Behavioural Neuroscience Final SAQ

What is the endocrine system

System of glands responsible for producing and secreting hormones into the blood sypply

How does the pituitary gland work

Hormones relased in the hypothalamus enter the anterior pituitary gland

Anterior pituitary gland controls secretion

What are the male and female reproductive ducts called

Male - Wolffian

Female - Mullerian

How does the internal reproductive system develop - Ovaries and Testes

• At 6 weeks after conception, the XX and XY primordial gonads are identical

• Primordial gonads develop into an ovary if no Y chromosome is present

• Medulla of the primordial gonads develop into testes

How does the internal reproductive system develop - Reproductive Ducts

• At 6 weeks, human fetuses have the beginnings of wolffian and mullerian reproductive ducts

• Under the influence of testosterone, the wolffian system producing anti-mullerian hormone causing the mullarian system to degenerate

• In the absence of testosterone, the mullerian system develops into the female reproductive ducts and the wolffian system fails to develop

Development of the external reproductive system

Conversion of testosterone to dihydrotestosterone (DHT) leads to differentiation of external genitalia

• Absence of testosterone/DHT allows female genitalia to develop

Sex differences in the brain

• Male brains 15% larger

• Female hemispheres share more functions than men

Causes of sex differences in the brain

Masculinising of the brain caused by estradiol

• Testosterone cannot cross blood-brain barrier so must be converted to estradiol

What hormone controls secondary sex characteristics

Gonadotropin releasing hormones - Stimulate the release of gonadtropic hormones

• Testosterone and estradiol can have activational effects

What is androgen insensitivity syndrome

No internal reproductive system develops

• XY individuals are not sensitive to testosterone so the wolffian system does not develop

• Sensitive to anti-mullerian hormone so mullerian system does not develop either

• External female genitalia develop as they are not sensitive to DHT

What is congenital adrenal hyperplasia

Caused by overactivity of the adrenal gland which produces testosterone in males and females

What is turner’s syndrome

Individuals have XO

• Neither ovaries or testes develop

• Female external genitalia

What is mullerian duct syndrome

Internal male and female sex organs develop

• Caused by a failure to produce anti-mullerian hormone or the absence of anti-mullerian receptors

What is 5-a reductase deficiency

Differentiation of external genitalia is impaired

• Penis forms at puberty when hypothalamus released gonadtropin releasing hormones

• Batista family

How do hormones affect sexual behaviour in males

• Less testosterone = less sexual behaviour

• Thinking about sex = increase in testosteron

• Oxytocin responsible for refractory period

How do hormones affect sexual behaviour in females

• Testosterone release highest prior to ovulation

• Testosterone injections increased sexual motivation in women following a hysterectomy

• Synchronisation of menstrual cycle

Hormonal control of sexual orientation

• No difference in testosterone levels between homosexual and heterosexual males

• Higher testosterone in 30% of homosexual females

• Homosexuality 4x higher in CAH women

What hormones are involved in the control of maternal behaviour

Oxytocin / Prolactin / Progesterone / Estradiol

what is the role of oxytocin in maternal behaviour

• Aids parent-infant bond formation

• Reduced maternal behaviour in animals given an oxytocin antagonist

What hormone is most important for paternal behaviour

Prolactin - Assiciated with stronger feelings of empathy and activation upon hearing infant cry

What did Jaak Panksepp say about emotions

Emotions emerge from hardwired neurobiological systems

What did Lisa Feldman Barrett say about emotions

Emotions are socially constructed

How is the amygdala involved in emotion

• The amygdala responds to salience

• Amygdala activates in response to emotion faces and pictures

• Greater amygdala activation to unpredictable vs predictable sounds

How is the ventromedial prefrontal cortex involved in emotion

• The vmPFC is a regulator

• vmPFC activation during active emotional regulation

What happens if the amygdala or vmPFC is damages

• Emotional outbursts

• Poor social functioning

• Hyperactive amygdala

• Low levels of serotonin in the vmPFC = more aggression

Why are facial expressions innate and universal

• Newborns imitate facial expressions

• Similar expressions between blind and sighted individuals

• Individuals from different cultures display facial expressions when hearing emotive stories

When do individuals suppress emotions

• Children less likely to cry in front of peers compared to caregivers

• Cultural differences within and between countries

Is it possible to fake emotions

Some microexpressions cannot be seen naturally but can be detected using facial electromyography

How are emotions recognised

The amygdala responds to others’ emotions

• Lesions in the amygdala result in difficulty recognising emotions in the self and others

How does engagement of facial muscles affect emotion

• Easier to recognise others’ happiness or feel happiness when the relevent facial muscles are engaged

• Easier to feel happiness when the relevant facial muscles are engaged

What is the effect of imitating other’s expressions

Mirroring other’s facial expressions helps to understand how they feel

What happened to HM and how was his memory affected

• Medial temporal lobe removed to control his epileptic seizures

• Anterograde amnesia - Could not form memories that occured after the brain surgery

