Brain and Behaviour

Question 1

what is the definition of neural control/regulation?

Answer 1

Functional interactions between networks of neurons that regulate/control a behaviour/function.

Question 2

what is neural control of breathing?

Answer 2

• How the brain controls respiratory rate
  
  • Basis of breathing (reflex- little cognitive effort):
    ○ Increase and decrease of volume
    Decrease and increase of pressure
  • Control by the brainstem of the intercostal muscles:
    ○ Pons and medulla

Question 3

what is basal breathing?

Answer 3

○ Counterbalance air outside- change pressure to make air move in and out
○ Dorsal respiratory region of the medulla
* Inspiratory neurons spontaneously fire (no signals needed from other parts of the body to create the firing)
○ AP propagates automatically.

Question 4

which muscles are innervated when more air is needed in the lungs?

Answer 4

the external intercostal muscles

Question 5

which signals innervate the diphragm via the phrenic nerve?

Answer 5

C3,4,5 (only the diaphragm is needed for quite breathing)
§ Innervate the diaphragm
§ Contraction of intercostals leads to a reduction of pressure (as the diaphragm moves up)- increases volume in lugs- more air comes in)

Question 6

what does basal breathing occur?

Answer 6

most dorsal region of the medulla

Question 7

what is the aortic arch?

Answer 7

chemoreceptive neurons pick up concentration of increased CO2 and decreased O2, decreased hydrogen ions
STIMULATES NEURONS TO BREATH A BIT MORE

Question 8

what is the neurotoxic area?

Answer 8

switch (back of pons- most dorsal region)
○ Change in the neuron firing.
○ Tells neurons to stop so shortens the breath in
§ Increases respiratory rate (INHIBITORY SIGNALS)

Question 9

where does air move when their is low pressure iside the lungs?

Answer 9

air moves high to low so goes into the lungs

Question 10

give some examples of neural control?

Answer 10

homeostasis
temperature control
breathing control
eating regulation
behaviour control
heart rate control

Question 11

what is the diencephalon?

Answer 11

• Processing occurs in subcortical region (specifically diencephalon)
  
  • Division of forebrain
    ○ Located between telencephalon & mesencephalon (start of the brainstem) (midbrain)
    ○ Surrounding the third ventricle- cerebrospinal fluid
    Contains the thalamus (takes on info from all senses and coordinates it to send it out for where it needs to be understood further) and the hypothalamus (for lower regions of the body, is connected to the thalamus)

Question 12

what is the structure of the hypothalamus?

Answer 12

• Small but important
  
  • Below thalamus at base of brain
  • Ventral part of diencephalon
  • Consists of a group of nuclei & fibre tracts
  • ANS

Question 13

what system is the hypothalamus part of?

Answer 13

endocrine system

Question 14

what is the funtion of the hypothalamus?

Answer 14

• Hormone production
  
  • Primary function is homeostasis
  • Organizes survival behaviours
  • Contains “biological clock” which regulates certain body functions that vary:
    ○ Daily (diurnally)
    ○ Over a period of many days
  • Involved in control of emotional expression, such as rage, pleasure & fear
  • Controls autonomic NS
  • Controls endocrine system
    ○ via the pituitary gland
    Fight and flight, fleeing, feeding

Question 15

what is homeostasis?

Answer 15

the state of stedy internal, physcial and chemical conditions maintained in living systems
the condition of optimal functioning for the organism and includes many variables

Question 16

what are the 4 f’s?

Answer 16

• fighting
• fleeing
• feeding
• mating

Question 17

what is the pituitory gland?

Answer 17

• Important structure near the hypothalamus
  ○ Attached to base of hypothalamus via pituitary stalk
  
  • Two main lobes (anterior & posterior)
    Anterior pituitary gland is considered “master” gland

Question 18

what does the pituitary gland control?

Answer 18

• Controls the hormone release
  
  • Anterior= growth, testosterone, hormone release, stress and fear release
  • Posterior= childbirth, compassion, blood pressure
    Sends release hormones to the hormones location so they release their hormone.

Question 19

what is the hypothalamuis control of the pituitory gland?

Answer 19

• Communicates with both anterior and posterior pituitary gland to alter hormone secretion:
  ○ Anterior pituitary gland (indirect) = hormones (use release hormones)
  § Cortisol= stress hormone
  Posterior pituitary gland (direct) = synaptic transmission (doesn’t make own hormones)- hypothalamus makes the hormones and it just transfers them via cingulate.

