Psych Central News
Mice Study Suggest Specific Neurons Influence Stay-or-Go Behavior
Neuroscientists from Cold Spring Harbor Laboratory (CSHL) have now identified key circuit elements that contribute to such decisions in the anterior cingulate cortex (ACC), part of the prefrontal cortex.
In a study published in Nature, Adam Kepecs, Ph.D., and his team discovered, for the first time, specific brain cell types to a particular behavior pattern in mice – a “stay or go” pattern called foraging behavior.
The paper shows that the firing of two distinct types of inhibitory neurons, known as somatostatin (SOM) and parvalbumin (PV) neurons, has a strong correlation with the start and end of a period of foraging behavior.
Linking specific neuronal types to well-defined behaviors has proved extremely difficult.
“There’s a big gap in our knowledge between our understanding of neuron types in terms of their physical location and their place in any given neural circuit, and what these neurons actually do during behavior,” Kepecs said.
Part of the problem is the technical challenge of doing these studies in live, freely behaving mice.
Key to solving that problem is a mouse model developed in the laboratory of Cold Spring Harbor Laboratory, in which the mouse has a genetic modification that allows investigators to target a specific population of neurons with any protein of interest.
Kepecs’ group, led by Duda Kvitsiani and Sachin Ranade, used this mouse to label specific neuron types in the ACC with a light-activated protein — a technique known as optogenetic tagging.
Whenever they shone light onto the brains of the mice they were recording from, only the tagged PV and SOM neurons responded promptly with a spike in activity, enabling the researchers to pick them out from the vast diversity of cellular responses seen at any given moment.
The team recorded neural activity in the ACC of these mice while they engaged in foraging behavior.
They discovered that the PV and SOM inhibitory neurons responded around the time of the foraging decisions — in other words whether to stay and drink or go and explore elsewhere. Specifically, when the mice entered an area where they could collect a water reward, SOM inhibitory neurons shut down and entered a period of low-level activity, thereby opening a ‘gate’ for information to flow in to ACC.
When the mice decided to leave that area and look elsewhere, PV inhibitory neurons fired and abruptly reset cell activity.
“The brain is complex and continuously active, so it makes sense that these two types of inhibitory interneurons define the boundaries of a behavior such as foraging, opening and then closing the ‘gate’ within a particular neural circuit through changes in their activity,” said Kepecs.
This is an important advance, addressing a problem in behavioral neuroscience that scientists call “the cortical response zoo.”
When researchers record neural activity in cortex during behavior, and they don’t know which type of neurons they are recording from, a bewildering array of responses is seen.
This greatly complicates the task of interpretation. Hence the significance of the Kepecs team’s results, for the first time showing that specific cortical neuron types can be linked to specific aspects of behavior.
“We think about the brain and behavior in terms of levels; what the cell types are and the circuits or networks they form; which regions of the brain they are in; and what behavior is modulated by them,” Kepecs said.
“By observing that the activity of specific cell types in the prefrontal cortex is correlated with a behavioral period, we have identified a link between these levels.”
Source: Cold Spring Harbor Laboratory
Brain neurons photo by shutterstock.
World of Psychology
Locked up at Mathari Hospital: Mental Health Treatment Lags in Kenya
Mental health treatment continues to lag — sometimes quite severely — in under-developed countries throughout the world. Many countries in Africa continue to treat people with a mental illness as though they had leprosy or some other inexplicable, communicable disease.
Because so little is understood about mental illness by some of the peoples of these countries, family members are often outcast and given over to well-meaning — but severely understaffed and under-resourced — professionals. This is of little surprise when poverty is so rampant in countries like Kenya.
The Mathari psychiatric hospital — which has 675 patients in its general wards — lies close to the sprawling Mathare slum district of Nairobi. Kenya’s only psychiatric hospital also appears to confine and immobilize many of its patients, using drugs that put them in a comatose-like state.
Worse, if the hospital is full (and it nearly always is), family members apparently get their loved ones locked up somewhere else anyway, “Currently those who cannot access the right rehabilitation services are locked up and subjected to very inhumane treatments by their families and communities,” according to Edah Maina, the chief executive officer of the Kenya Society For the Mentally Handicapped.
But you know things are bad when your patients need to plan a prison-break to leave your “treatment” facility.
The Carter Center’s Janice Cooper, Ph.D. said this of Liberians, another poverty-stricken African country: “To most Liberians, people with a mental illness are useless for society. Some think that mental health conditions are contagious, or that victims are under the spell of witchcraft.”
The Carter Center’s Mental Health Program did something about the poor mental health treatment in Africa. It teamed up with Georgia Tech’s Computing for Good Initiative to help the Liberian government monitor the country’s mental health needs and train local mental health clinicians to help work reduce stigma and discrimination against mental illnesses in that country.
Sadly, there’s only so much money to go around. Perhaps if it works in Liberia — it’s a 5 year program — it can act as a model for other African countries.
But back in Kenya, this are not so good at the country’s sole psychiatric hospital:
‘‘They should be in a program … one that they consent to and is not forced on to them; and among other things, a program that ensures their continued productivity as members of society, not one that immobilizes them through use of outdated/outlawed drugs that turns them into mere zombies,’’ said Maina.
We couldn’t agree more. In the U.S., we call it “community treatment” — treat patients as close to home as possible. This resulted in more outpatient services being delivered and the closing of many state psychiatric hospitals across the country throughout the past four decades. It has also led to greater use of group homes (for people who need more supervised daily care) and day treatment programs (for people who need structured daily activities and can’t work because of their mental illness).
Programs like this can be rolled out in Africa, too, but it’s no wonder they haven’t. If we recall Maslow’s Hierarchy of Needs, we’re reminded that before we can turn to treatment for mental illness, we need basic physiological needs to be met — food, water, sleep and shelter.
And in countries like Kenya, such basics are sometimes hard to find.
Read the article: Kenya’s mental hospital drugs, confines patients
Watch a video: Locked Up In Kenyan Mental Health Hospital
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