum in motor control? 

sophisticated control of movements

What is the role of the basal ganglia in motor control?

initiation and termination of voluntary movements

• How is the substantia nigra involved? 

receive critical inputs from Substantia Nigra

What neurotransmitter does the substantia nigra use?

Dopamine (DA)

What is acetylcholinesterase? 

• What is it function?

the “off switch” for acetylcholine signaling.

remove excess ACh from synaptic cleft through enzyme destruction  

• Where is acetylcholinesterase located? 

With ACh in neuron

Describe an agonist and an antagonist 

natural or synthetic chemicals that enhance or mimic the effects of a neurotransmitter

: natural or synthetic chemicals that block or reduce the effects of a neurotransmitter

What is the stretch reflex?

knee tap; when patellar tendon is stretched, leads to contraction of quadriceps muscle

What is Parkinson’s disease? 

results from loss of dopamine-producing neurons in the substantia nigra that innervate the striatum (caudate nucleus, putamen)

What are the symptoms? (Be sure to distinguish between POSITIVE, NEGATIVE, and COGNITIVE symptoms, and know what it means to have each type

Positive:increased tone or stiffness in the muscles, resting tremor, involuntary movement

Negitive: poor balance/posture, slowness of movement/no movement, walking problems, speech problems

Cognitive:impoverishment of feeling, libido, motive, and attention; slowed thinking

What are the treatments for Parkinson’s ?

Levodopa (L-DOPA) CAN cross the Blood-Brain-Barrier and enter the brain when taken orally 

Physical therapy

Brain tissue transplants

What is MPTP and how is it important in gaining a better understanding of Parkinson’s disease?

highly and specifically toxic to the dopamine neurons in the substantia nigra, good for animal testing

What is homeostasis? 

the process of maintaining a relatively stable internal environment, despite a constantly-changing external environment

What is one major brain region associated with maintaining homeostasis?

Hypothalamus

Describe three ways/routes that the body is able to maintain homeostasis

Regulatory behaviors: behavior motivated to meet survival needs

Autonomic Nervous System (ANS): involuntary; not normally under conscious control

Endocrine system: hormones are released from several tissues in the body (pancreas, ovaries/testes, thyroid gland)

What is the autonomic nervous system? 

involuntary; not normally under conscious control

How does it compare to the somatic nervous system? 

2 instead of 1 motor neuron, involuntary functions,

Know the major divisions of the ANS: sympathetic and parasympathetic nervous systems 

• What is the general function of each?

Parasympathetic: rest and digest

Sympathetic: Fight or flight

• Which neurotransmitter does each system use, and where? 

Parasympathetic: Acetylcholine

Sympathetic: Norepinephrine

Know the three major difference between the two divisions of the ANS 50. What is the endocrine system? 

Location of preganglionic and postganglionic neurons

S:Thoraco-lumbar

P: Cranio-sacral

Neurotransmitters used at target tissue

General function

Endocrine system: hormones are released from several tissues in the body (pancreas, ovaries/testes, thyroid gland)

What important structure (besides the hypothalamus) is part of the endocrine system? 

Pituitary gland

How does a neurotransmitter differ from a hormone?

Neurotransmitters: released into synaptic clefts between axon terminal and another neuron’s dendrites/cell body, or between axon terminal and skeletal muscle  only have to travel a short distance

Hormones: released into blood, travel through entire body, but only have an action at tissue where there are proper receptors present

What is stress? 

any stimulus that threatens homeostasis

What are the two major types of stress? Give an example of each 

Physical stressors: stimuli that pose real threats to body homeostasis, and which require the stress response to restore homeostasis

Infection, injury, large changes in external temperature, dehydration, lack of sleep, poor nutrition

Psychological stressors: stimuli that are perceived as being threatening to homeostasis

What brain regions are important for responses to each type of stress?

physical: Hypothalamus

Psychological: cortical and limbic processing

What is the two-system view of stress response? 

Fast-acting stress response:

Slow-acting stress response:

Explain how Fast-acting stress response and Slow-acting stress response and important components for each

: hypothalamus signals through the spinal cord  sympathetic nervous system  autonomic neural activation (adrenal medulla)

: hypothalamus signals through the pituitary gland  hormonal activation (adrenal cortex)

When can stress be beneficial

ACUTE- Helps us mount an appropriate response to a threat – critically involved in performance

What is chronic stress?

prolonged stress 

What are some consequences of chronic stress? 

Increased blood pressure/heart disease, Damage to muscle tissue, Infertility, Stunted growth (in children), Inhibition of immune system

What is the limbic system?

Necessary for true emotion (Amygdala, hippocampus, cingulate (limbic) cortex)

What is the Duchenne smile?

true emotional smile

How does the ANS affect emotions/emotional states?

We are able to measure ANS activity and also to measure subtle contractions of muscles that control facial expressions

What brain region is particularly susceptible to chronic stress?

Hippocampus