Question 20

what does the anterior pituitory gland control?

Answer 20

• Indirect control - Hormones
  ○ Specialised neurons in hypothalamus secrete hormones
  ○ Hormones travel to anterior pituitary via blood vessels
  Hormones secreted from hypothalamus stimulate hormone release from anterior pituitary gland

Question 21

what is the HPA axis?

Answer 21

• Paraventricular nucleus secretes corticotropin-releasing hormone (CRH)
  
  • Stimulates anterior pituitary glad to release adrenocorticotropic hormone (ACTH)
  • Enters blood and stimulates adrenal cortex to release cortisol
    The stress response

Question 22

what are the effects of prolongued exposure to cortisol?

Answer 22

• Increased blood pressure
  
  • Increased HR
  • Increased lining of blood vessels increasing chance of heart attack
  • Changes gut system
  • Changes gut bacteria- changes digestion
  • Increases appetite
    Stress can make brain smaller as it reduces neural connections and fewer brain cells meaning it is harder to remember things.

Question 23

what are the responses to cortisol and epigenetics?

Answer 23

• Stress responses seem to be altered by environment and epigenetics
  
  • Alteration in the expression of genes due to nurture
  • Rat studies:
    ○ Offspring of nurturing mothers more resilient to stress
    ○ Offspring of negligent mothers more affected by stress
    Effect seen in future generations

Question 24

what does the psoterior pituitory gland control?

Answer 24

• Direct control
  ○ Synaptic transmission
  
  • Considered an extension of hypothalamus
  • Hypothalamus actually produces the posterior pituitary hormones & directly controls their secretion
  • Neurons in hypothalamus have axons which extend down pituitary stalk and end in posterior pituitary gland
  • Hormones produced in hypothalamus but released from posterior pituitary gland

Question 25

what is the neural control of sexual behaviours?

Answer 25

• Control of sexual behaviour (at least in lab animals) involves different mechanisms in males and females
  
  • Spinal areas involved in sexual behaviour- lumbar regions
  • Medial preoptic area- males
  • Ventromedial nucleus of hypothalamus (VMH)- females
  • Medial amygdala recover chemosensory info from the vomeronasal system and somatosensory info from the genitals
    Mediates signals to midbrain and the medulla

Question 26

what is the role of the nPGi of the medulla in male sexual behaviour?

Answer 26

• tactile info from genitals
• normally inhibits mating behaviour
• inhibited in the MPA

Question 27

what is the role of the central tegmental field in male sexual behaviour?

Answer 27

• mating causes production of Fos protein

Question 28

what is the role of the periaqwueductal gray matter in male sexual behaviour?

Answer 28

• normall excites the nPGi
• inhibited by the MPA

Question 29

where does the input come from in male sexual behaviour?

Answer 29

olfactory bulb abd vomeronasal organ

Question 30

what is the role of the medial proptic area in male sexual behaviour?

Answer 30

• destrution abolishes sexual behaviour
• prenatal stress reduces size of sexuallt dimorphic nucleus, decreasing sexual behaviour
• mating causes production of Fos protein
• injection of testosterone enhances sexual behaviour of castrated rats

Question 31

what is the role of the medical amygdala in male sexual behaviour?

Answer 31

• destruction disrupts sexual behaviour
• mating causes production of Fos protein

Question 32

what is the role of the nPGi medulla in female sexual behaviour?

Answer 32

• mating behaviour

Question 33

what is the role of the PAG of the midbrain in female sexual behaviour?

Answer 33

• tactile info from genitals

Question 34

what is the role of the medial amygdala in female sexual behaviour?

Answer 34

• mating causes production of fos protein
• neurons contain oestrogen and progesterone receptors

Question 35

what is the role of the ventromedial nucleus of the hypothalamus in female sexual behaviour?

Answer 35

• destruction abolishes sexual behaviour
• mating causes production of Fos protein
• neurons contain oestrogen and progesterone receptors
• injection of oestradiol and progesterone enhance sexual behaviour of overiectomaised rats

Question 36

what interacts with they hypothalamus during sexual arousal of humans?

Answer 36

cingulate cortex

Question 37

what is the neural regulation of sexual behaviour?

Answer 37

Circuit includes
* Limbic system (hypothalamus, hippocampus and amygdala)
* Paralimbic areas (ACC, frontal lobe and insula)
* The associate cortices (inferior temporal lobe and occipital cortices)
Other subcortical and cortical sensory relays (thalamus and sensory/somatosensory cortex)