Lateralization

Question 1

Vad är Brain Dynamics?

Answer 1

Fast & Efficient reciprocal interaction of neuronal circuits representing different behavioral options

Question 2

How can the brain dynamic be kept in balance?

Answer 2

Reciprocity!

Eg. Dimorphous displays of emotions: Positive and negative expressions occur simultaneously to help the brain to balance an overwhelmingly positive emotion with a negative response (vice versa)

Question 2

Hur kan kognitiva deficits vara relaterade till brain dynamics?

Answer 2

All cognitive deficitis are related to bad brain dynamics => the reciprocal interactions of neural circuits do not work well.

Eg. Problem with attention or response inhibition is due to bad brain dynamics?

Question 3

What is Antithesis?

Answer 3

Our behavior is balanced on neural connections of opposing components eg. positive vs sad.

Question 4

What is interhemispheric transfer of neural plasticity?

Answer 4

Neuroplasticity is the ability of neural networks to change through growth and reorganisation.

Corpus Callosum can transfer the plasticity interhemispherically

Eg. In the flying fox experiment, where the receptive fields for both sides changed

Question 5

Can motor learning also be transfered interhemispherically?

Answer 5

Yes. Motorcortical areas cooperate during unilateral training.

When learning a task both motor cortex becomes activated and learns the task.

This is shown in blind type where there is a clear interference between fingers.

Question 6

How is the Go/No-go cue related to interhemispheric activations?

Answer 6

Response inhibition is achived by a formation of reciprocal conditioned reflex to no-go stimuli. i.e activation of the network of the opposite arm.

If one hemisphere’s activity decreases => the opposite automatically activates.

Question 7

Why are Callosal connections said to be conditional?

Answer 7

The callosal connections depend on the difficulty and type of task. If the task is easy there isn’t a need for both hemispheres, however if the task is more demanding both hemispheres can be activated to process.

Question 8

What are the macroanatomical Right-Left differences?

Answer 8

1. Volume of both hemispheres
2. Volume and shape of specific Brain Areas
3. Gyrification pattern
4. The form and lenght of certain Sulci
5. Brain Torque - The right side is slightly warped forward
6. Planum Temporale: One of the most assymetric ares

Question 9

What are some microanatomical differences between the two hemispheres?

Answer 9

1. Size of dendritic tree
2. Neuronal Cell size
3. Cytoarchitecture

Question 10

What are Genetic and Epigentic factors of lateralization?

Answer 10

Genetic: Lateralized gene expression is associated with lateralized behavior

Epigenetic:
- Possible causes of asymmetry between homotopic areas is the difference in:

1. Their afferent connectivity and the sensory inputs conveyed by those connections
2. Mechanisms of synaptic plasticity that translate these differences in inputs into microstructural changes
3. Task dependent increase in connectivity from the non-dominant to the dominant hemisphere

Question 11

Is lateralization of brain function unique to humans?

Answer 11

No. Lateralization can be found in many animals.

Eg. Domestic Chickens have a lateralization due to the right eye being exposed to light in the egg. The right eye is better att distinguising food from pebbels, and the left eye respons to emotionally charged stimuli such as predators.

Rats uses their left eye for spatial navigation , and the control of singing in songbirds is controlled by the left hemisphere

Question 12

What is the specialization of the left and right hemispheres?