Exam 1 (Models of Tinnitus) Flashcards
what is the limbic system
Functions → emotion, long-term memory, and other aspects of behavior
Amygdala → important in a person’s emotional response to sounds
Functions → emotion, long-term memory, and other aspects of behavior
limbic system
important in a person’s emotional response to sounds
Amygdala
what is the autonomic system
Function → controls vital bodily functions like homeostasis (maintenance of bodily stability)
Activated when we hear potentially dangerous sounds
Activated when we hear potentially dangerous sounds
ANS
define tinnitus
Phantom auditory perception → perception of sounds without corresponding acoustic or mechanical correlates in the cochlea
Tinnitus is the perception of sound (must be heard) & involuntary (not produced intentionally)
perception of sound (must be heard) & involuntary (not produced intentionally)
tinnitus
maintenance of bodily stability
homeostasis
what are tinnitus models
conceptual frameworks that aim to explain the overall phenomenon of tinnitus including its generation, perception and associated distress
what is the significance of tinnitus models
Offer explanations for various tinnitus-related phenomena
Integrate findings from multiple research domains
Guides research & clinical approaches
what is the basis of neurophysiological models
Biological basis of tinnitus in the auditory system
Focuses on different anatomical or physiological aspects; none are definitely proven
Consensus → tinnitus results from perception of abnormal activity
3 proposed mechanisms for how tinnitus is coded in the auditory cortex
Increased spontaneous activity fed by increase or decrease in activity.
Cross-fiber correlation with normal or increased spontaneous activity.
More fibers with similar best frequency following hearing loss–induced auditory plasticity.
what are examples of neurophysiological models
maladaptive plasticity
role of HL in tinnitus perception
central gain
Jasterboff’s model
describe maladaptive plasticity and how it leads to tinnitus
Tinnitus is thought to result from maladaptive plasticity in the CNS in response to HL or other unknown causes
In response to causes, mechanisms that keep the nervous system in balance (homeostasis) leads to changes that result in the perception of tinnitus
Neurophysiological models have logically nominated the increase in spontaneous activity as a mechanism of tinnitus
increases spontaneous activity to compensate because it compensates for the decrease in the auditory input; hyperactivity heard by the cortex is the tinnitus sound
when plasticity can lead to side effects, then it is maladaptive; you tried to help and fix something but messed it up
how does HL lead to tinnitus perception
HL leads to input to the auditory system decrease
The brain then attempts to maintain homeostasis through compensation for reduced input due to the HL
Compensation → increasing neural gain and sensitivity in the auditory system
Increase in gain leads to higher spontaneous neural activity even without acoustic simulation
Increased spontaneous activity is proposed as the key mechanism for tinnitus perception
Changes in neural activity are likely transmitted to and represented in the auditory cortex
what is central gain
Compensatory increase in the central auditory activity in response to the loss of sensory input
Tinnitus occurs due to central gain which is the brain reaction to auditory deprivation
Explains why when you cut the auditory nerve and the brain still hears the tinnitus
central gain and how it leads to the perception of tinnitus
Auditory deprivation and central gain plus altered spontaneous neural activity leads to tinnitus
There is a decrease in auditory input, neurons become more excitable (hyperactivity) doing more than they need due, and this leads to the tinnitus perception
what is a limitation to central gain
need to have hearing loss to explain this but there are cases where they do not have HL
why is the brain compensating and resulting in tinnitus?
explains why those with hL can have tinnitus but not why those with no HL has the tinnitus
can not explain why those with HL do not have tinnitus
what is Jasterboff’s model
Focuses on the interaction between auditory and non-auditory systems & based on general neurophysiology & behavioral neuroscience
Hypothesis → many systemas in the brain are involved in tinnitus with auditory system playing a secondary role
key components in Jasterboff’s model
Limbic system → highlights the emotional processing that is attached to the sound of the tinnitus
Sympathetic autonomic nervous system
Reticular formation → awareness?
focuses on the non-auditory systems
jasterboff’s model
Foundation for TRT (tinnitus retraining therapy)
Explains why some with hearing loss do not experience tinnitus
jasterboff’s
what is the tiger in the room in jasterboff’s model
Focusing on the tinnitus increases the arousal (stress; anxiety) making it harder to ignore it making the limbic system involved in those PTs with emotional reactions
brought a tiger into the classroom and it sits in the corner and tells us not to worry about it it hasn’t eaten anyone in a couple of weeks you should be fine
saying that you know that the tiger is threatening and it could jump at anyone but no matter how hard you try to listen to the lecture, your brain is occupied by the tiger in the room you cannot do anything else
same with tinnitus, brain is preoccupied with it because it perceives it as negative, dangerous, threatening