• Procedural memory intact / Episodic memory damaged

What is the sensory memory

Initial sensation of environmental stimuli is remembered

• Duration ranges from fractions of a second to a few second

• Occurs in each of the senses

What is the short term memory

Contains meaningful or salient information from the sensory memory

• Duration ranges from seconds to minutes

• Capacity is limited to a few items

What can increase STM duration

Maintenance rehearsal

What can increase STM capacity

Chunking items together

What is long term memory

Contains information from the STM

• Relatively permanent store

• Subdivided into declarative and non-declarative memory

How does information pass from the STM to the LTM

If it is consolidated - elaborative rehearsal

What is declarative memory

Memory of events and facts

• Episodic

• Semantic

• Spatial memories

What is non-declarative memory

Unconscious memories

• Procedural

What is Hebb’s Law

Synaptic connections between neurons strengthen when they are repeatedly activated at the same time

What are the two types of spatial memory

Egocentric / Allocentric

What is egocentric memory

• Body-centred and self-referential

• Based on the individual’s location and orientation in the environment

• Environment changes dependent on observer’s POV

What is allocentric memory

• World-centered

• Based on the location of objects

• Relative to other objects or landmarks

• Independent of the observer’s POV

What did Morris find using his water maze

Rats with hippocampal lesions has significantly impaired spatial navigation when the platform was hidden, not the case when it was visible

• Hippocampus essential for creating spatial cognitive maps

How does the hippocampus consolidate declarative memories

• Places episodic memories in the right order

• Modifies memories and links them together from different association cortexes

What is the function of the left hippocampus

Verbal memory

Language processing

Episodic memory

What is the function of the right hippocampus

Spatial navigation

Visual memory

Spatial memory

What is long term potentiation

Synapses are strengthened based on patterns of recent activity

What is the role of glutamate

Allows long term potentiation to happen by unblocking NDMA receptors and creating more AMPA receptors

• Allows Na+ and calcium ions to be let into neuron

How does synaptic strengthening occur

• Calcium ions enter neuron through NMDA receptors

• Activates enzymes which causes AMPA receptors to move into the spine

• More AMPA receptors strengthens the synapse

Why do animals communicate

To warn other animals

• Alarm calls more likely to be made when with genetic relatives

What was found about chimpanzee alarm calls

Chimpanzees are more likely to make alarm calls when other group members are ignorant of potential danger

What are the levels of deceptive behaviour - Mitchell

First Level - Appearance related

• Mimicry in insects - Butterfly wings having eyespots

Second Level - Stimulus response process

• Animal faking injury to distract predator from their offspring

Third Level - Result of learned association

Fourth Level - Intentionally creating a false belief

• Telling lies

How did Mitchell and Anderson demonstrating deception in monkeys

Monkeys pointed to the wrong bowl so the competitor would not know where the food was and only they would be rewarded

What factors did Canteloup find influenced deceptive behaviours

Concealment by inhibiting interest - Pretending to not be interest so competitor did not notice food

Distraction by leading - Walking away from food so competitor would also move away from food

What are the 4 shared features of languages - Hockett

• Arbitrariness - Units of language should not look or sound like the thing they are trying to convey

• Displacement

• Semanticity - Signals must have meaning

• Productivity - Units can be used in different orders to create different sentences

How is verbal behaviour lateralised in the brain

Speech is lateralised to the left hemisphere in 90% of people

• Found in the right hemisphere of 27% of left handed people

At what age does laterality develop

Age 5

What are the risks of damage after laterality has developed

Damage is worse and functions are more likely to be impaired

• Left hemispherectomy in adults results in aphasia but most children completely recover language functions

What is the function of Broca’s area

Associated with speech production

Where is Broca’s area

Left frontal cortex

What is Broca’s aphasia

• Speech is slow, laborious and non-fluent

• Still able to understand conversation

• Mispronounce words or jumble order of letters

• Agrammatism

What is the function of Wernicke’s area

Associated with speech comprehension

Where is Wernicke’s area

Left temporal lobe

What is Wernicke’s aphasia

• Poor speech comprehension

• Meaningless speech is produced

• Fluent speech

What is pure word deafness (recognition)

There is no recognition of words but comprehension is intact

• Still able to speak, read and write

• Patient could not understand spoken commands but could understand written instructions

What is transcortical sensory aphasia (comprehension)

There is recognition without comprehension

• Cannot spontaneously produce meaningful speech

• Able to repeat speech

• Patient could learn songs from the radio but could not produce own words

What is conduction aphasia

Inability to repeat words or phrases despite having good comprehension and spontaneous speech

What causes transcortical sensory aphasia and conduction aphasia

Subcortical damage to the fibre bundle connecting Broca’s area to Wernicke’s area

What is the direct and indirect connection between Broca’s area and Wernicke’s area

Direct connection conveys speech sounds

• Damage here causes conduction aphasia

Indirect connection conveys meaning

• Damage here causes transcortical sensory aphasia

What brain structures are associated with reading

• Primary visual cortex

• Visual association cortex

• Visual word form area

• Broca’s area

What is pure lexia / pure word blindness

Loss of the ability to read without loss of the ability to write

What causes pure lexia / pure word blindness

Cause by damage to the connection between the right visual field in the occipital lobe and the left VWFA - Corpus callosum damage

What two processes are involved in reading

Direct recognition of the word as a whole

Sounding out the word letter by letter - phonetic reading

What is surface dyslexia

A person is able to read words phonetically but has difficulty reading irregularly spelled words

• Yacht or sew

What is phonological dyslexia

A person is able to read familiar words but has difficulty reading unfamiliar or pronounceable non-words

• Perspicacious or glab